national board inspection code

Code

Inspection

Board

NationalNationalBoardInspectionCode

NationalBoardInspectionCode

TheNationalBoardof Boiler and

Pressure Vessel

Inspectors

NB B

I

®

Since 1919

ANSI/NB-23

An American National Standard

2001

•

RECOGNIZED

•

INTERNATIONALLY

ii

Library of Congress Catalog Card No. 52-44738Printed in the United States of America

All Rights Reserved

© 2001The National Board of Boiler

and Pressure Vessel Inspectors

Headquarters1055 Crupper Avenue

Columbus, Ohio 43229-1183614.888.8320

614.847.1828 FAX

Testing Laboratory7437 Pingue Drive

Worthington, Ohio 43085-1715614.888.8320

614.848.3474 FAX

Training and Conference Center1065 Crupper Avenue

Columbus, Ohio 43229-1183614.888.8320

614.847.5542 FAX

www.nationalboard.org

Note: Pages ii through viii are not part of thisAmerican National Standard

iii

THE NATIONAL BOARD OF BOILER AND PRESSURE VESSEL INSPECTORS

BOARD OF TRUSTEES

OFFICERS

D.A. Douin – ChairmanR. Reetz – First Vice Chairman

W.C. Lundine – Second Vice ChairmanD.E. Tanner – Secretary-Treasurer

MEMBERS AT LARGE

Y. NagpaulR.D. Mile

M.J. Wheel

PAST CHAIRMAN

R.R. Cate

ADVISORY COMMITTEE

F.M. LucasRepresenting organized labor

W.D. DotyRepresenting the welding industry

R.I. MullicanRepresenting National Board stamp holders

C.A. NeumannRepresenting boiler and pressure vessel users

M.H. JawadRepresenting boiler manufacturers

J. StoeckingerRepresenting pressure vessel manufacturers

S. RudnickasRepresenting authorized inspection agencies (insurance companies)

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COMMITTEE ON NATIONAL BOARD INSPECTION CODE

R.H. Murray

C.A. NeumannEastman Kodak Company

J. PillowABB Combustion Engineering

H.M. RichardsSouthern Company

L.R. ShippGeorgia Pacific Corporation

H. StaehrFactory Mutual Engineering

R.C. SulzerBabcock & Wilcox Construction Co., Inc.

H.N. TiterMIRANT Mid-Atlantic

R.V. Wielgoszinski-Hartford Steam Boiler Inspectionand Insurance Co.

M.J. WheelState of Vermont

R.C. Howard, ChairHartford Steam Boiler Inspection& Insurance Co.

G. Bynog, Vice ChairState of Texas

S.E. BaconTOSCO Refining Company

J. CoakerUnited States Postal Service

W.D. DotyDoty and Associates, Inc.

P.D. EdwardsStone & Webster Inc.

George GalanesMidwest Generation

C. HopkinsSeattle Boiler Works

F.M. LucasUnited Assoc. of Plumbers andPipefitters

R.I. MullicanM & M Welding Fabricators, Inc.

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NBIC SUB-COMMITTEE ON OVERPRESSURE PROTECTION

D.A. Bowers, Jr., ChairmanVelan Valve

J.F. Ball, P.E., SecretaryThe National Board of Boiler andPressure Vessel Inspectors

R. BeckTotal Valve Systems

M. BrodeurInternational Valve & Instr. Corporation

S. CammeresiAllied Valve

J.A. CoxDeluca Test Equipment

D. DeMichaelDuPont Company

R.W. DonalsonAnderson, Greenwood & Co.

R.G. FriendCrosby Valve Company

P. HackfordState of Utah

B.E. HrubalaIndustrial Risk Insurers

L. JonesUnion Carbide Corporation

C.A. NeumannEastman Kodak Company

J. RichardsonDresser Industries, Inc.

A.J. SpencerFactory Mutual Engineering

C.S. WithersState of Colorado

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NATIONAL BOARD MEMBERS

Alaska ........................................................................................................................................................... Mark R. PetersonArizona .............................................................................................................................................................. Robert BartlettArkansas ............................................................................................................................................................. Sam E. LyonsCalifornia ......................................................................................................................................................... John A. LemireColorado ..................................................................................................................................................... Charles S. WithersConnecticut .................................................................................................................................................................................Delaware ......................................................................................................................................................... James B. HarlanFlorida .................................................................................................................................................. Mohammad A. MalekGeorgia ................................................................................................................................................................... Earl EverettHawaii ................................................................................................................................................................ Yash NagpaulIllinois .............................................................................................................................................................. David A. DouinIndiana ................................................................................................................................................... Anthony W. MeiringIowa ................................................................................................................................................................... Robert B. WestKansas ...........................................................................................................................................................Donald J. JenkinsKentucky ...................................................................................................................................................... Roger A. CoomesLouisiana ........................................................................................................................................................... Robert R. CateMaine ................................................................................................................................................................ John H. BurpeeMaryland....................................................................................................................................................... John J. EngelkingMassachusetts ................................................................................................................................................... Mark MooneyMichigan ....................................................................................................................................................... Robert J. Aben Jr.Minnesota ............................................................................................................................................................... Joel AmatoMississippi .................................................................................................................................................. Henry T. McEwenMissouri ........................................................................................................................................................... Darryl K. PeetzMontana ......................................................................................................................................................................................Nebraska ......................................................................................................................................................... Daniel E. BurnsNevada ......................................................................................................................................................... Gerard F. MankelNew Hampshire ............................................................................................................................................. Wayne BrighamNew Jersey ................................................................................................................................................ Milton WashingtonNew Mexico ................................................................................................................................................................................New York ....................................................................................................................................................... Ronald K. WhiteNorth Carolina ................................................................................................................................................... H.D. HanrathNorth Dakota ....................................................................................................................................................... Robert ReetzOhio ................................................................................................................................................................... Dean T. JaggerOklahoma ............................................................................................................................................... Marion L. HollowayOregon ...................................................................................................................................................... William C. LundinePennsylvania ................................................................................................................................................... John D. PaytonRhode Island ...............................................................................................................................................................................South Dakota ................................................................................................................................................. Howard D. PfaffTennessee .......................................................................................................................................................... Martin R. TothTexas .............................................................................................................................................................. George R. BynogUtah ............................................................................................................................................................... Pete C. HackfordVermont ........................................................................................................................................................ Malcolm J. WheelVirginia ............................................................................................................................................................... Fred P. BartonWashington .................................................................................................................................................. Robert D. MarvinWest Virginia ...................................................................................................................................................... Murray ShuffWisconsin ................................................................................................................................................. Michael J. Verhagen

Chicago, IL ............................................................................................................................................ Edward A. AndersonDetroit, MI ............................................................................................................................................. Charles D. RedmondLos Angeles, CA ........................................................................................................................................... Bennett RenfrowMilwaukee, WI ............................................................................................................................................... Randal S. Pucek

Alberta .................................................................................................................................................................. Ken K.T. LauBritish Columbia .................................................................................................................................................. Susana KatzManitoba .......................................................................................................................................................... I. Wayne MaultNew Brunswick .................................................................................................................................................... Dale E. RossNewfoundland & Labrador .....................................................................................................................................................Northwest Territories ..................................................................................................................................... Steve DonovanNova Scotia .................................................................................................................................................... Charles J. CastleOntario .................................................................................................................................................................. Rick D. MilePrince Edward Island .....................................................................................................................................Kenneth HynesQuebec ............................................................................................................................................................ Madiha M. KotbSaskatchewan ................................................................................................................................................Nicholas SurteesYukon Territory ................................................................................................................................................ Daniel C. Price

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NATIONAL BOARD INSPECTION CODE

2001 EDITION

DATE OF ISSUE — AUGUST 2001

This code was developed under procedures accredited as meeting the criteria for AmericanNational Standards. The Consensus Committee that approved the code was balanced toassure that individuals from competent and concerned interests had an opportunity to partici-pate. The proposed code was made available for public review and comment which providedan opportunity for additional public input from industry, academia, regulatory and jurisdic-tional agencies, and the public-at-large.

The National Board does not “approve,” “rate,” or “endorse” any item, construction, propri-etary device, or activity.

The National Board does not take any position with respect to the validity of any patent rightsasserted in connection with any items mentioned in this document, and does not undertake toinsure anyone utilizing a standard against liability for infringement of any applicable LettersPatent, nor assume any such liability. Users of a code are expressly advised that determinationof the validity of any such patent rights, and the risk of infringement of such rights, is entirelytheir own responsibility.

Participation by federal agency representative(s) or person(s) affiliated with industry is not tobe interpreted as government or industry endorsement of this code.

The National Board accepts responsibility for only those interpretations issued in accordancewith governing National Board procedures and policies which preclude the issuance of inter-pretations by individual committee members.

The footnotes in this document are part of this American National Standard.

The above National Board symbols are registered with the U.S. Patent Office.

“National Board” is the abbreviation for The National Board of Boiler and Pressure VesselInspectors.

No part of this document may be reproduced in any form, in an electronic retrieval system orotherwise, without the prior written permission of the publisher.

R

NRRR

NB B

I

®

R®

ix

FOREWORD

The National Board of Boiler and Pressure Vessel Inspectors is an organization comprised ofChief Inspectors, for the states, cities and territories of the United States; provinces and terri-tories of Canada; and Mexico. It is organized for the purpose of promoting greater safety to lifeand property by securing concerted action and maintaining uniformity in the construction,installation, inspection, repair and alteration of pressure retaining items, thereby assuringacceptance and interchangeability among jurisdictional authorities responsible for theadministration and enforcement of various codes and standards.

In keeping with the principles of promoting safety and maintaining uniformity, the NationalBoard originally published The National Board Inspection Code (NBIC) in 1946, establishing rulesfor inspection and repairs to boilers and pressure vessels. The National Board Inspection Code(NBIC) Committee is charged with the responsibility for maintaining and revising the NBIC.In the interest of public safety, the NBIC Committee decided, in 1995, to revise the scope of theNBIC to include rules for the repair or alteration to pressure retaining items.

The NBIC Committee’s function is to establish rules of safety governing the repair, alterationand inspection of pressure retaining items, and to interpret these rules when questions ariseregarding their intent. In formulating the rules, the NBIC Committee considers the needs ofusers, repair organizations, and Inspectors. The objective of the rules is to afford reasonablycertain protection of life and property so as to give a reasonably long, safe period of useful-ness. Advancements in design and material and the evidence of experience are recognized.

The rules established by the NBIC Committee are not to be interpreted as approving, recom-mending, or endorsing any proprietary or specific design, or as limiting in any way the repairorganization’s freedom to choose any method of repair or alteration that conforms to the NBICrules.

The NBIC Committee meets regularly to consider revisions of the rules, new rules, andrequests for interpretations. Requests for interpretation must be addressed to the Secretary inwriting and must give full particulars in order to receive consideration and a written interpre-tation (see Mandatory Appendix “1” covering preparation of technical inquiries). Proposedrevisions to the Code resulting from inquiries will be presented to the NBIC Committee forappropriate action.

Proposed revisions to the Code approved by the NBIC Committee are submitted to theAmerican National Standards Institute and published in the National Board BULLETIN toinvite comments from all interested persons. After the allotted time for public review and finalapproval, revisions are published annually in Addenda to the NBIC.

Repair organizations or users of pressure retaining items are cautioned against making use ofrevisions that are less restrictive than former requirements without having assurance that theyhave been accepted by the jurisdiction where the pressure retaining item is installed.

The general philosophy underlying the NBIC is to parallel those provisions of the originalcode of construction, as they can be applied to a repair or alteration.

x

The NBIC does not contain rules to cover all details of repair or alteration. Where completedetails are not given, it is intended that the repair organization, subject to the acceptance ofthe Inspector, provide details for the repair or alteration which will be as safe as otherwiseprovided by the rules in the original code of construction.

Repairs not conforming to the rules of the original code of construction or the NBIC mustreceive specific approval of the jurisdiction, who may establish requirements for design, in-spection, testing and documentation.

There are instances where the NBIC serves to warn a repair organization or Inspector againstpitfalls; but the Code is not a handbook, and cannot substitute for education, experience, andsound engineering judgment.

It is intended that this Edition of this NBIC and any subsequent Addenda not be retroactive.Unless the jurisdictional authority imposes the use of an earlier edition, the latest effectiveEdition and Addenda is the governing document.

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INTRODUCTION

It is the purpose of the National Board Inspection Code (NBIC) to maintain the integrity ofpressure retaining items after they have been placed into service by providing rules for inspec-tion, repair and alteration, thereby ensuring that these objects may continue to be safely used.

The NBIC is intended to provide guidance to jurisdictional authorities, Inspectors, users, andorganizations performing repairs and alterations, thereby encouraging the uniform adminis-tration of rules pertaining to pressure retaining items.

It provides guidance for the process of inspection, repair and alteration but does not providedetails for all conditions found in pressure retaining items. Where complete details are notprovided in this Code, the Code user is advised to seek technical guidance.

ADDENDA

Colored-sheet Addenda, which include revisions and additions to this Code, are publishedannually. Addenda are permissive on the date issued and become effective six months afterthe date of issue. The addenda will be sent automatically to purchasers of the Code up to thepublication of the next issue.

INTERPRETATIONS

On request, the NBIC Committee will render an interpretation of any requirement of this Code.Interpretations are not part of this Code or its addenda.

JURISDICTIONAL PRECEDENCE

Reference is made throughout this Code to the requirements of the “jurisdictional authority”.Where any provision herein presents a direct or implied conflict with any jurisdictional regulation, thejurisdictional regulation shall govern.

AMERICAN PETROLEUM INSTITUTE

The American Petroleum Institute Code, API-510, covers the maintenance, inspection, repair,alteration and rerating procedures for pressure vessels used by the petroleum and chemicalprocess industries. Similarly, API-570 covers piping used by the petroleum and chemicalprocess industries. It is the intent of the NBIC that this Code cover installations other thanthose covered by API-510 and API-570, unless the jurisdiction rules otherwise.

UNITS OF MEASUREMENT

Both inch-pound units and SI units are used in the NBIC. The value stated in inch-poundunits or SI units are to be regarded separately as the standard. Within the text, the SI units areshown in brackets.

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TABLE OF CONTENTSForeword ............................................................................................................................. ix

Introduction ........................................................................................................................... xi

Part RA Administrative Requirements ......................................................................... 1

Part RB Inservice Inspection of Pressure Retaining Items ........................................ 37

Part RC Repairs and Alterations ................................................................................... 81

Part RD Repair Methods ................................................................................................. 95

Mandatory Appendices

Appendix 1 Preparation of Technical Inquiries to the National BoardInspection Code Committee ..................................................................... 113

Appendix 2 Stamping and Nameplate Information ................................................... 115

Appendix 3 Steam Locomotive Firetube Boiler Inspection and Repair .................. 119

Appendix 4 Glossary of Terms ....................................................................................... 135

Appendix 5 National Board Forms ............................................................................... 141

Appendix 6 Examples of Repairs and Alterations ...................................................... 173

Appendix 7 Procedures to Extend the “VR” Certificate of AuthorizationStamp to ASME “NV” Stamped Pressure Relief Devices .................... 177

Appendix 8 Inspection, Repair and Alteration of Graphite Pressure Equipment . 181

Nonm0andatory Appendices

Appendix A Standard Welding Procedures .................................................................. 193

Appendix B Recommended Preheat Temperatures .................................................... 197

Appendix C Historical Boilers ........................................................................................ 201

Appendix D Recommended Guide for the Design of a Test System forPressure Relief Devices in Compressible Fluid Service ....................... 259

Appendix E Recommended Procedures for Repairing Pressure Relief Valves ...... 265

Appendix F Pressure Differential Between Safety or Safety Relief ValveSetting and Boiler or Pressure Vessel Operating Pressure ................... 271

Appendix G Safety Valves on the Low Pressure Side of SteamPressure Reducing Valves ......................................................................... 275

Appendix H Recommended Guide for the Inspection ofPressure Vessels in LP Gas Service .......................................................... 281

Interpretations ....................................................................................................................... 287

PART RA — ADMINISTRATIVE REQUIREMENTS

1

Administrative Requirements

Part RA

2


PART RA — ADMINISTRATIVE REQUIREMENTSTABLE OF CONTENTS

RA-1000 General ................................................................................................................................. 3RA-1010 Scope .................................................................................................................................... 3RA-1020 Review Team Leaders ........................................................................................................ 3

RA-2000 Accreditation of Repair Organizations ........................................................................... 4RA-2010 Scope .................................................................................................................................... 4

RA-2100 “R” Administrative Rules and Procedures ..................................................................... 5RA-2110 Scope .................................................................................................................................... 5RA-2120 Prerequisites for Issuing a National Board Certificate of Authorization .................. 5RA-2130 Procedure for Obtaining or Renewing a National Board Certificate

of Authorization ................................................................................................................. 5RA-2140 National Board “R” Symbol Stamp ................................................................................. 6RA-2150 Quality System .................................................................................................................... 7

RA-2200 “VR” Administrative Rules and Procedures................................................................ 10RA-2210 Scope .................................................................................................................................. 10RA-2220 Issuance and Renewal of the “VR” Certificate and Stamp ........................................ 11RA-2230 Use of the “VR” Stamp .................................................................................................... 13RA-2240 Scope of Repair Activities ............................................................................................... 14RA-2250 Quality System ................................................................................................................. 15RA-2260 Nameplates ....................................................................................................................... 19RA-2270 Field Repair ....................................................................................................................... 21RA-2280 Performance Testing and Testing Equipment .............................................................. 21RA-2290 Training and Qualifications of Personnel ..................................................................... 23

RA-2300 “NR” Accreditation Requirements ................................................................................ 24RA-2310 Scope .................................................................................................................................. 24RA-2320 Prerequisites for Issuing a National Board “NR” Certificate of Authorization ..... 24RA-2330 Procedure for Obtaining or Renewing a National Board “NR” Certificate

of Authorization ............................................................................................................... 24RA-2340 National Board “NR” Symbol Stamp............................................................................ 26RA-2350 Quality System Program ................................................................................................. 26RA-2360 Outline of Requirements for a Quality System Program for Qualification

for the National Board “NR” Symbol Stamp ............................................................... 26RA-2370 Interface With the Owner’s Repair, Modification, or Replacement Program ........ 32

RA-3000 Accreditation of Owner-User Inspection Organizations ........................................... 33RA-3010 Scope .................................................................................................................................. 33RA-3020 Prerequisites for Accreditation ....................................................................................... 33RA-3030 Procedure for Obtaining or Renewing a National Board Owner-User Certificate 33RA-3040 Quality System ................................................................................................................. 34RA-3050 General Conditions .......................................................................................................... 35


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RA-1000 GENERAL

RA-1010 SCOPE

a. This part describes the administrative re-quirements for the accreditation of repairorganizations and for the accreditation ofOwne-User Inspection Organizations.

b. Some jurisdictions independentlyadminister a program of authorization oforganizations to perform repairs and al-terations. The limits of such authorizationmay not extend beyond the jurisdiction.

c. The National Board administers four spe-cific accreditation programs as follows:

RA-1020 REVIEW TEAM LEADERS

Individuals functioning as team leaders forperforming reviews of “R”, “NR” and “VR”Certificate Holders and Owner-User Inspec-tion Organizations for the purpose of accredi-tation must meet the qualification require-ments prescribed by the National Board.

Accreditation Program Scope

“R” Symbol Stamp ........................................... Repairs and Alterations to Pressure............................................................................. Retaining Items

“VR” Symbol Stamp ........................................ Repairs to Pressure Relief Valves

“NR” Symbol Stamp ........................................ Repairs, modifications and replacements............................................................................. of Nuclear Items

Owne-User Inspection Organization ............ Inservice inspection of pressure retainingitems owned or used by the organizationwhich is accredited as an Owner-UserInspection Organization

4


RA-2000 ACCREDITATION OFREPAIR ORGANIZATIONS

RA-2010 SCOPE

a. The National Board administers threeseparate accreditation programs fororganizations performing repairs andalterations to pressure retaining items orpressure relief valves.

b. As part of the accreditation process, anapplicant is subject to a review. NationalBoard procedures provide for the confi-dential review of recommendations to is-sue, renew or revoke a Certificate of Au-thorization.

c. The “R” Symbol Stamp accreditationprogram provides requirements fororganizations performing repairs andalterations to pressure retaining items. Sixtypes of authorizations are offered,

depending upon the organization’s ex-pected scope of activities. Organizationsmay be authorized to perform:

Repairs Only – Shop OnlyRepairs Only – Field OnlyRepairs Only – Shop & FieldAlterations & Repairs – Shop OnlyAlterations & Repairs – Field OnlyAlterations & Repairs – Shop & Field

d. The “VR” Symbol Stamp accreditationprogram provides requirements for orga-nizations performing repairs to pressurerelief valves. The authorization may be forshop, field or a combination of both.

e. The “NR” Symbol Stamp accreditationprogram provides requirements fororganizations performing repairs, modi-fications and replacements of nuclearpower plant components.


5

RA-2100 “R” ADMINISTRATIVERULES AND PROCEDURES

RA-2110 SCOPE

a. This section provides requirements thatmust be met by organizations in order toobtain a National Board Certificate ofAuthorization to use the “R” SymbolStamp for the repair or alteration of pres-sure retaining items. Organizations may beauthorized to perform repairs only, orrepairs and alterations.

b. For further information contact:

Accreditation DepartmentThe National Board of Boiler and Pressure Vessel Inspectors1055 Crupper AvenueColumbus, OH 43229-1183

Phone: 614.888.8320Fax: 614.847.1828

c. The issuance of the “R” Stamp is not re-stricted to organizations whose primarybusiness is to repair and alter pressureretaining items, nor to manufacturers ofpressure retaining items. Owners and Us-ers of pressure retaining items and otherorganizations that qualify in accordancewith these rules may also obtain the “R”Stamp.

RA-2120 PREREQUISITES FORISSUING A NATIONALBOARD CERTIFICATE OFAUTHORIZATION

Before an organization can obtain a NationalBoard “R” Certificate of Authorization, the or-ganization shall:

a. have and maintain an Inspection Agree-ment with an Authorized InspectionAgency,

b. have a written Quality System which com-plies with the requirements of this section

and includes the expected scope of activ-ities,

c. have the current edition of the NationalBoard Inspection Code, and

d. have available a copy of the code of con-struction appropriate to the intended scopeof work.

RA-2130 PROCEDURE FOROBTAINING ORRENEWING A NATIONALBOARD CERTIFICATE OFAUTHORIZATION

a. Prior to issuance or renewal of a NationalBoard “R” Certificate of Authorization, theorganization and its facilities are subjectto a review of its Quality System. Theimplementation of the Quality Systemshall be satisfactorily demonstrated by theorganization. The National Board reservesthe absolute right to cancel, refuse to is-sue, or renew such authorization.

b. Organizations desiring to obtain aNational Board Certificate of Authoriza-tion shall apply to the National Boardusing forms obtained from the NationalBoard. Application for renewal shallbe made prior to the expiration date ofthe Certificate of Authorization. Applica-tions may be obtained from the NationalBoard.

c. When an organization has plants or shopsin more than one location, the organiza-tion shall submit separate applications foreach plant or shop. The organization mayperform repairs or alterations in its plants,shops, or in the field, provided such oper-ations are described in the organization’sQuality System.

d. Upon notification of the review datesfrom the National Board, it is the respon-sibility of the organization to make ar-rangements for the review.

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1Jurisdiction:The National Board member jurisdiction where the organization is located. Alternatively, wherethe jurisdiction elects not to perform the review or where there is no jurisdiction or where the juris-diction is the organization’s Authorized Inspection Agency, the National Board of Boiler and Pres-sure Vessel Inspectors will represent the jurisdiction. At the jurisdiction’s discretion, the jurisdic-tion may choose to be a member of the review team if the jurisdiction chooses not to be the teamleader.

e. The Review Team, as a minimum, shallconsist of one representative each fromthe Authorized Inspection Agency andthe Jurisdiction.1

f. The Review Team shall conduct an eval-uation of the organization’s QualitySystem. The organization shall demon-strate sufficient implementation of theQuality System to provide evidence of theorganization’s knowledge of welding,nondestructive examination, postweldheat treatment, and other repair or alter-ation activities performed appropriate forthe requested scope of work. The dem-onstration may be performed using cur-rent work, a demonstration mock-up, ora combination of both.

g. A recommendation to issue, renew, orwithhold the National Board Certificateof Authorization shall be included in aReview Report prepared by the ReviewTeam. The completed Review Report shallbe forwarded to the National Board.

h. If proper administrative fees are paid, andall other requirements are met, a Certifi-cate of Authorization will be issuedevidencing permission to use the “R”Symbol Stamp. The Certificate shall ex-pire on the triennial anniversary date.

i. When an organization holding a NationalBoard Certificate of Authorizationchanges ownership, name, location, oraddress, the National Board shall benotified. The Certificate of Authorizationmay be revised by submitting an appli-cation for National Board “R” Certificateof Authorization; however, a rereviewmay be required.

j. The holder of an ASME Code SymbolStamp, whose facilities were reviewed bythe jurisdiction, (with the exception of“V”, “UV”, “HV”, “NV”, “RP”, and “H”[cast iron]) may obtain National Board

authorization without a review of itsfacilities, provided:

1. The organization has a Quality Sys-tem to cover the scope of the repairsor alterations to be made, subject toreview by the jurisdiction, and

2. The ASME Certificate of Authoriza-tion was issued within one year of theapplication for the “R” Certificate ofAuthorization. The initial Certificateof Authorization shall be issued toexpire concurrent with the ASME Cer-tificate of Authorization. Subsequentcertificates shall be renewed upon asuccessful review and implementa-tion of its quality system by a NationalBoard representative.

k. The jurisdiction may audit the QualitySystem and activities of an organizationupon a valid request from an owner, user,inspection agency, or the National Board.

l. The National Board Inspection CodeCommittee may at any time change therules for the issuance of Certificates ofAuthorization and use of the “R” SymbolStamp. These rules shall become bindingon all certificate holders.

RA-2140 NATIONAL BOARD “R”SYMBOL STAMP

a. All “R” Symbol Stamps shall be obtainedfrom the National Board of Boiler andPressure Vessel Inspectors. Authorizationto use the “R” Symbol Stamp may begranted by the National Board at itsabsolute discretion.

b. The “R” Symbol Stamp is furnished onloan by the National Board for a nominalfee. Each organization shall agree, ifauthorization to use the “R” SymbolStamp is granted, that the “R” Symbol


7

Stamp is at all times the property of theNational Board and will be promptlyreturned upon demand. If the organiza-tion discontinues the use of the “R”Symbol Stamp, inspection agreementwith an Authorized Inspection Agency, orif the Certificate of Authorization has ex-pired and no new certificate has been is-sued, the “R” Symbol Stamp shall be re-turned to the National Board.

c. The organization’s Quality System shallprovide for adequate control of the “R”Symbol Stamp. Provisions may be madefor the issuance of the “R” Symbol Stampfor use at various field locations.

d. The holder of a Certificate of Authori-zation may obtain more than one “R”Symbol Stamp provided theorganization’s Quality System describeshow the use of such stamps is controlledfrom the location shown on the certificate.

e. An organization shall not permit othersto use the “R” Symbol Stamp loaned to itby the National Board.

RA-2150 QUALITY SYSTEM

A holder of a National Board Certificate ofAuthorization shall have and maintain awritten Quality System. The System shallsatisfactorily meet the requirements of theNational Board Inspection Code, and shall beavailable for review. The Quality System maybe brief or voluminous, depending on the cir-cumstances. It shall be treated confidentiallyby the National Board.

RA-2151 OUTLINE OFREQUIREMENTS FOR AQUALITY SYSTEM FORQUALIFICATION FOR THENATIONAL BOARD “R”SYMBOL STAMP

The following is a guide to features of a Qual-ity System that should be included in theorganization’s Quality System Manual. Eachorganization should address the features asneeded for the scope of work to be performed:

a. Title PageThe name and complete address of thecompany to which the National BoardCertificate of Authorization is issued shallbe included on the Title Page of the Qual-ity System Manual.

b. Contents PageThe manual should contain a page listingthe contents of the manual by subject,number (if applicable), and revision num-ber of each document.

c. Scope of WorkThe manual shall clearly indicate thescope and type of repairs or alterationsthe organization is capable of and intendsto carry out.

d. Statement of Authority andResponsibilityA dated Statement of Authority, signed byan officer of the organization, shall beincluded in the manual. Further, the State-ment of Authority shall include:

1. a statement that all repairs or alter-ations carried out by the organizationshall meet the requirements of theNational Board Inspection Code, andthe jurisdiction as applicable.

2. a statement that, if there is a disagree-ment in the implementation of theQuality System, the matter is to bereferred for resolution to a higherauthority in the company.

3. the title of the individual who will beresponsible to ensure that (1) above isfollowed, and has the freedom andauthority to carry out the responsi-bility.

e. Manual ControlThe manual shall include the necessaryprovisions for revising and issuing docu-ments to maintain the manual current.The title of the individual authorized toapprove revisions shall be included in themanual. Revisions must be accepted bythe Authorized Inspection Agency priorto issuance of the manual and implemen-tation.

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f. Organization1. An organizational chart shall be in-

cluded in the manual. It shall includethe title of the heads of all depart-ments or divisions that perform func-tions which can affect the quality ofthe repair or alteration and it shallshow the relationship between eachsuch department or division.

2. The manual shall identify those indi-viduals responsible for preparation,implementation, or verification of theQuality System. The responsibilitiesshall be clearly defined and the indi-viduals shall have the organizationalfreedom and authority to fulfill thoseresponsibilities.

g. Drawings, Design, and SpecificationsThe manual shall contain controls toensure that all design information,applicable drawings, design calculations,specifications, and instructions are pre-pared or obtained, controlled, and inter-preted in accordance with the originalcode of construction.

h. Repair and Alteration MethodsThe manual shall include controls forrepairs and alterations, including theselection of the welding procedure speci-fication, materials, nondestructive exami-nation methods, preheat and postweldheat treatment.

i. MaterialsThe manual shall describe the methodused to assure that only acceptable mate-rials (including welding material) is usedfor repairs and alterations. The manualshall include a description of how exist-ing material is identified and new mate-rial is ordered, verified, and identified.The manual shall identify the title of theindividual(s) responsible for each func-tion and a brief description of how thefunction is to be performed.

j. Method of Performing WorkThe manual shall describe the methodsfor performing and documenting repairsand alterations in sufficient detail to per-mit the Inspector to determine at whatstages specific inspections are to be per-formed. The method of repair or alter-ation must have prior acceptance of theInspector.

k. Welding, NDE, and Heat TreatmentThe manual shall describe controls forwelding, nondestructive examination,and heat treatment. The manual is toindicate the title of the individual(s)responsible for the welding procedurespecification and its qualification, and thequalification of welders and weldingoperators. It is essential that only weld-ing procedure specifications and weldersor welding operators qualified, as re-quired by the National Board InspectionCode, be used in the repair or alteration ofpressure retaining items. It is also essen-tial that welders and welding operatorsmaintain their proficiency as required bythe NBIC, while engaged in the repair oralteration of pressure retaining items.Similar responsibility for nondestructiveexamination and heat treatment shall bedescribed in the manual.

l. Examinations and TestsReference shall be made in the manual forexaminations and tests upon completionof the repair or alteration.

m. CalibrationThe manual shall describe a system forthe calibration of examination, measur-ing, and test equipment used in the per-formance of repairs and alterations.

n. Acceptance and Inspection of Repair orAlterationThe manual shall specifically indicate thatbefore the work is started, acceptance ofthe repair/alteration shall be obtained


9

from an Inspector who will make the re-quired inspections and confirm NationalBoard Inspection Code compliance bysigning and dating the applicableNational Board Inspection Code ReportForm2 upon completion of the work.

o. InspectionsThe manual shall make provisions for theInspector to have access to all drawings,design calculations, specifications, proce-dures, process sheets, repair or alterationprocedures, test results, and other docu-ments as necessary to assure compliancewith the National Board Inspection Code.A copy of the current manual shall beavailable to the Inspector.

p. Report of Welded Repair or AlterationFormThe manual shall indicate the title of theindividuals responsible for preparing,signing, and presenting the NationalBoard Inspection Code Report Forms tothe Inspector. The distribution of the Na-tional Board Inspection Code ReportForms shall be described in the manual.

2NBIC Report Form: National Board Form R-1 for Welded Repairs, Form R-2 for Alterations, or Form R-3 forParts Fabricated by Welding.

q. ExhibitsAny forms referenced in the manual shallbe included except standard forms con-tained in referenced codes and standardsneed not be included. The form may be apart of the referencing document or in-cluded as an appendix. For clarity, theforms may be completed and identifiedas examples. The name and accepted ab-breviations of the “R” Certificate Holdershall be included in the manual.

r. Construction CodeThe manual shall include provisions foraddressing the requirements that pertainto the specific construction code for theequipment being repaired or altered.

s. Nonconforming ItemsThere shall be a system acceptable to theInspector for the correction of noncon-formities. A nonconformity is any condi-tion which does not comply with theapplicable rules of the National BoardInspection Code, construction code, juris-dictional requirements or the qualitysystem. Nonconformities must be cor-rected or eliminated before the repairedor altered component can be consideredin compliance with the National BoardInspection Code.

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RA-2200 “VR” ADMINISTRATIVERULES AND PROCEDURES

RA-2210 SCOPE

a. These administrative rules and proce-dures are provided for those who wish toobtain a National Board Certificate of Au-thorization for use of the “VR” (Repair ofPressure Relief Valves) symbol stamp. Itshould be noted that the issuance of the“VR” stamp is not restricted to companieswhose primary business is the repair ofpressure relief valves nor to manufactur-ers or assemblers that hold an ASME “V”,“HV”, “UV” or “NV” Code symbolstamp. Owners and users of boilers andpressure vessels and other organizationsthat qualify in accordance with theNational Board Rules and Regulationsmay also obtain the “VR” Certificate andstamp.

b. Realizing the importance of the proper re-pair of pressure relief valves, The NationalBoard of Boiler and Pressure VesselInspectors Executive Committee autho-rized the development of rules and pro-cedures for the issuance of the NationalBoard Certificate of Authorization for useof the Valve Repair (“VR”) stamp. Theserules and procedures were initiallyapproved by the National Board Execu-tive Committee on January 26, 1977.

c. In order to provide due process in theissuance, renewal, and revocation of “VR”symbol stamps and certificates of autho-rization, the National Board Board ofTrustees authorized the formation of theNational Board Accreditation Committee.National Board Accreditation Commit-tee procedures provide an affected “VR”Certificate of Authorization applicant theright of appeal or provide additional in-formation which may affect theCommittee’s decision.

d. The National Board Accreditation Com-mittee consists of a balance of represen-tatives of the National Board staff, “VR”certificate holders, valve manufacturers,jurisdictions, the insurance industry anduser interest categories. Procedures ap-

proved by the National Board Board ofTrustees provide this important right ofappeal and reconsideration.

e. For further information contact:

Pressure Relief DepartmentThe National Board of Boiler and Pressure Vessel Inspectors7437 Pingue DriveWorthington, OH 43085-1715

Phone: 614.888.8320Fax: 614.848.3474

RA-2212 JURISDICTIONALPARTICIPATION

The National Board member jurisdiction inwhich the “VR” organization is located isencouraged to participate in the review anddemonstration of the applicant’s quality sys-tem. The jurisdiction may require participa-tion in the review of the repair organizationand the demonstration and acceptance of therepair organization’s quality system manual.

RA-2213 TRAINING

These procedures provide for National Boardcoordinated training courses for valve repairorganization personnel to further their skillsand knowledge in the repair of pressurerelief valves. Many relief valve manufac-turers also sponsor training courses on therepair and maintenance of their respectivevalve types and series. Pressure relief valverepair organizations are encouraged to havetheir personnel participate in these courses.It is also recommended that valve repairorganizations cooperate and establish work-ing relationships with valve manufacturersto help ensure the proper repair of the manu-facturers’ specific valves.

RA-2214 GENERAL RULES

a. The general rules of the National Board“VR” certification program apply only tothe repair of National Board capacity cer-tified ASME Code Section I “V” stamped,


11

Section IV “HV” marked, and Section VIII“UV” stamped pressure relief valves that:

1. have been in service or have beenexposed to environmental or otherconditions such that there is reason toquestion their ability to performequivalent to the standards for newvalves; or

2. any or all of the valve’s externaladjustment seals have been broken,opened or otherwise disturbedregardless of the valve’s age orservice status.

b. The scope of the repair organization’squalifications is listed on the “VR”Certificate of Authorization.

RA-2215 REPAIR OFNUCLEAR VALVES

Provided that the requirements of Appendix7 and applicable requirements of these rulesare met, the “VR” certificate may be extendedto apply to the repair of any ASME CodeSection III, Class 1, 2 or 3 pressure reliefdevices which have been capacity certified bythe National Board and have been in service,regardless of their intended function, in anuclear system. The scope of the repairorganization’s qualifications is listed on the“VR” Certificate of Authorization (RA-2330(c) and (d)).

RA-2216 DEFINITIONS

Unless otherwise specified in these rules andprocedures, the definitions relating to pres-sure relief devices in Section 2 of ANSI/ASME PTC-25-1994 shall apply.

RA-2217 TECHNICAL INQUIRIES

Refer to Appendix 1 for information on pre-paring technical inquiries on the subject ofvalve repair.

RA-2220 ISSUANCE AND RENEWALOF THE “VR” CERTIFICATEAND STAMP

RA-2221 GENERAL

Authorization to use the stamp bearing theofficial National Board Valve Repair symbolas shown in Appendix 2 will be granted bythe National Board pursuant to the provisionsof the following administrative rules and pro-cedures. Appendix 7 provides rules for therepair of ASME Section III “NV” stampedpressure relief devices.

RA-2222 ISSUANCE OF CERTIFICATE

a. Repair organizations, manufacturers,assemblers or users that make repairs tothe American Society of Mechanical En-gineers (ASME) Code symbol and TheNational Board of Boiler and PressureVessel Inspectors (National Board) capac-ity certified pressure relief valves mayapply to the National Board for a Certifi-cate of Authorization to use the “VR”symbol. The National Board may at anytime, through the National Board Inspec-tion Code Committee, modify the regu-lations concerning the issuance and useof such Valve Repair symbol. All suchmodified regulations shall become bind-ing upon holders of valid Valve RepairCertificates of Authorization.

b. Authorization to use the Valve Repairstamp may be granted or withheld by theNational Board in its absolute discretion.If authorization is granted and properadministrative fees paid, a certificate ofauthorization will be issued evidencingpermission to use such a symbol, expir-ing on the triennial anniversary date. Thecertificate will be signed by the Chairmanof the National Board Board of Trustees,the executive director, or any other dulyauthorized officer.

c. The certificate shall indicate authorizationto repair ASME Section I, III, IV and/orVIII valves, as verified by testing and ascovered by the repair organization’s qual-ity system manual. In addition, the cer-tificate shall list the physical, permanentaddress of record for the certificateholder ’s shop/plant. For field-onlyscopes, this address of record is where ad-

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ministrative, technical and quality aspectsof the business are controlled.

RA-2223 RENEWAL OF CERTIFICATE

The certificate of authorization is renewableevery three (3) years subject to a review ofthe quality system by a representative of theNational Board, review and acceptance of therepresentative’s report by the National Board,and successful completion of capacity verifi-cation tests. See paragraph RA-2258(a) forexceptions. The applicant should apply to theNational Board for renewal of authorizationand reissuance of the certificate prior to thedate of expiration. The National Board re-serves the absolute right to cancel, refuse toissue or renew such authorization.

RA-2224 REVIEW OF APPLICANT’SFACILITY

a. Before issuance or renewal of pressurerelief Valve Repair Certificates ofAuthorization, the repair organization, itswritten quality system and its facilities aresubject to a review and verification ofimplementation of its quality system bya representative of the National Board.The implementation demonstration shallinclude, as a minimum, disassembly,inspection, repair, application of specialprocesses, reassembly, setting and testingof valves within the scope of theapplicant’s quality system.

b. The applicant shall repair and submit forverification testing one (1) valve for eachCode section (except Section III) and testfluid (steam, air/gas, liquid) which willappear on the certificate of authorization.A minimum of two (2) valves are requiredregardless of Code sections or test fluid.The valves shall be within the capabili-ties of the National Board accepted labo-ratory. When an applicant is using theprovisions of paragraph RA-2282, theapplicant shall submit one additional Sec-tion VIII steam valve set on air for verifi-cation testing on steam.

c. The applicant shall have the latest editionand addenda of the National Board Pres-

sure Relief Device Certifications publicationNB-18, The National Board Inspection Code(NBIC), and the ASME Code section(s)that the organization is including in itsscope.

d. It is the responsibility of the valve repairorganization to make arrangements forthis review. Certificates cannot be issuedor renewed until the National Board is inreceipt of approval of this review. Wher-ever possible, National Board reviewsof valve repair organizations shall becoordinated with ASME reviews, whenapplicable.

e. For field only repair scopes, the reviewshall encompass both the applicant’saddress of record and field repairdemonstration site. The demonstrationsite shall be representative of that typi-cally encountered by the applicant (SeeRA-2229 (a)).

RA-2228 VERIFICATION TESTING

a. Before the “VR” Certificate of Authoriza-tion and stamps may be issued or re-newed, the demonstration valves mustsuccessfully complete capacity and opera-tional verification tests at a NationalBoard accepted testing laboratory. Seeparagraphs RA-2229 and RA-2258(a) forexceptions. The valves shall be typical ofthose repaired by the organization andwithin the capabilities of the testinglaboratory.

b. Tests conducted at the accepted testinglaboratory shall be witnessed by a repre-sentative of the National Board. Thepurpose of the tests is to ensure that therepairs have been satisfactorily carriedout and the function and operation of thevalves meet the requirements of the sec-tion of the ASME Code to which theywere manufactured.

c. Valves not meeting the function or opera-tional requirements of the section of theASME Code to which they were manu-factured shall be considered to havefailed. Replacement valves shall be re-paired and selected for testing as stated


13

above, at a rate of two (2) valves for eachone (1) that failed.

1. If either or both of these replacementvalves fail to meet the above criteria,the applicant shall document thecause of the noted deficiencies andactions taken to guard against futureoccurrence. Upon acceptance of thisinformation by the National Board,one (1) additional valve for each re-placement valve that failed shall berepaired and tested. The valve(s) shallbe of the same ASME Codesection, fluid and set pressure scopeas the valve previously failing to meetthe test requirement.

2. Failure of this valve(s) to meet theASME Code to which the valve wasmanufactured shall be cause forconsideration by the National Boardof revocation of the “VR” Certificateof Authorization or acceptance of al-ternative corrective action.

RA-2229 VERIFICATION TESTINGALTERNATIVES

a. In such cases where all valves repaired bythe applicant for a specified ASME Codesection or test fluid, exceed the capabili-ties of the accepted testing laboratory,valves for that ASME Code section or testfluid shall be selected as specified inRA-2224(b) and a demonstration test shallbe successfully performed in lieu of veri-fication testing specified in paragraphRA-2228(b) above. The demonstrationtests shall be conducted at a facility mu-tually agreeable to the National Boardrepresentative, the facility owner, and theapplicant. The purpose of these tests is todemonstrate, in the presence of a NationalBoard representative, that the repairedvalves shall have adequate seat tightnessat the maximum expected operating pres-sure prior to lifting, shall open within therequired set pressure tolerance, operateconsistently without chatter, and reclosewithin the required blowdown.

b. If a valve lift-assist device is used by theapplicant to establish set pressure after

repairs, this device must also be used toset the demonstration valves.

c. If either of these valves fail to meet theabove criteria, then replacement valvesshall be repaired and tested at a rate oftwo (2) valves for each one (1) that failed.

1. If either or both of these replacementvalves fail to meet the above criteria,the applicant shall document thecause of the noted deficiencies andactions taken to guard against futureoccurrence. Upon acceptance of thisinformation by the National Board,one (1) additional valve for each re-placement valve that failed shall berepaired and tested. The valve(s) shallbe of the same ASME Code section,fluid and set pressure scope as thevalve previously failing to meet thetest requirement.

2. Failure of this valve(s) to meet theASME Code to which the valve wasmanufactured shall be cause for con-sideration by the National Boardof revocation of the “VR” Certificateof Authorization or acceptance of al-ternative corrective action.

RA-2230 USE OF THE “VR” STAMP

RA-2231 CONDITIONS OF USE

The “VR” stamp shall be applied only topressure relief valves which meet both of thefollowing conditions:

a. are stamped with an ASME “V”, “UV” or“NV” Code symbol or marked with anASME “HV” symbol and have beencapacity certified on the applicable fluidby the National Board; and

b. have been disassembled, inspected andrepaired by the certificate holder, suchthat the valves’ condition and perfor-mance are equivalent to the standards fornew valves.

1. The standard referred to above fornew valves is the ASME Boiler and

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repair locations. It may make the repairs inits plant, shop, or in the field, provided suchoperations are controlled by the plant or shop.Certificates shall indicate if authorization isfor shop, shop and field, or field only.

RA-2240 SCOPE OF REPAIRACTIVITIES

RA-2241 SCOPE

The repair organization’s quality system shalladdress the scope of repair activities intendedto be performed (reference paragraph RA-2256(f)).

RA-2242 CERTIFICATE OFAUTHORIZATIONCONTENTS

a. Qualification for repair location, Codesection, special processes and test mediashall be specified on the repairorganization’s “VR” Certificate of Autho-rization.

b. Repair of a pressure relief valve is con-sidered to be the disassembly, replace-ment, remachining, or cleaning of anycritical part, lapping of a seat and disc,reassembly, adjustment, testing or anyother operation that may affect the flowpassage, capacity, function or pressureretaining integrity.

c. Conversions, changes or adjustmentsaffecting critical parts are also consideredrepairs (see RA-2231). The scope of con-versions may include changes in servicefluid, and changes such as bellows, softseats, and other changes that mayaffect type/model number, provided suchchanges are recorded on the documentrequired by RA-2256(i) and the repairnameplate (see RA-2260).

d. The scope of repair activites shall notinclude changes in ASME Code status.

Pressure Vessel Code. ASME CodeCases shall be used for repairs whenthey were used in the originalconstruction of the valve. ASME CodeCases may be used when they havebeen accepted for use by revision orinterpretation by the National BoardInspection Code Committee.

2. The Code Case number shall be notedon the repair document specifiedin paragraph RA-2256(i)(1) andwhen required by the Code Case,stamped on the repair nameplate.The applicable jurisdiction shallbe consulted for any uniquerequirements it may have established.

RA-2232 STAMP SERIALIZATION

Each Valve Repair symbol stamp shall be se-rialized and used only by the repair firmwithin the scope, limitations and restrictionsunder which it was issued.

RA-2233 RETURN OF STAMP

Each applicant shall agree, if authorization touse the stamp is granted, that the stamp is atall times the property of the National Boardand will be promptly returned upon demand.If the applicant discontinues the repair of suchvalves, or if the Valve Repair Certificate ofAuthorization issued to such applicant hasexpired and no new certificate has been is-sued, the stamp will be returned to the Na-tional Board.

RA-2234 MULTIPLE LOCATIONS

A holder of a National Board Valve Repairstamp shall not permit any others to use the“VR” symbol stamp loaned to it by theNational Board. When a repair organization,manufacturer, or user has a repair departmentand/or equipment in fixed plants or shopslocated in more than one geographical area,it must submit separate applications for eachplant or shop with the addresses of all such


15

RA-2243 CHANGES TOCERTIFICATES OFAUTHORIZATION

a. When a Valve Repair Certificate holderintends to change the address of record(location), the certificate holder shall no-tify the National Board in writing priorto relocating. The new facilities and re-lated quality system for the new locationshall be reviewed in accordance withparagraph RA-2224. Issuance of a newCertificate of Authorization is subject tothe procedures herein.

b. When a Valve Repair Certificate holderintends to change ownership or scope, thecertificate holder shall notify the NationalBoard in writing prior to the change. Areview, in accordance with paragraph RA-2224, may be required depending uponthe nature and extent of the change to thequality system manual, repair proceduresor facilities. Issuance of a new Certificateof Authorization is subject to the proce-dures herein.

RA-2244 ISSUANCE OF MORE THANONE “VR” SYMBOL STAMPTO A CERTIFICATE OFAUTHORIZATION HOLDER

The holder of a certificate of authorizationmay obtain more than one “VR” symbolstamp provided its quality system manualcontrols the use of such stamps from the ad-dress of record shown on the certificate ofauthorization. In such cases, the certificate ofauthorization will indicate the serial numbersof each “VR” symbol stamp which has beenissued on loan to the repair organization.

RA-2245 REPAIRS TO PRESSURERELIEF VALVES

a. The initial installation testing and adjust-ments of a new pressure relief valve on aboiler or pressure vessel are not consid-ered a repair if made by the manufactureror assembler of the valve.

b. The jurisdiction may authorize properlytrained and qualified employees of boiler

or pressure vessel users or their designeesto make adjustments to set pressure and/or blowdown to pressure relief valvesowned by them, provided the adjustedsettings and/or capacities and the date ofthe adjustment are recorded on a metaltag secured to the seal wire. All externaladjustments shall be resealed showing theidentification of the organization makingthe adjustments.


RA-2251 GENERAL

Each applicant for a new or renewed “VR”Certificate of Authorization shall have andmaintain a quality system which shall estab-lish that all of these rules and administrativeprocedures and applicable ASME Coderequirements, including material control, fab-rication, machining, welding, examination,setting, testing and inspection, will be met.

RA-2252 WRITTEN DESCRIPTION

A written description of the system theapplicant will use shall be available for re-view and shall contain, as a minimum, thefeatures set forth in paragraph RA-2256. Thisdescription may be brief or voluminous, de-pending upon the circumstances, and shallbe treated confidentially. In general, the qual-ity system shall describe and explain whatdocuments and procedures the repair firmwill use to validate a valve repair.

RA-2254 REVIEW

A review of the applicant’s quality systemwill be performed by a representative of theNational Board. The review will include ademonstration of the implementation of theprovisions of the applicant’s quality system.

RA-2255 MAINTENANCE OFCONTROLLED COPY

Each applicant to whom a “VR” Certificateof Authorization is issued shall maintain

16


thereafter a controlled copy of the acceptedquality system manual with the NationalBoard. Except for changes which do notaffect the quality system, revisions to the qual-ity system manual shall not be implementeduntil such revisions are accepted by theNational Board.

RA-2256 OUTLINE OFREQUIREMENTS FOR AQUALITY SYSTEM

The following establishes the minimum re-quirements of the written description of thequality system. It is required that each valverepair organization develop its own qualitysystem which meets the requirements of itsorganization. For this reason it is not possibleto develop one quality system which couldapply to more than one organization. Thewritten description shall include, as a mini-mum, the following features:

a. Title PageThe title page shall include the name andaddress of the company to which theNational Board Certificate of Authoriza-tion is to be issued. It should also list thesections of the ASME Code to which therepairs apply.

b. Revision LogA revision log is required to assure revi-sion control of the quality system manual.The log should contain sufficient space fordate, description and section of revision,company approval, and National Boardacceptance.

c. Contents PageThe contents page should list and refer-ence, by paragraph and page number, thesubjects and exhibits contained therein.

d. Statement of Authority andResponsibilityA statement of authority and responsibil-ity shall be dated and signed by an officerof the company. It shall include:

1. a statement that the “VR” stamp shallbe applied only to pressure relief

valves which meet both of the follow-ing conditions:

a. are stamped with an ASME “V”,“UV”, or “NV Code symbol ormarked with an ASME “HV”symbol and have been capacitycertified by the National Board;and

b. have been disassembled,inspected, and repaired by thecertificate holder such that thevalves’ condition and perfor-mance are equivalent to thestandards for new valves.

2. the title of the individual responsibleto ensure that the quality system is fol-lowed and who has authority andfreedom to effect the responsibility;

3. a statement that if there is a disagree-ment in the implementation of thewritten quality system, the matter isto be referred to a higher authority inthe company for resolution; and

4. the title of the individual authorizedto approve revisions to the writtenquality system and the method bywhich such revisions are to be submit-ted to the National Board for accep-tance before implementation.

e. Organization ChartA chart showing the relationship betweenmanagement, purchasing, repairing,inspection and quality control personnelis required and shall reflect the actualorganization in place.

f. Scope of Work1. The scope of work section shall indi-

cate the scope and type of valverepairs, including conversions, theorganization is capable of and intendsto perform. The location of repairs(shop, shop and field, or field only),the test medium (air, gas, liquid orsteam, or combinations thereof) andspecial processes (machining,welding, postweld heat treatment ornondestructive examination, or com-


17

binations thereof) shall be specificallyaddressed.

2. The types and sizes of valves to berepaired, pressure ranges and otherlimitations, such as engineering, andtest facilities, should also beaddressed.

g. Drawings and Specification ControlThe drawings and specification controlsystem shall provide procedures assuringthat the latest applicable drawings,specifications and instructions requiredare used for valve repair, including con-versions, inspection and testing.

h. Material and Part ControlThe material and part control section shalldescribe purchasing of parts from thevalve manufacturer, if applicable, and ofmaterial with request for mill test certifi-cation as required. It shall also describereceiving, storage and issuing.

1. State the title of the individual re-sponsible for the purchasing of allmaterial.

2. State the title of the individual respon-sible for certification and otherrecords as required.

3. All incoming material and parts shallbe checked for conformance with thepurchase order and, where applicable,the material specifications or draw-ings. Indicate how material or part isidentified and how identity is main-tained by the quality system.

4. All critical parts shall be fabricated bythe valve manufacturer or to his speci-fications. (See Appendix 4 for defini-tion of “Critical Parts”.)

i. Repair and Inspection ProgramThe repair and inspection program sec-tion shall include reference to a document(such as a report, traveler or checklist)which outlines the specific repair and in-spection procedures used in the repair ofpressure relief valves. Repair proceduresshall require verification that the critical

parts meet the valve manufacturers speci-fication. Appendix E outlines recom-mended procedures covering some spe-cific items. Provisions shall be made toretain this document for a period of atleast five (5) years.

.1. Each valve or group of valves shall be

accompanied by the document re-ferred to above for processing throughthe plant. Each valve shall have aunique identifier (e.g., repair serialnumber, shop order number, etc.) ap-pearing on the repair nameplate suchthat traceability to the repair docu-mentation is established.

2. The document referred to above shalldescribe the original nameplate infor-mation, including the ASME Codesymbol stamping and the repairnameplate information, if applicable.In addition, it shall include materialcheck, replacement parts, conversionparts, or both, reference to items suchas the welding procedure specifica-tions (WPS), fitup, NDE technique,heat treatment, and pressure testmethods to be used. Application of the“VR” stamp to the repair nameplateshall be recorded in this document.Specific conversions performed withthe new Type/Model number shall berecorded on the document. There shallbe a space for “signoffs” at each op-eration to verify that each step hasbeen properly performed.

3. The system shall include a method ofcontrolling the repair or replacementof critical valve parts. The method ofidentifying each spring shall beindicated.

4. The system shall also describe thecontrols used to ensure that anypersonnel engaged in the repair ofpressure relief valves are trained andqualified in accordance with para-graph RA-2290.

j. Welding, NDE and Heat Treatment(when applicable)When weld repairs are made by the “VR”certificate holder, the quality system

18


manual shall indicate the title of theperson(s) responsible for and describe thesystem used in the development, ap-proval and qualification of welding pro-cedure specifications, and the qualifica-tion of welders and welding operators inaccordance with the requirements of theASME Boiler and Pressure Vessel Code,Section IX. Similarly, NDE and heat treat-ment techniques must be covered in thequality system manual. When outside ser-vices are used for NDE and heat treat-ment, the quality system manual shalldescribe the system whereby the use ofsuch services meet the requirements of theapplicable section of the ASME Code.

k. Valve Testing, Setting and SealingThe system shall include provisions thateach valve shall be tested, set and all ex-ternal adjustments sealed according to therequirements of the applicable ASMECode section and the National Board. Theseal shall identify the “VR” certificateholder making the repair. Abbreviationsor initials shall be permitted, providedsuch identification is acceptable to theNational Board.

l. Valve Repair NameplatesAn effective valve stamping system shallbe established to ensure proper stampingof each valve as required by paragraphRA-2260. The manual shall include a de-scription of the nameplate or a drawing.

m. Calibration of Measurement and TestEquipment1. The calibration of measurement and

test gage system shall include theperiodic calibration of measuringinstruments and pressure gages.

2. Pressure gages used for setting valvesare to be checked periodically (indi-cate time schedule) by the person au-thorized (indicate title) in the depart-ment. The calibration standard used(master gage or dead weight tester) isto be indicated and results recorded.

3. All calibration standards shall be cali-brated against certified equipment

having known valid relationships tonationally recognized standards.

n. Manual ControlThe quality system shall include:

1. measures to control the issuance ofand revisions to the quality systemmanual;

2. provisions for a review of the systemin order to maintain the manualcurrent with these rules and theapplicable sections of the ASME Boilerand Pressure Vessel Code;

3. the title(s) of the individual(s) respon-sible for control, revisions and reviewof the manual;

4. provision of a controlled copy of thewritten quality system manual to besubmitted to the National Board.Revisions shall be submitted foracceptance by the National Boardprior to being implemented.

o. NonconformitiesThe system shall establish measures forthe identification, documentation, evalu-ation, segregation and disposition ofnonconformities. A nonconformity is acondition of any material, item, productor process in which one or more charac-teristics do not conform to the establishedrequirements. These may include, but arenot limited to, data discrepancies, proce-dural and/or documentation deficienciesor material defects. Also, the title(s) of theindividual(s) involved in this processshall be included.

p. ExhibitsForms used in the quality system shall beincluded in the manual with a writtendescription. Forms exhibited should bemarked SAMPLE and completed in amanner typical of actual valve repair pro-cedures.

q. Testing EquipmentThe system shall include a means to con-trol the development, addition or modi-


19

fication of testing equipment to ensure therequirements of RA-2281(b) are met.

RA-2258 ASME “V”, “HV” OR “UV”CERTIFICATE HOLDERS

a. A manufacturer holding a valid ASMECertificate of Authorization for use of anASME “V”, “HV” or “UV” Code symbolstamp, may obtain the “VR” Certificateof Authorization for the repair of pressurerelief valves covered by the ASME Cer-tificate of Authorization and which meetthe requirements of paragraph RA-2231.This can be accomplished without areview of the facilities, provided there isa written quality system to cover thescope of the repairs to be made and therepairs are carried out at the same loca-tion where the ASME valves are manu-factured. Unless the repaired valves aretested on the same facilities and to thesame procedures as new valves, two (2)repaired valves shall be selected by aNational Board representative for verifi-cation tests.

b. The initial Certificate of Authorizationshall be issued to expire concurrent withthe ASME Certificate of Authorization.Subsequent certificates shall be renewedupon a successful review and verificationof implementation of its quality systemby a National Board representative. Thisreview shall be performed concurrentlywith the ASME Certificate renewal re-view.

c. A manufacturer may also perform fieldrepairs of pressure relief valves coveredby the ASME Certificate of Authorizationprovided the provisions of paragraph RA-2272 are met.

d. Assemblers holding ASME Certificates ofAuthorization shall qualify for the “VR”Certificate of Authorization as requiredelsewhere in these rules.

e. The quality system manual shall be sub-mitted for review and acceptance by theNational Board.

f. In order for an ASME Code symbol stampholder to qualify for the National Board“VR” stamp, the following areas to thewritten quality system usually requireattention.

1. Statement of Authority andResponsibilityThis should clearly indicate that valverepairs are carried out in accordancewith the requirements and the rulesof the National Board and the qualitysystem manual. In addition, the scopeand type of valve repairs covered bythe manual should be indicated.

2. OrganizationUnless the functions which affect thequality of valve repairs are carried outby individuals other than thoseresponsible for manufacturing orassembly, it should not be necessaryto revise the organization chart.

3. General Quality FunctionsUsually quality system requirementsregarding valve repairs may be con-trolled in the same manner as forASME manufacturing or assembly,provided applicable shop and/orfield activities are covered. If this isthe case, the applicant for the “VR”stamp should include in its qualitysystem manual a separate section cov-ering valve repairs which referencesthe applicable section of the manual.For a more explicit explanation seeparagraph RA-2256, Written Descrip-tion of the Quality System.

RA-2260 NAMEPLATES

RA-2261 GENERAL

When a pressure relief valve is repaired, ametal repair nameplate stamped with theinformation required by paragraph RA-2262shall be permanently attached to the valveeither above, adjacent to or below the origi-nal stamping. If there is insufficient space on

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the valve for the repair nameplate to be per-manently attached, then a metal tag showingthe repair nameplate information may besecurely attached to the repaired valve. Seeparagraph RA-2245(b), for exception.

RA-2262 NAMEPLATE CONTENTS

a. As a minimum, the information on thevalve repair nameplate (see Appendix 2,Figure 5) shall include:

1. The name of the repair organizationpreceded by the words “repaired by”;

2. The “VR” repair symbol stamp andthe “VR” Certificate Number;

3. Unique identifier (e.g., repair serialnumber, shop order number, etc.);

4. Date of repair;

5. Set pressure;

6. Capacity (only when changed);

7. Type/Model Number (only whenchanged).

b. Changes to original pressure relief valvenameplate information:

1. If the set pressure is changed, the setpressure, capacity and blowdown, ifapplicable, on the original nameplateor stamping shall be marked out butleft legible. The new capacity shall bebased on that for which the valve wasoriginally certified.

2. If the service fluid is changed, the setpressure and capacity, including units,on the original nameplate or stamp-ing shall be marked out but left leg-ible. The new capacity shall be basedon that for which the valve was origi-nally certified, or if a conversionhas been made as described inRA-2242(b), on the capacity certifica-tion for the valve as converted.

3. If the type/model number is changed,the type/model number on the origi-

nal nameplate shall be marked out butleft legible.

RA-2263 ILLEGIBLE ORREPLACEMENT OFMISSING NAMEPLATES

RA-2264 ILLEGIBLE NAMEPLATES

When the information on the originalmanufacturer’s or assembler’s nameplate orstamping is illegible, the nameplate or stamp-ing will be augmented or replaced by a name-plate furnished by the “VR” stamp holderstamped “duplicate”. It shall contain allinformation which originally appeared on thenameplate or valve, as required by the appli-cable section of the ASME Code, except the“V”, “HV” or “UV” symbol and the NationalBoard mark. The repair organization’s name-plate, with the serialized “VR” stamp andother required data specified in paragraphRA-2262, will make the repairer responsibleto the owner and the jurisdiction that theinformation on the duplicate nameplate iscorrect.

RA-2265 MISSING NAMEPLATES

When the original valve nameplate is miss-ing, the repair organization is not authorizedto perform repairs to the valve under the“VR” program, unless positive identificationcan be made to that specific valve and verifi-cation that the valve was originally stampedwith an ASME “V” or “UV” symbol, ormarked with an ASME “HV” symbol. Valvesthat can be positively identified will beequipped with a duplicate nameplate as de-scribed in paragraph RA-2264, in addition tothe repairer’s “VR” stamped nameplate. Therepairer’s responsibilities for accurate data,as defined in paragraph RA-2264, shall ap-ply.

RA-2266 MARKING OF ORIGINALCODE STAMP

When a duplicate nameplate is affixed to avalve, as required by paragraph RA-2264 orRA-2265, it shall be marked “Sec. I”, “Sec. IV”


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or “Sec. VIII”, as applicable, to indicate theoriginal ASME Code stamping.

RA-2270 FIELD REPAIR

RA-2272 EXTENSION TO FIELD

Repair organizations may obtain a “VR” Cer-tificate of Authorization for field repair, ei-ther as an extension to their in-shop/plantscope or as a field only scope, provided that:

a. qualified technicians in the employ of thecertificate holder perform such repairs;

b. an acceptable quality system coveringfield repairs, including field audits, ismaintained;

c. all functions affecting the quality of therepaired valves are supervised from theaddress of record where the “VR” certifi-cation is issued.

RA-2273 AUDIT REQUIREMENTS

Upon issuance of a certificate of authoriza-tion, provided field repairs are performed,annual audits of the work carried out in thefield are performed to ensure that the require-ments of the certificate holder ’s qualitysystem are met. The audit shall include, butnot be limited to, performance testing, inaccordance with paragraph RA-2280, ofvalve(s) which were repaired in the field. Theaudits shall be documented.

RA-2274 USE OF OWNER-USERPERSONNEL

For the repair of pressure relief valves at anowner-user’s facility for the owner-user’sown use, the “VR” certificate holder mayutilize owner-user personnel to assist certifi-cate holder technician(s) in the performanceof repairs provided:

a. the use of such personnel is addressed inthe “VR” certificate holder ’s qualitysystem;

b. the owner-user personnel are trained andqualified in accordance with paragraphRA-2290;

c. owner-user personnel work under directsupervision and control of the “VR” cer-tificate holder’s technician(s) during anystage of the repair when they are utilized;

d. the “VR” certificate holder shall have theauthority to assign and remove owner-user personnel at its own discretion;

e. the names of the owner-user personnelutilized are recorded on the documentrequired by paragraph RA-2256(i).

RA-2280 PERFORMANCE TESTINGAND TESTINGEQUIPMENT

Each pressure relief valve to which the “VR”repair symbol stamp is to be applied shall besubjected to the following tests by the repaircertificate holder.

RA-2281 TEST MEDIUM ANDTESTING EQUIPMENT

a. Valves marked for steam service, or hav-ing special internal parts for steam ser-vice, shall be tested on steam. Valvesmarked for air, gas or vapor service shallbe tested with air or gas. Valves markedfor liquid service shall be tested withwater or other suitable liquid. Section IVhot water valves shall be tested on water,steam or air. Each valve shall be tested todemonstrate set pressure (as defined bythe valve manufacturer and as listed inNB-18), response to blowdown, if re-quired, and seat tightness in accordancewith the requirements of the applicablesections of the ASME Code.

b. The equipment used for the performancetesting prescribed by RA-2281(a) shallmeet the following requirements:

1. The performance testing equipmentshall include a pressure vessel of ad-equate volume and pressure source

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capacity to ensure compliance withRA-2281(a).

2. Prior to use, all performance testingequipment shall be qualified by theCertificate Holder to ensure that theequipment and testing procedureswill provide accurate results whenused within the ranges established forthat equipment. This qualificationmay be accomplished by bench marktesting, comparisons to equipmentused for verification testing (RA-2228)or comparisons to field performance.This qualification shall be docu-mented and provisions made to retainsuch documentation for a period of atleast five years after the testing equip-ment is retired. Documentation of thisqualification shall include but not belimited to:

a. schematic of the performance testequipment,

b. size and pressure ranges of valvesto be tested,

c. dimensions of test vessels,

d. accuracy of pressure measuringequipment,

e. size and design type of valvesused to control flow, and

f. method of qualifying.

3. Prior to the implementation of any ad-dition or modification to the testingequipment which would alter thecontents of the document required inRA-2281(b)(2), the Certificate Holdershall requalify the performance testequipment in accordance with RA-2281(b)(2). If the equipment changedwas used to satisfy the requirementsof verification testing, the CertificateHolder shall notify the National Boardand additional verification testing inaccordance with RA-2228 may berequired.

RA-2282 OWNER-USER SECTIONVIII STEAM TESTING

When ASME Section VIII valves are repairedby the owner for the owner’s own use, valvesfor steam service may be tested on air for setpressure and, if possible, blowdown adjust-ment, provided manufacturer’s correctionsfor differential in set pressure between steamand air are applied to the set pressure.

RA-2283 LIFT ASSIST TESTING

a. A device may be used to apply an auxil-iary lifting load on the spring of a repairedvalve to establish the set pressure in lieuof the tests required in paragraphRA2281(a) when such testing at fullpressure:

1. may cause damage to the valvebeing tested; or

2. is impractical when system designconsiderations preclude testing at fullpressure.

b. While actual valve blowdown and valveperformance characteristics cannot beverified, valve set pressure may be deter-mined to an acceptable degree of accuracyusing this testing technique, provided, asa minimum, that:

1. equipment utilized is calibrated asrequired in paragraph RA-2256(m);

2. the device and test procedures whichhave proved to give accurate resultsare used and followed;

3. a static inlet pressure is applied withthe test medium specified in para-graph RA-2281(a);

4. adjustments are made in accordancewith the valve manufacturer’s recom-mendations as to ensure proper liftand blowdown.


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RA-2290 TRAINING ANDQUALIFICATION OFPERSONNEL

RA-2291 GENERAL

It is essential that valve repair organizationsensure that their personnel engaged in repairsto pressure relief valves are knowledgeable,and qualified within the scope of the repairsto be conducted.

RA-2292 CONTENTS OF TRAININGPROGRAM

The repair organization shall establish a docu-mented in-house training program. This pro-gram shall establish training objectives andprovide a method of evaluating training ef-fectiveness. As a minimum, training objec-tives for knowledge level shall include:

a. applicable ASME Code and NBICrequirements;

b. responsibilities within the organ-ization’s quality system;

c. knowledge of the technical aspectsand mechanical skills for the appli-cable position held.

RA-2293 QUALIFICATION OFPERSONNEL

Each repair organization shall establish mini-mum qualification requirements for thosepositions within the organization as they di-rectly relate to pressure relief valve repair.Each repair organization shall document theevaluation and acceptance of an individual’squalification for the applicable position.

RA-2294 ANNUAL REVIEW OFQUALIFICATION

The repair organization shall annually reviewthe qualifications of repair personnel to verifyproficiency as well as compliance with thecertificate holder ’s quality system. Thisreview shall include training records, docu-mented evidence of work performed and,when necessary, monitoring job performance.The review shall be documented.

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RA-2300 “NR” ACCREDITATIONREQUIREMENTS

RA-2310 SCOPE

a. This section provides requirements thatmust be met for an organization to obtaina National Board Certificate of Authori-zation to use the “NR” Symbol Stamp forthe Repair, Modification or Replacementof Nuclear Components.

b. For further information contact:

Accreditation DepartmentThe National Board of Boiler and Pressure Vessel Inspectors1055 Crupper AvenueColumbus, OH 43229-1183

Phone: 614.888.8320Fax: 614.847.1828

c. The issuance of the “NR” stamp is notrestricted to organizations whose pri-mary business is to repair, modify or re-place nuclear components nor to manu-facturers or assemblers that hold anASME “N” type Code symbol stamp.Owners and users of nuclear componentsand other organizations that qualify inaccordance with these rules may also ob-tain the “NR” stamp.

RA-2320 PREREQUISITES FORISSUING A NATIONALBOARD “NR” CERTIFICATEOF AUTHORIZATION

Before an organization can obtain a NationalBoard “NR” Certificate of Authorization, theorganization shall:

a. have and maintain an Inspection Agree-ment with an Authorized Nuclear Inspec-tion Agency,

b. have a written Quality System Programthat complies with the requirements ofthis section and addresses controls for theintended scope of activities,

c. have a current edition of the NationalBoard Inspection Code, and

d. have available copies of the original codeof construction appropriate to theintended scope of work and ASMESection XI.

RA-2330 PROCEDURE FOROBTAINING ORRENEWING A NATIONALBOARD “NR” CERTIFICATEOF AUTHORIZATION

a. Prior to issuance or renewal of a NationalBoard “NR” Certificate of Authorization,the organization and its facilities are sub-ject to a review of its Quality System Pro-gram. The implementation of the QualitySystem Program shall be satisfactorilydemonstrated by the organization. TheNational Board reserves the absolute rightto cancel, refuse to issue, or renew suchauthorization. The National Board willreturn fees paid for the unexpired termof the certificate.

b. Organizations desiring to obtain aNational Board Certificate of Authoriza-tion shall apply to the National Boardusing forms obtained from the NationalBoard. Application for renewal shall bemade prior to the expiration date of theCertificate of Authorization. Applicationsmay be obtained from the National Board.

c. These procedures also apply to qualifiedorganizations that make repairs to ASMESection III “NV” pressure relief devices.An organization that holds a valid “NR”Certificate of Authorization shall, forthe purpose of these procedures, beknown as an authorized nuclear repairorganization.

d. Authorized Nuclear Inspection Agenciesand Inspectors referred to in these proce-dures shall meet the requirements of andhave been qualified and commissioned inaccordance with the provisions of theNational Board Rules for Commissioned In-spectors.

e. Repair, modification and replacementwork performed under the “NR” Certifi-cate of Authorization must be in accor-dance with the provisions of the NBIC,


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Section XI of the ASME Code, and therules of the jurisdiction.

f. Each authorized nuclear repair organiza-tion shall maintain a documentedQuality System Program which meets therequirements of RA-2360. The QualitySystem Program shall be commensuratewith the scope of the organization’sactivities and shall be acceptable to thejurisdiction, the Authorized NuclearInspection Agency and the NationalBoard.

g. Before an “NR” Certificate of Authoriza-tion will be issued or renewed, the appli-cant must have the Quality SystemProgram and the implementation of theprogram reviewed and found acceptableby representatives of the National Board,the jurisdiction and the AuthorizedNuclear Inspection Agency. If the appli-cant is an ASME “N” type certificate ofauthorization holder, has demonstratedwithin the last 12 months the implemen-tation of the quality program, and canverify by documentation that the organi-zation is capable of implementing itsquality program as being in compliancewith this part, a further verification imple-mentation by the survey team may not benecessary.

h. Applicants that do not hold valid ASME“N” type certificates of authorization shalldemonstrate, by documentation and ac-tual implementation, that they are capableof performing repair, replacement andmodification activities in accordance withthe requirements of Section XI and thescope of their application for an“NR”Certificate of Authorization.

i. For National Board authorization to re-pair ASME “NV”/”NB” stamped pres-sure relief devices, the applicant shallhold a valid “VR” Certificate of Authori-zation for the repair of ASME Section IIIpressure relief valves; and also meet theapplicable requirements for “NR” certifi-cation and Appendix 7.

When these requirements have been met,the applicant may be issued an “NR”

Certificate of Authorization which clearlyoutlines the scope of work for Section IIIpressure relief devices.

j. The jurisdiction will be the NationalBoard member jurisdiction in which theapplicant is located. If the implementationof the Quality System Program takesplace outside of the jurisdiction where theapplicant’s program was reviewed, theNational Board member in the jurisdic-tion where the implementation takesplace may participate in this portion ofthe survey. At the request of the jurisdic-tion, the National Board representativemay also act for said jurisdiction.

k. Where there is no National Board mem-ber jurisdiction, the applicant’s QualitySystem Program shall be acceptable torepresentatives of the National Board andthe Authorized Nuclear InspectionAgency.

l. The applicant shall request the NationalBoard to evaluate the Quality SystemProgram and implementation prior to theissuance of an “NR” Certificate of Autho-rization. The National Board, whenrequested through the appropriate form,will arrange for an evaluation of theapplicant’s Quality System Program. Theprogram will be evaluated on the basis ofits compliance with the National Boardrules for certification. The program shallbe adequate to control the scope of workfor which the applicant has applied. The“NR” Certificate of Authorization whichis issued shall specify the scope andlimits of work for which the applicant iscertified.

m. Revisions to the Quality System Programshall be acceptable to the AuthorizedNuclear Inspector Supervisor of theAuthorized Nuclear Inspection Agencybefore implementation.

n. The “NR” Certificate of Authorizationholder shall be subject to audit annuallyby the Authorized Nuclear InspectionAgency to assure compliance with theQuality System Program.

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National Board and will be promptlyreturned upon demand. If the organiza-tion discontinues the use of the “NR”Symbol Stamp or if the Certificate ofAuthorization has expired and no newcertificate has been issued, the “NR”Symbol Stamp shall be returned to theNational Board.

c. The organization’s Quality System Pro-gram shall provide for adequate controlof the “NR” Symbol Stamp. Provisionsmay be made for the issuance of the “NR”Symbol Stamp for use at various fieldlocations.

d. An organization shall not permit othersto use the “NR” Symbol Stamp loaned toit by the National Board.

RA-2350 QUALITY SYSTEMPROGRAM

A holder of a National Board Certificate ofAuthorization shall have and maintain a writ-ten Quality System Program. The system shallsatisfactorily meet the requirements of theNational Board Inspection Code, jurisdic-tional requirements and shall be available forreview. The Quality System Program may bebrief or voluminous, depending on the cir-cumstances. It shall be treated confidentiallyby the National Board.

RA-2360 OUTLINE OFREQUIREMENTS FOR AQUALITY SYSTEMPROGRAM FORQUALIFICATION FOR THENATIONAL BOARD “NR”SYMBOL STAMP

These rules set forth the requirements forplanning, managing and conducting QualitySystem Programs for controlling the qualityof activities performed during repairs, modi-fications or replacements of components andsystems in nuclear power plants within thescope of the applicable edition and addendaof Section XI of the ASME Code. These rulesare to be the basis for evaluating such pro-grams prior to the issuance of the NationalBoard “NR” Certificate of Authorization.

o. Upon notification of the review datesfrom the National Board, it is the respon-sibility of the organization to make ar-rangements for the review.

p. The Survey Team, as a minimum, shallconsist of one representative each fromthe National Board, Authorized NuclearInspection Agency and jurisdiction.

q. A recommendation to issue, renew, orwithhold the National Board Certificateof Authorization shall be included in aReport prepared by the Team. Thecompleted Report shall be forwarded tothe National Board.

r. If proper administrative fees are paid, andall other requirements are met, a Certifi-cate of Authorization will beissued evidencing permission to use the“NR” Symbol Stamp. The Certificate shallexpire on the triennial anniversary date.

s. When an organization holding a NationalBoard Certificate of Authorizationchanges ownership, name, or address, theNational Board shall be notified. The Cer-tificate of Authorization may be revisedby submitting an application for NationalBoard “NR” Certificate of Authorization.

t. The National Board may at any timechange the rules for the issuance of theCertificate of Authorization and use of the“NR” Symbol Stamp. These rules shallbecome binding on all certificate holders.

RA-2340 NATIONAL BOARD “NR”SYMBOL STAMP

a. All “NR” Symbol Stamps shall be ob-tained from the National Board of Boilerand Pressure Vessel Inspectors. Authori-zation to use the “NR” Symbol Stampmay be granted by the National Board atits absolute discretion.

b. The “NR” Symbol Stamp is furnished onloan by the National Board for a nominalfee. Each organization shall agree, ifauthorization to use the “NR” SymbolStamp is granted, that the “NR” SymbolStamp is at all times the property of the


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a. Organization1. The authority and responsibility of

those in charge of the Quality SystemProgram and activities affecting qual-ity shall be clearly established anddocumented. The person and organi-zation performing Quality Systemfunctions shall have sufficient andwell-defined responsibility, authority,and organizational freedom to:

a. identify Quality problems;

b. initiate action which results insolutions;

c. verify implementation of solu-tions to those problems;

d. control further processing, deliv-ery, or installation of a noncon-forming item, deficiency, or unsat-isfactory condition until properdisposition has been made.

2. The person and organization respon-sible for defining and for measuringthe overall effectiveness of theQuality System Program shall be des-ignated sufficiently independent fromthe pressure of production, have di-rect access to responsible manage-ment at a level where appropriate ac-tion can be required, and report regu-larly on the effectiveness of the pro-gram. Assurance of quality requiresmanagement measures which pro-vide that the individual or group as-signed the responsibility of inspec-tion, testing, checking, or otherwiseverifying that an activity has been cor-rectly performed, is independent ofthe individual or group directly re-sponsible for performing the specificactivity. The specific responsibilities ofthe Quality Assurance organization ofthe “NR” certificate holder shall in-clude the review of written proce-dures and monitoring of all activitiesconcerned with the Quality SystemProgram as covered in these rules.

b. Quality System Program1. Before becoming a holder of an “NR”

Certificate of Authorization, the ap-

plicant shall establish a Quality Sys-tem Program for the control of thequality of work to be performed. Theprogram shall define the organiza-tional structure within which theQuality System Program is to beimplemented and shall clearly delin-eate the responsibilities, levels of au-thority, and lines of communicationfor the various individuals involved.The program shall be documented indetail in a Quality System Manualwhich shall be a major basis for dem-onstration of compliance with theNational Board Inspection Code. Theapplicant’s Quality System Programshall be documented by written poli-cies, procedures, and instructions andshall be based on the organization’sscope of work to be performed.

2. The applicant’s program need not bein the same format or sequentialarrangement as the requirements inthese rules as long as all applicableprogram requirements have beencovered. The program shall providefor the accomplishment of activitiesaffecting quality under suitablycontrolled conditions. Controlled con-ditions include the use of appropri-ate equipment, suitable environmen-tal conditions for accomplishing theactivity and assurance that prerequi-sites for the activity have beensatisfied. The program shall take intoaccount the need for special controls,processes, test equipment, tools, andskills to attain the required qualityand need for the verification of qual-ity by inspection and test. The pro-gram shall provide for ready detectionof nonconforming material and itemsand for timely and positive correctiveactions.

3. The program shall provide for indoc-trination and training of personnelperforming activities affecting qualityas necessary to assure that suitableproficiency is achieved and main-tained. It shall be the responsibility ofthe “NR” certificate holder to assurethat all personnel performing qualityfunctions within the scope of these

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rules, including personnel of subcon-tracted services, are qualified as speci-fied in these rules. The assignment ofqualified personnel shall be at thediscretion of the “NR” certificateholder.

4. The “NR” certificate holder shall beresponsible for advising his Autho-rized Nuclear Inspection Agency ofany proposed changes to the QualitySystem Manual, and shall have accep-tance of the Authorized NuclearInspection Agency’s AuthorizedNuclear Inspector Supervisor beforeputting such changes into effect. Acurrent copy of the Quality SystemManual shall be made available to theAuthorized Nuclear Inspector by the“NR” certificate holder. The “NR”certificate holder shall be responsiblefor promptly notifying the Autho-rized Nuclear Inspector of such ac-cepted changes, including evidence ofacceptance by the Authorized NuclearInspection Agency.

5. The quality of all repairs, modifica-tions or replacements shall becontrolled at all points necessary toassure conformance with the require-ments of these rules and the “NR”certificate holder’s Quality SystemManual.

6. The certificate holder shall makeavailable to the Authorized NuclearInspector such drawings and processsheets as are necessary to make theQuality System Program intelligible.

c. Design ControlMeasures shall be established to assurethat applicable requirements of theowner’s design specifications are cor-rectly incorporated into the “NR” certifi-cate holder’s specifications, drawings,procedures, and instructions which maybe necessary to carry out the work. Themeasures shall include provisions toassure that appropriate quality standardsare specified and included in these docu-ments. Such documents shall be reviewed

for compliance with the owner’s designspecification and requirements of SectionXI of the ASME Code.

d. Procurement Document ControlDocuments for procurement of materials,items, and subcontracted services shallinclude requirements to the extent neces-sary to assure their compliance with theowner’s specifications and Section XI ofthe ASME Code. To the extent necessary,procurement documents shall requiresuppliers to maintain a Quality SystemProgram consistent with the applicablerequirements of the section of the ASMECode to which the items are constructed.Measures shall be established to assurethat all purchased material, items, andservices conform to these requirements.

e. Instructions, Procedures, and DrawingsActivities affecting quality shall be pre-scribed by documented instructions,procedures, or drawings of a type appro-priate to the circumstances and shall beaccomplished in accordance with theseinstructions, procedures, or drawings.Instructions, procedures, or drawingsshall include appropriate quantitative andqualitative criteria for determining thatactivities affecting quality have beensatisfactorily accomplished. The “NR”certificate holder shall maintain a writtendescription of the procedures used by hisorganization for control of quality andexamination, showing in detail the imple-mentation of the Quality System require-ments. Copies of these procedures shallbe readily available to the AuthorizedNuclear Inspector.

f. Document ControlThe program shall include measures tocontrol the issuance, use and dispositionof documents, such as specifications,instructions, procedures, and drawings,including changes thereto. These mea-sures shall assure that the latest applicabledocuments, including changes, arereviewed for adequacy and approved forrelease by authorized personnel and dis-tributed for use at the location where theprescribed activity is performed.


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g. Control of Purchased Material, Itemsand ServicesMeasures shall be established to assurethat all purchased material, items andservices conform to the requirements ofthe owner’s specifications and applicableedition and addenda of Section XI of theASME Code. These measures shallinclude identification for traceability andprovisions, as appropriate, for sourceevaluations, objective evidence of qualityfurnished by the supplier, examinationat the source, and examination upondelivery.

h. Identification and Control of Materialand Items1. Measures shall be established for

identification and control of materialand items, including partially fabri-cated assemblies. These measuresshall assure that identification ismaintained and traceable, either onthe material or component, or onrecords throughout the repair, modi-fication or replacement. These mea-sures shall be designed to prevent theuse of incorrect or defective items, andthose which have not received the re-quired examinations, tests, or inspec-tions.

2. Permanent or temporary unit identi-fication marks shall be applied usingmethods and materials which arelegible and not detrimental to thecomponent or system involved. Suchidentification shall be located in areasthat will not interfere with the func-tion or quality aspects of the item.

3. All characteristics required to be re-ported by the material specificationsshall appear on checklists and eachsuch characteristic shall be comparedwith the applicable acceptancestandard and the results recorded.Characteristics included on CertifiedMaterial Test Reports or Certificatesof Compliance need not be duplicatedin the checklists. Checklists shall pro-vide for a record that the Certified Ma-terial Test Reports and Certificates ofCompliance have been received,reviewed, and found acceptable.

When the results of the examinationor test procedure conducted by the“NR” certificate holder are necessaryto show compliance with materialspecification or other requirements,the checklists shall show the requiredrange of values.

i. Control of Processes1. The “NR” certificate holder shall

operate under a controlled systemsuch as process sheets, checklists,travelers, or equivalent procedures.Measures shall be established toassure that processes, such as weld-ing, nondestructive examination andheat treating, are controlled in accor-dance with the rules of the applicablesection of the ASME Code and areaccomplished by qualified personnelusing qualified procedures.

2. Process sheets, checklists, travelers orequivalent documentation shall beprepared, including the documentnumbers and revisions to which theprocess conforms, with spaceprovided for reporting results ofcompletion of specific operations atcheckpoints of repair, modification orreplacement.

j. Examinations, Tests, and Inspections1. In-process and final examinations and

tests shall be established to assureconformance with specifications,drawings, instructions, and proce-dures which incorporate or referencethe requirements and acceptancelimits contained in applicable designdocuments. Examination activities toverify the quality of work shall be per-formed by persons other than thosewho performed the activity beingexamined. Such persons shall notreport directly to the immediate su-pervisors responsible for the workbeing examined.

2. Process sheets, travelers, or checklistsshall be prepared, including the docu-ment numbers and revision to whichthe examination or test is to be per-formed, with space provided forrecording results.

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3. Mandatory hold points at whichwitnessing is required by the “NR”certificate holder’s representative orthe Authorized Nuclear Inspectorshall be indicated in the controllingdocuments. Work shall not proceedbeyond mandatory hold pointswithout the consent of the “NR”certificate holder’s representative orthe Authorized Nuclear Inspector, asappropriate.

k. Test Control1. Testing shall be performed in accor-

dance with the owner’s written testprocedures which incorporate orreference the requirements andacceptance limits contained in appli-cable design documents.

2. Test procedures shall include provi-sions for assuring that prerequisitesfor the given test have been met, thatadequate instrumentation is availableand used, and that necessary moni-toring is performed. Prerequisitesmay include calibrated instrumenta-tion, appropriate equipment, trainedpersonnel, condition of test equip-ment and the item to be tested, suit-able environmental conditions, andprovisions for data acquisition.

3. Test results shall be documented andevaluated to assure that test require-ments have been satisfied.

l. Control of Measuring and TestEquipmentMeasures shall be established and docu-mented to assure that tools, gages,instruments, and other measuring andtesting equipment and devices used inactivities affecting quality are of theproper range, type and accuracy to verifyconformance to established requirements.A procedure shall be in effect to assurethat they are calibrated and properlyadjusted at specified periods or use inter-vals to maintain accuracy within specifiedlimits. Calibration shall be traceable toknown, national standards.

m. Quality Records1. The owner is responsible for designat-

ing records to be maintained.Measures shall be established for the“NR” certificate holder to maintainthese records [see (2) following]required for Quality Assurance of re-pairs, modifications or replacements.These shall include documents suchas records of materials, manufactur-ing, examination, and test data takenbefore and during repair, modificationor replacement and the procedures,specifications, and drawings usedshall be fully identified by pertinentmaterial or item identificationnumbers, revision numbers, and issuedates. The records shall also includerelated data such as qualification ofpersonnel, procedures, equipment,and related repairs. The “NR” certifi-cate holder shall take such steps asmay be required to provide suitableprotection from deterioration anddamage for all records while in hiscare. These records may be either theoriginal or a reproduced, legible copyand shall be transferred to the ownerat his request.

2. Records to be maintained as requiredin (1) above may include the follow-ing:

a. an index to records in the file;

b. data reports, properly executed,for each replacement component,part, appurtenance, piping sys-tem, and piping assembly whenrequired by the design specifica-tion or the owner;

c. the required as-constructed draw-ings certified as to correctness;

d. copies of applicable CertifiedMaterial Test Reports;

e. as-built sketch including tabula-tions of materials;


31

f. nondestructive examination re-ports including results of exami-nations. These reports shall alsogive the name and SNT-TC-1Alevel of the nondestructive exami-nation personnel interpreting theexamination results. Final radio-graphs shall be included whereradiography has been performed;

g. records of all heat treatments.These records may be either theheat treatment charts or a sum-mary description of heat treat-ment time and temperature datacertified by the “NR” certificateholder. Heat treatments per-formed by the material manufac-turer to satisfy requirements of thematerial specifications may be re-ported on the Certified MaterialTest Report;

h. the completed Form NR-1 or FormNVR-1, as applicable.

3. After a repair, modification or replace-ment, all records including auditreports required to verify compliancewith the applicable engineeringdocuments and the “NR” certificateholder’s Quality System Program,except those required by the owner orlisted in (2)(a) through (g) above, shallbe maintained at a place mutuallyagreed upon by the owner and the“NR” certificate holder. These recordsshall be maintained for a period of fiveyears after completion of the repair,modification or replacement, but notless than two years after furthernormal operation of the plant.

4. The original and one legible copy ofthe completed Form NR-1 or FormNVR-1, as applicable, shall be for-warded to the National Board and thejurisdiction, if required.

n. Examination or Test StatusMeasures shall be established to indicateby the use of markings such as stamps,tags, labels, routing cards, or other suit-able means, the status of examinationsand tests performed upon individual

items. These measures shall provide forthe identification of those items whichconform to examination and test require-ments and those that do not conform.They shall also include procedures forcontrol of status indicators, including theauthority for application and removal ofaforesaid markings.

o. Nonconforming Materials or ItemsMeasures shall be established to controlmaterials or items which do not conformto requirements in order to prevent theirinadvertent use, including measures toidentify and control the proper installa-tion of items and to preclude nonconfor-mance with the requirements of theserules. These measures shall include pro-cedures for identification, documentation,segregation, and disposition. Noncon-forming items shall be reviewed foracceptance, rejection, or repair in accor-dance with documented procedures. Theresponsibility and authority for the dis-position of nonconforming items shall bedefined. Repaired or modified items shallbe reexamined in accordance with theapplicable procedures. Measures whichcontrol further processing of a noncon-forming or defective item, pending adecision on its disposition, shall be estab-lished and maintained. Ultimate disposi-tion of nonconforming items shall bedocumented.

p. Corrective Action1. Measures shall be established to

assure that conditions adverse toquality, such as failures, malfunctions,deficiencies, deviations, defectivematerial and equipment, and othernonconformances, are promptly iden-tified and corrected.

2. In the case of significant conditionsadverse to quality, the measures shallalso assure that the cause of these con-ditions be determined and correctedto preclude repetition. The identifica-tion of significant conditions adverseto quality, the cause and condition,and the corrective action taken shallbe documented and reported to theappropriate levels of management.

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3. The requirements shall also extend tothe performance of subcontractors’corrective action measures.

q. AuditsA comprehensive system of planned andperiodic audits shall be carried out by the“NR” certificate holder’s organization toassure compliance with the QualitySystem Program and to determine its ef-fectiveness. The audits shall be performedin accordance with written procedures orchecklists by personnel not having directresponsibilities in the areas being audited.Audit results shall be documented bythe auditing personnel for review bymanagement having responsibility in thatarea. Follow-up action, including re-audit of deficient areas, shall be takenwhere indicated. Audit results shall bemade available to the Authorized NuclearInspector.

r. Authorized Nuclear InspectorMeasures shall be taken to reference thecommissioned National Board Autho-rized Nuclear Inspector, qualified inaccordance with the National Board Rulesfor Commissioned Inspectors, to ensure thatthe latest documents including the Qual-ity System Program will be made avail-able to him. The Authorized Nuclear In-spector shall be consulted prior to the is-suance of a repair program inorder that he may select any inspectionor hold points in the program. He shallnot sign Form NR-1 or Form NVR-1, asapplicable, unless he is satisfied that allwork was carried out in accordance withthe NBIC, ASME Section XI and jurisdic-tional requirements.

RA-2370 INTERFACE WITH THEOWNER’S REPAIR,MODIFICATION, ORREPLACEMENT PROGRAM

Interface with the owner’s repair, modifica-tion or replacement program shall meet thefollowing:

a. The repair, modification and replacementprogram shall be subject to the acceptanceof the jurisdiction, and the owner’s ANII.

b. Repair, modification or replacement ofnuclear components shall meet the re-quirements of Section XI of the ASMECode and the jurisdiction where thenuclear power plant is located.

c. Documentation of the repair, modificationor replacement of nuclear componentsshall be recorded on the National BoardReport of Nuclear Repair, Modification orReplacement, Form NR-1 or Form NVR-1, as applicable. The completed formsshall be signed by a representative of theauthorized nuclear repair organizationand the Authorized Nuclear Inspector, ifthe repair, modification or replacementmeets the requirements of ASME SectionXI. For modifications, Form NR-1 or FormNVR-1, as applicable, shall indicate theresponsible organization accepting designresponsibility.

d. The authorized nuclear repair organiza-tion shall provide a copy of the signedForm NR-1 or Form NVR-1, as applicable,to the owner, the jurisdiction, and theAuthorized Nuclear Inspection Agency.The original and one legible copy of FormNR-1 or Form NVR-1, as applicable, shallbe filed with the National Board by theauthorized nuclear repair organization.

e. The authorized nuclear repair organiza-tion shall provide a nameplate/stampingfor each repaired, replaced, or modifiedcomponent unless otherwise required bythe Owner’s Quality System program.The required information and formatshall be as shown in Appendix 2.


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RA-3000 ACCREDITATION OFOWNER-USER INSPECTIONORGANIZATIONS

RA-3010 SCOPE

This section provides requirements for the ac-creditation of Owner-User InspectionOrganizations.

RA-3020 PREREQUISITES FORACCREDITATION

Before an organization can qualify as anOwner-User Inspection Organization, it shallmeet the following criteria:

a. It must be an organization that owns/operates pressure retaining items.

b. It must employ Inspectors, all of whichshall have a valid Owner-User commis-sion issued by the National Board.

c. It must have an organizational structureand inspection program that supports theinspection process.

d. It must meet the jurisdictional require-ments appropriate to the location.

e. It must have its inspection program andfacilities reviewed by the jurisdiction3.

f. It must have the current Edition of theNational Board Inspection Code.

RA-3030 PROCEDURE FOR OBTAININGOR RENEWING A NATIONALBOARD OWNER-USERCERTIFICATE

a. Prior to the issuance or renewal of aNational Board Owner/User Certificatethe organization and its facilities are sub-ject to a review of its Quality System. Theimplementation of the Quality System

must be satisfactorily demonstrated bythe organization. The National Board re-serves the right to cancel, refuse to issue,or renew such certificate.

b. Organizations desiring to obtain a Na-tional Board Owner-User Certificate shallapply to the National Board using formsobtained from the National Board. Appli-cations for renewal shall be made priorto the expiration date of the Certificate.

c. When an Owner-User Inspection Organi-zation has multiple facilities located inone or more jurisdictions or geographi-cal area, the organization shall submitseparate applications for each facility.

d. Upon notification of the review datesfrom the National Board, it is theresponsibility of the organization to makearrangements for the review.

e. The review shall be conducted by a repre-sentative of the jurisdiction.3

f. A recommendation to issue, renew orwithhold the National Board Owner-UserCertificate shall be included in a reviewreport. The completed review report shallbe forwarded to the National Board.

g. If proper administrative fees are paid, andall other requirements are met, an Owner-User Certificate will be issued. The Cer-tificate shall expire on the triennial anni-versary date.

h. The jurisdiction may audit the QualitySystem and the activities of the organiza-tion upon a valid request from an owner,user, inspection agency, or the NationalBoard.

i. The National Board Inspection CodeCommittee may at any time change therules for the issuance of Owner-User Cer-tificates. These rules become binding onall certificate holders.

3Jurisdiction: The National Board member jurisdiction where the organization is located. Alternatively, where thejurisdiction elects not to perform the review or where there is no jurisdiction the National Board ofBoiler and Pressure Vessel Inspectors will represent the jurisdiction. At the jurisdiction’s discretion,the jurisdiction may choose to be a member of the review team if the jurisdiction chooses not to be theteam leader.

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A holder of a National Board Owner-UserCertificate shall have and maintain a writtenQuality System. The System shall satisfacto-rily meet the requirements of the NationalBoard Inspection Code, and shall be availablefor review. The Quality System may be briefor voluminous, depending on the circum-stances. It shall be treated confidentially bythe National Board.

RA-3041 OUTLINE OFREQUIREMENTS FORQUALITY SYSTEM

The following is a guide to features of a Qual-ity System that shall be included in theorganization’s Quality System Manual. Eachorganization should address the features asneeded for the scope of work to be performed:

a. Title PageThe name and complete address of thecompany to which the National BoardOwner-User Certificate is issued shall beincluded on the Title Page of the QualitySystem Manual.

b. Contents PageThe manual should contain a page listingthe contents of the manual by subject,number (if applicable), and revisionnumber of each document.

c. Scope of WorkThe manual shall clearly indicate thescope and type of inservice and accep-tance inspections that the organization iscapable of and intends to perform on pres-sure retaining items owned or operatedby the organization. The locations wherethe inspections are to be performed shallbe identified.

d. Statement of Authority andResponsibilityA dated Statement of Authority, signed byan officer of the organization, shall beincluded in the manual. Further, the State-ment of Authority shall include:

1. The title of the Owner-User Inspectorwho will be responsible to maintainand implement the program.

2. A statement that, if there is a disagree-ment in the implementation of theQuality System, the matter is to be re-ferred to a higher authority in thecompany.

e. Manual ControlThe manual shall include the necessaryprovisions for revising and issuing docu-ments to maintain the manual current.The title of the individual authorized toapprove revisions shall be included in themanual.

f. Organization1. An organizational chart or description

of the organizational structure shall beincluded in the manual.

2. The manual shall identify those indi-viduals responsible for preparation,implementation, or verification of theQuality System. The responsibilitiesshall be clearly defined and the indi-viduals shall have the organizationalfreedom and authority to fulfill thoseresponsibilities.

g. Inspection Methods1. The method of developing, approving

and controlling the writtenprocess covering the inspection ofpressure retaining items including thescope of expected activity shall be in-cluded in the manual. The method forperforming and documenting inspec-tion activities shall be described insufficient detail to permit the owner-user inspector to determine at whatstages specific inspections are due tobe performed. The inspection meth-ods must have prior acceptance of theowner-user inspector.

2. A description of the process of autho-rizing and accepting repairs and/oralterations (including signing theNBIC report forms) if the owner-user


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inspection organization performssuch acceptance inspections on pres-sure retaining items owned and/oroperated by the organization.

h. CalibrationA description of the system for the cali-bration of examination, measuring andtest equipment used in performinginspection services.

i. ReportsThe manual shall indicate the title of theindividuals responsible for preparing,signing, distributing and maintaininginspection report forms or other docu-mentation.

j. ReportingA description of the process used by theowner-user inspector to take necessaryaction if an unsafe condition is encoun-tered and to resolve conflicts by referringto a higher authority of the organizationin accordance with RA-3041(d).

k. TrainingA description of a program that willensure that the owner-user inspector re-ceives proper and adequate training toperform assigned duties. Also, it shall in-clude a description of the process used toensure that individuals performing in-spection services, such as NDE, are quali-fied to perform the designated work.

l. Control of Contracted ServicesA description of the process for contract-ing and control of services such as NDEif applicable.

m. ExhibitsAny forms referenced in the manual shallbe included. The form may be a part ofthe referencing document or included asan appendix. For clarity, the forms maybe completed and identified as examples.

RA-3050 GENERAL CONDITIONS

a. An accredited Owner-User Inspection Or-ganization may perform inserviceinspections and certification of pressureretaining items owned/operated by thecompany.

b. An accredited Owner-User Inspection Or-ganization may perform authorization,in-process and acceptance inspections (in-cluding signing the NBIC report forms)associated with repairs and alterations ofpressure retaining items owned/operatedby the company. This includes repairs andalterations performed by the Owner-UserInspection Organization holding an “R”Certificate or by other “R” CertificateHolders performing work on pressure re-taining items owned/operated by theOwner-User Inspection Organization. Adescription of the process for performingthese inspections including the interfacewith the jurisdiction, must be included inthe written program.

c. An Owner-User Inspection Organizationmay also hold a National Board “R”Certificate, provided the Inspection Or-ganization complies with the accredita-tion requirements of that program, exceptthat the requirements of RA-2120(a) donot apply to an accredited Owner-User In-spection Organization when:

1. There is no conflict with jurisdictionalrequirements.

2. The scope of the “R” Certificate islimited to work on pressure retainingitems owned/operated by the Owner-User.

3. The line authority of the Owner-UserInspection Organization shall beindependent of the organization re-sponsible for the execution of the “R”program work.

4. The process is described in the writ-ten Owner-User quality systemmanual.

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37

PART RB — INSERVICE INSPECTION OF PRESSURE RETAINING ITEMS

Inservice Inspection ofPressure Retaining Items

Part RB

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PART RB — INSERVICE INSPECTION OF PRESSURE RETAINING ITEMSTABLE OF CONTENTS

RB-1000 General .............................................................................................................................. 40RB-1010 Scope ................................................................................................................................. 40

RB-2000 Personnel Safety .............................................................................................................. 41RB-2010 Scope ................................................................................................................................. 41RB-2020 Internal Inspections – Boilers ........................................................................................ 41RB-2030 Internal Inspection – Pressure Vessels ......................................................................... 42

RB-3000 Inspection Methods ........................................................................................................ 44RB-3010 Scope ................................................................................................................................. 44

RB-3100 Inspection of Boilers ....................................................................................................... 45RB-3110 General Conditions ......................................................................................................... 45RB-3120 Pre-Inspection Activities ................................................................................................ 45RB-3130 Assessment of Installation, Causes of Deterioration, Types of Defects .................. 45RB-3140 Evidence of Leakage ....................................................................................................... 46RB-3150 Inspection of Piping, Parts and Appurtenances ......................................................... 46RB-3160 Gages, Safety Devices and Controls ............................................................................. 49RB-3170 Records Review ............................................................................................................... 51RB-3180 Conclusions ...................................................................................................................... 51

RB-3200 Inspection of Pressure Vessels ....................................................................................... 52RB-3210 General Conditions ......................................................................................................... 52RB-3220 Pre-Inspection Activities ................................................................................................ 52RB-3230 Assessment of Installation ............................................................................................. 52RB-3240 Causes of Deterioration .................................................................................................. 59RB-3250 Inspection of Parts and Appurtenances ...................................................................... 62RB-3260 Gages, Safety Devices and Controls ............................................................................. 62RB-3270 Records Review ............................................................................................................... 63RB-3280 Conclusions ...................................................................................................................... 63

RB-3300 Inspection of Water Heaters Supplying Hot Water for Purposes OtherThan Space Heating ........................................................................................................ 64

RB-3310 General Conditions ......................................................................................................... 64RB-3320 Inspection of Parts and Appurtenances ...................................................................... 64RB-3330 Gages, Safety Devices and Controls ............................................................................. 64

RB-3400 Inspection of Piping Systems ........................................................................................ 65RB-3410 General Conditions ......................................................................................................... 65RB-3420 Precautions Before Conducting Inspection ................................................................. 65RB-3430 Assessment of Installation; Types of Defects .............................................................. 65RB-3440 Evidence of Leakage ....................................................................................................... 66RB-3450 Provisions for Expansion and Support ........................................................................ 66RB-3460 Gages, Safety Devices and Controls ............................................................................. 66RB-3470 Records Review ............................................................................................................... 66RB-3480 Conclusions ...................................................................................................................... 67

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RB-3500 Inspection of Safety Devices for Overpressure Protection ....................................... 68RB-3510 Scope ................................................................................................................................. 68RB-3520 Device Data ...................................................................................................................... 68RB-3530 Device Condition ............................................................................................................ 68RB-3540 Installation Condition..................................................................................................... 69RB-3550 Operational Inspection ................................................................................................... 69RB-3560 Recommended Test Frequencies ................................................................................... 70RB-3570 Additional Inspection Information .............................................................................. 71

RB-3600 Inspection of Deaerators ................................................................................................ 73RB-3610 General Conditions ......................................................................................................... 73RB-3620 Assessment of Installation; Causes of Deterioration; Types of Defects .................. 73RB-3630 Evidence of Leakage ....................................................................................................... 73RB-3640 Inspection of Parts and Appurtenances ...................................................................... 73RB-3650 Gages, Safety Devices and Controls ............................................................................. 74RB-3660 Records Review ............................................................................................................... 74RB-3670 Conclusions ...................................................................................................................... 74

RB-3700 Inspection of Liquid Ammonia Vessels ....................................................................... 75RB-3710 Scope ................................................................................................................................. 75RB-3720 Assessment of Installation, Causes of Deterioration ................................................. 75RB-3730 Evidence of Leakage ....................................................................................................... 75RB-3740 Inspection of Parts and Appurtenances ...................................................................... 75RB-3750 Gages and Safety Devices .............................................................................................. 76RB-3760 Records Review ............................................................................................................... 76RB-3770 Conclusions ...................................................................................................................... 76

RB-3800 Inspection of Pressure Vessels With Quick Actuating Closures .............................. 77RB-3810 Scope ................................................................................................................................. 77RB-3820 Assessment of Installation ............................................................................................. 77RB-3830 Evidence of Leakage ....................................................................................................... 77RB-3840 Inspection of Parts and Appurtenances ...................................................................... 77RB-3850 Gages, Safety Devices and Controls ............................................................................. 78RB-3860 Records Review ............................................................................................................... 79RB-3870 Conclusions ...................................................................................................................... 79

RB-4000 Restamping or Replacement of Stamped Data ........................................................... 80RB-4010 Scope ................................................................................................................................. 80RB-4020 ASME Stamped Items..................................................................................................... 80RB-4030 Other Items ...................................................................................................................... 80RB-4040 Reporting .......................................................................................................................... 80

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RB-1000 GENERAL

RB-1010 SCOPE

a. This part provides guidelines for inserviceinspection of pressure retaining items, in-cluding precautions for personal safety.The safety of the Inspector is the mostimportant aspect of any inspection activ-ity. Appropriately, this Part begins withrequirements for Inspector safety. Accept-able methods of inspecting a variety ofpressure retaining items are described in

detail. This Part concludes with a descrip-tion of the procedure for restamping orreplacing a nameplate.

b. Jurisdictional requirements describe thefrequency, scope, type of inspection,whether internal, external or both, andtype of documentation for the inspection.The Inspector should have a thoroughknowledge of these regulations.

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RB-2000 PERSONNEL SAFETY

RB-2010 SCOPEThe owner-user and Inspector shall deter-mine that the pressure retaining items maybe entered safely. This shall include:

a. potential hazards associated with entryinto the object have been identified by theowner-user and are brought to the atten-tion of the Inspector, along with accept-able means or methods for dealing witheach of these hazards;

b. coordination of entry into the object bythe Inspector and an owner-userrepresentative(s) working in or near theobject;

c. if personal protective equipment is re-quired to enter an object, the necessaryequipment is available, and the Inspec-tor is properly trained in its use;

d. an effective energy isolation program isin place and in effect that will prevent theunexpected energizing, start up or releaseof stored energy (lock out and/or tag out);

e. all applicable safety regulations areotherwise being followed. This includesapplicable governmental, state, regional,and/or local rules and regulations. Theowner-user programs or the Inspectors’employers’ safety programs or similarregulations also apply. In the absence ofsuch rules, prudent and generallyaccepted engineering safety proceduressatisfactory to the Inspector shall beemployed by the owner-user.

RB-2020 INTERNAL INSPECTION –BOILERS

a. When a boiler is to be prepared for inter-nal inspection, the water should not bewithdrawn until the setting has beensufficiently cooled at a rate to avoiddamage to the boiler.

b. The owner or user should prepare a boilerfor internal inspection in the followingmanner:

1. The fuel supply and ignition systemshall be locked out and/or tagged out,in accordance with the owner-user’sprocedures.

2. Water shall be withdrawn and thewaterside thoroughly washed.

3. Manhole and handhole plates, wash-out plugs, as well as inspection plugsin water column connections shall beremoved as required by the Inspector.The boiler shall be cooled andthoroughly cleaned.

4. Any leakage of steam or hot waterinto the boiler shall be prevented bydisconnecting the pipe or valve at themost convenient point or anyappropriate means approved by theInspector.

5. Before opening the manhole(s) andentering any part of a boiler which isconnected to a common header withother boilers, the required steam orwater system stop valves (includingbypass) must be closed, locked outand/or tagged out in accordance withthe owner-user ’s procedures, anddrain valves or cocks between the twoclosed stop valves opened. Afterdraining the boiler, the blowoff valvesshall be closed, locked out and/ortagged out in accordance with theowner-user’s procedures. Alterna-tively, lines may be blanked or sec-tions of pipe removed. Blowoff lines,where practicable, shall be discon-nected between pressure parts andvalves. All drains and vent lines shallbe open.

c. The Inspector shall not enter a boiler be-fore all safety precautions in (a) above

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have been taken. The Inspector shallensure that all free blow vent or drainvalves are open. The temperature of theboiler shall be such that the inspectingpersonnel will not be exposed toexcessive heat.

d. The Inspector shall be satisfied that asafe atmosphere exists before enteringeither the fire side or water side of a boiler.The Inspector shall not be permitted toenter an area containing toxic, flammableor inert gases, vapors or dusts withoutappropriate personal protective equip-ment. The oxygen content of the breath-able atmosphere shall be between 19.5%and 23.5%.

e. Personal protective equipment and cloth-ing must be worn as appropriate. Thismay include, among other items, protec-tive outer clothing, gloves, eye protection,and foot protection. The Inspector shallhave the proper training governing theselection and use of any personal protec-tive equipment necessary to safely per-form each inspection. Particular attentionshall be afforded respiratory protection ifthe testing of the atmosphere of the ob-ject reveals any of the hazards noted inparagraph (d) above.

f. If requested by the Inspector or requiredby regulation or applicable procedure, aresponsible person (“attendant”) shallremain outside the boiler at the point ofentry while the Inspector is inside andshall monitor activity inside and outsideand communicate with the Inspector asnecessary. The attendant shall have ameans of summoning rescue assistanceif needed and to facilitate rescue proce-dures for those inside the boiler withoutpersonally entering the boiler.

IF A BOILER HAS NOT BEEN PROP-ERLY PREPARED FOR AN INTERNALINSPECTION, THE INSPECTOR SHALLDECLINE TO MAKE THE INSPECTION.

RB-2030 INTERNAL INSPECTION –PRESSURE VESSELS

a. The owner-user should prepare a pres-sure vessel for internal inspection in thefollowing manner or as deemed necessaryby the Inspector. The requirements of theapplicable occupational safety and healthregulations (federal, state, local, or other),as well as the owner-user’s own programand the Inspector’s employer’s safetyprogram are also applicable.

b. When the vessel normally operates athigh temperature or low temperature (be-low -20˚F or -7˚C), the vessel shall be al-lowed to cool or warm at a rate to avoiddamage to the vessel.

c. The vessel shall be drained of all liquidand shall be purged of any toxic or flam-mable gases or other contaminants thatwere contained in the vessel. Mechanicalventilation using a fresh air blower or fanshall be started after the purging opera-tion and maintained until all pockets of“dead air” which may contain toxic, flam-mable or inert gas are eliminated. Duringair purging and ventilation of vesselsinvolved with flammable gases, the con-centration of vapor in air may passthrough the flammable range before a safeatmosphere is obtained. All necessary pre-cautions shall be taken to eliminate thepossibility of explosion or fire.

d. When a vessel is connected in a systemwhere there is the presence of liquid orgases, the vessel shall be isolated byclosing, locking and/or tagging stopvalves. When toxic or flammablematerials are involved, additional safetyprecautions may require removing pipesections or blanking pipelines beforeentering the vessel. The means ofisolating the vessel shall be acceptable tothe Inspector and in compliance withapplicable occupational safety and healthregulations and procedures.

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e. Prior to entering a vessel that containedtoxic or flammable gases or an inertatmosphere, the vessel atmosphereshall be tested by qualified personnelusing appropriate atmospheric testinginstruments.

f. Personal protective equipment and cloth-ing shall be worn as appropriate. Thismay include, among other items, protec-tive outer clothing, gloves, eye protection,and foot protection. The atmosphere ofthe vessel shall be tested to determine ifrespiratory protection is required. TheInspector shall have the proper traininggoverning the selection and use of anypersonal protective equipment necessaryto safely perform each inspection.

g. If requested by the Inspector or requiredby regulation or applicable procedure, aresponsible person (“attendant”) shallremain outside the vessel at the point ofentry while the Inspector is inside andshall monitor activity inside and outsideand communicate with the Inspector asnecessary. The attendant shall have ameans of summoning assistance if neededand to facilitate rescue procedures forthose inside the vessel without personallyentering the vessel.

IF A VESSEL HAS NOT BEEN PROP-ERLY PREPARED FOR AN INTERNALINSPECTION, THE INSPECTOR SHALLDECLINE TO MAKE THE INSPECTION.

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RB-3000 INSPECTION METHODS

RB-3010 SCOPE

This part describes acceptable inspectionmethods to be employed in the inspectionof pressure retaining items.

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RB-3100 INSPECTION OF BOILERS

RB-3110 GENERAL CONDITIONS

a. Boilers are designed for a variety of ser-vice conditions. The temperature andpressure at which they operate should beconsidered in establishing inspectioncriteria. This part is provided for guid-ance of a general nature. There may beoccasions where more detailed proce-dures will be required.

b. The condition of the complete installa-tion, including maintenance and opera-tion, can often be used by the Inspectoras a guide in forming an opinion of thecare given to the boiler.

c. Usually the conditions to be observed bythe Inspector are common to both powerand heating boilers, however, where ap-propriate, the differences are noted.

RB-3120 PRE-INSPECTIONACTIVITIES

a. A review of the known history of theboiler should be performed. This shouldinclude a review of information, such as:

1. Operating conditions

2. Date of last inspection

3. Current jurisdictional inspectioncertificate

4. ASME Code Symbol Stamping ormark of code of construction

5. National Board and/or jurisdictionregistration number

b. The following parts should be removedas required to permit the inspection:

1. Manhole and handhole plates

2. Washout plugs

3. Inspection plugs in water columnconnectors

4. Grates of internally fired boilers

5. Insulation and brickwork, as appro-priate

6. Pressure gage should be removed fortesting, unless there is other informa-tion to assess its accuracy.

c. The boiler shall be cooled and thoroughlycleaned.

RB-3130 ASSESSMENT OFINSTALLATION, CAUSESOF DETERIORATION,TYPES OF DEFECTS

RB-3131 ASSESSMENT OFINSTALLATION

The external inspection of a boiler is made todetermine if it is in a condition to operatesafely. Upon entering the boiler area, thegeneral cleanliness and accessibility of theboiler and its auxiliary apparatus should benoted. The boiler fittings, valves and pipingshould be checked for compliance with ASMECode or other standards or equivalentrequirements.

RB-3132 CAUSES OFDETERIORATION

Deterioration of boilers may be caused byimproper or inadequate water treatment,excessive fluctuations in pressure or tempera-ture, or improper or lack of maintenance.

RB-3133 TYPES OF DEFECTS

Defects may include bulged or blisteredplates, cracks or other defects in welds or heat-affected zones, pinhole leaks, improper orinadequate safety devices, wasted or erodedmaterial.

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RB-3140 EVIDENCE OF LEAKAGE

a. It is not normally necessary to remove in-sulating material, masonry, or fixed partsof a boiler for inspection unless defectsor deterioration are suspected or are com-monly found in the particular type ofboiler being inspected. Where there is evi-dence of leakage showing on the cover-ing, the Inspector should have the cover-ing removed in order that a thorough in-spection of the area may be made. Suchinspection may require removal ofinsulating material, masonry, or fixedparts of the boiler.

b. For additional information regarding aleak in a boiler or the extent of a possibledefect, a pressure test may be necessary.

1. To determine tightness, the test pres-sure need be no greater than the maxi-mum allowable working pressurestamped on the pressure retainingitem.

2. During a pressure test, where the testpressure will exceed the set pressureof a pressure relief device, the deviceshall be prepared as recommended bythe valve manufacturer.

3. The temperature of the water used toapply a pressure test should not beless than 70˚F (21˚C), and the maxi-mum temperature during inspectionshould not exceed 120˚F (49˚C).

4. Hold-time for the pressure test shallbe 10 minutes prior to the examina-tion by the Inspector.

5. Hold-time for the examination by theInspector shall be the time necessaryfor the Inspector to conduct theinspections.

6. When the introduction of water for ahydrostatic test will cause damage toa boiler or boiler component, othertesting media or vacuum testing may

be used provided the precautionaryrequirements of the applicable sectionof the original code of construction orother standards are followed. In suchcases, there shall be agreement as tothe testing procedure between theowner and the Inspector.

RB-3150 INSPECTION OF PIPING,PARTS ANDAPPURTENANCES

RB-3151 PIPING

Piping should be inspected in accordancewith RB-3400.

RB-3152 WATERSIDE DEPOSITS

a. All accessible surfaces of the exposedmetal on the waterside of the boilershould be inspected for deposits causedby water treatment, scale, oil, or othersubstances. Oil or scale in the tubes ofwatertube boilers or on plates over the fireof any boiler is particularly detrimentalsince this can cause an insulating effectresulting in overheating, weakening andpossible metal failure by bulging orrupture.

b. Any excessive scale or other depositsshould be removed by chemical ormechanical means.

RB-3153 STAYS

a. All stays, whether diagonal or through,should be examined to determinewhether or not they are in even tension.The stayed plates should be examined todetermine whether cracks exist wherethey are punched or drilled for the staysor staybolts. Stays or staybolts which arenot in tension or adjustment should berepaired. Broken stays shall be replaced.

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b. The Inspector should test firebox stayboltsby tapping one end of each bolt with ahammer and, where practicable, a ham-mer or other heavy tool should be heldon the opposite end to make the test moreeffective. An unbroken bolt should give aringing sound while a broken bolt willgive a hollow sound. Staybolts with tell-tale holes should be examined forevidence of leakage which willindicate a broken or cracked bolt. Brokenstaybolts shall be replaced.

RB-3154 FLANGED AND OTHERCONNECTIONS

a. The manhole and reinforcing plates, aswell as nozzles or other connectionsflanged or bolted to the boiler should beexamined for evidence of defects bothinternally and externally. Wheneverpossible, observation should be madefrom the inside of the boiler as to whetherconnections are properly made to theboiler.

b. All openings leading to external attach-ments, such as water column connections,low water fuel cutoff devices, openingsin dry pipes, and openings to safetyvalves, should be examined to ensure theyare free from obstruction.

RB-3155 BULGES AND BLISTERS

a. A bulge may be caused by overheating ofthe entire thickness of the metal, therebylowering the strength of the metal whichis then deformed by the pressure in theboiler. Bulges may also be caused by creepor temperature gradients.

b. A blister may be caused by a defect in themetal such as a lamination where the sideexposed to the fire overheats but theinner side retains its strength due to thecooling effect of the boiler water.

RB-3156 OVERHEATING

a. Overheating is one of the most seriouscauses of boiler deterioration. Deforma-tion and possible rupture of pressureparts such as tubes may result. Tubes maybecome damaged by poor circulation,steam binding, or deposition of scale.

b. Particular attention should be given to theplate or tube surfaces exposed to the fire.It should be observed whether any partof the boiler has become deformed dueto bulging or blistering. If a bulge or blis-ter is large enough to weaken the plate ortube, or when evidence of leakage is notedcoming from those defects, proper repairsmust be made. The blistered area shouldbe removed, the remaining thickness de-termined and repairs made as required.A bulge on a water tube should alwaysbe repaired. A bulge on a plate, if not ex-tensive, may be driven back into place,otherwise the affected areas should berepaired with a flush patch.

RB-3157 CRACKS

a. Cracks may result from flaws existing inmaterial. The design and operatingconditions may also cause cracking.Cracking can be caused by fatigue of themetal due to continual flexing and maybe accelerated by corrosion. Fire cracksare caused by the thermal differentialwhen the cooling effect of the water is notadequate to transfer the heat from themetal surfaces exposed to the fire. Somecracks result from a combination of allthese causes mentioned.

b. Cracks noted in shell plates should berepaired.

1. Fire cracks that run from the edge ofthe plate into the rivet holes of girthseams, and

48


2. Thermal fatigue cracks determinedby engineering evaluation to be selfarresting may be left in place.

c. Areas where cracks are most likely to ap-pear should be examined. This includesthe ligaments between the tube holes inwatertube boiler drums, between the tubeholes on the tube sheet of firetube boil-ers, from and between rivet holes, at anyflange where there may be repeatedflexing of the plate during operation andaround welded pipe and tube connec-tions.

d. Lap joint boilers are subject to crackingwhere the plates lap in the longitudinalseam. If there is any evidence of leakageor other distress at this point, the Inspec-tor should thoroughly examine the areaand, if necessary, have the plate notchedor slotted in order to determine whethercracks exist in the seam. Repairs of lapjoint cracks on longitudinal seams areprohibited.

e. Where cracks are suspected, it may benecessary to subject the boiler to non-destructive examination to determinetheir location.

RB-3158 CORROSION

a. Corrosion causes deterioration of themetal surfaces. It can affect large areas orit can be localized in the form of pitting.Isolated, shallow pitting is not consideredserious if not active.

b. The most common causes of corrosion inboilers are the presence of free oxygen anddissolved salts in the feedwater. Whereactive corrosion is found, the Inspectorshould advise the owner or user to ob-tain competent advice regarding properfeedwater treatment.

c. For the purpose of estimating the effectof severe corrosion over large areas on thesafe working pressure, the thickness of the

remaining sound metal should be deter-mined by ultrasonic examination or bydrilling.

d. Grooving is a form of metal deteriorationcaused by localized corrosion and may beaccelerated by stress concentration. Thisis especially significant adjacent to rivetedjoints.

e. All flanged surfaces, should be inspected,particularly the flanges of unstayedheads. Grooving in the knuckles of suchheads is common since there is slightmovement in heads of this design whichcauses a stress concentration.

f. Some types of boilers have ogee orreversed-flanged construction which isprone to grooving and may not be readilyaccessible for examination. The Inspectorshould insert a mirror through an inspec-tion opening to examine as much area aspossible. Other means of examinationsuch as the ultrasonic method may be em-ployed.

g. Grooving is usually progressive andwhen it is detected, its effect should becarefully evaluated and corrective actiontaken.

h. The fireside surfaces of tubes in horizon-tal firetube boilers usually deterioratemore rapidly at the ends nearest the fire.The Inspector should examine the tubeends to determine if there has beenserious reduction in thickness. The tubesurfaces in some vertical tube boilers aremore susceptible to deterioration at theupper ends when exposed to the heat ofcombustion. These tube ends should beclosely examined to determine if there hasbeen a serious reduction in thickness. Theupper tube sheet in a vertical “dry top”boiler should be inspected for evidenceof overheating.

i. Pitting and corrosion on the watersidesurfaces of the tubes should be examined.In vertical firetube boilers excessive cor-

49


rosion and pitting is often noted at andabove the water level. Excessive scale onwaterside surfaces should be removedbefore the boiler is placed back in service.

j. The surfaces of tubes should be carefullyexamined to detect corrosion, erosion,bulges, cracks, or evidence of defectivewelds. Tubes may become thinned byhigh velocity impingement of fuel and ashparticles or by the improper installationor use of soot blowers. A leak from a tubefrequently causes serious corrosion orerosion on adjacent tubes.

k. In restricted fireside spaces, such as whereshort tubes or nipples are used to joindrums or headers, there is a tendency forfuel and ash to lodge at junction points.Such deposits are likely to cause corro-sion if moisture is present and the areashould be thoroughly cleaned and exam-ined.

RB-3159 MISCELLANEOUS

a. The piping to the water column shouldbe carefully inspected to ensure thatwater cannot accumulate in the steamconnection. The position of the water col-umn should be checked to determine thatthe column is placed in accordance withASME Code or other standard or equiva-lent requirements.

b. The gas side baffling should be inspected.The absence of the proper baffling or de-fective baffling can cause high tempera-tures and overheat portions of the boiler.The location and condition of combustionarches should be checked for evidence offlame impingement which could result inoverheating.

c. Any localization of heat caused byimproper or defective installation orimproper operation of firing equipmentshould be corrected before the boiler isreturned to service.

d. The supports and settings should be care-fully examined, especially at points wherethe boiler structure comes near the settingwalls or floor, to ensure that deposits ofash or soot will not bind the boiler andproduce excessive strains on the structuredue to the restriction of movement of theparts under operating conditions.

e. When tubes have been rerolled orreplaced, they should be inspected forproper workmanship. Where tubes arereadily accessible, they may have beenover rolled. Conversely, when it is diffi-cult to reach the tube ends they may havebeen under rolled.

RB-3160 GAGES, SAFETY DEVICESAND CONTROLS

RB-3161 GAGES

a. Ensure that the water level indicated iscorrect by having the gage tested as fol-lows:

1. Close the lower gage glass valve, thenopen the drain cock and blow theglass clear.

2. Close the drain cock and open thelower gage glass valve. Water shouldreturn to the gage glass immediately.

3. Close the upper gage glass valve, thenopen the drain cock and allow thewater to flow until it runs clean.

4. Close the drain cock and open theupper gage glass valve. Water shouldreturn to the gage glass immediately.

b. If the water return is sluggish, the opera-tion should be repeated. A sluggishresponse could indicate an obstruction inthe pipe connections to the boiler. Anyleakage at these fittings should bepromptly corrected to avoid damage tothe fittings or a false waterline indication.

50


c. Each hot water boiler should be fittedwith a temperature gage at or near theboiler outlet that will at all times indicatethe water temperature.

d. Where required, all the pressure gagesshall be removed, tested and their read-ings compared to the readings of astandard test gage or a dead weight tester.

e. The location of a steam pressure gageshould be noted to determine whether itis exposed to high temperature from anexternal source or to internal heat due tolack of protection by a proper siphon ortrap. The Inspector should check thatprovisions are made for blowing out thepipe leading to the steam gage.

f. The pressure indicated on the pressuregage should be compared with othergages on the same system or with a stan-dard test gage, if necessary. The Inspec-tor should observe the reading duringtests; for example, the reduction in pres-sure when testing the low water fuel cut-off control or safety valve on steam boil-ers. Defective gages should be promptlyreplaced.

RB-3162 SAFETY DEVICES

See Section RB-3500 for the inspection ofsafety devices (pressure relief valves) used toprevent the overpressure of boilers.

RB-3163 CONTROLS

a. Verify operation of low water protectiondevices by observing the blowdown ofthese controls or the actual lowering ofboiler water level under carefullycontrolled conditions with the burneroperating. These tests should shut off theheat source to the boiler. The return tonormal condition such as the restart of theburner, the silencing of an alarm or stop-ping of a feed pump, should be noted. A

sluggish response could indicate anobstruction in the connections to theboiler.

b. The operation of a submerged low waterfuel cutoff control mounted directly in asteam boiler shell should be tested bylowering the boiler water level carefully.This should be done only after beingassured that the water level gage isindicating correctly.

c. On a high-temperature water boiler it isoften not possible to test the control bycutoff indication, but where the control isof the float type externally mounted, thefloat chamber should be drained to checkfor the possible accumulation of sedi-ment.

d. In the event that controls are inoperativeor the correct water level is not indicated,the boiler should be taken out of serviceuntil the unsafe condition has beencorrected.

e. All automatic low water fuel cutoff andwater feeding devices should be exam-ined by the Inspector to ensure that theyare properly installed. The Inspectorshould have the float chamber types ofcontrol devices disassembled and the floatlinkage and connections examined forwear. The float chamber should be exam-ined to ensure that it is free of sludge orother accumulation. Any necessarycorrective action should be taken beforethe device is placed back into service. TheInspector should check that the operatinginstructions for the devices are readilyavailable.

f. Check that the following controls areprovided:

1. Each automatically fired steam boileris protected from over pressure by notless than two pressure operatedcontrols, one of which may be anoperating control.

51


2. Each automatically fired hot waterboiler is protected from over-tempera-ture by not less than two temperatureoperated controls, one of which maybe an operating control.

3. Each hot water boiler is fitted with athermometer that will at all timesindicate the water temperature at ornear the boiler outlet.

RB-3170 RECORDS REVIEW

a. A review of the boiler log, records ofmaintenance and feedwater treatmentshould be made by the Inspector to en-sure that regular and adequate tests havebeen made on the boiler and controls.

b. The owner or user should be consultedregarding repairs or alterations, if any,which have been made since the lastinspection. Such repairs or alterationsshould be reviewed for compliance withthe applicable requirements.

RB-3180 CONCLUSIONS

a. During all tests the actual operating andmaintenance practices should be noted bythe Inspector and a determination madeas to their acceptability.

b. Any defects or deficiencies in the condi-tion, operating and maintenance practicesof the boiler and auxiliary equipmentshould be discussed with the owner oruser at this time and recommendationsmade for correction.

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RB-3200 INSPECTION OF PRESSUREVESSELS


Pressure vessels are designed for a variety ofservice conditions. The media that a pressurevessel contains and the temperature andpressure at which it operates should beconsidered in establishing inspection criteria.This part is provided for guidance of ageneral nature. There may be occasions wheremore detailed procedures will be required.

RB-3220 PRE-INSPECTIONACTIVITIES

a. A review of the known history of thepressure vessel should be performed. Thisshould include a review of information,such as:

1. Operating conditions

2. Normal contents of the vessel

3. Date of last inspection

4. Current jurisdictional inspectioncertificate

5. ASME Code Symbol Stamping ormark of code of construction

6. National Board and/or jurisdictionalregistration number

7. Records of wall thickness checks, es-pecially on vessels where corrosion isa consideration

b. The following activities should beperformed as required to support theinspection:

1. Inspection plugs and covers should beremoved.

2. Vessel should be sufficiently cleanedto allow for visual inspection of inter-nal and external surfaces.

3. Pressure relief devices, see RB-3500.


The type of inspection given to pressurevessels should take into consideration thecondition of the vessel and the environmentin which it operates. This inspection may beeither external or internal, and use a varietyof nondestructive examination methods. Theinspection method may be performed whenthe vessel is operating on-stream or depres-surized, but shall provide the necessaryinformation that the essential sections of thevessel are of a condition to continue tooperate for the expected time interval. On-stream inspection, including while underpressure, may be used to satisfy inspectionrequirements provided the accuracy of themethod can be demonstrated.

RB-3231 EXTERNAL INSPECTION

The purpose of an external inspection is toprovide information regarding the overallcondition of the pressure vessel. Thefollowing should be reviewed:

a. Insulation or Other CoveringsIf it is found that external coverings suchas insulation and corrosion resistantlinings are in good condition and there isno reason to suspect any unsafe conditionbehind them, it is not necessary to removethem for inspection of the vessel. How-ever, it may be advisable to remove smallportions of the coverings in order toinvestigate their condition and the con-dition of the metal.

53


b. Evidence of LeakageAny leakage of gas, vapor or liquidshould be investigated. Leakage comingfrom behind insulation coverings, sup-ports or settings, or evidence of past leak-age should be thoroughly investigated byremoving any covering necessary untilthe source is established.

c. Structural AttachmentsThe pressure vessel mountings should bechecked for adequate allowance forexpansion and contraction, such asprovided by slotted bolt holes or unob-structed saddle mountings. Attachmentsof legs, saddles, skirts or other supportsshould be examined for distortion orcracks at welds.

d. Vessel ConnectionsManholes, reinforcing plates, nozzles orother connections should be examined forcracks, deformation or other defects. Boltsand nuts should be checked for corrosionor defects. Weep holes in reinforcingplates should remain open to provide vi-sual evidence of leakage as well as to pre-vent pressure build up between the ves-sel and the reinforcing plate. Accessibleflange faces should be examined for dis-tortion and to determine the condition ofgasket-seating surfaces.

e. Miscellaneous Conditions1. ABRASIVES – The surfaces of the

vessel should be checked for erosion.

2. DENTS – Dents in a vessel are defor-mations caused by their coming incontact with a blunt object in such away that the thickness of metal is notmaterially impaired. In some cases, adent can be repaired by mechanicallypushing out the deformation.

3. DISTORTION – If any distortion issuspected or observed, the overalldimensions of the vessel shall bechecked to determine the extent andseriousness of the distortion.

4. CUTS OR GOUGES – Cuts or gougescan cause high stress concentrationsand decrease the wall thickness.Depending upon the extent of the de-fect, it may be necessary to repair thearea by welding or patching. Blendgrinding may be a useful method ofeliminating some minor types of cutsor gouges.

5. SURFACE INSPECTION – Thesurfaces of shells and heads should beexamined for possible cracks, blisters,bulges, and other evidence of deterio-ration, giving particular attention tothe skirt and to support attachmentand knuckle regions of the heads.

6. WELD JOINTS – Welded joints andthe adjacent heat affected zonesshould be examined for cracks orother defects. Magnetic particle or liq-uid penetrant examination is a usefulmeans for doing this.

7. RIVETED VESSELS – On riveted ves-sels, examine rivet head, butt strap,plate and caulked edge conditions. Ifrivet shank corrosion is suspected,hammer testing or spot radiographyat an angle to the shank axis may beuseful.

RB-3232 INTERNAL INSPECTION

a. A general visual inspection is the first stepin making an internal inspection. All partsof the vessel should be inspected forcorrosion, erosion, hydrogen blistering,deformation, cracking and laminations.

b. The following should be reviewed:

1. Vessel ConnectionsThreaded connections should beinspected to ensure that an adequatenumber of threads are engaged. Allopenings leading to any external fit-tings or controls should be examined

54


as thoroughly as possible to ensurethey are free from obstructions.

2. Vessel ClosuresAny special closures including thoseon autoclaves, normally termed quickactuating (quick opening) closures(RB-3800) which are used frequentlyin the operation of a pressure vessel,should be checked by the Inspector foradequacy and wear. A check shouldalso be made for cracks at areas ofhigh stress concentration.

3. Vessel InternalsWhere pressure vessels are equippedwith removable internals, theseinternals need not be completelyremoved, provided assurance existsthat deterioration in regions renderedinaccessible by the internals is notoccurring to an extent that might con-stitute a hazard or to an extent beyondthat found in more readily accessibleparts of the vessel.

If a preliminary inspection reveals un-safe conditions such as loose or cor-roded internals or badly corroded in-ternal ladders or platforms, stepsshould be taken to remove or repairsuch parts so that a detailed inspec-tion may be made.

4. CorrosionThe type of corrosion (pitted or uni-form), its location and any obviousdata should be established. Datacollected for vessels in similar servicewill aid in locating and analyzingcorrosion in the vessel beinginspected. The liquid level lines, thebottom and the shell area adjacent toand opposite inlet nozzles are oftenlocations of most severe corrosion.Welded seams and nozzles and areasadjacent to welds are often subjectedto accelerated corrosion.

RB-3233 NONDESTRUCTIVEEXAMINATION (NDE)

Listed below are a variety of methods thatmay be employed to assess the conditionof the pressure vessel. These examinationmethods should be implemented byexperienced and qualified individuals.Generally, some form of surface preparationwill be required prior to the use of theseexamination methods: magnetic particle,liquid penetrant, ultrasonic, radiography,eddy current, visual, metallographic exami-nation, and acoustic emission. When there isdoubt as to the extent of a defect or detrimen-tal condition found in a pressure vessel, theInspector may require additional NDE.

RB-3234 PRESSURE TESTING

a. A pressure test normally need not bemade as part of a periodic inspection.However, a test shall be made when in-spection discloses unusual, hard to evalu-ate forms of deterioration that may affectthe safety of the vessel. A pressure testmay also be necessary after certain repairsand alterations.

b. To determine tightness, the test pressureneed be no greater than the set pressureof the pressure relief valve having thelowest setting.

c. The pressure test shall not exceed 1-1/2times the maximum allowable workingpressure adjusted for temperature. Whenthe original test pressure includes consid-eration of corrosion allowance, the testpressure may be further adjusted basedupon the remaining corrosion allowance.

d. During a pressure test, where the testpressure will exceed the set pressure of apressure relief device, the device shall beprepared as recommended by the valvemanufacturer.

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e. The metal temperature during a pressuretest should not be less than 60°F (15.6°C)unless the owner provides information onthe toughness characteristics of the ves-sel material to indicate the acceptabilityof a lower test temperature.

f. The metal temperature is not to be morethan 120°F (49°C) unless the owner speci-fies the requirement for a higher test tem-perature. If the test is conducted at 1-1/2times the MAWP and/or the owner speci-fies a temperature higher than 120°F(49°C), the pressure should be reduced tothe MAWP and the temperature to 120°F(49°C) for close examination.

g. When contamination of the vessel con-tents by any other medium is prohibitedor when a hydrostatic test is not practi-cal, other testing media may be used pro-viding the precautionary requirements ofthe applicable section of the original con-struction code or other standards are fol-lowed. In such cases, there shall be agree-ment as to the testing procedure betweenthe owner and the Inspector.

RB-3235 REMAINING LIFE ANDINSPECTION INTERVALS

New pressure vessels are placed in service tooperate under their design conditions for aperiod of time determined by the service con-ditions and the corrosion rate. If the pressurevessel is to remain in operation, the allow-able conditions of service and the length oftime before the next inspection shall be basedon the conditions of the vessel as determinedby the inspection.

RB-3236 REMAINING LIFECALCULATION

a. Where the corrosion rate controls the lifeof the pressure vessel, the remaining lifeshall be calculated by the followingformula:

t(actual)- t(required)Remaining life (years)=

corrosion rate

WHERE:t(actual) = thickness in inches (mm)

measured at the time ofinspection for the limiting sectionused in the determination oft(required).

t(required) = minimum allowable thickness ininches (mm) for the limiting sec-tion of the pressure vessel or zone.It shall be the higher of the follow-ing:1. The calculated thickness, ex-

clusive of the corrosion allow-ance, required for the pressurerelieving device set pressure,static head or other loading,and design temperature or

2. The minimum thickness per-mitted by the provision of theapplicable section of the origi-nal code of construction.

CorrosionRate = inches (mm) per year of metal re-

moval as a result of corrosion.

b. For new pressure vessels or vessels forwhich service conditions are beingchanged, one of the following methodsshall be employed to determine the prob-able rate of corrosion from which theremaining wall thickness, at the time ofthe next inspection, can be estimated:

1. the corrosion rate as established bydata collected by the owner or useron pressure vessels in the same orsimilar service;

2. if data for the same or similar serviceare not available, the corrosion rateas estimated from the Inspector’sknowledge and experience withpressure vessels in similar service;

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3. if the probable corrosion rate cannotbe determined by either of theabove methods, on-stream thicknessdeterminations shall be made afterapproximately 1,000 hours of service.Subsequent sets of thickness measure-ments shall be taken after additionalsimilar intervals until the corrosionrate is established.

RB-3237 INSPECTION INTERVAL

The maximum period between internal in-spections or a complete on-stream evaluationof pressure vessels shall not exceed one-halfof the estimated remaining life of the vesselor ten years, whichever is less. Where the re-maining operating life is less than four years,the inspection interval may be the full remain-ing safe operating life up to a maximum oftwo years.

RB-3238 CONDITIONS THATAFFECT REMAINING LIFEEVALUATION

There are a variety of conditions that mayaffect the remaining life of a pressure vessel.These should be evaluated and the inspectioninterval reviewed for possible adjustment.The common conditions are listed below:

a. DeteriorationThis includes bulging, sagging, stress cor-rosion cracking, creep rupture, thermal ormechanical fatigue, hydrogen blistering,high temperature hydrogen attack,carburization, graphitization or erosion.Deterioration may also be caused bymechanical forces such as thermal shock,cyclic temperature changes, vibration,pressure surges, excessive temperature,external loading, and faulty material andfabrication.

b. Corrosion Rate Not a ConsiderationWhen the corrosion rate of a pressurevessel is known to be zero, the vessel need

not be inspected internally provided allof the following conditions are met andcomplete external inspections, includingthickness measurements, are madeperiodically on the vessel:

1. The noncorrosive character of thecontent, including the effect of tracecomponents, has been established byat least five years comparable serviceexperience with the fluid beinghandled.

2. No questionable condition is dis-closed by the periodic external inspec-tion.

3. The operating temperature of thepressure vessel does not exceed thelower limits for the creep rupturerange of the vessel metal. (The lowertemperature limit for the creep rup-ture range for carbon steel is at least700˚F (371˚C). The limit for alloy steelis often higher. The limit for othermetals depends upon the specificcomposition. Specialized metallurgi-cal advice should be obtained for al-loy steels and non-ferrous metals.)

4. The pressure vessel is protectedagainst inadvertent contamination.

c. Corrosion Resistant LiningWhen part or all of the pressure vesselwall has a corrosion resistant lining, theinterval between inspections of thosesections so protected may be based onrecorded experience with the same typeof lining in similar service, but shallnot exceed ten years. If there is no experi-ence on which to base the intervalbetween inspections, performance of theliner shall be monitored by a suitablemeans such as the use of removablecorrosion probes of the same material asthe lining, ultrasonic examination orradiography. To check the effectiveness ofan internal insulation liner, metal tem-peratures may be obtained by surveyingthe pressure vessel shell with temperaturemeasuring or indicating devices.

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d. Two or More ZonesWhen a pressure vessel has two or morezones and the required thickness, corro-sion allowance or corrosion rate differ somuch that the foregoing provisions givesignificant differences in maximumperiods between inspections for therespective zones (e.g., the upper andlower portions of some fractionating tow-ers), the period between inspections maybe established individually for each zoneon the basis of the condition applicablethereto, instead of being established forthe entire vessel on the basis of the zonerequiring the more frequent inspection.

e. Above-Ground VesselsAll pressure vessels above ground shallbe given an external examination afteroperating the lesser of five years or quar-ter life, preferably while in operation.Inspection shall include determining thecondition of the exterior insulation, thesupports, and the general alignment ofthe vessel on its supports. It is not neces-sary to remove any insulation if the tem-perature of the entire pressure vessel shellis maintained sufficiently low or suffi-ciently high to preclude the presence ofwater. Pressure vessels which are knownto have a remaining life of over ten yearsor which are prevented from being ex-posed to external corrosion (such as be-ing installed in a cold box in which theatmosphere is purged with an inert gas,or by the temperature being maintainedsufficiently low or sufficiently high to pre-clude the presence of water), need nothave the insulation removed for the ex-ternal inspection. However, the conditionof the insulating system and/or the outerjacketing, such as the cold box shell, shallbe observed periodically and repaired ifnecessary.

f. Interrupted ServiceThe periods for inspection referred above,assume that the pressure vessel is incontinuous operation, interrupted only bynormal shutdown intervals. If the pres-sure vessel is out of service for an

extended interval, the effect of the exter-nal and internal environmental conditionsduring such an interval shall be consid-ered in revising the date of the nextinspection which was established andreported at the time of the previous in-spection. If the pressure vessel is out ofservice for one year or more, it shall begiven an inspection before being placedin service.

The actual thickness and maximumdeterioration for any part of the pressurevessel shall be determined by one of thefollowing methods:

1. Any suitable nondestructive examina-tion may be used provided the thick-ness determinations are accuratewithin the following tolerances:

wall thickness, permissiblet (in. or mm) tolerance

5/16 in.(8 mm) 0.10tand less

Over 5/16 in. 1/32 in. (.8mm)(8mm) or 0.05t

whichever isgreater

2. If suitably located existing openingsare available, measurements may betaken through the openings.

3. When it is impossible to determinethickness by nondestructive means, ahole may be drilled through the metalwall and thickness gage measure-ments taken.

g. Circumferential StressesFor a corroded area of considerable sizein which the circumferential stresses gov-ern the MAWP, the least thicknesses alongthe most critical plane of such area maybe averaged over a length not exceeding:

1. The lesser of one-half the pressurevessel diameter, or 20 in. (508 mm) for

58


vessels with inside diameters of 60 in.(1.52m) or less, or

2. The lesser of one-third the pressurevessel diameter, or 40 in. (1.02 m), forvessels with inside diameters greaterthan 60 in. (1.52m), except that if thearea contains an opening, the distancewithin which thicknesses are averagedon either side of such opening shall notextend beyond the limits of reinforce-ment as defined in the section of theASME Code for ASME Stamped ves-sels and for other vessels in their ap-plicable standards.

h. Longitudinal StressesIf because of wind loads or other factorsthe longitudinal stresses would be ofimportance, the least thicknesses in alength of arc in the most critical plane per-pendicular to the axis of the pressurevessel shall be averaged for computationof the longitudinal stresses. The thick-nesses used for determining corrosionrates at the respective locations shallbe the most critical value of averagethickness.

i. PittingWidely scattered pits may be disregardedprovided that:

1. their depth is not more than one-halfthe required thickness of the pressurevessel wall (exclusive of corrosionallowance);

2. the total area of the pits does notexceed 7 sq. in. (45.2cm2) within any8 in. (203 mm) diameter circle; and

3. the sum of their dimensions along anystraight line within this circle does notexceed 2 in. (50.8 mm).

j. Weld Joint Efficiency FactorWhen the surface at a weld having a jointefficiency factor of other than one (1) iscorroded as well as surfaces remote from

the weld, an independent calculationusing the appropriate weld joint efficiencyfactor must be made to determine if thethickness at the weld or remote from theweld governs the maximum allowableworking pressure. For the purpose of thiscalculation, the surface at a weld includesone inch (25.4 mm) on either side of theweld, or two times the minimum thick-ness on either side of the weld, whicheveris greater.

k. Ellipsoidal and Torispherical Heads1. When measuring the corroded thick-

ness of ellipsoidal and torisphericalheads, the governing thickness maybe:a. that of the knuckle region with the

head rating calculated by the ap-propriate head formula; or

b. that of the central portion of thedished region, in which case thedished region may be considereda spherical segment whose allow-able pressure is calculated by theformula for spherical shells in theASME Code for ASME Stampedvessels and for other vessels intheir applicable standards.

2. The spherical segment of bothellipsoidal and torispherical headsshall be considered to be that arealocated entirely within a circle whosediameter is equal to 80% of the shelldiameter. The radius of the dish of atorispherical head is to be used as theradius of the segment (equal to thediameter of the shell for standardheads, though other radii have beenpermitted). The radius of the spheri-cal segment of ellipsoidal heads shallbe considered to be the equivalentspherical radius K1D where D is theinside diameter of the shell (equal tothe major axis) and K1 is given in Table1 below. In the table, h is one-half thelength of the minor axis (equal to theinside depth of the ellipsoidal head)

59


measured from the tangent line(headbend line). For many ellipsoidalheads, D/2h=2.0.

TABLE 1 —Values of Spherical Radius Factor, K1

K1D = Equivalent spherical radiusD/2h = axis ratio(Interpolation permitted for intermediatevalues.)

D/2h –3.00 2.80 2.60 2.40 2.20 2.00 1.80 1.60 1.40 1.201.00

K1 –1.36 1.27 1.18 1.08 0.99 0.90 0.81 0.73 0.65 0.570.50

l. Adjustments in Corrosion RateIf, upon measuring the wall thicknessat any inspection, it is found that an inac-curate rate of corrosion has been assumed,the corrosion rate to be used for determin-ing the inspection frequency shall beadjusted to conform with the actual ratefound.

m. Riveted Pressure VesselsFor a pressure vessel with riveted joints,in which the strength of one or moreof the joints is a governing factor in es-tablishing the maximum allowable work-ing pressure, consideration shall be givenas to whether and to what extent corro-sion will change the possible modes offailure through such joints. Also, eventhough no additional thickness may haveoriginally been provided for corrosion al-lowance at such joints, credit may betaken for the corrosion allowance inher-ent in the joint design.


There are a variety of conditions that causedeterioration in pressure vessels. The com-mon conditions are listed below.

a. CORROSION – Corrosion is one of themost prevalent conditions found inpressure vessels. The following types ofcorrosion are commonly found:

1. PITTING – Shallow, isolated, scat-tered pitting over a small area thatdoes not substantially weaken thevessel. It could, however, eventuallycause leakage.

2. LINE CORROSION – This is a condi-tion where pits are connected, ornearly connected, to each other in anarrow band or line. Line corrosionfrequently occurs in the area of inter-section of the support skirt and thebottom of the vessel, or liquid-vaporinterface.

3. GENERAL CORROSION – This iscorrosion which covers a considerablearea of the vessel. When this occurs,consideration must be given to thesafe working pressure of the vesselwhich is directly related to the remain-ing material thickness.

4. GROOVING – This type of corrosionis a form of metal deterioration causedby localized corrosion, and may beaccelerated by stress concentration.Grooving may be found adjacent toriveted lap joints or welds and onflanged surfaces, particularly theflanges of unstayed heads.

5. GALVANIC CORROSION – Two dis-similar metals in contact with eachother and with an electrolyte (i.e., afilm of water containing dissolvedoxygen, nitrogen and carbon dioxide)constitute an electrolyte cell, and theelectric current flowing through thecircuit may cause rapid corrosion ofthe less noble metal (the one havingthe greater electrode potential). Thiscorrosion mechanism is most activewhen there are large differences

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between the electrode potentials of thetwo metals, but galvanic corrosionmay also exist with relatively minorchanges of alloy composition (i.e.,between a weld metal and the basemetal). Natural (i.e., an oxide coatingon aluminum) or protective coatingsmay inhibit galvanic corrosion, but inmost instances the metals or alloysmust be selected on the basis ofintrinsic resistance to corrosion. Inpressure vessels the effects of galvaniccorrosion are most noticeable at riv-ets, welds or at flanged and boltedconnections.

b. FATIGUE – Stress reversals (such ascyclic loading) in parts of equipment arecommon, particularly at points of highsecondary stress. If stresses are high andreversals frequent, failure of parts mayoccur because of fatigue. Fatigue failuresin pressure vessels may also result fromcyclic temperature and pressure changes.Locations where metals having differentthermal coefficients of expansion arejoined by welding may be susceptibleto thermal fatigue.

c. CREEP – Creep may occur if equipmentis subjected to temperatures above thosefor which the equipment is designed.Since metals become weaker at highertemperatures, such distortion may resultin failure, particularly at points of stressconcentration. If excessive temperaturesare encountered, structural property andchemical changes in metals may also takeplace which may permanently weakenequipment. Since creep is dependent ontime, temperature, and stress, the actualor estimated levels of these quantitiesshould be used in any evaluations.

d. TEMPERATURE – At subfreezing tem-peratures, water and some chemicalshandled in pressure vessels may freezeand cause failure. Carbon and low alloysteels may be susceptible to brittle failureat ambient temperatures. A number offailures have been attributed to brittle

fracture of steels which were exposed totemperatures below their transitiontemperature and which were exposed topressures greater than 20% of the requiredhydrostatic test pressure. However, mostbrittle fractures have occurred on the firstapplication of a particular stress level(that is, the first hydrostatic test or over-load). Special attention should be givento low alloy steels because they are proneto temper embrittlement. (Temperembrittlement is defined as a loss of duc-tility and notch toughness due topostweld heat treatment or high tempera-ture service, above 700°F (371°C).

e. HYDROGEN ATTACK – High-tempera-ture, high-pressure hydrogen environ-ments can degrade the mechanicalstrength of carbon steels and low alloysteels. This type of damage is called hy-drogen attack. It is caused by hydrogenpermeating the steel and reacting withcarbon to form methane. Since carbon isa strengthening agent in steel, its removalby the reaction with hydrogen causes thesteel to lose strength. In addition, meth-ane can become trapped within the steelat high pressures, eventually formingbubbles, fissures (cracks), and/or blisters.

Damage caused by hydrogen attack ispreceded by an incubation period with nonoticeable change in properties. After theincubation period, decarburization and/or blistering and fissuring will occur. Thelength of the incubation period varieswith temperature, pressure, and alloycontent of the steel. Damage is reversibleduring the incubation period, duringwhich no loss of mechanical propertieswill have occurred. Once permanent deg-radation begins, the damage is irrevers-ible.

Hydrogen attack is a concern primarilyin refinery and petrochemical plantequipment handling hydrogen and hy-drogen-hydrocarbon streams at tempera-tures above about 450°F and pressuresabove 100psi. A guideline for selection of

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steels to avoid hydrogen attack is givenin API Publication 941, “Steels for Hydro-gen Service at Elevated Temperatures andPressures in Petroleum Refineries andPetrochemical Plants.” Also widelyknown as the “Nelson Curves,” API 941shows that the severity of hydrogenattack depends on temperature, hydrogenpartial pressure, exposure time, and steelcomposition. Additions of chromium andmolybdenum to the steel compositionincrease resistance to hydrogen attack.

It is important to understand that hydro-gen attack is different from hydrogenembrittlement, which is discussed next.Hydrogen attack occurs in the absence ofliquid water at elevated temperatures(above 450°F). Hydrogen embrittlementprimarily occurs as a result of corrosionreactions occurring in aqueous solutionsat temperatures generally below about200°F.

f. HYDROGEN EMBRITTLEMENT – A lossof strength and/or ductility in steelscaused by atomic hydrogen dissolved inthe steel. It is a low temperature phenom-enon, seldom encountered above 200°F,and most often occurs as a result of hy-drogen evolved from aqueous corrosionreactions. It can vary in its appearanceand can occur in differing environments,thus giving rise to the various terms bywhich it is known, including sulfide stresscracking, wet H2S cracking, hydrogenstress cracking, blistering, blister cracking,hydrogen-induced cracking (HIC), stress-oriented hydrogen-induced cracking(SOHIC), and others. Weld underbeadcracking (also known as delayed crack-ing and cold cracking) is also a form ofhydrogen embrittlement, however in thiscase, the hydrogen comes from the weld-ing operation rather than from a corro-sion reaction.

Some forms of hydrogen embrittlementrequire an applied stress or residual stressfor cracking to occur (sulfide stress crack-ing, SOHIC, weld underbead cracking),

while others occur in the absence ofapplied or residual stress, the internalpressure from the recombined hydrogengas being sufficient to cause the damage(blistering, HIC).

Susceptibility to sulfide stress crackingand similar forms of hydrogen embrittle-ment depends on the strength of the steel.Higher strength steels are more suscep-tible. The strength level at which suscep-tibility arises depends on the severity ofthe environment that the steel is exposedto. Hydrogen sulfide, hydrogen cyanide,and arsenic, in aqueous solutions, allgreatly increase the severity of the envi-ronment towards hydrogen embrittle-ment by increasing the amount ofhydrogen that is absorbed by the steelduring the corrosion reaction. In hydro-gen sulfide environments, cracking cangenerally be avoided by using steels witha strength level below that equivalent toa hardness of Rockwell C-22.

Similarly, weld underbead cracking iscaused by hydrogen dissolved in a hard,high strength weld heat affected zone.Use of low hydrogen welding practice tominimize dissolved hydrogen, and/oruse of high preheat, and/or postweld heattreatment to reduce heat affected zonehardness, will reduce the likelihood ofweld underbead cracking in a susceptiblesteel.

Hydrogen embrittlement is reversible aslong as no physical damage, e.g.,cracking, has occurred in the steel. If theatomic hydrogen is removed from thesteel before any damage occurs, for ex-ample by heating for a short time in theabsence of hydrogen to between 300°Fand 400°F, normal mechanical propertieswill be restored.

Cracking that can occur in vessels oper-ating in aqueous H2S service (i.e., wet H2Scracking) will not always be readilyapparent upon visual inspection. Othermethods, such as magnetic particle

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(including wet fluorescent) or liquidpenetrant, may be required to reveal thecracks.

Welding procedures, repair methods, andinspection procedures must includecareful consideration of potential failurein corrosive environments, including thevarious forms of hydrogen embrittlement.

g. STRESS CORROSION CRACKING –Cracking of a metal caused by thecombined action of stress and a corrosiveenvironment. Stress corrosion crackingonly occurs with specific combinations ofmetal and environment. The stressrequired may be either applied orresidual. Examples of stress corrosioncracking include chloride stress corrosioncracking of stainless steels in hot, aqueouschloride solutions; caustic cracking ofcarbon steel in hot sodium hydroxidesolutions, and ammonia stress corrosioncracking of brass in ammonia solutions(season cracking).

Corrosivity alone is not a good indicatorof the likelihood of a particularenvironment to cause stress corrosioncracking in a particular metal. Solutionsthat are highly corrosive to a materialalmost never promote stress corrosioncracking.

The principal variables affecting stresscorrosion cracking are tensile stress,service temperature, solution chemistry,duration of exposure, and metalproperties. Modifying any one of theseparameters sufficiently can reduce oreliminate the possibility of stresscorrosion cracking occurring in service.

RB-3250 INSPECTION OF PARTSAND APPURTENANCES

The parts and appurtenances which shouldbe inspected depend upon the type of vessel

and its operating conditions. The Inspectorshould be familiar with the operatingconditions of the vessel and with the causesand characteristics of potential defects anddeterioration.


RB-3261 GAGES

The pressure indicated by the required gageshould be compared with other gages on thesame system. If the pressure gage is notmounted on the vessel itself, it should beinstalled in such a manner that it correctlyindicates the actual pressure in the vessel.When required, the accuracy of pressuregages should be verified by comparing thereadings with a standard test gage or a deadweight tester.

The location of a pressure gage should beobserved to determine whether it is exposedto high temperature from an external sourceor to internal heat due to lack of protectionby a proper siphon or trap. Provisions shouldbe made for blowing out the pipe leading tothe steam gage.


See Section RB-3500 for the inspection ofsafety devices (Pressure relief valves and non-reclosing devices such as rupture disks) usedto prevent the overpressure of pressurevessels.

RB-3263 CONTROLS

a. Any control device attached to a vesselshould be demonstrated by operation orthe Inspector should review the proce-dures and records for verification ofproper operation.

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a. Location and thickness of moni-tor samples and other critical in-spection locations;

b. Limiting metal temperature andlocation on the vessel when thisis a factor in establishing the mini-mum allowable thickness;

c. Computed required metal thick-nesses and maximum allowableworking pressure for the designtemperature and pressurerelieving device opening pressure,static head, and other loadings;

d. Test pressure if tested at the timeof inspection;

e. Scheduled (approximate) date ofnext inspection;

f. Date of installation and date ofany significant change in serviceconditions (pressure, tempera-ture, character of contents or rateof corrosion);

g. Drawings showing sufficient de-tails to permit calculation of theservice rating of all componentson pressure vessels used in pro-cess operations subject to corro-sive conditions. Detailed datawith sketches where necessarymay serve this purpose whendrawings are not available.

RB-3280 CONCLUSIONS

Any defect or deficiency in the condition,operating and maintenance practices of thepressure vessel should be discussed with theowner or user at the time of inspection and,if necessary, recommendations made for thecorrection of such defect or deficiency.

b. Temperature measuring devices shouldbe checked for accuracy and general con-dition.


a. The Inspector should review any pressurevessel log, record of maintenance, corro-sion rate record or any other examinationresults. The Inspector should consult withthe Owner or User regarding repairs oralterations made, if any, since the last in-ternal inspection. The Inspector shouldreview the records of such repairs oralterations for compliance with applicablerequirements.

b. A permanent record shall be maintainedfor each pressure vessel. This record shallinclude the following:

1. An ASME Manufacturer ’s DataReport or, if the vessel is not ASMECode stamped, other equivalentspecifications.

2. Form NB-5 Boiler or Pressure VesselData Report - First Internal Inspection,may be used for this purpose. It shallshow the following identificationnumbers as applicable.

National Board No.Jurisdiction No.Manufacturer’s Serial No.Owner-User’s No.

3. Complete pressure relieving deviceinformation including safety or safetyrelief valve spring data or rupturedisk data, and date of latest inspec-tion.

4. Progressive record including, but notlimited to, the following:

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RB-3300 INSPECTION OF WATERHEATERS SUPPLYING HOTWATER FOR PURPOSESOTHER THAN SPACEHEATING


A water heater is intended to supply potablehot water with 100% makeup from a potablewater supply system. Therefore, certaincontrols and indicating instruments, such aswater level indicator, low water cut-offs,and pressure and altitude gages are notnecessary on a water heater.


a. The water supply to the water heater mustbe independent of other openings orconnections.

b. When water pressure to the water heaterexceeds 75% of the maximum allowableworking pressure of the unit, a pressurereducing valve must be provided.

c. The expansion tank, if installed, shall beconstructed in accordance with acceptablecodes or standards.

d. The expansion tank maximum allowableworking pressure may not be less than themaximum allowable working pressure ofthe water heater.

e. A drain must be installed at or near theexpansion tank.

f. A stop valve must be installed betweenthe expansion tank and the water heater.

g. Operating stop valves should be installedon the water heater inlet and outlet sidesso that the unit may be isolated whennecessary.

h. The bottom drain valve should be testedto insure proper operation.

i. Bottom drains should discharge safely.

j. Discharge piping, if installed, should runfull size to a safe point of discharge.


RB-3331 GAGES

The installed thermometer when required bythe construction code is the only externaldevice which indicates internal operation. Adefective thermometer should be promptlyreplaced.


See Section RB-3500 for the inspection ofsafety devices (Pressure relief valves) used toprevent the overpressure of water heaters.

RB-3333 CONTROLS

When practical, the operation of all controlsshould be observed. If any control is founddefective or inoperative, the water heatershould be taken out of service until thedeficiency is corrected. Control devices whichshow evidence of tampering should beconsidered suspect of improper operation.

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RB-3400 INSPECTION OF PIPINGSYSTEMS


Piping systems are designed for a variety ofservice conditions. The media that a pipingsystem contains and the temperature at whichit operates should be considered inestablishing inspection criteria. Particularattention should be given to piping systemsthat are subject to corrosion and those whichoperate at high temperatures.

RB-3420 PRECAUTIONS BEFORECONDUCTINGINSPECTION

Prior to conducting the inspection, the areashould be reviewed for potential safetyhazards such as exposure to falling objects,safety of any scaffolding or location of thepiping system in a confined space.

RB-3430 ASSESSMENT OFINSTALLATION; TYPES OFDEFECTS


All pipe material and fittings should be prop-erly rated for the maximum service condi-tions to which they are subjected under nor-mal operations. Operating history should bereviewed to determine if there have been anychanges in service conditions outside of theoriginal design. If operating conditions havechanged, records should be reviewed toensure piping system components are satis-factory.

Piping should be inspected to ensure thereis:

a. Provision for expansion

b. Provision for adequate support

c. No evidence of leakage

d. Proper alignment of connections. Thepurpose is to determine if any changesof position have placed undue strainon the piping or other connections.

e. Proper rating for the service condi-tions

f. No evidence of corrosion, erosion,cracking or other detrimental condi-tions


a. Corrosion occurs in the presence of freeoxygen and dissolved salts, such as maybe found in improperly treated boilerfeedwater. If corrosion is found in a pres-sure vessel, the associated piping systemsshould be considered suspect. Corrosioncan deteriorate large areas of the metalsurfaces or it can be localized in the formof pitting or galvanic corrosion. For thepurpose of estimating the effect of severecorrosion over large areas on the safeworking pressure, the thickness orremaining sound metal should be deter-mined by the use of ultrasonic equipmentor by drilling.

b. Cracks may result from design and oper-ating conditions where continual flexingfrom thermal or mechanical fluctuationscauses metal fatigue. Cracking underthese conditions may be accelerated bycorrosion. Cracking may also resultfrom fatigue at imperfections existingin material at the time of pipingsystem fabrication. Cracks resulting fromfabrication defects will normally occurfirst at areas subject to high stress and acorrosive environment. Suspect areasshould be examined periodically forcracking.

c. Erosion may occur as a result of abrasiveaction of a liquid or vapor. The presence

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of solid particles of matter in suspension,or entrained liquids in vapor are factorsin this type of mechanism. Erosiongenerally occurs in areas where flow isrestricted or flow direction is changed.Suspect areas should be examined forevidence of erosion.


a. A leak should be thoroughly investigatedand corrective action initiated.

b. A pressure test may be required to obtainadditional information regarding theextent of a defect or detrimental condi-tion.

c. To determine tightness, the test pressureneed be no greater than the normal oper-ating pressure. The metal temperatureshould be not less than 70˚F (21˚C) andthe maximum temperature during inspec-tion should not exceed 120˚F (49˚C). Thepotential corrosive effect of the test fluidon the pipe material should be consid-ered.

RB-3450 PROVISIONS FOREXPANSION AND SUPPORT

Visual inspection should include a check forevidence of improper support. The alignmentof connections between anchored equipmentshould be observed to determine if anychange in position of the equipment, due tosettling or other causes, has placed an unduestrain on the piping or its connection.Inadequate support or the lack of provisionfor expansion may cause broken attachmentwelds, cracks, or leakage at fittings. Any signsof leakage should be investigated to deter-mine the cause and the condition corrected.Missing, damaged or loose insulation mate-rials may be an indication of vibration or pipemovements resulting from improper support.


RB-3461 GAGES

Piping system pressure gages should beremoved for testing unless there is otherinformation to assess their accuracy. Faultypressure gages should be recalibrated orreplaced as necessary.


See Section RB-3500 for the inspection ofsafety devices (Pressure relief valves) used toprevent the overpressure of piping systems.

RB-3463 CONTROLS

Piping connections utilizing a quick-discon-nect coupling should be checked to ensurethat the coupling and its holding elements arefully engaged in their intended operatingposition. Means should be provided thatwarn the operator against disengaging thecoupling or prevent the opening mechanismfrom operating unless the piping is com-pletely depressurized.


The owner or user should maintain records(including drawings) that permit the deter-mination of design conditions, operatingconditions, material specifications, compo-nent ratings, repairs and other records nec-essary for evaluation of the piping system.As part of the evaluation process, records andthe results of previous inspections should bereviewed.

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RB-3480 CONCLUSIONS

a. During any tests the actual operating andmaintenance practices should be notedand a determination made as to theiracceptability.

b. Any defects or deficiencies in the condi-tion, operating and maintenance practicesof the piping system equipment shouldbe discussed with the owner or user atthis time and recommendations made forcorrection.

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RB-3500 INSPECTION OF SAFETYDEVICES FOROVERPRESSUREPROTECTION

RB-3510 SCOPE

a. The most important appurtenances onany pressurized system are the safetydevices provided for overpressure protec-tion of that system. These are devices suchas safety valves, safety relief valves, pilotvalves and rupture disks or other non-reclosing devices which are called uponto operate and reduce an overpressurecondition.

b. These devices are not designed orintended to control the pressure in thesystem during normal operation. Instead,they are intended to function when nor-mal operating controls fail or abnormalsystem conditions are encountered.

c. Periodic inspection and maintenance ofthese important safety devices is criticalto ensure their continued functioning andto provide assurance that they will beavailable when called upon to operate.

d. The following inspection points aredivided into areas of:

1. device data,

2. condition of the device itself,

3. condition of the installation, and

4. operational inspection.

e. Inspection criteria applicable to all instal-lations are given first, followed by addi-tional items to be considered for specifictypes of installations or services.

RB-3511 SAFETY CONSIDERATIONS

Inspectors are cautioned that the operationof these safety devices involve the discharge

of high pressure and/or high temperaturefluids. Extreme caution should be used whenworking around these devices due to hazardsto personnel. Because extremely high noiselevels may be encountered during testingwhich can damage hearing, suitable hearingprotection should be provided.

RB-3520 DEVICE DATA

a. Nameplate marking or stamping of thedevice should be compared to stampingon the pressure retaining item. The setpressure shall be no higher than themaximum allowable working pressure(MAWP) marked on the pressure retain-ing item.

b. If multiple devices are provided, thedifference between set pressures shall notexceed that permitted by the original codeof construction.

c. Verify nameplate capacity and if possible,compare to system capacity requirements.

d. Check identification on seals and ensurethey match nameplates or other identifi-cation (repair or reset nameplate) on thevalve or device.

RB-3530 DEVICE CONDITION

a. Check for evidence that the valve ordevice is leaking or not sealing properly.

b. Seals should be intact and show noevidence of tampering.

c. Connecting bolting should be tight andall bolts intact.

d. The valve should be examined for depos-its or material buildup.

e. Evidence of rust or corrosion should bechecked.

f. Check for damaged or misapplied parts.

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g. If a drain hole is visible, ensure it is notclogged with debris or deposits.

RB-3540 INSTALLATIONCONDITION

a. Inspect inlet piping and ensure it meetsthe requirements of the original code ofconstruction. Especially check that the in-let pipe size is not smaller than the de-vice inlet size.

b. Inspect discharge piping and ensure itmeets the original code of construction.Check that the discharge pipe size is notsmaller than the device outlet size.

c. Check that the valve drain piping is open.

d. Check drainage of discharge piping.

e. Check that discharge piping is not bind-ing on the valve body which can lead todistortion of the valve body and leakageor malfunction.

f. Check the condition and adequacy ofpiping supports. Discharge piping shouldbe supported independent of the deviceitself.

g. Check for possible hazards to personnelfrom the valve discharge or dischargepipe.

h. Check that there are no intervening valves(such as a block valve) between the pres-sure source and the valve inlet or betweenthe valve outlet and its point of discharge.(Block valves may be permitted in somepressure vessel service – see the specificsection for pressure vessels and jurisdic-tional requirements. Block valves are notpermitted for power boilers, heatingboilers or water heaters).

i. If a pressure test indicates the valve doesnot open within the requirements of theoriginal code of construction, but other-wise is in acceptable condition, minor

adjustments (defined as no more thantwice the permitted set pressure toler-ance) shall be made by a organization thatmeets the requirements of RA-2200 to re-set the valve to the correct opening pres-sure. All adjustments shall be resealedwith a seal identifying the responsible or-ganization and a tag identifying the or-ganization and the date of the adjustmentshall be installed.

j. If a major adjustment is needed, this mayindicate the valve is in need of repair orhas damaged or misapplied parts. Its con-dition should be investigated accordingly.

k. Systems with multiple valves will requirethe lower set valves to be held closed topermit the higher set valves to be tested;a test clamp or “gag” should be used forthis purpose. The spring compressionscrew shall not be tightened. It is recom-mended that the test clamps be appliedin accordance with the valve manufactur-ers instructions when the valve is at ornear the test temperature and be appliedhand tight only to avoid damage to thevalve stem or spindle.

RB-3550 OPERATIONALINSPECTION

a. Pressure relief valves must be periodicallytested to ensure that they are free tooperate and will operate in accordancewith the requirements of the code ofconstruction.

b. Testing may be accomplished by theowner on the unit where the valve is in-stalled or at a qualified test facility. Inmany cases, testing on the unit may beimpractical, especially if the service fluidis hazardous or toxic. Testing on the unitmay involve the bypassing of operatingcontrols and should only beperformed by qualified individuals undercarefully controlled conditions. It isrecommended that a written procedure beavailable to conduct this testing.

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1. The Inspector should assure thatcalibrated equipment has been usedto perform this test and the resultsshould be documented by the owner.

2. If the testing was performed at a testfacility, the record of this test shouldbe reviewed to ensure the valve meetsthe requirements of the original codeof construction.

c. As an alternative, the valve may bechecked by the owner for freedom ofoperation by activating the test or trylever. This test should be performed onlyat a pressure greater than 75% of thestamped set pressure of the valve or thelifting device may be damaged. This testwill only indicate that the valve is freeto operate and does not provide anyinformation on the actual set pressure.

d. If a valve is found to be stuck closed, thesystem should immediately be taken outof service until the condition can becorrected unless special provisions havebeen made to operate on a temporarybasis (such as additional relief capacityprovided by another valve).

e. If a pressure test indicates the valve doesnot open within the requirements of theoriginal code of construction, but other-wise is in acceptable condition, minor ad-justments (defined as no more than twicethe permitted set pressure tolerance) shallbe made by an organization that meets therequirements of RA-2200 to reset the valveto the correct opening pressure. All ad-justments shall be resealed with a sealidentifying the responsible organizationand a tag identifying the organization andthe date of the adjustment shall be in-stalled.

f. If a major adjustment is needed, this mayindicate the valve is in need of repair orhas damaged or misapplied parts. Its con-dition should be investigated accordingly.

g. Systems with mulitple valves will requirethe lower set valves to be held closed topermit the higher set valves to be tested.A test clamp or “gag” should be used forthis purpose. The spring compressionscrew shall not be tightened. It is recom-mended that the test clamps be appliedin accordance with the valvemanufacturer’s instructions when thevalve is at or near the test temperature andbe applied hand tight only to avoid dam-age to the valve stem or spindle.

RB-3560 RECOMMENDED TESTFREQUENCIES

a. Power Boilers and Hot Water BoilersPressure less than 400 psig: manual checkevery 2 months; pressure test annually.Pressure greater than 400 psig: as deter-mined by operating experience.

Note: This operating experience shouldbe verified against testing history. A pres-sure test prior to bringing the boiler downfor internal inspection is suggested soneeded repairs or adjustments can bemade while the boiler is down.

b. Water HeatersManual check every 2 months. Due to therelatively low cost of safety valves for thisservice, it is recommended that a defec-tive valve be replaced with a new valve ifa repair or resetting is indicated.

c. Pressure Vessels and PipingFrequency of test and inspection of valvesfor pressure vessel and piping service isgreatly dependent on the nature of thecontents of the system and only generalrecommendations can be given. Inspec-tion frequency should be based on previ-ous inspection history. If valves are foundto be defective or damaged by systemcontents during inspection, intervalsshould be shortened until acceptable in-spection results are obtained. With this in

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mind, the following frequencies are sug-gested.

Service Inspection FrequencySteam .................... AnnualAir & Clean

Dry Gasses ....... Every three yearsPropane,

Refrigerant ....... Every five yearsAll others ............. Per inspection history

RB-3570 ADDITIONAL INSPECTIONINFORMATION

The following additional items should beconsidered for the specified services.

a. BoilersIf boilers are piped together withmaximum allowable working pressuresdiffering by more than 6%, additionalprotective devices may be required on thelower pressure units to protect them fromoverpressure from the higher pressureunit.

b. Hot-Water Heating Boilers and WaterHeaters1. These units generally do not use any

water treatment and therefore may bemore prone to problems with depos-its forming which may impair a safetydevice’s operation. Particularattention should be paid to signs ofleakage through valves or buildups ofdeposits.

2. Hot-water boilers tend to have build-ups of corrosion products since thesystem is closed with little makeup.These products can foul or block thevalve inlet.

3. Water heaters will have cleaner wa-ter due to continuous makeup. How-ever these valves usually have a ther-mal element which will cause the

valve to open slightly when the wa-ter is heated and not removed fromthe system. When this hot waterevaporates in the discharge pipingcalcium deposits may tend to form inthe valve inlet and outlet.

c. Pressure VesselsStandard practice for safety devices is tonot permit any type of block valve eitherbefore or after the safety device. However,some pressure vessel standards permitblock valves under certain controlled con-ditions when shutting down of the vesselto repair a damaged or leaking valvewould be difficult. If block valves areemployed, their use should be carefullycontrolled by written procedures and theblock valves should have provisions to belocked in an open position when notbeing used. For ASME Section VIII,Division 1 pressure vessels, see paragraphUG-135, Appendix M and jurisdictionalrules for more information.

d. Rupture DisksRupture disks or other non-reclosingdevices may be used as sole relievingdevices or in combination with safetyrelief valves to protect pressure vessels.When rupture disks are used with safetyrelief valves, the following additionalitems should be considered duringinspections.

1. The rupture disk nameplate informa-tion including stamped burst pressureand coincident temperature should bechecked to ensure it is compatiblewith the vessel and/or safety reliefvalve.

2. Markings indicating direction of flowshould be carefully checked to ensurethey are correct. Some rupture diskswhen installed in the incorrectposition may burst well above thestamped pressure.

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3. Check that the space between arupture disk and a safety relief valveis supplied with a pressure gage, trycock or tell tale indicator to indicatesigns of leakage through the rupturedisk. Leaking disks shall be replaced.

4. If a rupture disk is used on a valveoutlet, the valve design must be of atype not influenced by back pressuredue to leakage through the valve. Fornon-toxic and non-hazardous fluids,the space between the valve and theruptured disk shall be vented ordrained to prevent the accumulationof pressure.

5. For rupture disks installed on thevalve inlet, the installation should bereviewed to ensure that the combina-tion rules of the code of constructionhave been applied.

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RB-3600 INSPECTION OFDEAERATORS


Deterioration of deaerators may beaccelerated by certain operational conditionssuch as water hammer, improper orinadequate feedwater treatment, excessiveoxygen entering the system through thecondensate return system, limited oxygenremoval in the degasifier, and/or excessivefluctuations in operating pressures andtemperatures.

RB-3620 ASSESSMENT OFINSTALLATION; CAUSESOF DETERIORATION;TYPES OF DEFECTS


A careful observation should be made of thecondition of the complete installation,including maintenance and operation, as aguide in forming an opinion of the care theequipment receives. Also, the Inspectorshould establish the history of the deaeratorincluding: date built, materials ofconstruction, extent of postweld heattreatment, repairs performed, and priorinspection results.


Deterioration can result from oxygencontamination of the feedwater due tomechanical breakdown at feedwater pumpsor turbine gland seals. Deaerator problemssuch as misaligned trays or plugged spraynozzles can also result in oxygencontamination.


a. Defects found in feedwater deaerators –especially the storage section – mayinclude: pinhole leaks, cracks in oradjacent to welded seams, cracks insurface areas containing the remains ofwelds for nonpermanent attachments,and cracks in surface areas opposite ex-ternally welded supports.

b. The most common failure mechanism iscorrosion-fatigue, caused usually by acombination of residual and operatingcondition stresses. Cracks are generallylimited to non-postweld heat treatedvessels, either longitudinal or transverseto the weld, and develop in the weld andheat-affected zone (HAZ). The area mostlikely to be subject to cracking is on thevessel’s internal surface near and belowthe vapor-liquid level. Cracks maydevelop within a relatively short periodof time; therefore, frequent inspection isessential where cracks or other defects(which could affect the structuralintegrity or the pressure retaining capa-bility of the vessels) are suspected.Vessels manufactured with full radio-graphic examination of the weld jointsand postweld heat treatment at aminimum of 1100°F have a superiorservice record.


Any steam or water leak should bethoroughly investigated and corrective actioninitiated.


A thorough visual inspection with adequateillumination should be performed on the

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internal surfaces, with special attention givento welds and heat-affected zones (HAZ), forindications of cracking. This inspectionshould not only include the welded shell andhead seams, but also welded nozzles,manway and other connections, and surfaceareas containing the remains of welds usedfor nonpermanent attachments and surfaceareas opposite externally welded supports.Close inspection should be made of thesurface area immediately above andanywhere below the normal liquid line. Thisshould be followed by a complete examina-tion of internal welds and the HAZ using oneor more suitable nondestructive examination(NDE) methods. The wet fluorescentmagnetic particle (WFMT) method hasproven most effective provided the area to beexamined is clean and free of scale andforeign materials. In order to obtainmeaningful test results, all inspection areasshould be cleaned by power wire brushing,light grinding or other suitable methods. Careshould be taken that the surface preparationmethod will not mask discontinuities orinterfere with examination results. If theWFMT process detects cracks, it may benecessary to employ a volumetric type NDEprocess to determine the extent of the defects.


RB-3651 GAGES

The Inspector should note the pressureindicated by the gage and compare it withother gages on the same system. If thepressure gage is not mounted on thedeaerator itself, it should be ascertained thatthe gage is on the system and installed in such

a manner that it correctly indicates actualpressure in the deaerator.


See Section RB-3500 for the inspection ofsafety devices (pressure relief valves) used toprevent the overpressure of feedwaterdeaerators.


a. Any operating logs, maintenance records,corrosion rate records, tests andinspection records should be reviewed.The owner or user should be consultedregarding repairs made since the lastinspection. Repairs or alterations shouldbe reviewed for compliance withapplicable requirements.

b. The operation and maintenance of thedeaerator should be checked to determineif the manufacturer’s instructions, and theowner’s or user’s supplemental writteninstructions and procedures are followed.

RB-3670 CONCLUSIONS


b. Any defects or deficiencies in thecondition, operating and maintenancepractices of the deaerator and auxiliaryequipment should be discussed with theowner or user and recommendationsmade for correction.

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a. Where existing openings permit, performa visual internal inspection of the vessel.Look for any obvious cracks (veryadvanced SCC) and note areas which aresubject to high stress such as welds,welded repairs, head-to-shell transitions,sharp interior corners and interiorsurfaces opposite external attachments orsupports. It is not intended that thevessel provide for access. It is understoodthat internal inspections will be made ifthe vessel has access to the internalsurfaces.

b. If valves or fittings are in place, check toensure that these are complete andfunctional. Parts of copper, zinc, silver oralloys of these metals are unsuitable forammonia service and should be replacedwith parts of steel or other suitablematerials.

c. Fittings should be removed or otherwiseprotected from power buffing or lightsandblasting when preparing the interiorsurface of the vessels for inspection.

d. All interior welds and highly stressedareas should be examined by the wetfluorescent magnetic particle-testingmethod (WFMT) using an A/C yoke formagnetization. Note that weld cracks areoften transverse in orientation. It isextremely important to ensure that theNDE method used will disclose cracks inany orientation.

e. If cracks are discovered, a calculationmust be made to determine what depthof grinding may be carried out for crackremoval (without encroaching on theminimum thickness required by theconstruction standard or equivalent).

f. Where possible, crack removal bygrinding is the preferred method of repair.Since the stresses at the crack tips are quitehigh, even very fine cracking should beeliminated.

RB-3700 INSPECTION OF LIQUIDAMMONIA VESSELS

RB-3710 SCOPE

Pressure vesssels containing liquid ammoniarequire special attention because the mediais corrosive.

RB-3720 ASSESSMENT OFINSTALLATION; CAUSESOF DETERIORATION


The Inspector should make a carefulobservation of the condition of the completeinstallation, including maintenance andoperation, as a guide in forming an opinionof the care the equipment receives. TheInspector should establish the history of thevessel: date built, materials of construction,extent of postweld heat treatment, previousinspection and test results, repairs oralterations performed, whether liquidammonia was water-inhibited, etc.


It is known that vessels in liquid ammoniaservice are susceptible to stress corrosioncracking (SCC) in areas of high stress. Highstrength and coarse-grained materials seemto be more at risk of SCC than are fine-grainedor more moderate strength materials,although no commonly used steels appear tobe immune to the problem. Postweld heattreatment of new or weld-repaired vessels orcold formed heads is beneficial in reducingthe incidence of SCC. The presence of 0.2%minimum water in the liquid ammonia alsoinhibits SCC.


Any leak should be thoroughly investigatedand the necessary corrective action initiated.

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g. Reinspect by WFMT to ensure completecrack removal. The use of other evalua-tion methods, such as acoustic emissionand fracture mechanics, is acceptable.

h. Where crack depth is such that removalrequires weld repair, a weld procedureshould be employed that will minimizeHAZ hardening and residual stresses.Whenever possible, weld repairs–regardless of their size–should bepostweld heat treated.

i. It is not intended to inhibit or limit theuse of other evaluation methods. It isrecognized that acoustic emission andfracture mechanics are acceptabletechniques for assessing structuralintegrity of vessels. Analysis by fracturemechanics may be used to assess thestructural integrity of vessels whencomplete removal of all ammonia stresscracks is not practical. If alternativemethods are used, the aboverecommendation that all cracks be re-moved, even fine cracks, may not apply.

RB-3750 GAGES AND SAFETYDEVICES

RB-3751 GAGES

The Inspector should note the pressureindicated by the gage and compare it withother gages on the same system. If thepressure gage is not mounted on the vesselitself, it should be ascertained that the gageis on the system and installed in such amanner that it correctly indicates actualpressure in the vessel.


See Section RB-3500 for the inspection ofsafety devices (pressure relief valves) used toprevent the overpressure of liquid ammoniavessels. Pressure relief devices in ammoniaservice cannot be tested in place usingsystem pressure.


a. Any operating logs, maintenance records,test or inspection records should bereviewed. The owner or user should beconsulted regarding repairs or alterationsmade since the last inspection. Any re-pairs or alterations should be reviewedfor compliance with applicable require-ments.

b. The operation and maintenance of thevessel should be checked to determine ifthe manufacturer’s instructions, and theowner’s or user’s supplemental writteninstructions and procedures are followed.

RB-3770 CONCLUSIONS


b. Any defects or deficiencies in thecondition, operating and maintenancepractices of the vessel and auxiliaryequipment should be discussed with theowner or user and recommendationsmade for correction.

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RB-3800 INSPECTION OF PRESSUREVESSELS WITH QUICKACTUATING CLOSURES

RB-3810 SCOPE

a. This part describes guidelines forinspection of pressure vessels equippedwith quick-actuating closures. Due to themany different designs of quick-actuatingclosures, potential failures of componentsthat are not specifically covered shouldbe considered. The scope of inspectionshould include areas affected by abuse orlack of maintenance and a check forinoperable or bypassed safety andwarning devices.

b. Temperatures above that for which thequick-actuating closure was designed canhave an adverse effect on the safeoperation of the device. If parts are foundto be damaged and excessivetemperatures are suspected as the cause,the operating temperatures mayhave exceeded those temperaturesrecommended by the manufacturer.Rapid fluctuations in temperatures due torapid start-up and shutdown may lead tocracks or yielding caused by excessivewarping and high thermal stress.


A careful observation should be made of thecondition of the complete installation,including maintenance and operation, as aguide in forming an opinion of the care theequipment receives. The history of the vesselshould be established, including: date built,materials of construction, extent of postweldheat treatment, previous inspection resultsand repairs or alterations performed.


Any leak should be thoroughly investigatedand the necessary corrective action initiated.


a. Seating surfaces of the closure device,including but not limited to the gaskets,O-rings, or any mechanical appurtenanceto ensure proper alignment of the closureto the seating surface, should be in-spected. This inspection can be made byusing powdered chalk, or any substancethat will indicate that the closure is prop-erly striking the seating surface of thevessel flange. If this method is used, acheck should be made to ensure that:

1. the material used will not contaminatethe gasket or material with which itcomes into contact, and

2. the transfer substance should becompletely removed after theexamination.

b. The closure mechanism of the deviceshould be inspected for freedom of move-ment and proper contact with the lock-ing elements. This inspection should in-dicate that the movable portions of thelocking mechanism are striking the lock-ing element in such a manner that fullstroke can be obtained. Inspection shouldbe made to ensure that the seating sur-face of the locking mechanism is free ofmetal burrs and deep scars, which wouldindicate misalignment or improper opera-tion. A check should be made for properalignment of the door hinge mechanismsto ensure that adjustment screws andlocking nuts are properly secured. Whendeficiencies are noted, the following cor-rective actions should be initiated:

1. If any deterioration of the gasket,O-ring, etc., is found, the gasket,O-ring, etc. should be replacedimmediately. Replacements should bein accordance with the vesselmanufacturer’s specifications.

2. If any cracking or excessive wear isdiscovered on the closing mechanism,

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the owner or user should contact theoriginal manufacturer of the devicefor spare parts or repair information.If this cannot be accomplished, theowner or user should contact anorganization competent inquick-actuating closure design andconstruction prior to implementingany repairs.

3. Defective safety or warning devicesshould be repaired or replaced priorto further operation of the vessel.

4. Deflections, wear or warping of thesealing surfaces may cause out-of-roundness and misalignment. Themanufacturer of the closure should becontacted for acceptable tolerances forout-of-roundness and deflection.

c. The operation of the closure devicethrough its normal operating cycle shouldbe observed. This should indicate if theoperator is following posted proceduresand if the operating procedures for thevessel are adequate.


RB-3851 GAGES

a. The required pressure gage should beinstalled so that it is visible from theoperating area located in such a way thatthe operator can accurately determine thepressure in the vessel while it is inoperation. The gage dial size should beof such a diameter that it may be easilyread by the operator. This gage shouldhave a pressure range of at least 1-1/2times, but not more than four times, theoperating pressure of the vessel. Thereshould be no intervening valve betweenthe vessel and gage.

b. The pressure gage should be of a type thatwill give accurate readings, especially

when there is a rapid change in pressure.It should be of rugged construction andcapable of withstanding severe serviceconditions. Where necessary, the gageshould be protected by a siphon or trap.

c. Pressure gages intended to measure theoperating pressure in the vessel are notusually sensitive or easily read at lowpressures approaching atmospheric. Itmay be advisable to install an auxiliarygage which reads inches of water (mm ofmercury) and is intended to measurepressure from atmospheric through lowpressures. This gives assurance that thereis zero pressure in the vessel beforeopening. It would be necessary toprotect the auxiliary low pressure gagefrom the higher operating pressures.

d. Provisions should be made to calibratepressure gages or to have them checkedagainst a master gage as frequently asnecessary.


A check should be made to ensure that theclosure and its holding elements must be fullyengaged in their intended operating positionbefore pressure can be applied to the vessel.A device should be provided that preventsthe opening mechanism from operating un-less the vessel is completely depressurized.

RB-3853 CONTROLS

Quick-actuating closures held in position bymanually operated locking devices ormechanisms, and which are subject toleakage of the vessel contents prior todisengagement of the locking elements andrelease of the closure, shall be provided withan audible and/or visible warning device towarn the operator if pressure is applied to thevessel before the closure and its holdingelements are fully engaged, and to warn theoperator if an attempt is made to operate thelocking device before the pressure within the

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vessel is released. Pressure tending to forcethe closure clear of the vessel must be releasedbefore the closure can be opened for access.


a. A review of any equipment logs,maintenance records, test or inspectionrecords should be made. The owner oruser should be consulted regarding re-pairs or alterations made since the last in-spection. Any repairs should be reviewedfor compliance with applicable require-ments.

b. The operation and maintenance of thevessel should be checked to determine if

the manufacturer’s instructions, and theowner’s or user’s supplemental writteninstructions and procedures are followed.

RB-3870 CONCLUSIONS


b. Any defects or deficiencies in thecondition, operating and maintenancepractices of the vessel and auxiliaryequipment should be discussed with theowner or user and recommendationsmade for correction.

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RB-4000 REPLACEMENT OFSTAMPED DATA

RB-4010 SCOPE

When the stamping on a pressure retainingitem becomes indistinct or the nameplate islost, illegible or loose, but traceability to theoriginal pressure retaining item is stillpossible, the Inspector shall instruct theowner or user to have the stamped data re-placed. All restamping shall be done in ac-cordance with the original code of construc-tion. Requests for permission to restamp orreplace nameplates shall be made to the ju-risdiction in which the pressure retaining itemis located. Application must be made on theReplacement of Stamped Data Form NB-136(Appendix 5) and proof of the original stamp-ing and other such data as is available shallbe furnished with the request. The jurisdic-tion may grant such requests if satisfied withthe information submitted. Permission fromthe jurisdiction is not required for the reat-tachment of nameplates that are loose or notfully attached. When traceability cannot beestablished, the jurisdiction shall be con-tacted.

RB-4020 ASME STAMPED ITEMS

Restamping or replacement authorized by thejurisdiction shall be done only in the presenceof an Inspector and shall be identical to theoriginal stamping. When the Code symboland National Board number are to be

restamped, it shall be done only by anemployee of the original manufacturer in thepresence of an Inspector employed by thesame Authorized Inspection Agency as theoriginal Inspector who signed themanufacturer’s data report. Replacementnameplates shall be clearly marked“replacement”.

RB-4030 OTHER ITEMS

Restamping or replacement authorized by thejurisdiction shall be done in the presence ofan Inspector and shall be identical to theoriginal stamping. When required by theconstruction code or standard, restamping ofthe original symbol stamp shall be done byan employee of the original manufacturer inthe presence of an Inspector employed by thesame employer as the original Inspector whoaccepted or certified the item, or an Inspec-tor in the employ of the jurisdiction. Wherethe construction code or standard does notpermit restamping of the original symbol orwhere there is no original symbol, the rulesof the jurisdiction at the point of installationshall apply.

RB-4040 REPORTING

Form NB-136 shall be filed with the jurisdic-tion by the owner or user together with a fac-simile of the stamping or nameplate as ap-plied and shall also bear the signature of theInspector who witnessed the replacement.

PART RC — REPAIRS AND ALTERATIONS OF PRESSURE RETAINING ITEMS

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Repairs and Alterationsof Pressure Retaining Items

Part RC

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PART RC — REPAIRS AND ALTERATIONS OF PRESSURE RETAINING ITEMS TABLE OF CONTENTS

RC-1000 General Requirements ..................................................................................................... 83RC-1010 Scope .................................................................................................................................. 83RC-1020 Construction Standards ................................................................................................... 83RC-1030 Accreditation ..................................................................................................................... 83RC-1040 Materials ............................................................................................................................ 83RC-1050 Replacement Parts ............................................................................................................ 83RC-1060 Authorization.................................................................................................................... 84RC-1070 Inspector ............................................................................................................................ 84RC-1090 Welding .............................................................................................................................. 84RC-1100 Heat Treatment ................................................................................................................. 85RC-1110 Nondestructive Examination ......................................................................................... 86RC-1120 Pressure Gages, Measurement, Examination and Test Equipment .......................... 86RC-1130 Acceptance Inspection ..................................................................................................... 86RC-1140 Stamping ............................................................................................................................ 86RC-1150 Registration of Documentation ...................................................................................... 87

RC-2000 Additional Requirements for Repairs ........................................................................... 88RC-2010 Scope .................................................................................................................................. 88RC-2020 Drawings ........................................................................................................................... 88RC-2030 Authorization.................................................................................................................... 88RC-2050 Examination and Test ...................................................................................................... 88RC-2060 Stamping ............................................................................................................................ 89RC-2070 Documentation ................................................................................................................. 90RC-2080 Repair of ASME Code Section VIII, Division 2, Pressure Vessels ............................. 90

RC-3000 Additional Requirements for Alterations ..................................................................... 91RC-3010 Scope .................................................................................................................................. 91RC-3020 Design ................................................................................................................................ 91RC-3030 Examination and Test ...................................................................................................... 92RC-3040 Stamping ............................................................................................................................ 93RC-3050 Documentation ................................................................................................................. 93


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RC-1000 GENERAL REQUIREMENTS

RC-1010 SCOPE

This part provides general requirements thatapply to repairs and alterations to pressureretaining items, and shall be used inconjunction with Parts RC-2000 and RC-3000.

RC-1020 CONSTRUCTIONSTANDARDS

a. When the standard governing theoriginal construction is the ASME Code,repairs and alterations shall conform,insofar as possible, to the section andedition of the ASME Code most appli-cable to the work planned.

b. When the standard governing theoriginal construction is not the ASMECode, repairs or alterations shall conform,insofar as possible, to the edition of theconstruction standard or specificationmost applicable to the work. Where thisis not possible or practicable, it ispermissible to use other codes, standards,or specifications, including the ASMECode, provided the “R” Certificate Holderhas the concurrence of the Inspector andthe jurisdiction where the pressureretaining item is installed.

RC-1030 ACCREDITATION

Organizations performing repairs oralterations shall be accredited as described inPart RA, as appropriate for the scope of workto be performed.

RC-1040 MATERIALS

The materials used in making repairs oralterations shall conform to the requirementsof the original code of construction. Carbonor alloy steel having a carbon content of morethan 0.35% shall not be welded. The “R”

Certificate Holder is responsible for verify-ing identification of existing materials fromoriginal data, drawings or units records andidentification of the materials to be installed.Consideration shall be given to the conditionof the existing material, especially in the weldpreparation area.

RC-1050 REPLACEMENT PARTS

a. Replacement parts which will be subjectto internal or external pressure thatconsist of new materials which may beformed to the required shape by casting,spinning, forging, die forming and onwhich no fabrication welding isperformed, shall be supplied as material.Such parts shall be marked with thematerial and part identification and thename or trademark of the partsmanufacturer. In lieu of full identifica-tion marking on the material or part, thepart manufacturer may use a coded mark-ing system traceable to the original mark-ing. Such markings shall be consideredas the parts manufacturer’s certificationthat the part complies with the originalcode of construction. Examples includeseamless or welded tubes or pipe, forgednozzles, heads or tube sheets, or subas-semblies attached together mechanically.

b. Replacement parts which will be subjectto internal or external pressure that arepreassembled by attachment welds shallhave the welding performed in accor-dance with the original code ofconstruction. The supplier or manufac-turer shall certify that the material andfabrication are in accordance with theoriginal code of construction. This certi-fication shall be supplied in the form ofbills of material and drawings with state-ment of certification. Examples includeboiler furnace wall or floor panel assem-blies, prefabricated openings in boiler fur-nace walls, such as burner openings, airports, inspection openings, or sootbloweropenings.

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c. When ASME is the original code ofconstruction, replacement parts subject tointernal or external pressure fabricated bywelding, which require shop inspectionby an Authorized Inspector shall befabricated by an organization having anappropriate ASME Certificate of Autho-rization. The item shall be inspected andstamped as required by the applicablesection of the ASME Code. A completedASME Manufacturer’s Partial Data Re-port shall be supplied by the manufac-turer.

d. When the original code of constructionis other than ASME, replacement partssubject to internal or external pressure,fabricated by welding, shall be manufac-tured by an organization certified as re-quired by the original code of construc-tion. The item shall be inspected andstamped as required by the original codeof construction. Certification to the origi-nal code of construction as required bythe original code of construction orequivalent shall be supplied with theitem. When this is not possible or practi-cable, the organization fabricating the partmay have a National Board Certificate ofAuthorization; replacement parts shall bedocumented on Form R-3 and the “R”symbol stamp applied as described inAppendix 2.

RC-1060 AUTHORIZATION

The Inspector’s authorization to perform arepair or alteration shall be obtained prior toinitiation of a repair or alteration to a pres-sure retaining item. The Inspector makingthe acceptance inspection should be the sameInspector who authorized the repair or alter-ation, but, in all cases, shall be an employeeof the same organization as that of the Inspec-tor that authorized the repair or alteration.

RC-1070 INSPECTOR

Inspection and certification shall be made byan Inspector employed by one of thefollowing:

a. A Jurisdictional Authorized InspectionAgency,

b. The Authorized Inspection Agency of the“R” Certificate Holder making the repairor alteration,

c. The Authorized Inspection Agency whichinsures the pressure retaining item, or

d. The Owner-User Inspection Organiza-tion. An Inspector employed by anOwner-User Inspection Organizationmay authorize and accept work only onpressure retaining items owned-used bythe company. The company’s organiza-tion and inspection procedures shall havethe specific approval of the Jurisdiction,or in the absence of a Jurisdiction, by theNational Board.

RC-1090 WELDING

Welding shall be performed in accordancewith the requirements of the original code ofconstruction used for the pressure retainingitem.

RC-1091 WELDING PROCEDURESPECIFICATIONS

Welding shall be performed in accordancewith Welding Procedure Specifications (WPS)qualified in accordance with the original codeof construction. When this is not possible orpracticable, the WPS may be qualified inaccordance with Section IX of the ASMECode.


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RC-1092 STANDARD WELDINGPROCEDURESPECIFICATIONS

An “R” Certificate Holder may use one ormore applicable Standard Welding ProcedureSpecifications shown in Appendix A.

RC-1093 PERFORMANCEQUALIFICATION

Welders or welding operators shall bequalified for the welding processes that areused. Such qualification shall be in accor-dance with the requirements of the originalcode of construction, or Section IX of theASME Code.

RC-1094 RECORDS

The “R” Certificate Holder shall maintain arecord of the results obtained in weldingprocedure qualifications, except for thosequalifications for which the provisions ofRC-1092 are used and of the results obtainedin welding performance qualifications. Theserecords shall be certified by the “R” Certifi-cate Holder and shall be available to the In-spector.

RC-1095 WELDERS’IDENTIFICATION

The “R” Certificate Holder shall establish asystem for the assignment of a unique iden-tification mark to each welder/welding op-erator qualified in accordance with the re-quirements of the NBIC. The “R” CertificateHolder shall also establish a written proce-dure whereby all welded joints can be identi-fied as to the welder or welding operator whomade them. This procedure shall use one ormore of the following methods and beacceptable to the Inspector. The welder’s orwelding operator’s identification mark maybe stamped (low stress stamp) adjacent to allwelded joints made by the individual, or inlieu of stamping, the “R” Certificate Holder

may keep a record of welded joints andthe welders or welding operators used inmaking the joints.

RC-1096 WELDERS’ CONTINUITY

The performance qualification of a welder orwelding operator shall be affected when oneof the following conditions occur:

a. When the welder or welding operator hasnot welded using a specific process dur-ing a period of six (6) months or more,their qualifications for that process shallexpire.

b. When there is specific reason to questiontheir ability to make welds that meet thespecification, the qualification which sup-ports the welding that is being performedshall be revoked. All other qualificationsnot questioned remain in effect.

RC-1100 HEAT TREATMENT

RC-1101 PREHEATING

Preheating may be employed duringwelding to assist in completion of the weldedjoint (Appendix B). The need for and thetemperature of preheat are dependent on anumber of factors, such as chemical analysis,degree of restraint of the items being joined,material thickness, and mechanical proper-ties. The welding procedure specification forthe material being welded shall specify thepreheat temperature requirements.

RC-1102 POSTWELD HEATTREATMENT

Postweld heat treatment shall be performedas required by the original code ofconstruction in accordance with a writtenprocedure. The procedure shall contain theparameters for postweld heat treatment.

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RC-1103 ALTERNATIVE POSTWELDHEAT TREATMENTMETHODS

Under certain conditions, postweld heattreatment in accordance with the code ofconstruction may be inadvisable orimpractical. In such instances, alternativemethods of postweld heat treatment orspecial welding methods acceptable to theInspector may be used. Methods which maybe used as alternatives to postweld heat treat-ment are described in Part RD.

RC-1110 NONDESTRUCTIVEEXAMINATION

a. The nondestructive examination (NDE)requirements, including technique, extentof coverage, procedures, personnel quali-fication, and acceptance criteria, shall bein accordance with the original code ofconstruction used for construction of thepressure retaining item. Weld repairs andalterations shall be subjected to the samenondestructive examination requirementsas the original welds. Where this is notpossible or practicable, alternative NDEmethods acceptable to the Inspector andthe jurisdiction where the pressure retain-ing item is installed, where required, maybe used.

b. NDE personnel shall be qualified inaccordance with the requirements of theoriginal code of construction. When thisis not possible or practicable, NDE per-sonnel may be qualified in accordancewith ASNT SNT-TC-1A (1992 Edition)Recommended Practice for Nondestruc-tive Testing Personnel Qualification andCertification.

RC-1120 PRESSURE GAGES,MEASUREMENT,EXAMINATION AND TESTEQUIPMENT

The calibration of pressure gages, measure-ment, examination and test equipment anddocumentation of calibration shall be per-formed as required by the applicable standardused for construction.

RC-1130 ACCEPTANCE INSPECTION

Before signing the appropriate NBIC ReportForm, the Inspector shall review thedrawings, assure the welding was performedin accordance with the original code ofconstruction, witness any pressure testapplied, assure that the required nondestruc-tive examinations have been performed sat-isfactorily, and that the other functions nec-essary to assure compliance with the require-ments of this Code have been performed.

RC-1140 STAMPING

The stamping of, or attaching of a nameplateto, a pressure retaining item shall indicate thatthe work was performed in accordance withthe requirements of this Code. Suchstamping or attaching of a nameplate shallbe done only with the knowledge andauthorization of the Inspector. The “R”Certificate Holder responsible for the repairor alteration shall apply the stamping.Required stamping and nameplate informa-tion is shown in Appendix 2.


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RC-1141 REMOVAL OF ORIGINALSTAMPING ORNAMEPLATE

If it becomes necessary to remove theoriginal stamping, the Inspector shall, sub-ject to the approval of the Jurisdiction, wit-ness the making of a facsimile of the stamp-ing, the obliteration of the old stamping, andthe transfer of the stamping to the new item.When the stamping is on a nameplate, theInspector shall witness the transfer of thenameplate to the new location. Anyrelocation shall be described on the applicableNBIC Form. ASME Code items shall not berestamped with the ASME Code Symbol.

RC-1150 REGISTRATION OFDOCUMENTATION

Organizations performing repairs oralterations under an “R” stamp program mayregister such repairs or alterations with theNational Board.

It should be noted that some jurisdictions mayrequire registration of repairs and alterationswith the National Board.

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RC-2000 ADDITIONALREQUIREMENTS FORREPAIRS

RC-2010 SCOPE

This section provides additional requirementsfor repairs to pressure retaining items andshall be used in conjunction with PartRC-1000.

RC-2020 DRAWINGS

As appropriate, drawings shall be preparedto describe the repair. Drawings shall includesufficient information to satisfactorilyperform the repair.

RC-2030 AUTHORIZATION

a. Repairs to pressure retaining items shallnot be initiated without the authorizationof the Inspector, who shall determine, thatthe repair methods are acceptable.

b. Subject to acceptance of the Jurisdiction,the Inspector may give prior approval forroutine repairs, provided the Inspectorassures that the “R” Certificate Holder hasacceptable procedures covering the re-pairs.

RC-2031 ROUTINE REPAIRS

Prior to performing routine repairs the “R”Certificate Holder should determine thatroutine repairs are acceptable to thejurisdiction where the pressure retaining itemis installed.

a. The four categories of routine repairs are:

1. Welded repairs or replacements oftubes or pipes, or sections thereof five(5) NPS in diameter and under, andtheir attachments.

2. The addition or repair of non-loadbearing attachments to pressureretaining items where postweld heattreatment is not required.

3. Weld buildup of wasted areas in shellsand heads not exceeding 100 sq. in.or 25% of nominal wall thickness or1/2 in., whichever is less.

4. Corrosion resistance weld overlay notexceeding 100 sq. in.

b. Routine repairs shall be performed underthe “R” Certificate Holder ’s qualitysystem program; however, the require-ment for in-process involvement of theInspector and stamping may be waived.See RC-2060.

c. The process of identifying, controllingand implementing routine repairs shall bedocumented in the “R” CertificateHolder’s quality system program.

d. Routine repairs shall be documented ona Form R-1 with a statement on line 9,Remarks: “Routine Repair”.

RC-2050 EXAMINATION AND TEST

The following requirements shall apply to allrepairs to pressure retaining items:

a. The integrity of repairs and replacementparts used in repairs shall be verified byexamination or test.

b. The “R” Certificate holder is responsiblefor all activities relating to examinationand test of repairs.

c. Examinations and tests to be used shallbe subject to acceptance of the Inspector,and where required, acceptance of thejurisdiction.


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RC-2051 METHODS

Based on the nature and scope of the repairactivity, one or a combination of the followingexamination and test methods shall beapplied to repairs and replacement parts usedin repairs.

a. Liquid Pressure TestPressure testing of repairs shall meet thefollowing requirements:

1. Pressure tests shall be conductedusing water or other liquid medium.The test pressure shall be theminimum required to verify the leaktightness integrity of the repair, butnot more than 150% of the maximumallowable working pressure (MAWP)stamped on the pressure retainingitems, as adjusted for temperature.When original test pressure includedconsideration of corrosion allowance,the test pressure may be furtheradjusted based on the remainingcorrosion allowance.

2. During a pressure test, where the testpressure will exceed the set pressureof the pressure relief device, thedevice shall be removed or preparedas recommended by the devicemanufacturer.

3. The metal temperature for thepressure test shall be in accordancewith the original code of construction,but not less than 60°F (15.6°C) unlessthe owner provides information onthe toughness characteristics of thematerial to indicate the acceptabilityof a lower test temperature. Duringclose examination the metaltemperature shall not exceed 120°F(49°C) unless the owner specifiedrequirements for a higher testtemperature and it is acceptable to theInspector.

4. Hold-time for the pressure test shallbe a minimum of 10 minutes prior to

examination by the Inspector. Wherethe test pressure exceeds the MAWPof the item, the test pressure shall bereduced to the MAWP for closeexamination by the Inspector.Hold-time for close examination shallbe as necessary for the Inspector toconduct the examination.

b. Pneumatic TestA pneumatic test may be conducted.Concurrence of the owner shall beobtained in addition to the Inspector, andjurisdiction where required. The testpressure shall be the minimum requiredto verify leak tightness integrity of therepair, but shall not exceed the maximumpneumatic test pressure of the originalcode of construction. Precautionaryrequirements of the original code ofconstruction shall be followed.

c. Initial Service Leak TestWhen an initial service leak test is per-mitted by the original code of con-struction, such testing may also be usedto verify the leak tightness integrity ofrepairs.

d. Vacuum TestA vacuum test may be conducted.Vacuum test methods used shall be suit-able to verify the leak tightness integrityof the repair.

e. Nondestructive ExaminationNondestructive examination (NDE) maybe conducted. NDE methods used shallbe suitable for providing meaningfulresults to verify the integrity of the repair.

RC-2060 STAMPING

a. Pressure retaining items repaired inaccordance with the NBIC shall bestamped as required by Appendix 2.

b. Subject to the acceptance of thejurisdiction and the concurrence of the

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Inspector, nameplates and stamping maynot be required for routine repairs(RC-2031). In all cases, the type andextent of repairs necessary shall beconsidered prior to waiving therequirement.

RC-2070 DOCUMENTATION

Repairs that have been performed inaccordance with the National BoardInspection Code shall be documented onForm R-1 Report of Welded Repair, as shownin Appendix 5. Form R-4 Report Supplemen-tary Sheet shall be used to record additionaldata when space is insufficient on Form R-1.

RC-2071 PREPARATION OFFORM R-1

a. Preparation of Form R-1 shall be theresponsibility of the “R” CertificateHolder performing the repair.

b. An Inspector shall indicate acceptance bysigning the Form R-1.

c. The Form R-3 and the manufacturer’sdata reports described in RC-1050 shallbe a part of the completed Form R-1 andshall be attached thereto.

RC-2072 DISTRIBUTION

a. Legible copies of the completed FormR-1, together with attachments, shall bedistributed to the owner or user, the In-spector, the jurisdiction if required, andthe Authorized Inspection Agency re-sponsible for inservice inspection. FormR-1 may be registered with the NationalBoard as noted in RC-1150.

b. Distribution of Form R-1 and attachmentsshall be the responsibility of the organi-zation performing the repair.

RC-2080 REPAIR OF ASME CODESECTION VIII, DIVISION 2,PRESSURE VESSELS

RC-2081 SCOPE

The following requirements apply for therepair of pressure vessels constructed to therequirements of Section VIII, Division 2, ofthe ASME Code.

RC-2082 REPAIR PLAN

The user shall prepare or cause to haveprepared a detailed plan covering the scopeof the repair.

a. Professional Engineer ReviewThe repair plan shall be reviewed andcertified by a professional engineer whois registered in one or more of the statesof the United States of America or theprovinces of Canada and is experiencedin pressure vessel design. The review andcertification shall be such as to ensure thatthe work involved in the repair iscompatible with the user ’s designspecification and the manufacturer ’sdesign report.

b. Authorized InspectionAgency AcceptanceFollowing review and certification, the re-pair plan shall be submitted foracceptance to the Authorized InspectionAgency whose Inspector will make theacceptance inspection and sign the FormR-1.


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RC-3000 ADDITIONALREQUIREMENTS FORALTERATIONS

RC-3010 SCOPE

This section provides additional requirementsfor alterations to pressure retaining items, andshall be used in conjunction with RC-1000.

RC-3020 DESIGN

The “R” Certificate Holder performingalterations shall establish controls to ensurethat all required design information,applicable drawings, design calculations,specifications and instructions are prepared,obtained, controlled and interpreted toprovide the basis for an alteration inaccordance with the original code of construc-tion. When a Manufacturer’s Data Report isrequired by the original constructionstandard, a copy of the original Data Reportshall be obtained for use in the design of thealteration. When the original Manufacturer’sData Report cannot be obtained, agreementson the method of establishing design basis forthe alteration shall be obtained from theInspector and the jurisdiction.

RC-3021 CALCULATIONS

A set of calculations shall be completed priorto the start of any physical work. All designwork shall be completed by an organizationexperienced in the design portion of the stan-dard used for construction of the item. Allcalculations shall be made available forreview by the Inspector accepting the design.

RC-3022 RE-RATING 4

Re-rating of a pressure retaining item byincreasing the maximum allowable working

4Re-rating: This code does not provide rules for derating boilers or pressure vessels; however, when the MAWPand/or allowable temperature of a boiler or pressure vessel is reduced, the jurisdiction wherein theobject is installed should be contacted to determine if specific procedures should be followed.

pressure (internal or external) or temperature,or decreasing the minimum temperature suchthat additional mechanical tests are required,shall be done only after the followingrequirements have been met to thesatisfaction of the jurisdiction at the locationof the installation:

a. Revised calculations verifying the newservice conditions shall be prepared inaccordance with the “R” CertificateHolder’s Quality Control System.

b. All re-ratings shall be established inaccordance with the requirements of theconstruction standard to which thepressure retaining item was built.

c. Current inspection records verify that thepressure retaining item is satisfactory forthe proposed service conditions.

d. The pressure retaining item has beenpressure tested, as required, for the newservice conditions.

RC-3023 DRAWINGS

As appropriate, drawings shall be preparedto describe the alteration. Drawings shallinclude sufficient information to satisfactorilyperform the alteration.

RC-3024 ALLOWABLE STRESSES

For rerating or recalculating a new minimumwall thickness for a pressure retaining itemusing a later edition/addenda of the originalcode of construction, that permits use ofhigher allowable material stress values thanwere used in the original construction, theadditional requirements of RD-3000 shallapply.

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RC-3030 EXAMINATION AND TEST

The following requirements shall apply to allalterations to pressure retaining items:

a. The integrity of alterations and replace-ment parts used in alterations shall beverified by examination or test.

b. The “R” Certificate Holder is responsiblefor all activities relating to examinationand test of alterations.

c. Examinations and tests to be used shallbe subject to acceptance of the Inspector,and where required, acceptance of thejurisdiction.

RC-3031 METHODS

Based on the nature and scope of thealterations activity, one or a combination ofthe following examination and test methodsshall be applied to alterations andreplacement parts used in alterations.

a. Liquid Pressure TestPressure testing of alterations shall meetthe following requirements:

1. A pressure test as required by theoriginal code of construction shall beconducted. The test pressure shall notexceed 150% of the maximum allow-able working pressure (MAWP)stamped on the pressure retainingitem, as adjusted for temperature.When the original test pressureincluded consideration of corrosionallowance, the test pressure may befurther adjusted based on theremaining corrosion allowance. Thepressure test for replacement partsmay be performed at the point ofmanufacture or point of installation.

2. As an alternative to pressure testingconnecting welds in accordance withthe original code of construction,connecting welds may be tested or

examined in accordance with the rulesfor repairs (see RC-2051). Connectingwelds are defined as welds attachingthe replacement part to the pressureretaining item.

3. During a pressure test, where the testpressure will exceed the set pressureof the pressure relief device, thedevice shall be removed or preparedas recommended by the device manu-facturer.

4. The metal temperature for the pres-sure test shall be in accordance withthe original code of construction, butnot less than 60°F (15.6°C) unless theowner provides information on thetoughness characteristics of thematerial to indicate the acceptabilityof a lower test temperature. Duringclose examination the metal temper-ature shall not exceed 120°F (49°C)unless the owner specifies require-ments for a higher test temperatureand it is acceptable to the Inspector.

5. Hold-time for the pressure test shallbe a minimum of 10 minutes prior toexamination by the Inspector. The testpressure shall be reduced to theMAWP for close examination by theInspector. Hold-time for close exami-nation shall be as necessary for theInspector to conduct the examination.

b. Pneumatic TestA pneumatic test may be conducted whencontamination of the pressure retainingitem by liquids is possible or when liquidpressure testing is not practicable.Concurrence of the owner shall be ob-tained in addition to the Inspector, andjurisdiction where required. Pneumatictest requirements and precautions shall bein accordance with the original code ofconstruction.

c. Nondestructive ExaminationNondestructive examination (NDE) maybe conducted when contamination of the


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pressure retaining item by liquids is pos-sible or when pressure testing is not prac-ticable. Concurrence of the owner shall beobtained in addition to the Inspector, andjurisdiction where required. NDE meth-ods used shall be suitable for providingmeaningful results to verify the integrityof the alteration.

RC-3040 STAMPING

The nameplate or stamping shall be appliedadjacent to the original manufacturer ’sstamping or nameplate in accordance withAppendix 2.

RC-3050 DOCUMENTATION

Alterations performed in accordance with theNational Board Inspection Code shall bedocumented on Form R-2, Report ofAlteration, as shown in Appendix 5. FormR-4 Report Supplementary Sheet shall beused to record additional data when space isinsufficient on Form R-2.

RC-3051 PREPARATION

a. Preparation of Form R-2, shall be theresponsibility of the “R” CertificateHolder performing the alteration. Themanufacturer’s reports or Form R-3, asdescribed in RC-1050, and for boilers andpressure vessels a copy of the originalManufacturer ’s Data Report, whenavailable, shall be attached to and becomea part of the completed Form R-2.

b. The “R” Certificate Holder that certifiesthe “Design Change” shall complete andsign the “Design Certification” section ofthe Form R-2. An Inspector shall indicateacceptance of the design by signing the“Certificate of Design Change Review”section of the Form R-2.

c. The “R” Certificate Holder performingthe alteration shall complete and sign the“Construction Certification” section of theForm R-2. An Inspector shall indicateacceptance of the installation by signingthe “Certificate of Inspection” section ofthe Form R-2.

RC-3052 DISTRIBUTION

a. Legible copies of the completed FormR-2, Report of Alteration, together withattachments, shall be distributed by the“R” Certificate Holder performing thealteration, to the Inspector, the Autho-rized Inspection Agency responsible forthe in-service inspection of the pressureretaining item, the owner or user, and thejurisdiction, if required.

b. If the item is registered with theNational Board, one original and one leg-ible copy shall be submitted to the Na-tional Board.

c. If the item is not registered with theNational Board, one original and onelegible copy may be submitted to theNational Board.

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PART RD — REPAIR/ALTERATION METHODS

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Repair/Alteration Methods

Part RD

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PART RD — REPAIR/ALTERATION METHODSTABLE OF CONTENTS

RD-1000 Welding Methods as Alternatives to Postweld Heat Treatment ............................... 97RD-1010 Scope .................................................................................................................................. 97RD-1020 Nondestructive Examination of Welds ......................................................................... 97RD-1030 Welding Method 1 ............................................................................................................ 97RD-1040 Welding Method 2 ............................................................................................................ 98RD-1050 Welding Method 3 ............................................................................................................ 99RD-1060 Welding Method 4 .......................................................................................................... 101

RD-2000 Repair Methods .............................................................................................................. 104RD-2010 Scope ................................................................................................................................ 104RD-2020 Defect Repairs ................................................................................................................. 104RD-2030 Wasted Areas ................................................................................................................... 104RD-2040 Seal Welding.................................................................................................................... 105RD-2050 Re-Ending or Piecing Pipes or Tubes .......................................................................... 105RD-2060 Patches ............................................................................................................................. 105RD-2070 Stays ................................................................................................................................. 105

RD-3000 Alterations Based on Allowable Stress Values ........................................................... 111RD-3010 Re-rating ........................................................................................................................... 111RD-3020 Minimum Wall Thickness .............................................................................................. 111


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RD-1000 WELDING METHODS ASALTERNATIVES TOPOSTWELD HEATTREATMENT

RD-1010 SCOPE

a. Under certain conditions, postweld heattreatment in accordance with the originalcode of construction may be inadvisableor impractical. In such instances, the fol-lowing alternative methods may be used.

b. Competent technical advice shall beobtained from the manufacturer of thepressure retaining item or from anotherqualified source, such advice being espe-cially necessary if the alternative is to beused in highly stressed areas, if serviceconditions are conducive to stress corro-sion cracking, if materials are subject tohydrogen embrittlement or are operatingat temperatures in the creep range, or ifthe alternative is being considered for“on-stream” repairs or “hot tapping” onpiping systems. Selection of the weldingmethod used shall be based on the rulesof the original code of constructiontogether with the above mentioned adviceconcerning the adequacy of the weld inthe as-welded condition at operating andpressure test conditions.

c. When reference is made in this part tomaterials by the ASME designation, P-Number and Group Number, the require-ments of this part apply to the applicablematerials of the original code of construc-tion, either ASME or other, which con-form by chemical composition and me-chanical properties to the ASME P-Num-ber and Group Number designations.

RD-1020 NONDESTRUCTIVEEXAMINATION OF WELDS

Prior to welding, the area prepared for weld-ing shall be examined using either themagnetic particle (MT) or the liquid penetrant

(PT) examination method to determine thatno defects exist. After the finished repair weldhas reached ambient temperature, the weldshall be examined again by either of the abovemethods to determine that no defects existusing acceptance standards acceptable to theInspector or original code of construction. Inaddition, welded repairs greater than 3/8 in.(9.6 mm) deep or welds in a boiler, pressurevessel or piping systems that were originallyrequired to be radiographed by the rules ofthe original code of construction, shall be ra-diographically examined. In situations whereit is not practical to perform radiography theaccessible surfaces of each nonradiographedrepair weld shall be fully examined using theMT or PT method to determine that no de-fects exist, and the maximum allowable work-ing pressure and/or allowable temperatureshall be reevaluated to the satisfaction of thejurisdiction at the location of installation.

RD-1030 WELDING METHOD 1

a. This method may be used when theapplicable rules of the original code ofconstruction did not require notch tough-ness testing.

b. The materials shall be limited to P-No. 1,Group 1, 2, and 3, and to P-No. 3, Group1 and 2 (excluding Mn-Mo steels in Group2), as permitted for welded constructionby the applicable rules of the original codeof construction.

c. The welding shall be limited to theshielded metal-arc welding (SMAW), gasmetal-arc welding (GMAW), fluxcored arcwelding (FCAW) and gas tungsten-arcwelding (GTAW) processes.

d. The welders and welding procedures(WPS) shall be qualified in accordancewith the applicable rules of the originalcode of construction, except that the post-weld heat treatment of the test couponused to qualify the weld procedure shallbe omitted.

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e. The weld area shall be preheated andmaintained at a minimum temperature of300˚F (149˚C) during welding. The 300˚F(149˚C) temperature should be checked toassure that 4 in. (102 mm) of the materialor four times the material thickness(whichever is greater) on each side of thegroove (or full thickness of joint for agroove weld) is maintained at the mini-mum temperature during welding. Themaximum interpass temperature shall notexceed 450˚F (232˚C). When the welddoes not penetrate through the full thick-ness of the material, the minimum pre-heat and maximum interpass tempera-tures need only be maintained at a dis-tance of 4 in. (102 mm) or four times thedepth of the repair weld, whichever isgreater on each side of the joint.


a. This method shall be used when theapplicable rules of the original code ofconstruction required notch toughnesstesting or shall be used when the appli-cable rules of the original code of con-struction did not require notch toughnesstesting provided the adequacy of thenotch toughness of the weld, includingthe heat-affected zone, in the as-weldedcondition at operating and pressure testconditions is verified.

b. The materials shall be limited to carbonand low alloy steels permitted for weldedconstruction by the applicable rules of theoriginal code of construction, includingthose materials conforming to any of thefollowing ASME P-No. designations:P-No. 1, Group 1, 2 and 3, P-No. 3, Group1, 2 and 3, P-No. 4, P-No. 5A, P-No. 5B, P-No. 5C, P-No. 9A, P-No. 10A, P-No. 11A,or P-No. 11B.

c. The welding shall be limited to theshielded metal-arc welding (SMAW), gasmetal-arc welding (GMAW), fluxcoredarc welding (FCAW) and gas tungsten-arcwelding (GTAW) processes.

d. The welders and welding procedures(WPS) shall be qualified in accordancewith the applicable rules of the originalcode of construction, except that the post-weld heat treatment of the test couponused to qualify the weld procedure shallbe omitted. The qualification thicknessfor the test plates and repair grooves shallbe in accordance with Table 1.

e. As shown in Table 1, the depth of therepair groove (or full thickness of a jointfor a groove weld) in base metal or inweld metal is not limited provided the testmaterial thickness for the welding proce-dure qualification is at least five times thedepth of the repair but need not exceedthe thickness of the material to be re-paired, provided the required test speci-mens can be removed. When the thick-ness of the base metal to be repaired isgreater than 2 in. (51 mm), the procedurequalification test material need not exceed2 in. (51 mm); however, the depth of thegroove in the test material shall be thegreater of 1 in. (25 mm) or the depth ofthe groove to be repaired.

f. The test material for the welding proce-dure qualification shall be of the samematerial specification (including specifi-cation type, grade, class and condition ofheat treatment) as the original materialspecification for the repair. In the eventthat the notch toughness of the materialto be repaired is unknown, evidence fromtests of that material or from another ac-ceptable source (see RD-1010) may beused for the base metal notch toughnesswhen qualifying the WPS as required in(g). In the event that the original materialspecification is obsolete, the test materialused should conform as close as possibleto the original material used for construc-tion, but in no case shall the material belower in strength.

g. The organization making the repair shallinclude, when qualifying its WPS, suffi-cient tests to determine that the toughnessof the weld metal and the heat-affected


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zone of the base metal in the as-weldedcondition is adequate at the minimumoperating and pressure test temperatures(including start-up and shutdown).When these conditions are met, any origi-nal code of construction credit for PWHTmay be continued. If for reasons of cor-rosion resistance, special hardness limitsare necessary, such limits shall be in-cluded when qualifying the WPS.

h. Notch toughness shall be determined andevaluated by Charpy impact tests inaccordance with the provisions of theoriginal code of construction.

i. The WPS shall include the followingadditional requirements:

1. The supplemental essential variableof ASME Code, Section IX, paragraphQW-250, shall apply;

2. The maximum weld heat input foreach layer shall not exceed that usedin the procedure qualification test;

3. The minimum preheat temperaturefor welding shall not be less than thatused in the procedure qualificationtest;

4. The maximum interpass temperaturefor welding shall not be greater thanthat used in the procedure qualifica-tion test;

5. The preheat temperature shall bechecked to assure that 4 in. (102 mm)of the material or four times the ma-terial thickness (whichever is greater)on each side of the weld joint will bemaintained at the minimum tempera-ture during welding. When the welddoes not penetrate through the fullthickness of the material, the mini-mum preheat temperature need onlybe maintained at a distance of 4 in.(102 mm) or four times the depth ofthe repair weld, whichever is greateron each side of the joint;

6. For the welding process in (c) above,use only electrodes and filler metalswhich are classified by the filler metalspecification with an optional supple-mental diffusible-hydrogen designa-tor of H8 or lower. When shieldinggases are used with a process, the gasshall exhibit a dew point that is nolower than -60°F (-50°C). Surfaces onwhich welding will be done shall bemaintained in a dry condition duringwelding and be free of rust, millscale and hydrogen producingcontaminents such as oil, grease andother organic materials.

7. The welding technique shall be acontrolled-deposition, temper bead orhalf bead technique. The specifictechnique or specific combinations oftechniques shall be that used in theprocedure qualification test;

8. For welds made by SMAW andFCAW, after completion of weldingand without allowing the weldmentto cool below the minimum preheattemperature, the temperature of theweldment shall be raised a tempera-ture of 500°F ± 50°F (260°C ± 30°C) fora minimum period of two hours. Thishydrogen bake-out treatment may beomitted provided the electrode usedis classified by the filler metal specifi-cation with an optional supplemen-tal diffusible-hydrogen designator ofH4 (e.g., E7018-H4); and

9. After the finished repair weld hascooled to ambient temperature, thefinal temper bead reinforcement layershall be removed substantially flushwith the surface of the base material.


a. This method may be used when theapplicable rules of the original code ofconstruction did not require notch tough-ness testing.

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b. The materials shall be limited to any P-No. 1 or P-No. 3 material as permitted forwelded construction by the applicablerules of the original code of construction.

c. The welding shall be limited to the shieldedmetal-arc welding (SMAW) and gas tungsten-arc welding (GTAW)processes.

d. The welders and welding procedures(WPS) shall be qualified in accordancewith the applicable rules of the originalcode of construction, except that the post-weld heat treatment of the test couponused to qualify the weld procedure shallbe omitted. The qualification thicknessesfor the test plates and repair grooves shallbe in accordance with Table 1.

e. As shown in Table 1, the depth of therepair groove (or full thickness of a jointfor a groove weld) in base metal or inweld metal is not limited provided the testmaterial thickness for the welding proce-dure qualification is at least five times thedepth of the repair but need not exceedthe thickness of the material to be re-paired, provided the required test speci-mens can be removed. When the thick-ness of the base metal to be repaired isgreater than 2 in. (51 mm), the procedurequalification test material need not exceed2 in. (51 mm); however, the depth of thegroove in the test material shall be thegreater of 1 in. (25 mm) or the depth ofthe groove to be repaired.

f. The test material for the welding proce-dure qualification shall be of the sameP-No. and Group No. as the originalmaterial specification for the repair. In theevent that the original material specifica-tion is obsolete, the test material usedshould conform to the nominal composi-tion and carbon equivalent (IIW formula)as the original material used for construc-tion, but in no case shall the material belower in strength.

g. If for reasons of corrosion resistance,special hardness limits are necessary, such

limits shall be included when qualifyingthe WPS.

h. The WPS shall include the followingadditional requirements:

1. The maximum weld heat input foreach layer shall not exceed that usedin the procedure qualification test;

2. The minimum preheat temperaturefor welding shall be 350°F (177°C) andthe maximum interpass temperatureshall be 450°F (232°C);

3. For SMAW, only electrodes with lowhydrogen characteristics shall beused;

4. The welding technique shall be acontrolled-deposition, temper bead orhalf bead technique. The specifictechnique or specific combinations oftechniques shall be that used in theprocedure qualification test;

5. For SMAW the electrode size shall notexceed 1/8 in. (3.2 mm) and for GTAWthe electrode size and the filler metalsize shall not exceed 3/32 in. (2.4 mm);

6. For welds made by SMAW, aftercompletion of welding and withoutallowing the weldment to cool belowthe minimum preheat temperature,the temperature of the weldment shallbe raised to a temperature of 500°F± 50°F (260°C ± 30°C) for a minimumperiod of two hours. This hydrogenbake-out treatment may be omittedprovided the electrodes used are clas-sified by the filler metal specificationwith an optional supplemental diffus-ible-hydrogen designator of H4 (e.g.,E7018-H4); and

7. After the finished repair weld hascooled to ambient temperature, thefinal temper bead reinforcement layershall be removed substantially flushwith the surface of the base material.


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a. This method is limited to boilers for whichthe applicable rules of the original codeof construction did not require notchtoughness testing.

b. The materials shall be limited to P-No. 4,Groups 1 and 2 and P-No. 5A steels aspermitted for welded construction by theapplicable rules of the original code ofconstruction.

c. The welding shall be limited to theshielded metal-arc welding (SMAW) pro-cess using low hydrogen electrodes clas-sified by the filler metal specification withan optional supplemental diffusable-hy-drogen designator of H8 or lower andsuitably controlled by maintenance pro-cedures to avoid contamination by hydro-gen producing sources. The surface of themetal prepared for welding shall be freeof contaminants.

d. The welders and welding proceduresshall be qualified in accordance with theapplicable rules of the original code ofconstruction, except that the postweldheat treatment of the test coupon used toqualify the weld procedure shall be omit-ted.

e. As shown in Table 1, the depth of the re-pair groove (or full thickness of a joint fora groove weld) in the base metal or inweld metal is not limited provided the testmaterial thickness for the welding proce-dure qualification is at least five times thedepth of the repair, but need not exceedthe thickness of the material to be re-paired, provided the required test speci-mens can be removed. When the thick-ness of the base metal to be repaired isgreater than 2 in. (51 mm), the procedurequalification test material need not exceed2 in. (51 mm); however, the depth of thegroove in the test material shall be thegreater of 1 in. (25 mm) or the depth ofthe groove to be repaired.

f. The test material for the welding proce-dure qualification shall be of the same P-No. and Group No. as the original mate-rial specification for the repair. In theevent that the original material specifica-tion is obsolete, the test material usedshall conform to the nominal compositionand carbon equivalent (IIW formula) asthe original material used for construc-tion, and in no case shall the material belower in strength.

g. If for reasons of corrosion resistance, spe-cial hardness limits are necessary, suchlimits shall be included when qualifyingthe WPS.

h. The WPS shall include the following ad-ditional requirements:

1. The minimum preheat temperaturefor welding shall be 300°F (150°C) forP-No. 4 material and 400°F (200°C) forP-No. 5A material. The preheat tem-perature shall be checked to assurethat 4 in. (100 mm) of the material orfour times the material thickness(whichever is greater) on each side ofthe groove (or full thickness of jointfor a groove weld) is maintained at theminimum temperature during weld-ing. The maximum interpass tem-perature shall not exceed 800°F(430°C). When the weld does not pen-etrate through the full thickness of thematerial, the minimum preheat andmaximum interpass temperatureneed only be maintained for 4 in. (100mm) or four times the depth of therepair weld (whichever is greater) oneach side of the joint.

2. The welding technique shall be a con-trolled-deposition temper bead tech-nique and shall include a butteringlayer deposited over the entire groovefaces (or fillet leg faces) using a3/32 in. (2.4 mm) diameter electrode.The buttering layer shall be deposited

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using stringer beads with an overlapof approximately 50%. The secondand remaining layers shall be depos-ited over the buttering layer using a1/8 in. (3.2 mm) diameter electrode.The second and remaining layers shallnot contact the base material and shallbe deposited using stringer beads.After the groove is filled (or fillet sizeis achieved), a 1/8 in. (3.2 mm) thickreinforcement layer shall be depositedto temper the prior weld layer. Thistemper layer shall be deposited towithin 1/8 in. (3.2 mm) of the toe ofthe weld, but no closer than 1/16 in.(1.6 mm).

3. After completion of welding and with-out allowing the weldment to cool

below the minimum preheat tempera-ture, the temperature of the weldmentshall be raised to a temperature of500°F ± 50°F (260°C ± 30°C) for a mini-mum period of two hours. This hy-drogen bake-out treatment may beomitted provided the electrode usedis classified by the filler metal specifi-cation with an optional supplementaldiffusable-hydrogen designator of H4(e.g., E7018-H4).

4. After the finished repair weld hascooled to ambient temperature, the fi-nal temper bead reinforcement layershall be removed substantially flushwith the surface of the base metal (andfor a fillet weld to the required sizeand suitable contour of the toes).


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TABLE 1 —WELDING METHODS AS ALTERNATIVES TO POSTWELD HEAT TREATMENT

QUALIFICATION THICKNESSES FOR TEST PLATES AND REPAIR GROOVES

BASE METAL REPAIR PQR TEST MATERIAL PQR GROOVE THICKNESSTHICKNESS GROOVE THICKNESS DEPTH QUALIFIED

DEPTH NOTE (2) NOTE (1)

< 2" <1" 5 times the repair <1" See PQRcavity depth, but testneed not exceed materialthe thickness of thicknessthe base metal to columnbe repaired and ≤ PQR

groovedepth

≤ 2" >1" Thickness of the >1" ≤ PQR testbase metal to be materialrepaired thickness

and ≤ PQRgroovedepth

>2" 1" 2" 1" All basemetalthicknessand ≤ 1"repairgroovedepth

>2" >1" 2" >1" All basemetalthicknessand ≤ PQRgroovedepth

1. Repair groove depth is limited to the maximum depth qualified.

2. The depth of the groove used for procedure qualification must be deep enough to removetest specimens.

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RD-2000 REPAIR METHODS

RD-2010 SCOPE

A repair of a defect, such as a crack in awelded joint or base material, shall not bemade until the defect has been removed. Asuitable nondestructive examination methodsuch as magnetic particle (MT) or liquid pen-etrant (PT) may be necessary to assure com-plete removal of the defect. If the defect pen-etrates the full thickness of the material, therepair shall be made with a complete penetra-tion weld such as a double butt weld or asingle butt weld with or without backing.Before repairing a cracked area, care shouldbe taken to investigate its cause and to deter-mine its extent. Where circumstances indicatethat the crack is likely to recur, considerationshould be given to removing the cracked areaand installing a patch or taking other accept-able, corrective measures.

RD-2020 DEFECT REPAIRS

a. Unstayed Boiler Furnace CracksCracks at the knuckle or at the turn of theflange of the furnace opening require im-mediate replacement of the affected areaor specific approval of repairs by the ju-risdiction. (See Figure 1).

b. Rivet or Staybolt Hole CracksCracks radiating from rivet or stayboltholes may be repaired if the plate is notseriously damaged. If the plate is seri-ously damaged, it shall be replaced. Forsuggested methods of repair, see Figure2.

c. Minor DefectsMinor cracks, isolated pits and small plateimperfections should be examined to de-termine the extent of the defect andwhether repair by welding is required.Prior to repair by welding, the defectsshall be removed to sound metal. Liquidpenetrant or magnetic particle examina-tion may be used before or after welding.

d. Defective BoltingDefective bolting material shall not be re-paired but shall be replaced with suitablematerial which meets the specifications ofthe original code of construction.

RD-2030 WASTED AREAS

a. Shells, Drums, HeadersWasted areas in stayed and unstayedshells, drums and headers may be builtup by welding provided that in the judge-ment of the Inspector the strength of thestructure has not been impaired. Whereextensive weld buildup is employed, theInspector may require an appropriatemethod of NDE for the completed surfaceof the repair. For suggested methods ofbuilding up wasted areas by welding, seeFigure 3.

b. Access OpeningWasted areas around access openingsmay be built up by welding or they maybe repaired as described in Figure 4.

c. FlangesWasted flange faces may be cleaned thor-oughly and built up with weld metal.They should be machined in place if pos-sible to a thickness not less than that ofthe original flange or that required by cal-culations in accordance with the provi-sions of the original code of construction.Wasted flanges may also be remachinedin place without building up with weldmetal provided that metal removed in theprocess does not reduce the thickness ofthe flange to a measurement below thatcalculated above. Flanges which leak be-cause of warpage or distortion and whichcannot be remachined shall be replacedwith new flanges which have at least thedimensions conforming to the originalcode of construction.

d. TubesWasted areas on tubes may be repairedby welding provided that in the judge-


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ment of the Inspector the strength of thetube has not been impaired. Wheredeemed necessary, competent technicaladvice should be obtained from themanufacturer or from another qualifiedsource. This may be necessary when con-sidering such items as size limitations ofrepaired areas, minimum tube thicknessto be repaired, tube environment, locationof the tube in the boiler and other similarconditions.

RD-2040 SEAL WELDING

a. Seal Welding of TubesTubes may be seal welded provided theends of the tubes have sufficient wallthickness to prevent burn through and therequirements of the original code of con-struction are satisfied. (See Figure 5).

b. Seal Welding of Riveted JointsEdges of buttstraps, plate laps andnozzles, or of connections attached byriveting may be restored to originaldimensions by welding. Seal welding ofriveted joints, buttstraps or rivets shall re-quire the approval of the jurisdiction. Ifseal welding is approved, suggestedmethods and precautions are shown inFigure 6.

RD-2050 RE-ENDING OR PIECINGPIPES OR TUBES

Re-ending or piecing pipes or tubes is per-mitted provided the thickness of the remain-

ing pipe or tube is not less than 90% of thatrequired by the original code of construction.

RD-2060 PATCHES

a. Flush PatchesThe weld around a flush patch shall bea full penetration weld and theaccessible surfaces shall be ground flushwhere required by the applicable originalcode of construction. Examples of flushwelded patches are shown in Figure 7.The welds shall be subjected to the non-destructive examination method used inthe original code of construction or an al-ternative acceptable to the Inspector.

b. Tube PatchesIn some situations it is necessary to welda flush patch on a tube, such as whenreplacing tube sections and accessibilityaround the complete circumference of thetube is restricted or when it isnecessary to repair a small bulge. This isreferred to as a window patch. Suggestedmethods for window patches are shownin Figure 8.

RD-2070 STAYS

Threaded stays may be replaced by welded-in stays provided that in the judgement of theInspector, the material adjacent to the staybolthas not been materially weakened by dete-rioration or wasting away. All requirementsof the original code of construction govern-ing welded-in stays shall be met.

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FIGURE 1 — UNSTAYEDBOILER FURNACES

Cracks at the knuckle orat the turn of the flangeof the furnace openingrequire immediatereplacement of theaffected area. If repairsare attempted, specificapproval of the jurisdictionis required.

FIGURE 2 — RIVETAND STAYBOLTHOLE CRACKS

Cracks radiating fromrivet or staybolt holesmay be repaired if theplate is not seriouslydamaged. If the plate isseriously damaged, itshall be replaced. Asuggested repair methodis described below:

a. Prior to welding, therivets or staybolts fromwhich the cracks extendand the adjacent rivets (orstaybolts if appropriate)should be removed.b. In riveted joints, tack boltsshould be placed in alternateholes to hold the plate lapsfirmly.c. The cracks should thenbe prepared for weldingby chipping, grinding orgouging.d. In riveted joints, crackswhich extend past the inneredge of the plate lap shouldbe welded from both sides.e. Rivet holes should bereamed before new rivetsare driven.

CIRCUMFERENTIAL CRACKS AT GIRTH SEAMS

FIRE CRACKS AT GIRTH SEAMS

CRACKS IN STAYED PLATES


107

f. Threaded staybolt holesshould be retapped and newstaybolts properly driven andheaded.

FIGURE 3 — WELD BUILDUPOF WASTED AREA

Rivet and Stayboltsa. Prior to welding, the rivetsor staybolts in the wasted areashould be removed.b. Threaded staybolt holes shouldbe retapped after welding.c. Rivet holes should be reamedafter welding.d. Welding should not coverrivet or staybolt heads.Tubesheeta. Prior to welding, the tubesin the wasted area should beremoved.b. After welding, the tube holesmay be reamed before new tubesare installed.Wasted areas in stayed andunstayed surfaces may berepaired by weld build upprovided that in the judgment ofthe Inspector the strength of thestructure will not be impaired.Where extensive weld buildup isemployed, the Inspector mayrequire an appropriate method ofNDE for the complete surface ofthe repair.

FIRE CRACKS AT DOOR OPENINGS

TUBESHEET

RIVET AND STAYBOLT

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FIGURE 4 — REPAIRS FORACCESS OPENINGS

A badly wasted manholeflange may be removed andreplaced with a ring-typeframe as shown at right. Therequirements for flushpatches shall be met. A fullpenetration weld is required.May be either double orwelded from one side withor without a backing ring.

A badly wasted area arounda handhole opening may berepaired by adding a ring asshown at right on the insideof the object.

FIGURE 5 — TYPICALEXAMPLES OF SEALWELDING TUBES

Tubes may be seal weldedprovided the ends of thetubes have sufficient wallthickness to prevent burn-through. Seal weldingshould be applied with amaximum of three lightlayers in lieu of one or twoheavy layers.

In watertube boilers, tubesmay be seal welded on theinside or outside of thetubesheet.


109

FIGURE 6 — SEAL WELD-ING OF RIVETED JOINTS

Seal welding of rivetedjoints requires the approvalof the jurisdiction. Sealwelding shall not be consid-ered a strength weld.Prior to welding, the areashould be examined by anappropriate method of NDEto assure that there are nocracks radiating from therivet holes. If necessary, therivets should be removed toassure complete examina-tion of the area. Seal weldingshould not be performed ifcracks are present in rivetedareas.

FIGURE 7 — FLUSHPATCHES

Before installing a flushpatch, the defective materialshould be removed untilsound material is reached.The patch should be rolledor pressed to the propershape or curvature. Theedges should align withoutoverlap.

In stayed areas, the weldseams should comebetween staybolt rowsor riveted seams.Patches should be madefrom a material that is atleast equal in quality andthickness to the originalmaterial.

Patches may be of anyshape or size. If the patchis rectangular, an adequateradius should be providedat the corners. Squarecorners should beavoided.

TYPICAL RIVET JOINT SHOWING SEAL WELD

FLUSH PATCHES IN UNSTAYED AREAS

FLUSH PATCHES IN STAYED AREAS

110


FIGURE 8 — TUBE WINDOWPATCHING METHOD

It may be necessary to weld aflush patch on a tube since insome situations accessibilityaround the complete circumfer-ence of the tube is restricted.Listed below are the suggestedmethods for making windowpatches:

a. The patch should be madefrom tube material of the sametype, diameter and thicknessas the one being repaired.

b. Fit-up of the patch is importantto weld integrity. The root openingshould be uniform around thepatch.

c. The gas tungsten-arc weldingprocess should be used for theinitial pass on the inside of thetube and for the initial passjoining the patch to the tube.

d. The balance of the weld maybe completed by any appropriatewelding process.

SIDE VIEW SHOWING PATCH FIT AND WELDING

FRONT AND SIDE VIEW OF TUBE


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RD-3000 ALTERATIONS BASED ONALLOWABLE STRESSVALUES

RD-3010 RE-RATING

The following requirements shall apply for re-rating a pressure retaining item by using a lateredition/addendum of the original code of con-struction which permits higher allowable stressvalues for the material than was used in theoriginal construction.

a. The “R” Certificate Holder shall verify, bycalculations and other means, that the re-rated item can be satisfactorily operated atthe new service condition (e.g., stiffness,buckling, external mechanical loadings,etc.).

b. The pressure retaining item shall not beused in lethal service.

c. The pressure retaining item shall not beused in high-cycle operation or fatigue ser-vice (i.e., loadings other than primary mem-brane stress are controlling design consid-erations).

d. The pressure retaining item shall have beenconstructed to the 1968 Edition or later edi-tion/addenda of the original code of con-struction.

e. The pressure retaining item shall be shownto comply with all relevant requirements ofthe edition/addenda of the code of con-struction which permits the higher allow-able stress values (e.g., reinforcement,toughness, examination, pressure testing,etc.).

f. The pressure retaining item shall have a sat-isfactory operating history and current in-spection of the pressure retaining item shallverify the item exhibits no unrepaired dam-age (e.g., cracks, corrosion, erosion, etc.).

g. The re-rating shall be acceptable to the In-spector and, where required, the jurisdic-tion.

h. All other requirements of Part RC shall bemet.

i. Use of this paragraph shall be documentedin the Remarks Section of Form R-2.

RD-3020 MINIMUM WALLTHICKNESS

The following requirements shall apply for re-calculating a new minimum wall thickness fora pressure retaining item by using a later edi-tion/addendum of the original code of con-struction which permits higher allowable stressvalues for the material than was used in theoriginal construction.

a. The “R” Certificate Holder shall verify, bycalculations and other means, that the af-fected portions of the pressure retainingitem can be satisfactorily operated (e.g.,stiffness, buckling, external mechanicalloadings, etc.).

b. The pressure retaining item shall not beused in lethal service.

c. The pressure retaining item shall not beused in high-cycle operation or fatigue ser-vice (i.e., loadings other than primary mem-brane stress are controlling design consid-erations).

d. The pressure retaining item shall have beenconstructed to the 1968 Edition or later edi-tion/addenda of the original code of con-struction.

e. The pressure retaining item shall be shownto comply with all relevant requirements ofthe edition/addenda of the code of con-struction which permits the higher allow-able stress values (e.g., reinforcement,toughness, examination, pressure testing,etc.).

f. The pressure retaining item shall have a sat-isfactory operating history and current in-spection of the pressure retaining item shallverify the item exhibits no unrepaired dam-

112


age (e.g., cracks, etc.). Areas of corrosion orerosion may be left in place provided theremaining wall thickness is greater than thenew minimum thickness.

g. The design shall be acceptable to the Inspec-tor and, where required the jurisdiction.

h. All other requirements of Part RC shall bemet.

i. Use of this paragraph shall be documentedin the Remarks Section of Form R-2.

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Preparation of Technical Inquiries to theNational Board Inspection Code Committee

Appendix 1

114


APPENDIX 1 — PREPARATION OF TECHNICAL INQUIRIES TO THENATIONAL BOARD INSPECTION CODE COMMITTEE

1.0 INTRODUCTION

a. The National Board Inspection CodeCommittee meets regularly to considerwritten requests for interpretations andrevisions to the Code rules, and to de-velop new rules as dictated by technologi-cal development. The Committee’s activi-ties in this regard are limited strictly tointerpretations of the rules or to the con-sideration of revisions to the present ruleson the basis of new data or technology.As a matter of published policy theNational Board does not approve, certify,or endorse any item, construction, propri-etary device, or activity, and, accordingly,inquiries requiring such considerationwill be returned. Moreover, the NationalBoard does not act as a consultant onspecific engineering problems or on thegeneral application or understanding ofthe Code rules. If, based on the inquiryinformation submitted, it is the opinionof the Committee that the inquirer shouldseek assistance, the inquiry will bereturned with the recommendation thatsuch assistance be obtained.

b. All inquiries that do not provide theinformation needed for the Committee’sfull understanding will be returned.

2.0 INQUIRY FORMAT

Inquiries shall be limited strictly to interpre-tations of the rules or to the considerationof revision to the present rules on the basis ofnew data or technology. Inquiries shall besubmitted in the following format:

a. ScopeInvolve a single rule or closely relatedrules. An inquiry letter concerningunrelated subjects will be returned.

b. BackgroundState the purpose of the inquiry, whichwould be either to obtain an interpre-tation of Code rules, or to propose con-sideration of a revision to the presentrules. Provide concisely the informationneeded for the Committee’s under-stand-ing of the inquiry, being sure to includereference to the applicable Code Edition,Addenda, paragraphs, and figures. Ifsketches are provided, they shall belimited to the scope of the inquiry.

c. Inquiry StructurePrepare statements in a condensedand precise question format, omittingsuperfluous background information,and, where appropriate, composed insuch a way that “yes” or “no” (perhapswith provisos) would be an acceptablereply. This inquiry statement should betechnically and editorially correct.

d. Proposed ReplyState what it is believed that the Coderequires. If in the inquirier’s opinion arevision to the Code is needed,recommended wording shall be pro-vided.

3.0 SUBMITTAL

Inquiries shall preferably be submittedin typewritten form; however, legible hand-written inquiries will also be considered.They shall include the name and mailingaddress of the inquirer, and be mailed to thefollowing address:

SecretaryNational Board Inspection Code Committee1055 Crupper AvenueColumbus, OH 43229

Fax: 614.847.1828Phone: 614.888.8320 ext. 232

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Stamping andNameplate Information

Appendix 2

116


APPENDIX 2 — STAMPING AND NAMEPLATE INFORMATION

1.0 SCOPE

When a pressure retaining item is repairedor altered, the Certificate Holder shall attacha nameplate or stamp the item, except whenotherwise permitted by these rules. Similarly,when pressure relief devices are repaired, theattachment of a nameplate is required. Thespecific requirements for nameplates/stamp-ing are described in this Appendix.

2.0 GENERAL REQUIREMENTSFOR STAMPING ANDNAMEPLATES

a. Required data shall be in characters atleast 5/32 in. (4 mm) high, except thatcharacters for pressure relief valve repairnameplates may be smaller. Markingsmay be produced by casting, etching,embossing, debossing, stamping, orengraving. The selected method shall notresult in any harmful contamination ofor sharp discontinuities to the pressureretaining item.

b. The National Board code symbols(“R”, “VR”, and “NR”) are to be stamped;do not emboss.

c. Stamping directly on items, whenused, shall be done with blunt-nose con-tinuous or blunt-nose interrupted dot diestamps. If direct stamping would be det-rimental to the item, required markingsmay appear on a nameplate affixed to theitem.

d. The Certificate Holder shall use its fullname as shown on the Certificate of Au-thorization or an abbreviation acceptableto the National Board.

Stamping or nameplate shall be applied ad-jacent to the original manufacturer’s stamp-ing or nameplate. A single repair nameplateor stamping may be used for more than onerepair to a pressure retaining item providedit is carried out by the same Certificate Holder.The date of each repair, corresponding withthe date on the associated Form R-1, shall bestamped on the nameplate.

Figure 1— Required Markings for Repairs withuse of National Board Form R-1

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APPENDIX 2 — STAMPING AND NAMEPLATE INFORMATION

(2)

(2)(TYPE/MODEL NUMBER)

Figure 3 — Required Markings for Re-ratings,with use of National Board Form R-2

Figure 2 — Required Markings for Alterations,with use of National Board Form R-2

Stamping or nameplate shall be applied ad-jacent to the original manufacturer’s stamp-ing or nameplate.

Figure 4 — Required Markings for PartsFabricated by Welding, with use of National

Board Form R-3

Stamping or nameplate shall be applied in aconspicuous location on the part.

Figure 5 — Required Markings for Repair ofASME/National Board “V”, “UV”, and “HV”

Stamped Pressure Relief Valves

1. Pressure relief valve repair stamping ornameplate shall be applied adjacent to theoriginal manufacturer ’s stamping ornameplate.

2. To be indicated only when changed.

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(TYPE/MODEL NUMBER)

Figure 6 — Required Markings for NuclearRepairs, Modifications, or Replacements

The stamping or nameplate shall be appliedadjacent to the original manufacturer ’sstamping or nameplate.

Figure 7 — Required Markings for Repair,Modification, or Replacement of Nuclear

Pressure Relief Valves

Stamping or nameplate to be applied adja-cent to the original manufacturer’s stampingor nameplate.

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Steam Locomotive FiretubeBoiler Inspection and Repair

Appendix 3

120


FIGURE 1 — Locomotive Boiler General Arrangement

Crown Sheet Perspective SectionThrough Combustion Chamber

Inside ThroatSheet

CombustionChamber

Front Tube Sheet

SmokeboxSmokebox and Shell Ring

Roof Sheet

Back HeadOutside Firebox Sheet

Dome Course

Throat Sheet

ConicalCourse

FirstCourse

Back Sheet

Back Tube Sheet

c

CombustionChamber

Smokebox andShell Ring

Back TubeSheet

CombustionChamber

SideSheet

RoofSheet

Throat Sheet

Inside Throat Sheet

Dome Course

Crown Sheet

Side Sheet

FIGURE 2 — Arrangement of Firebox Sheets (Staybolts Deleted for Clarity)

APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBEBOILER INSPECTION AND REPAIR

PURPOSE

This appendix is provided as a guide to repairs and alterations of steam locomotive firetubeboilers. It provides rules for the repair and alteration of steam locomotive boilers and shall beused in conjunction with the applicable rules of this Code.

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APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR

Taper Head CrownBolt-Type Staybolts

Rigid Staybolt EquippedWith Telltale Holes

Bucking Bar For BallSocket Flexible Staybolts

Ball Socket-TypeFlexible Staybolt

TaperHeadType

ButtonHeadType

ReducedSection

FIGURE 3 — Threaded Staybolts

MATERIAL SPECIFICATIONS RIVETMATERIAL

ASTM A 31-95 may be substituted forSA-31.

REPAIR OF STAYBOLT HOLES

1. Staybolt holes may be repaired by weld-ing, reaming or retapping to a larger sizeor by installing a flush patch.

2. If the staybolt hole was threaded and isto be repaired by welding, the threadsshall be removed prior to welding.

THREADED STAYBOLTS

1. All threaded staybolts shall have either11- or 12-thread pitch. Staybolt threadsshall have a good close fit in sheets.Changing the staybolt thread pitchfrom 11 to 12 or the reverse shall beconsidered a repair.

2. All staybolts shorter than 8 in. in lengthshall have telltale holes. Staybolt telltaleholes in existing bolts shall be 3/16 in.to 7/32 in. in diameter and at least1-1/4 in. deep in the outer end. Whenstaybolts 8 in. or less in length are re-placed, they shall be replaced withstaybolts that have a telltale hole3/16 in. to 7/32 in. in diameter their en-

122


tire length, or with ones that have a3/16 in. to 7/32 in. diameter hole in eachend, drilled a minimum of 1-1/4 in.deep. On reduced body staybolts thetelltale hole shall extend beyond the fil-let and into the reduced section of thestaybolt. Ball socket-type flexiblestaybolts may have telltale holes thatextend from the threaded end of the boltinto the bolt head for a distance of 1/3the spherical bolt head diameter.

3. Telltale holes shall be reopened afterdriving.

4. Staybolt length shall be sized so thelength of bolt projecting through thesheet is not less than 1/8 in., and is suf-ficient to produce a full head after driv-ing.

5. The thread lead of both bolt ends andboth firebox sheets shall be synchronizedto permit the bolt to be installed with-out stripping the threads.

6. When driving staybolt heads, the bolt’sopposite end shall be bucked or bracedto prevent damaging the bolt’s threads.Bracing can be done several ways, suchas using a pneumatic holder-on or aheavy steel bucking bar. Driving theheads on both ends of the staybolt simul-taneously using two pneumatic rivethammers (double gunning) is accept-able. Bolts are to be driven in such amanner as to expand radially the boltbody and threads into the sheet prior toforming the head. Merely driving overthe head is not acceptable.

7. Ball socket-type flexible staybolts shallnot be braced by inserting a spacerunder the cap.

8. Installation of different diameterstaybolts shall be considered a repair.

BALL SOCKET-TYPE FLEXIBLESTAYBOLTS, SLEEVES AND CAPS

1. Welded sleeves and welded caps thatleak at the welds or the sleeve shall berepaired.

2. Wasted caps and sleeves shall not berepaired by weld buildup.

3. Welded sleeves that have damaged capthreads shall be repaired or replaced. Ifthe sleeve has wasted to less than 60%of the original thickness at the threadedcap section, it may be repaired bycutting off the threaded section andwelding on a replacement section usingfull penetration welds.

4. Threaded or welded sleeves that arecracked or have wasted to less than 60%of the original thickness at any sectionother than the threaded cap section shallbe replaced.

5. Threaded sleeves that leak wherescrewed into the boiler shell or wrappersheet shall be repaired. Seal welding ofone pass not exceeding 3/16 in. leg sizeis permissible for caulking purposesonly. If seal welding is applied, the sleevethreads in the weld zone shall beremoved prior to welding.

6. New threaded sleeves seal welded afterinstallation shall have the threadsremoved from the weld zone of thesleeve prior to welding.

7. Threaded staybolt caps that leak shallnot be seal welded.

8. Substitution of one type of flexiblestaybolt sleeve by another type shallbe considered a repair.

9. Where necessary for boiler expansion,ball socket-type flexible staybolts shallbe positioned in such a manner as to not

123

threaded cover cap

threaded sleeve

ball socket staybolt consistingof a spherical nut on a threaded

rigid staybolt

ball socket staybolt

FIGURE 4 — Ball Socket-Type FlexibleStaybolts

Welded Cover Cap Type

ball socket staybolt

welded covercap

Welded Sleeve With ThreadedCover Cap Type

threaded cover capball socketstayboltwelded sleeve

Threaded Sleeve WithThreaded Cover Cap Type

this surface machined forfull penetration weld joint

thread for standard flexiblestaybolt cap and gasket

FIGURE 6 — Half Sleeve RepairProcedure for Damaged Ball SocketFlexible Staybolt Welded Sleeve

half sleeve

FIGURE 5 — Half Sleeve RepairProcedure for Damaged Ball SocketFlexible Staybolt Welded Sleeve

welded sleevedamaged atthreadedsection

remove threadedsection down togasket surface

do not remove existingflexible staybolt

FIGURE 7 — Half Sleeve Repair Procedurefor Damaged Ball Socket Flexible StayboltWelded Sleeve

half sleeveinstalled with fullpenetration weld


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FIGURE 9 — Diagonal Braces, Gusset Bracesand Throat Sheet / Tubesheet Braces

Diagonal Brace

Solid-Type Brace

Gusset Brace

Pin-Type Diagonal Brace

Throat Sheet / Tubesheet Brace

FIGURE 8 — Seal WeldedStaybolts

staybolt head seal weldedbefore driving

staybolt head seal weldedafter driving

interfere with boiler expansion. Whereindividual bolts are replaced, careshould be taken to assure that the stressload of the new bolt is compatible to theloading on adjacent bolts. Note: somelocomotive boiler designs positioned thebolts by backing the bolt head awayfrom the sleeve socket bottom a certainamount.

SEAL WELDED STAYBOLTS

1. Replacement threaded staybolts may beseal welded before or after driving.

2. Existing threaded staybolts that leakshall be repaired and may be sealwelded. When used, seal welding shallnot be the sole means of repair.

WELDED INSTALLATION OFSTAYBOLTS

1. The installation of unthreaded stayboltsusing full penetration welds is permis-sible.

2. All staybolts shorter than 8 in. in lengthshall have telltale holes. Telltale hole di-ameter shall be 3/16 in. to 7/32 in. indiameter and at least 1-1/4 in. deep inthe outer end. On reduced bodystaybolts, the telltale hole shall extendbeyond the fillet and into the reducedsection of the staybolt. Staybolts mayhave through telltale holes which arepreferred. Ball socket-type flexiblestaybolts may have telltale holes thatextend from the welded end of the boltinto the bolt head for a distance of 1/3the spherical bolt head diameter.

3. Where necessary for boiler expansion,ball socket-type flexible staybolts shallbe positioned in such a manner as to not

125

interfere with boiler expansion. Whereindividual bolts are replaced, careshould be taken to assure that the stressload of the new bolt is compatible to theloading of adjacent bolts. Note: some lo-comotive boiler designs positioned thebolts by backing the bolt head awayfrom the sleeve socket bottom a certainamount.

4. Installation of different diameterstaybolts shall be considered arepair.

DIAGONAL BRACES, GUSSETBRACES AND THROAT SHEET/TUBESHEET BRACES

1. Loose or damaged braces shall be re-paired or replaced.

2. Only steel braces may be repaired bywelding. All such welds shall be fullpenetration. Wrought iron braces shallnot be repaired by welding.

3. When repairs or alterations are com-pleted, the tightness and condition of thebraces and their staybolts, rivets,clevises, eyes and pins shall be verified.

TABLE L-2 MAXIMUM ALLOWABLE WORKING PRESSURES FOR STEEL TUBES OR FLUES FOR FIRETUBE BOILERS FOR DIFFERENTDIAMETERS AND GAGES OF TUBES CONFORMING TO THE REQUIREMENTS OF SPEC. SA-176, SA-192, SA-209, OR SA 210*

FIGURE 10 — Patch Bolts

Typical Patch Bolts

Typical Patch Bolt Application

1 470 690 — — — — — — — —1-1/2 320 460 570 720 860 — — — — —1-3/4 270 400 490 620 740 890 — — — —2 240 350 430 540 650 780 900 — — —2-1/4 210 310 380 480 580 690 800 960 — —2-1/2 190 280 350 430 520 630 720 860 970 10803 160 230 290 360 430 520 600 720 810 9003-1/4 — 210 270 330 400 480 550 660 750 8303-1/2 — 200 250 310 370 450 520 620 690 7704 — 180 220 270 330 390 450 540 610 6804-1/2 — 160 190 240 290 350 400 480 540 6005 — — 180 220 260 320 360 430 490 5405-3/8 — — 160 200 240 290 340 400 450 5005-1/2 — — — 200 240 290 330 390 440 4906 — — — 180 220 260 300 360 410 450

Outsidediameter oftube, inches

D

Minimum gage, Bwg

13 12 11 10 9 8 7 6 5 4t= t= t= t= t= t= t= t= t= t=

0.095 0.109 0.120 0.134 0.148 0.165 0.180 0.203 0.220 0.238

P = {(t–0.065)/D} x 15.550 where P = maximum allowable working pressure, pounds per square inch,t = minimum wall thickness, inches,D = outside diameter of tubes, inches.

For pressures other than those given in the table, the allowable working pressures shall be the next higher unit of 10 above the values given by the formulas.For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table.* These values have been rounded out to the next higher unit of 10.

Ref: 1952 ASME, Sec. III – Boilers of Locomotives


THREADED STUDS

1. Studs threaded into the boiler or fireboxsheets shall not be seal welded.

FLUE AND TUBE RE-ENDING

1. Each boiler tube or flue that is repairedby welding is limited to not more thanthree (3) circumferential welded joints.

2. Re-ending is permitted provided thethickness of the tube or flue to bere-ended is not less than 90% of that re-quired by table L-2.

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Figure 11b - Rectangular Shaped Patch

FIGURE 11 —Figure 11a illustrates what would be consid-ered a saw-tooth patch. Its advantage is that amaximum amount of welding is obtained forsecuring a given patch and by zig-zagging theweld, the weld is supported by three (3) rowsof staybolts instead of two (2). Its disadvantageis its irregular shape which causes greater dif-ficulty in fitting and applying.

Figure 11a - Saw-Tooth Patch

Figure 11c - Diamond Shaped Patch

WELD

WELD

WELD

3. Re-end pieces shall be new material andmeet the thickness requirements ofTable L-2.

PATCH BOLTS

1. Patch bolts may be replaced in kind.

2. Seal welding of bolts is permitted.

REPAIRS AND ALTERATIONS TOBOILER BARREL UNSTAYED AREAS

1. Defects such as cracks and wastage maybe repaired by weld buildup, a weldedflush patch or a riveted patch. Installa-tion of a riveted patch shall be consid-ered an alteration. Prior to repairingcracks, the plate shall be examined fordefects. Affected sections shall berepaired.

2. Weld buildup shall not be used if theaffected section of plate has wastedbelow 60% of the minimum requiredthickness.

3. If the cracked section of plate is retainedand is to be repaired by installation of ariveted patch, the crack may be stoppedby drilling stop holes at each end orremoved by a method such as grinding,cutting or machining. Results of stopdrilling or crack removal shall beverified by NDE.

4. Welded repairs at or near riveted seamsrequiring preheating or postweld heattreatment shall be carefully made inorder to prevent loosening in the rivetedseams, especially when localized heat-ing is used. Where necessary to controlexpansion or to gain access for welding,rivets at the defective section and to eachside of it may be removed. Reuse ofrivets and staybolts is prohibited.

5. All welded repairs to boiler barrelunstayed areas shall be radiographically

examined in accordance with the ASMECode, Section I when the size of therepaired area is greater than the maxi-mum size of an unreinforced opening ascalculated in accordance with the latestedition of the ASME Code, Section I.

6. Riveted patches may be any shape orsize provided the lowest patch efficiencyis equal to or greater than the lowestequivalent seam efficiency of the boilercourse to which it is applied. Ref: ASMECode, Section I.

7. The factor of safety of all riveted patchesshall not be less than four (4) for loco-motives operating under Federal Rail-road Administration regulations.

127

FIGURE 12 — Stayed Firebox SheetGrooved or Wasted at Mudring

First Staybolt Row

MudringMudring Rivet

Sheet Wasted BelowMudring Waterside

Firebox Sheets


FIREBOX SHEET REPAIR

1. Cracks in all stayed firebox sheets maybe repaired by welding or the installa-tion of a flush patch.

2. If the crack extends into a staybolt orrivet hole, the staybolt or rivet shall beremoved prior to making the repair.

FIREBOX PATCHES

1. Patches may be any shape provided theyare adequately supported by staybolts,rivets, tubes, or other forms of construc-tion. Patches on stayed surfaces shouldbe designed so weld seams pass betweenstaybolt rows. See Figure 11.

2. Patches are to be flush type, usingfull penetration welds. If the load on thepatch is carried by other forms of con-struction, such as staybolts, rivets ortubes, radiographic examination of thewelds is not required.

3. If the patch includes an existing rivetedseam, the patch shall be riveted at thatseam. Changing a riveted seam to awelded seam is considered an alteration.

4. All rectangular or angled patches shallhave adequate radius at all corners.Minimum radius to be not less than three(3) times plate thickness.

5. Patches shall fit flush on the watersideof the sheet. Misalignment shall notexceed one quarter (1/4) plate thicknesson edge alignment with the sheet waterside.

6. Staybolts and rivets should be installedafter welding of patch is completed. Re-use of staybolts and rivets is prohibited.

7. Weld seams parallel to a knuckle shallbe located no closer to the knuckle thanthe point of tangency of the knuckleunless the weld is radiographically

examined. Weld seams not located in theknuckle are preferred. See Figure 15.

8. Patches shall be made from material thatis at least equal in quality and thicknessto the original material.

REPAIR OF STAYED FIREBOX SHEETSGROOVED OR WASTED AT THEMUDRING

1. Grooved or wasted firebox sheets hav-ing greater than 60% of the minimumrequired thickness remaining may berepaired by weld buildup provided thewastage does not extend below the wa-terside surface of the mudring, and thestrength of the structure will not be im-paired. If extensive welding is required,the affected area shall be removed andreplaced with a flush patch.

2. If the sheet thickness has been reducedto less than 60% of the minimumrequired thickness, the affected sectionshall be removed and replaced with aflush patch.

128


FIGURE 13 — Mudring Repair

mudring

remove firebox sheets for access

full penetration weld

3. If wastage and grooving extends belowthe mudring waterside surface, and ifthe plate thickness remaining has beenreduced to less than the minimumrequired thickness, the affected sectionshall be removed and replaced with aflush patch.

4. Flush patches shall be arranged to in-clude the mudring rivets and at least thefirst row of staybolts above the mudring.

MUDRING REPAIRS

1. Pitted and wasted sections of mudringsmay be built up by welding, providedthe strength of the mudring will not beimpaired. Where extensive weld build-up is employed, the Inspector may re-quire an appropriate method of NDE forthe repair.

2. Cracked or broken mudrings may be re-paired by welding or installation of flushpatches using full penetration welds.Patches shall be made from material thatis at least equal in quality and thicknessto the original material. Patches shall fitflush on waterside surfaces. Where nec-essary, firebox sheets on both sides of thedefect may be removed to provide ac-cess for inspection and welding.

REPAIR OF FIREBOX ANDTUBESHEET KNUCKLES

1. Welds within the points of tangency ofa knuckle are permitted. Welds withangles of less than 45 degrees to the lon-gitudinal axis of the knuckle shall be ra-diographically examined. (See Figure15).

2. Any patch not supported by meansother than the weld, such as rivets,staybolts, tubes or other forms of con-struction, shall have all weld seams ra-diographically examined.

3. Patches shall be formed to proper shapeand curvature.

4. Wasted sections of knuckles that havenot wasted below 60% of the minimumrequired thickness may be repaired byweld buildup provided the strength ofthe structure will not be impaired.Where weld buildup is employed, theInspector may require an appropriatemethod of NDE for the repair.

5. Wasted sections of knuckles that havewasted below 60% of the minimumrequired thickness shall be replaced.

TUBESHEET REPAIRS

1. Cracked tubesheet ligaments may berepaired by welding using full penetra-tion welds.

2. Damaged tubesheet holes may berepaired by welding.

3. Sections of tubesheets damaged orwasted to less than 60% minimum

129


FIGURE 14 — Firebox TubesheetKnuckle Repair

knuckle patch welded around tube holes

knuckle patch welded through tube holes

top flue

fluesheet

line of weld is to be as nearlyhorizontal as conditioning willpermit

knuckle

staybolts transverse crackin tubesheetknuckle

parallel crack intubesheetknuckle

tubesheet

point of tangencyof knuckle

FIGURE 15 — Repair of Firebox andTubesheet Knuckles

knuckle radius

welds located no closerto knuckle than point oftangency do not requirereadiographic examina-tion

see layoutmethod inFigure 15A

FIGURE 15A — Layout Method of Determining Knuckle Weld Angle

xxxxxxx

=

=

Illustrations are of inside surface of knuckle.

longitudinal axispoint PT

b

bPT

R

To find the points of tangency(PT) of the knuckle:b = R - (R * cos )

Where:R = inside knuckle radius

ß = Angle of weld relative tothe Reference LongitudinalAxis of Knuckle.

ß

weld

Reference LongitudinalAxis of Knuckle Longitudinal Axis Point

True Longitudinal Axis

xxxxxxxxxxxxxxxxxxx

xxxxxxxxxxxxxxxx

xxx

xx

x

x xx x x x x

WELDS

LONGITUDINALAXIS

130


staybolt rows point oftangency of knuckle

knuckle

tube orstaybolt rows

FIGURE 16 — Repair of Firebox and TubesheetKnuckles

STAYED PATCH APPLIED TO BUTT WELDED SEAM

patch length

weld seams located betweenstaybolt rows and above first tuberow or staybolt row

STAYED PATCH APPLIED TO RIVETED SEAM

riveted seam

weld seams located betweentube rows below stayboltrows or tube rows

weld seam located above first tuberow or staybolt row

REPAIRS REQUIRING RADIOGRAPHICEXAMINATION OF WELD SEAMS

weld seam locatedin knuckle

patch notsupported bytubes, stayboltsor rivets

if access for welding or riveting is required,remove section of exterior or interior sheets

FIGURE 17 — Firebox ThroatSheet Knuckle

typical flush patches installed with fullpenetration welds

FIGURE 18 — Backhead Knuckle Repair

if access forwelding andriveting isre-quired,remove section ofexterior orinterior sheets

typical flush patch

patch lengthoriginal wrapper sheet

new rivets

weld located between staybolt rows

staybolts

transverse weld

FIGURE 19 — Fire Door Opening Repair

flush patchinstalled withfull penetrationwelds

patch installed with fullpenetration welds andeither patch bolts or rivets

SEC A-A

SEC A-A

patch bolts or rivets

patch length

patch lengthpatch length

weld seam located betweentube rows or staybolt rows

131


FIGURE 21 — Arch Tubes

arch tubeend rolledand flared

arch tubeend rolledand sealwelded

arch tubeend rolledand beaded

arch tube

typical tubesheet flush patches

tubesheet welded around tube holes

tubesheet welded through ligaments and tube holes

FIGURE 20 — Tubesheet Repairs Caulking Tool

Caulked Edge of Plate

FIGURE 20A

required thickness shall be repaired byinstalling a flush patch using full pen-etration welds.

4. Sections of tubesheets that have notwasted below 60% minimum requiredthickness may be repaired by weldbuildup provided the strength of thestructure will not be impaired. Whereweld buildup is employed, the Inspec-tor may require an appropriate methodof NDE for the repair.

CAULKING RIVETED SEAMS ANDRIVET HEADS

1. Caulking refers to the sealing of plateseams and rivet heads by driving theedge of one surface onto the other by useof an impact tool.

2. Riveted seams and rivet heads may becaulked in accordance with ASME Sec-tion I, 1971.

ARCH TUBES

1. Arch tubes that are damaged or reducedto less than minimum required wall thick-ness shall be replaced in entirety by newone-piece arch tubes. Welded repairs orpartial replacement is not permitted.Damage includes defects such as bulging,burns and cracks.

2. When arch tubes are installed by rolling,the tube end shall project through the fire-box sheet not less than 1/4 in. nor morethan 3/4 in. before flaring. At a minimumthe tube shall be expanded and flared atleast 1/8 in. greater than the diameter ofthe tube hole. Additionally, the tube maybe beaded and/or seal welded, providedthe throat of the seal weld is not more than3/8 in. and the tube is finished rolled af-ter welding.

132


3. An arch tube installed by welding shallbe considered a welded nozzle. Some ac-ceptable weld joints are shown on Fig-ure 22. Ref. ASME Section I, Part PW 16.1

4. A change in tube attachment from rolledto welded or welded to rolled shall beconsidered an alteration.

5. The minimum wall thickness of replace-ment arch tubes shall be:

Size Wall Thickness

Up to 3 in. OD 8 BWG

More than 3 in. ODto 4 in. OD 7 BWG

THERMIC SYPHONS

1. For repairs to syphon knuckles, seeRepair of Firebox and Tubesheet Knuck-les, and Figures 14, 15, 16 and 19.

2. All weld repairs to the unstayed sectionsof the syphon neck and body shall beradiographically examined.

CIRCULATORS

1. All butt welds on circulators shall beradiographically examined.

2. Welds applied to the circulator/fireboxsheet joint shall be in accordance withthe weld requirements for arch tubes.Reference Figure 22.

THREADED OPENINGS IN VESSELWALLS, BUSHINGS AND WELDEDNOZZLES (WASHOUT PLUG HOLESAND OTHER CONNECTIONS)

1. Threaded openings in vessel walls andwelded nozzles with damaged threadsthat cannot be repaired by retappingor rethreading may be repaired by weld-

FIGURE 22 — Welded Installation of Arch Tube

t = thickness of vessel shell or head, in.tn = thickness of nozzle wall, in.tw = dimension of partial penetration attachment

welds (fillet, single bevel, or single J), measuredas shown in Figure PW-16.1, in.

tc = not less than the smaller of 1/4 in. or 0.7 tmin.

(inside corner welds may be further limited by alesser length of projection of the nozzle wallbeyond the inside face of the vessel wall)

tmin = the smaller of 3/4 in. or the thickness of eitherof the weld parts joined by a fillet, single bevel,or single J-weld, in.

(y)

tn but not less than 1/4 in.

Section 1-11

1

tn but not less than 1/4 in.

tc

tn

tw

tc

tw

tntc

133


FIGURE 23 — Locomotive Firebox ThermicSyphon Installation

thermic syphon

neck

staybolted body

FIGURE 24 — Thermic Syphon Repair

full penetrationwelds

length to suit

section on w-w

full penetration weldradiographically examinedafter welding

syphon neck repair

flush patch on stayboltsyphon body

134


ing a nozzle in the sheet. The nozzle shallbe of such a size as to not interfere withproper washout and inspection. Ref:NBlC, Part RC.

2. Threaded bushings and nozzles found tobe defective shall be replaced. Seal weld-ing is not permitted.

3. New threaded bushings equipped withshoulders may be seal welded at theshoulder.

4. New threaded bushings withoutshoulders that are seal welded afterinstallation shall have the threadsremoved from the weld zone of the bush-ing prior to welding.

5. Threaded holes with damaged threadsmay be repaired by weld buildup andretapping. The threads shall be removedprior to welding.

MATERIAL LIST FOR STEAMLOCOMOTIVE BOILERS

The following list is intended as a basic guide-line only and covers just the basic carbon steeland some alloy steel material specifications.Other alloy materials may be available forthese applications if necessary.

Application Specification

Boiler Tubes & SA-178 Grade A,Flues, Arch Tubes SA-192, SA-210Superheated Units

Boiler & Firebox Plate SA-285 Grade C,SA-515, SA-516,SA-203, SA-204

Staybolts SA-675, SA-36,ASTM A-31-95

Staybolt Sleeves and SA-105 Forging,Caps SA-675

Boiler Braces SA-675, SA-36

Rivets SA-675, ASTMA-31-95

Forged Parts & Fittings SA-105, SA-181

Pressure Retaining SA-216, SA-217Steel Casings

Hollow Cylindrical SA-105 ForgingsPressure Retaining SA-675 Bar StockParts

Superheater Unit Bolts Bolts - SA-193,& Nuts Nuts -SA-194

Pipe Flanges SA-181, SA-105

Pipe SA-106, SA-53seamless

Bronze Castings & SB-61, SB-62Washout Plugs

a. SA-516 steel is recommended for fireboxrepairs. It is a fine grain that accepts flang-ing and bending with less chance of crack-ing than course grain steels such as SA-515 or SA-285 Grade C. Course grainsteels have, on occasion, been found tocrack or split after complicated flanging,bending and forming.

b. SA-36 is not to be used to make any pres-sure retaining part such as shells, stayboltsleeves or caps.

c. When rivets are made from SA-675, thefinished rivets must meet the physical andtest requirements of the original ASMErivet specification ASTM A-31-95 GradeA or B.

d. When staybolt material tensile strength isstronger than that of the firebox sheets,the firebox sheets deflect instead of thestaybolts, which can result in the sheetsdeveloping cracks and leaking staybolts.In addition, high tensile strength steels aredifficult to drive.

135

Glossary of Terms

Appendix 4

136


APPENDIX 4 — GLOSSARY OF TERMS

For the purpose of applying the rules ofthe National Board Inspection Code, thefollowing definitions of the terms used hereinshall apply:

Address of Record (applicable to RA-2200) –Complete address of the company to whichthe National Board Certificate of Authoriza-tion is issued (shop facility). For field onlycertificates of authorization, the address fromwhere the work is controlled.

Alteration – Any change in the itemdescribed on the original Manufacturer’sData Report which affects the pressure con-taining capability of the pressure retainingitem. Non-physical changes such as an in-crease in the maximum allowable workingpressure (internal or external) or design tem-perature of a pressure retaining item shall beconsidered an alteration. A reduction in mini-mum temperature such that additional me-chanical tests are required shall also be con-sidered an alteration.

ANSI – The American National Standards In-stitute

ASME Code – The American Society ofMechanical Engineers’ Boiler and PressureVessel Code published by that Society, includ-ing addenda and Code Cases, approved byits council.

Assembler (applicable to RA-2200) – An or-ganization who purchases or receives from amanufacturer the necessary component partsof valves and assembles, adjusts, tests, sealsand ships safety or safety relief valves at ageographical location and using facilitiesother than those used by the manufacturer.

Audit (applicable to RA-2300) – A docu-mented activity performed to verify by ex-amination and evaluation of objective evi-dence that applicable elements of the qualityprogram have been developed, documented,and implemented in accordance with speci-

fied requirements. An audit is separate frominspection or examination for the purpose ofprocess control or acceptance of materials oritems.

Authorized Inspection Agency – AnAuthorized Inspection Agency shall be either:

a. A jurisdiction which has adopted anddoes administer one or more sections ofthe ASME Code, one of which shall beSection I, as a legal requirement and isqualified to have a person represented asa member of the National Board; or

b. an insurance company which has beenlicensed or registered by the appropriateauthority of a state of the United Statesor a province of Canada to write boilerand pressure vessel insurance in suchstate or province; and the insurance com-pany shall show its willingness and ca-pability to provide boiler and pressurevessel insurance coverage by being ac-tively engaged in writing such insurancefor the general public in one or more ofthe states or provinces where so licensedor registered and shall also obtain autho-rization to provide inspection servicefrom the jurisdictional authorities whichhave the responsibility of administeringthe boiler and pressure vessel laws in theUnited States of America or the provincesof Canada which have adopted and doadminister one or more sections of theASME Code, one of which shall beSection I (Power Boilers), in which thecompany is so licensed or registered; theinsurance company shall provide autho-rized inspection service within such statesor provinces by Authorized Inspectors whoare employees and who meet the qualifica-tions for Authorized Inspectors as definedin the National Board Rules and Regulations.

Authorized Nuclear Inspection Agency(applicable to RA-2300) – An AuthorizedInspection Agency which employs Autho-

137


rized Nuclear Inspectors and providesnuclear inspection services in accordancewith the NBIC and Section XI of the ASMECode.

Authorized Nuclear Inspector (ANI) (appli-cable to RA-2300) – An Authorized Inspectoremployed by an Authorized Nuclear Inspec-tion Agency, qualified in accordance with theNational Board Rules for Commissioned In-spectors.

Authorized Nuclear Repair Organization(applicable to RA-2300) – See “NR” Certifi-cate Holder.

Capacity Certification – The verification bythe National Board that a particular valvedesign or model has successfully completedall capacity testing as required by the ASMEBoiler and Pressure Vessel Code.

Conversion – The change of a pressure reliefvalve from one capacity-certified configura-tion to another by use of manufacturer’s in-structions.

Critical Parts (applicable to RA-2200) – Criti-cal Parts are those that may affect the valveflow passage, capacity, function or pressureretaining integrity.

Demonstration – A program of making evi-dent by illustration, explanation and comple-tion of tasks documenting evaluation of anapplicant’s ability to perform code activitiesincluding the adequacy of the applicant’squality program and by a review of the imple-mentation of that program at the address ofrecord and/or work location.

Field Repairs (applicable to RA-2200) – Fieldrepairs are any repair conducted outside ofthe Certificate Holder’s fixed repair shoplocation. Field repairs may be conducted withthe aid of mobile facilities with repair capabili-ties and with or without testing capabilities.Field repairs may be conducted in user facili-ties without the use of mobile facilities as de-scribed above, or in any other “VR” certificateholder’s fixed repair shop location.

Inspector – See National Board Commis-sioned Inspector and National Board Owner-User Commissioned Inspector.

Jurisdiction or Jurisdictional Authority –A governmental entity which administers andenforces one or more sections of the ASMECode, one of which shall be Section I (PowerBoilers).

Lift Assist Device – A device used to applyan auxiliary load to a pressure relief valvestem or spindle, used to determine the valveset pressure as an alternative to a full pres-sure test.

Manufacturer (applicable to RA-2200) – Anorganization holding an ASME Certificate ofAuthorization to apply the Code Symbolstamp responsible for design, material selec-tion, capacity certification, manufacture of allcomponent parts, assembly, testing, sealing,stamping and shipping of pressure reliefvalves.

Manufacturer’s Documentation – The docu-mentation that includes technical informationand certification required by the original codeof construction.

Modification (applicable to RA-2300) – Anychange to an item which affects the existingdesign requirements. Modifications includenonphysical changes (such as an increase inthe MAWP or design temperature, or a reduc-tion in minimum temperature such thatadditional mechanical tests are required),design reconciliation and revision of designspecifications, and the process of makingphysical changes to an item as required tomeet revised design requirements.

“NR” Certificate Holder – An organizationin possession of a valid “NR” Certificate ofAuthorization issued by the National Board.

NBIC – The National Board Inspection Codepublished by The National Board of Boilerand Pressure Vessel Inspectors.

138


National Board – National Board of Boilerand Pressure Vessel Inspectors.

National Board Commissioned Inspector –An individual who holds a valid and currentNational Board Commission.

Nuclear Items – Items constructed in accor-dance with recognized standards to be usedin nuclear power plants.

Original Code of Construction – Documentspromulgated by recognized national stan-dards writing bodies that contain technicalrequirements for construction of pressureretaining items or equivalent to which thepressure retaining item was certified by theoriginal manufacturer.

Owner (applicable to RA-2300) – The orga-nization legally responsible for the operation,maintenance, safety, and power generation ofthe nuclear power plant, including the repair,modification, or replacement of items in theplant.

owner or user – As referenced in lower caseletters means any person, firm or corporationlegally responsible for the safe operation ofany pressure retaining item.

Owner-User Inspection Organization – Anowner or user of pressure retaining items thatmaintains an established inspection program,whose organization and inspection proce-dures meet the requirements of the NationalBoard rules and are acceptable to the juris-diction or jurisdictional authority wherein theowner or user is located.

Owner-User Inspector – An individual whoholds a valid and current National BoardOwner-User Commission.

Pressure Retaining Items (PRI) – Any boiler,pressure vessel, piping, or material used forthe containment of pressure, either internalor external. The pressure may be obtainedfrom an external source, or by the applica-tion of heat from a direct source, or any com-bination thereof.

Quality System (applicable to RA-2200 andRA-2300) – Those planned and systematicactions necessary to provide adequateconfidence that items repaired, modified,or replaced are in accordance with therequirements of the NBIC and Section XI ofthe ASME Code.

Repair (applicable to RA-2200) – Repair of apressure relief valve is considered to be thereplacement, remachining or cleaning of anycritical part, lapping of the seat or disk or anyother operation which may affect the pres-sure relief valve function or pressure retain-ing integrity. Disassembly, reassembly and/or adjustments which affect the pressure re-lief valve function are also considered a re-pair. The initial installation, testing and ad-justments of a new pressure relief valve on aboiler or pressure vessel are not considered arepair if made by the manufacturer or assem-bler of the valve.

Repair – The work necessary to restore pres-sure retaining items to a safe and satisfactoryoperating condition.

Repair (applicable to RA-2300) – The processof restoring a component or system to a safeand satisfactory condition such that the ex-isting design requirements are met.

Replacement (applicable to RA-2300) – Atype of repair completed by the fabricationand installation of spare or renewal compo-nents, appurtenances, and subassemblies, orparts of a component or system.

Re-rating – See alteration.

“R” Certificate Holder – An organizationin possession of a valid “R” Certificate ofAuthorization issued by the National Board.

Safety Relief Valves – A safety relief valveis a pressure relief valve characterized byrapid opening or pop action, or by openingin proportion to the increase in pressureover the opening pressure, depending onapplication.

139


Testing Laboratory – National Board acceptedlaboratory which performs functional and ca-pacity tests of pressure relief devices.

Unique Identifier (applicable to RA-2200) –Repair serial number, shop order number, etc.,that appears on a valve repair nameplate suchthat traceability to the repair documentationis established.

“VR” Certificate Holder – An organizationin possession of a valid “VR” Certificate ofAuthorization issued by the NationalBoard.

140


141

National Board Forms

Appendix 5

142


APPENDIX 5 — NATIONAL BOARD FORMS

Form R-1 Report of Welded Repair ......................................................................................................... 143

Form R-2 Report of Alteration .................................................................................................................. 145

Form R-3 Report of Parts Fabricated by Welding.................................................................................. 147

Form R-4 Report Supplementary Sheet .................................................................................................. 149

Guide for Completing National Board FORM R Reports ..................................................................... 151

Form NR-1 Report of Repair, Modification or Installation ofReplacement(s) to Nuclear Components and Systems in Nuclear Power Plants ............................. 155

Guide for Completing National Board FORM NR Reports .................................................................. 157

Form NVR-1 Report of Repair, Modification or Replacement of NuclearPressure Relief Devices ............................................................................................................................... 161

Replacement of Stamped Data Form ........................................................................................................ 163

Form NB-4 Notice of New Business or Discontinuance Used by AuthorizedInsurance Inspection Agencies .................................................................................................................. 165

Form NB-5 Boiler or Pressure Vessel Data Report - First Internal Inspection .................................. 167

Form NB-6 Boiler - Fired Pressure Vessel - Report of Inspection ....................................................... 169

Form NB-7 Pressure Vessels - Report of Inspection .............................................................................. 171

143

FORM R-2 REPORT OF WELDED REPAIRin accordance with provisions of the National Board Inspection Code

1. Work performed by ___________________________________________________ ________________

________________________________________________________________________________________

2. Owner ________________________________________________________________________________

________________________________________________________________________________________

3. Location of installation __________________________________________________________________

________________________________________________________________________________________

4.Unit identification ________________ Name of original manufacturer _______________________

5. Identifying nos.: ___________ ________________ ______________ ___________ _________

6. NBIC Edition/Addenda: ____________________________ _______________________________

Original Code of Construction for Item: _____________________ __________________________

Construction Code Used for Repair Performed: ___________________ ___________________

7. Description of work: __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Pressure Test, if applied ________ psi MAWP psi

8. Replacement Parts. Attached are Manufacturer’s Partial Data Reports or Form R-3s properlycompleted for the following items of this report:

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

9. Remarks: ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


(boiler, pressure vessel)

(mfg serial no.) (National Board No.) (jurisdiction no.) (other) (year built)

CERTIFICATE OF COMPLIANCE

I, ____________________________, certify that to the best of my knowledge and belief the statements in this report are correctand that all material, construction, and workmanship on this Repair conforms to the National Board Inspection Code.National Board “R” Certificate of Authorization No._________________________________expires on__________, _________Date__________, _________ _______________________________ Signed___________________________________________________________________________________________________________________________________________________________

CERTIFICATE OF INSPECTION

I, ____________________________, holding a valid Commission issued by The National Board of Boiler and Pressure VesselInspectors and certificate of competency issued by the jurisdiction of _______________________________ and employed by________________________________________________________________ of ______________________________________ haveinspected the work described in this report on __________, __________ and state that to the best of my knowledge and beliefthis work complies with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerningthe work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner forany personal injury, property damage or loss of any kind arising from or connected with this inspection.

Date__________, _________ Signed__________________________________ Commissions _____________________________

(edition) (addenda)

(name/section/division) (edition/addenda)


FORM R-1 REPORT OF WELDED REPAIRin accordance with provisions of the National Board Inspection Code

(use supplemental sheet, Form R-4, if necessary)

(name of part, item number, data report type, mfg’s. name and identifying stamp)

(National Board (incl endorsements),and jurisdiction, and no.)

(name of repair organization) (authorized representative)

(inspector)

1 2

3

4

5 6

7 8 8 8 9

10 10

(name of repair organization)

(address)

(name)

(address)

(name)

(address)

(Form R No.)

(P.O. No. Job No. etc.)

53

16

17 18

19 20 21

22

23

24 25

26

19 27 28

14

15

12

11 11

11 11

13 54

144


145

FORM R-2 REPORT OF ALTERATIONin accordance with provisions of the National Board Inspection Code

1. Work performed by ___________________________________________________ ________________

________________________________________________________________________________________

2. Owner ________________________________________________________________________________

________________________________________________________________________________________

3. Location of installation __________________________________________________________________

________________________________________________________________________________________

4.Unit identification ________________ Name of original manufacturer _______________________

5. Identifying nos.: ___________ ________________ ______________ ___________ _________

6. NBIC Edition/Addenda: ____________________________ _______________________________

Original Code of Construction for Item: _____________________ __________________________

Construction Code Used for Alteration Performed: __________________ ___________________

7. Description of work: __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Pressure Test, if applied ________ psi MAWP psi

8. Replacement Parts. Attached are Manufacturer’s Partial Data Reports or Form R-3s properlycompleted for the following items of this report:

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

9. Remarks: ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

(name of alteration organization)

(address)

(name)

(address)

(name)

(address)

(Form R No.)

FORM R-2 REPORT OF ALTERATIONin accordance with provisions of the National Board Inspection Code

(use supplemental sheet, Form R-4, if necessary)

(name of part, item number, data report type, mfg’s. name and identifying stamp)


(boiler, pressure vessel)

(mfg serial no.) (National Board No.) (jurisdiction no.) (other) (year built)


53

1 2

3

4

5 6

7 8 8 8 9

12

14

15

(edition) (addenda)



10

11

11

10

11

11

13 54

146


Form R-2 (back) ______________________(Form R No.)



16

17 18

19 20 21

22

23

24 25

26

19 27 28

16

17 18

19 20 21

22

23

24 25

19 27 28

(authorized representative)

(inspector)

(inspector)

(name of alteration organization)

(name of design organization)

2

CONSTRUCTION CERTIFICATION

I, ____________________________, certify that to the best of my knowledge and belief the statements in this report are correctand that all material, construction, and workmanship on this Alteration conforms to the National Board Inspection Code.National Board “R” Certificate of Authorization No._________________________________expires on__________, ___________

Date__________, _________ _______________________________ Signed_______________________________________________


I, ____________________________, holding a valid Commission issued by The National Board of Boiler and Pressure VesselInspectors and certificate of competency issued by the jurisdiction of _______________________________and employed by_____________________________________________________________of _________________________________________haveinspected the work described in this report on _______________, _________and state that to the best of my knowledge andbelief this work complies with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerningthe work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner forany personal injury, property damage or loss of any kind arising from or connected with this inspection.

Date__________, _________ Signed__________________________________ Commissions _____________________________

(authorized representative)

DESIGN CERTIFICATION

I, ____________________________, certify that to the best of my knowledge and belief the statements in this report are correctand that the Design Change described in this report conforms to the National Board Inspection Code.National Board “R” Certificate of Authorization No._________________________________expires on__________, ___________Date__________, _________ _______________________________ Signed_______________________________________________

CERTIFICATE OF DESIGN CHANGE REVIEW

I, ____________________________, holding a valid Commission issued by The National Board of Boiler and Pressure VesselInspectors and certificate of competency issued by the jurisdiction of ________________________________and employed by________________________________________________of _____________________________________________________ havereviewed the design change as described in this report and state that to the best of my knowledge and belief such changecomplies with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerningthe work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner forany personal injury, property damage or loss of any kind arising from or connected with this inspection.

Date__________, _________ Signed__________________________________ Commissions ________________________________

147

FORM R-3 REPORT OF PARTS FABRICATED BY WELDINGin accordance with provisions of the National Board Inspection Code

7. Remarks ______________________________________________________________________________________________________

36 37 38 39 40 41 13 9

(name of manufacturer)

(address)

(name of purchaser)

(address)

(name of organization)

(code year)

6. Description of Parts

(a) Connections other than tubes Heads or Ends (b) Tubes

Line Size and Material Thickness Shape Thickness Material Diameter Thickness MaterialNo. Shape Spec No. In. In. Spec No. In. In. Spec No.

15

38 42 43 44 45 46 43 47 48 43

1 2

29

30 31

32 33 34 35

(Form R No.)

(name of organization)

(formula on which MAWP is based)(code type and section)

1. Manufactured by _________________________________________________________________ ____________________________

________________________________________________________________________________________________________________

2. Manufactured for _______________________________________________________________________________________________

________________________________________________________________________________________________________________

3. Design Condition specified by _____________________________________ Code design by ____________________________

4. Design Code _________________________ ___________________ ____________________ ____________________________

5. Identification of Parts

Name of Part Qty. Line No. Manufacturer’s Manufacturer’s MAWP Shop Hydro YearIdentifying No. Drawing No. psi Built

(addenda date)



53

148



(Inspector)

(authorized representative)(name of R Certificate holder)

Form R-3 (back) ______________________(Form R No.)

2

22

23

24 25

26

16

17 18

19 20 21

19 27 28

CERTIFICATE OF SHOP COMPLIANCE

I, ____________________________, certify that to the best of my knowledge and belief the statements in this report are correctand that all material, fabrication, construction, and workmanship of the described parts conforms to the National BoardInspection Code and standards of construction cited.National Board “R” Certificate of Authorization No._________________________________expires on__________, ___________Date__________, _________ _______________________________ Signed_______________________________________________

CERTIFICATE OF SHOP INSPECTION

I, ____________________________, holding a valid Commission issued by The National Board of Boiler and Pressure VesselInspectors and certificate of competency issued by the jurisdiction of ________________________________and employed by________________________________________________of _____________________________________________________ haveinspected the parts described in this report on ________________ , _______ and state that to the best of my knowledge andbelief the parts comply with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerningthe work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner forany personal injury, property damage or loss of any kind arising from or connected with this inspection.

Date__________, ___________ Signed__________________________________ Commissions _____________________________

149

1. Work performed by _______________________________________________________ ___________________________________

________________________________________________________________________________________________________________

2. Owner ________________________________________________________________________________________________________

________________________________________________________________________________________________________________

3. Location of installation __________________________________________________________________________________________

________________________________________________________________________________________________________________

Reference Continued from Form R–_____

Line No.

19 21 20 49

19 27 28 49

FORM R-4 REPORT SUPPLEMENTARY SHEETin accordance with provisions of the National Board Inspection Code

(Form R reference)(name)

(address)

(name)

(address)

(name)

(address)

1 49 2 49

3 or 29 49

4 49

50

Date ________ , _______ Signed ______________________________________ Name ______________________________________

Date ________ , _______ Signed ______________________________________ Commissions _______________________________(Inspector)

(authorized representative) (authorized organization)

51 52




53 49

150


151


GUIDE FOR COMPLETING NATIONAL BOARD FORM R REPORTS

1. Name and address of the “R” Certificate organization which performed the work.

2. Form R Number assigned by the organization which performed the work. (A single,sequential log shall be maintained by the organization for R-1, R-2, and R-3 Formsregistered with the National Board).

3. Name and address of the Owner of the pressure retaining item.

4. Name and address of plant or facility where the pressure retaining item is installed.

5. Description of the pressure retaining item, such as boiler or pressure vessel.

6. Name of original manufacturer of the pressure retaining item if a boiler or pressurevessel. If other than a boiler or pressure vessel, complete if known.

7. Serial number of the pressure retaining item as assigned by the originalmanufacturer.

8. Identification of the pressure retaining item by applicable registration number. Ifinstalled in Canada, indicate the Canadian design registration number (CRN), andlist the drawing number under “other.”

9. Identify the year in which fabrication/construction of the item was completed.

10. Indicate edition and addenda of the NBIC under which this work is beingperformed.

11. Indicate the name, section, division, edition, and addenda of the original code ofconstruction for the pressure retaining item. Also indicate the name, section,division, edition, and addenda of the construction code used for the work beingperformed. If code cases are used, they shall be identified in the “Remarks” section.

12. State exact scope of work, and attach additional data, sketch, Form R-4, etc. asnecessary. If additional data is attached, so state.

13. Indicate test pressure applied.

14. To be completed for all welded pressure components added during the work.Indicate part, item number, manufacturer’s name, stamped identification, and datareport type.

15. Indicate any additional information pertaining to the work involved (e.g. routinerepairs, code cases). For Form R-3 the part manufacturer is to indicate the extent hehas performed any or all of the design function. If only a portion of the design, statewhich portion.

16. Type or print name of authorized representative of the “R” Certificate Holder.

152


17. Indicate National Board “R” Certificate or Authorization number.

18. Indicate month, day, and year that the “R” certificate expires.

19. Enter date certified.

20. Name of R Certificate organization which performed the identified work.

21. Signature of authorized representative.

22. Type or print name of Inspector.

23. Indicate Inspector’s jurisdiction.

24. Indicate Inspector’s employer.

25. Indicate address of Inspector’s employer (city and state or province).

26. Indicate month, day, and year of inspection by Inspector. In case of Routine Repairsthis shall be the month, day and year the Inspector reviews the completed RoutineRepair package.

27. Signature of Inspector.

28. National Board commission number of Inspector, including endorsements, jurisdic-tion, and certificate of competency numbers.

29. Name and address of organization which purchased the parts for incorporation inthe repair or alteration, if known. If built for stock, so state.

30. Name of organization responsible for specifying the code design conditions.

31. Name of organization responsible for performing the code design, if known.

32. Name, section, and division of the design code, if known.

33. Indicate code edition year used for fabrication.

34. Indicate code addenda date used for fabrication.

35. Indicate code paragraph reference for formula used to establish the MAWP, ifknown.

36. Identify name of part, such as “superheater header.”

37. Indicate quantity of named parts.

38. Match line number references for identification of parts and description of parts.

39. Indicate manufacturer’s serial number for the named part.

153


40. Indicate drawing number for the named part.

41. Indicate Maximum Allowable Working Pressure for the part, if known.

42. Use inside diameter for size; indicate shape as square, round, etc.

43. Indicate the complete material specification number and grade.

44. Indicate nominal thickness of plate and minimum thickness after forming.

45. Indicate shape as flat, dished, ellipsoidal, or hemispherical.

46. Indicate minimum thickness after forming.

47. Indicate outside diameter.

48. Indicate minimum thickness of tubes.

49. Complete information identical to that shown on the Form R to which this sheetis supplementary.

50. Indicate the Form R type. Example: Form R-1, Form R-2, Form R-3

51. Indicate the reference line number from the Form R to which this sheet is supple-mentary.

52. Complete information for which there was insufficient space on the referenceForm R.

53. If applicable, purchase order, job number, etc. assigned by the organizationperforming the work.

54. Indicate the maximum allowable working pressure of the pressure retaining item.

154


155


2 3

5

6

7

1

31 3131

32 32

33 33

32

33

34

3535

123456789101112

ActivityIdentification

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Type ofItem

Nat’l Bd.No.

Jurisd.No.

Other

Construction Code

Name/Section/Division

Repair/Mod/

Replace

CodeClass

CodeCase(s)

Edition/AddendaNo

YearBuilt

Mfg.Name

Mfg.Serial No.

_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Construction CodeIdentificationCodeClass

CodeCase(s)

Edition/Addenda

Name/Section/Division

Installed orReplaced

5a Item No

Type ofItem

Mfg.Name

Mfg.Serial No.

Nat’l Bd.No.

Jurisd.No.

Other YearBuilt

FORM NR–1 REPORT OF REPAIR MODIFICATION OR REPLACEMENTTO NUCLEAR COMPONENTS AND SYSTEMS IN NUCLEAR POWER PLANTS

1. Work performed by ____________________________________________________________ ______________________________(name of NR certificate holder) (P.O. no., job no., etc.)

_______________________________________________________________________________________________________________(address)

2. Owner _______________________________________________________________________________________________________(name)

_______________________________________________________________________________________________________________(address)

3. Name, address and identification of nuclear power plant __________________________________________________________________________________________________________________________________________________________________________

4. System _______________________________________________________________________________________________________5a. Items Which Required Repair, Modification, or Replacement Activities

5b. Items Installed During Replacement Activities

6. ASME Code Section XI applicable for inservice inspection: _________________ _________________ __________________(edition) (addenda) (Code Case(s))

7. ASME Code Section XI used for repairs, modifications, or replacements: ____________ ___________ _________________(edition) (addenda) (Code Case(s))

8. Construction Code used for repairs, modifications, or replacements: _____________ ___________ _________________(edition) (addenda) (Code Case(s))

9. Design responsibilities _________________________________________________________________________________________

10. Tests conducted: hydrostatic pnematic design pressure pressure _________ psi Code Case(s) ____________

9 10 12 13 16 17 18 19 20 20 2120

30303029282726252423229

156



I, ____________________________, certify that to the best of my knowledge and belief the statements made in this report arecorrect and the repair, modification or replacement activities described above conform to Section XI of the ASME Code andthe National Board Inspection Code “NR” rules.

National Board Certificate of Authorization No.______________to use the “NR stamp expires__________, ____________

NR Certificate Holder_______________________________________________________________________________________

Date________, _______ Signed______________________________________ ________________________________________

_______________________________________________________________________________________________________________


I, ____________________________, holding a valid commission issued by The National Board of Boiler and Pressure VesselInspectors and certificate of competency issued by the jurisdiction of _______________________________ and employed by________________________________________________________________ of ______________________________________ haveinspected the repair, modification or replacement described in this report on __________, _____________ and state that to thebest of my knowledge and belief, this repair, modification or replacement activity has been completed in accordance withSection XI of the ASME Code and the National Board Inspection Code “NR” rules.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerningthe work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner forany personal injury, property damage or a loss of any kind arising from or connected with this inspection.Date__________, ____________ Signed__________________________________ Commissions _____________________________

42

43 44

46 47 48

45

(name)

(authorized representative) (title)

46 55 54

(National Board (incl endorsements), jurisdiction, and no.)(inspector)

50

52

53

49

51

11. Description of work _________________________________________________________________________

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________12. Remarks ________________________________________________________________________________________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________

(use of properly identified additional sheet(s) or sketch(es) is acceptable)

40

41

157


GUIDE FOR COMPLETING NATIONAL BOARDFORM NR-1 AND NVR-1 REPORTS

1. Indicate whether the report is to cover repair, modification, or replacement activity.

2. Name and address of the organization, as shown on the Certificate of Authorization,which performed the repair, modification, or replacement activity.

3. Indicate the purchase order number, job number, etc., as applicable, assigned by theorganization which performed the work.

4. Name and address of the organization for which the work was performed.

5. Name and address of the Owner of the nuclear power plant.

6. Name and address of the nuclear power plant and, if applicable, identification of theunit.

7. Identify the system (e.g. residual heat removal, reactor coolant, etc.) with which therepair, modification, or replacement activity is associated.

8. Describe the type of pressure relief device (e.g. safety valve, safety relief valve,pressure relief valve, etc.)

9. Indicate the type of component (e.g. vessel, line valve, pump, piping system, etc.)

10. Manufacturer’s name of the repaired, modified, or replaced item.

11. Indicate the pressure relief device by the manufacturer’s valve series or catalognumber.

12. Manufacturer’s serial number of the repaired, modified, or replaced item.

13. National Board number, if applicable, of the repaired, modified, or replaced item.

14. Indicate the service as steam, liquid, gas, air, etc.

15. Indicate the pressure relief device by inlet size, in inches.

16. Indicate Jurisdiction number, if applicable, of the repaired, modified, or replaceditem.

17. Indicate plant tag or identification number, if applicable, of the repaired, modified,or replaced item.

18. Year the repaired, modified, or replaced item was manufactured.

19. Identify the name, section, and division of the original construction Code for therepaired, modified, or replaced item.

158


20. Identify the edition, addenda, and as applicable, Code Cases and class of the origi-nal construction Code for the repaired, modified, or replaced item.

21. Indicate the activity performed on this item, i.e. repair, modification, or replacement.

22. Indicate the Item No. from Section 5a with which this replacement item is associated.Attach the Manufacturer’s Data Report, as applicable.

23. Manufacturer’s name of this replacement item.

24. Manufacturer’s serial number of this replacement item.

25. National Board number, if applicable, of this replacement item.

26. Jurisdictional number, if applicable, of this replacement item.

27. Plant tag or identification number of this replacement item.

28. Year this replacement item was manufactured.

29. Name, section, and division of the construction Code for this replacement item.

30. Edition, addenda, and as applicable, Code Cases and class of the construction Codefor this replacement item.

31. Identify the edition, addenda, and any applicable Code cases of the ASME Section XICode used for inservice inspection.

32. Identify the edition, addenda, and any applicable Code Cases of the ASME SectionXI Code for the repair, modification, or replacement activity.

33. Identify the edition, addenda, and any applicable Code Cases of the constructionCode for the repair, modification, or replacement activity.

34. Identify the organization responsible for design or design reconciliation, if applicable.

35. Identify the type of pressure test (i.e. hydrostatic, pneumatic, or design) and appliedtest pressure. Also indicate any Code Cases used in connection with the pressuretest.

36. Indicate the set pressure of the valve.

37. Indicate blowdown, if applicable, as a percentage of set pressure.

38. Indicate the repair organization’s name and address.

39. Indicate the medium (steam, air, etc.) used for the adjustment of set pressure and, ifapplicable, blowdown.

159


40. State exact scope of work for the repair, modification, or replacement activity. Ifnecessary attach additional data, sketch, Form R-4, etc. If additional data is attached,so state.

41. Indicate any additional information pertaining to the work.

42. Type or print name of authorized representative from the certificate holder.

43. Indicate National Board Certificate of Authorization number.

44. Indicate month, day, and year the certificate expires.

45. Name of the certificate holder which performed the identified work.

46. Enter date certified.

47. Signature of authorized representative from the certificate holder.

48. Title of authorized representative.

49. Type or print name of Authorized Nuclear Inspector.

50. Indicate the jurisdiction where the work is performed.

51. Indicate Authorized Nuclear Inspector’s employer.

52. Indicate address of Authorized Nuclear Inspector’s employer (city and state orprovince).

53. Indicate month, day, and year of inspection by the Authorized Nuclear Inspector.

54. Signature of Authorized Nuclear Inspector.

55. National Board Commission number of the Authorized Nuclear Inspector, includingendorsements, jurisdiction, and certificate of competency numbers.

160


161


I, ____________________________, certify that to the best of my knowledge and belief the statements made in this report arecorrect and the repair, modification or replacement of the pressure relief devices described above conforms to Section XI ofthe ASME Code and the National Board Inspection Code “VR” and “NR” rules.National Board Certificate of Authorization No.______________to use the “VR” stamp expires__________, ____________National Board Certificate of Authorization No.______________to use the “NR” stamp expires__________, ____________

Date________, _______ _________________________________ Signed___________________________ ______________________________________________________________________________________________________________________


I, ____________________________, holding a valid commission issued by The National Board of Boiler and Pressure VesselInspectors and certificate of competency issued by the jurisdiction of _______________________________ and employed by________________________________________________________________ of ______________________________________ haveinspected the repair, modification or replacement described in this report on __________, _____________ and state that to thebest of my knowledge and belief, this repair, modification or replacement has been completed in accordance with Section XIof the ASME Code and the National Board Inspection Code “VR” and “NR” rules.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerningthe repair, modification or replacement described in this report. Furthermore, neither the undersigned nor my employer shallbe liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with thisinspection.Date__________, ____________ Signed__________________________________ Commissions _____________________________

FORM NVR–1 REPORT OF REPAIR MODIFICATION OR REPLACEMENTOF NUCLEAR PRESSURE RELIEF DEVICES

1. Work performed by ____________________________________________________________ ______________________________(name of certificate holder) (P.O. no., job no., etc.)

_______________________________________________________________________________________________________________(address)

2. Work performed for ___________________________________________________________________________________________(name and address)

3. Owner ______________________________________________________________________________________________________________________________________________________________________________________________________________________

4. Name, address and identification of nuclear power plant __________________________________________________________________________________________________________________________________________________________________________

5. a: Repaired pressure relief device: _____________________________________________________________________________b: Name of manufacturer _____________________________________________________________________________________c: Identifying nos. __________ _________ ________________ ________________ ________________ __________________

(type) (mfg’s serial no.) (Nat’l. Bd. No.) (service) (size) (year built)

d: Construction Code ____________ ______________ __________________ __________________ ________________________(name/section/division) (edition) (addenda) (Code Cases(s)) (Code Class)

6. ASME Code Section XI applicable for inservice inspection: _________________ _________________ __________________(edition) (addenda) (Code Case(s))

7. ASME Code Section XI used for repairs, modifications, or replacements: ____________ ___________ _________________(edition) (addenda) (Code Case(s))

8. Construction Code used for repairs, modifications, or replacements: _____________ ___________ _________________(edition) (addenda) (Code Case(s))

9. Design responsibility __________________________________________________________________________________________10. Opening pressure: _________ Blowdown (if applicable) ____________________ %. Set pressure and blowdown adjustment

made at: ________________________________________________________________ using ____________________________

11. Description of work: (include name and identifying number of replacement parts) ____________________________________

_______________________________________________________________________________________________________________

12. Remarks: ____________________________________________________________________________________________________

_______________________________________________________________________________________________________________


(National Board (incl endorsements),andjurisdiction, and no.)

(inspector)

2 3

(title)

42

43

43

44

44

50

48 47

52

53

46 45

49

51

46 55 54

1

4

5(name)

(address)

6

34

31 3131

32 3232

33 3333

11

2019 20 20 20

10

8

3736

12 13 14 15 18

(test medium)(location)

38

41

39

40

(authorized representative)(name of certificate holder)

162


163


164


165


166


167


168


169


170


171


172


173

Examples of Repairs and Alterations

Appendix 6

174


APPENDIX 6 — EXAMPLES OF REPAIRS AND ALTERATIONS

A. INTRODUCTION

The purpose of this appendix is to provideowners, users, repair organizations andInspectors with assistance in evaluatingwhether contemplated work on a pressureretaining item should be categorized as arepair or alteration. The significance of thiscategorization affects the qualifications of theorganization performing the work as well asthe resultant documentation.

B. EXAMPLES OF REPAIRS

Repairs are defined in the Glossary. Examplesof repairs are:

1. weld repairs or replacement of pressureparts or attachments that have failed in aweld or in the base material;

2. the addition of welded attachments topressure parts, such as:

a. studs for insulation or refractorylining

b. hex steel or expanded metal forrefractory lining

c. ladder clips

d. brackets, having loadings which donot affect the design of the pressureretaining item to which they areattached

e. tray support rings

3. corrosion resistant strip lining or weldoverlay;

4. weld buildup of wasted areas;

5. replacement of heat exchanger tube sheetsin accordance with the original design;

6. replacement of boiler and heat exchangertubes where welding is involved;

7. in a boiler, a change in the arrangementof tubes in furnace walls, economizer orsuper heater sections;

8. replacement of pressure retaining partsidentical to those existing on the pressureretaining item and described on theoriginal Manufacturer’s Data Report. Forexample:

a. replacement of furnace floor tubesand/or sidewall tubes in a boiler

b. replacement of a shell or head inaccordance with the original design

c. rewelding a circumferential or longi-tudinal seam in a shell or head

d. replacement of nozzles of a size wherereinforcement is not a consideration

9. installation of new nozzles or openingsof such a size that reinforcement is not aconsideration [for example, the installa-tion of a 3 NPS nozzle to a shell or headof 3/8 in. or less in thickness or theaddition of a 2 NPS nozzle to a shell orhead of any thickness];

10. the addition of a nozzle where reinforce-ment is a consideration may be consid-ered to be a repair provided the nozzle isidentical to one in the original design, lo-cated in a similar part of the vessel, andnot closer than three times its diameterfrom another nozzle. The addition of sucha nozzle shall be restricted by any servicerequirements;

11. the installation of a flush patch to apressure retaining item;

12. the replacement of a shell course in acylindrical pressure vessel;

175

APPENDIX 6 — EXAMPLES OF REPAIRS AND ALTERATIONS

13. welding of gage holes;

14. welding of wasted or distorted flangefaces;

15. replacement of slip-on flanges with weldneck flanges or vice-versa;

16. seal welding of buttstraps and rivets;

17. subject to the administrative proceduresof the jurisdiction and approval of theInspector, the replacement of a rivetedsection or part by welding;

18. the repair or replacement of a pressurepart with a Code accepted materialthat has a nominal composition andstrength that is equivalent to the originalmaterial, and is suitable for the intendedservice;

19. replacement of a pressure retaining partwith a material of different nominal com-position, equal to or greater in allowablestress from that used in the original de-sign, provided the replacement materialsatisfies the material and design require-ments of the original code of constructionunder which the vessel was built.

C. EXAMPLES OF ALTERATIONS

Alterations are defined in the Glossary.Examples are:

1. an increase in the maximum allowableworking pressure (internal or external) or

temperature of a pressure retaining itemregardless of whether or not a physicalchange was made to the pressure retain-ing item;

2. a decrease in the minimum temperaturesuch that additional mechanical tests arerequired;

3. the addition of new nozzles or openingsin a boiler or pressure vessel except thoseclassified as repairs;

4. a change in the dimensions or contour ofa pressure retaining item;

5. in a boiler, an increase in the heating sur-face or steaming capacity such that an in-crease in the relieving capacity is required;

6. the addition of a pressurized jacket to apressure vessel;

7. except as permitted in B-19, replacementof a pressure retaining part in a pressureretaining item with a material of differ-ent allowable stress or nominal composi-tion from that used in the original design.

8. The addition of a bracket or an increasein loading on an existing bracket whichaffects the design of the pressure retain-ing item to which it is attached.

176


177

Appendix 7

Procedures to Extend the “VR” Certificateof Authorization Stamp to ASME “NV”Stamped Pressure Relief Devices

178


APPENDIX 7 — PROCEDURES TO EXTEND THE “VR” CERTIFICATEOF AUTHORIZATION AND STAMP TO ASME “NV” STAMPED

PRESSURE RELIEF DEVICES

INTRODUCTION

Approval to extend the scope of the NationalBoard “VR” Certificate of Authorization to thecertificate holder to use the “VR” stamp onASME Code “NV” Class 1, 2 or 3 stampedpressure relief devices, which have beencapacity certified by the National Board, maybe given subject to the following provisions:

PART I ADMINISTRATIVEPROCEDURES

1. The repair organization shall hold a valid“VR” Certificate of Authorization.

2. The repair organization shall obtain aNational Board “NR” Certificate ofAuthorization and stamp to repair,modify or replace nuclear components.The requirements for said certificate andstamp include, but are not limited to, thefollowing. The repair organization shall:

a. maintain a documented quality assur-ance program which meets the appli-cable requirements of Section RA-2300of the NBIC. This program shall alsoinclude all the applicable require-ments for the use of the “VR” stamp;

b. have a contract or agreement with anInspection Agency to provide inspec-tion of repaired “NV” stamped pres-sure relief devices by Inspectors whohave been qualified in accordancewith the requirements of ANSI/ASME N-626.0;

c. successfully complete a survey of thequality assurance program and itsimplementation. This survey shall beconducted by representatives of theNational Board, the jurisdiction

wherein the applicant’s repairfacilities are located, and theapplicant’s Authorized InspectionAgency. Further verification of suchimplementation by the survey teammay not be necessary if the applicantholds a valid ASME “NV” certificateand can verify by documentation thecapability of implementing the qual-ity assurance program for repair of“NV” stamped pressure relief devices,covered by the applicant’s ASME“NV” certificate.

3. The application of the “NR” Certificate ofAuthorization and stamp shall clearlydefine the scope of intended activitieswith respect to the repair of Section III“NV” stamped pressure relief devices.

4. Revisions to the quality assurance pro-gram shall be acceptable to the AuthorizedNuclear Inspector Supervisor and theNational Board before being implemented.

5. Endorsement of the “VR” Certificate ofAuthorization for the repair of “NV”stamped pressure relief devices shallbe granted upon acceptance by theNational Board Accreditation Committeeon Nuclear Repair, Modification andReplacement.

6. Verification testing of valves repairedby the applicant shall not be required pro-vided such testing has been successfullycompleted under the applicant’s “VR”certification program.

7. A survey of the applicant for the “VR”Certificate of Authorization andendorsement of the repair of “NV”stamped pressure relief devices maybe made concurrently.

179

APPENDIX 7 — PROCEDURES TO EXTEND THE “VR” CERTIFICATE OF AUTHORIZATION STAMP TO ASME “NV” STAMPED PRESSURE RELIEF DEVICES

PART II GENERAL RULES

1. ASME Code Section III “NV” stampedpressure relief devices, which have beenrepaired in accordance with these rules,shall be stamped with both the “VR” and“NR” stamps.

2. The “VR” and “NR” stamps shall beapplied only to “NV” stamped (Class 1, 2or 3) National Board capacity certifiedpressure relief devices which have beendisassembled, inspected and repairedas necessary, such that the valves’ condi-tion and performance are equivalent to thestandards for new valves.

3. All measuring and test equipment usedin the repair of pressure relief devices shallbe calibrated against certified equipmenthaving known valid relationships tonationally recognized standards.

4. Documentation of the repair of “NV”stamped pressure relief devices shall berecorded on the National Board FormNVR-1, Report of Repair, Modification orReplacement of Nuclear Pressure ReliefDevices in accordance with the require-ments of RA-2300 of the NBIC.

5. When an ASME “NV” Stamped PressureRelief Device requires a duplicate name-plate because the original nameplate isillegible or missing, it may be appliedusing the procedures of RA-2264 orRA-2265 provided concurrence is obtainedfrom the Authorized Nuclear Inspector andjurisdiction. In this case the nameplate shallbe marked “SEC. III” to indicate theoriginal ASME Code stamping.

180


181

Appendix 8

Inspection, Repair and Alteration ofGraphite Pressure Equipment

182


APPENDIX 8 — INSPECTION, REPAIR AND ALTERATION OF GRAPHITEPRESSURE EQUIPMENT

8-1000 SCOPE

a. The purpose of this Appendix is to pro-vide requirements for inservice inspec-tion, repair, and alteration of pressureequipment manufactured from impervi-ous graphite materials.

b. Repair or alteration of metallic compo-nents shall comply with Part RC.

c. The impervious graphite (carbon, graph-ite, or graphite compound) used for theconstruction of graphite pressure vesselsis a composite material, consisting of“raw” carbon or graphite which is im-pregnated with a resin using a tightly con-trolled pressure/heat cycle(s). The inter-action between the raw material and theresin is the determining factor when con-sidering the design characteristics of thematerial. The design characteristics in-clude the strengths (flexural, compressive,and tensile), permeability, coefficient ofthermal expansion, thermal conductivity,and ultimately, the safe operating life ofthe vessel.

d. The process used in the manufacturing ofthe raw material is well documented. Theexpertise developed in this field allowsfor many different grades to be manufac-tured to meet the specific needs of vari-ous industries, including corrosive chemi-cal processing pressure vessels. In thechemical processing industry the proper-ties of the raw material are dictated by theManufacturer of the impregnated mate-rial, based on the pressure/temperaturecycle and the type of resin used for im-pregnation. The raw material require-ments are defined and communicated tothe manufacturer of the raw material. Thecycle and resin type may vary fromManufacturer to Manufacturer, and also

for each “grade” of impregnated mate-rial a Manufacturer produces.

e. Repairs to graphite pressure equipmentrequire the use of certified impregnatedgraphite and cement. The determiningfactor in establishing the desired materialproperties is the resin impregnation cycle.If the resin impregnation cycle is not con-trolled, it is not possible to meet the mini-mum design values.

f. With over a century of experience withgraphite pressure equipment, the essen-tial variables of the process have been de-fined and apply universally to all Manu-facturers of impervious graphite equip-ment. Therefore, by requiring the essen-tial variables of the resin impregnationcycle to be identified and verified, it ispossible to assign a “lot” number to allcertified materials at completion of theresin impregnation process. This can bedone with the assurance of meaningfuland consistent test results.

8-2000 APPLICATION

Due to inherent resistance to chemical attack,graphite pressure equipment is often used incorrosive applications, which may include le-thal service.

8-3000 OPERATIONS

The owner should maintain controlled con-ditions for use of graphite pressure equip-ment, including the use of temperature andpressure recorders and/or operating logs.The owner should maintain operating proce-dures, and ensure that pressure and tempera-ture are controlled. A thermal or pressurespike may damage the graphite or metal com-ponents.

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APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT

8-4000 INSERVICE INSPECTION

The guidelines provided in Part RB shall ap-ply to graphite pressure equipment, exceptas modified herein.

a. Graphite pressure vessels, pressure parts,and vessel components should receive anexternal visual examination biennially.All accessible surfaces should be chemi-cally cleaned. Cleaning fluids containingstrong oxidants should not be used.

b. Typical indicators which may necessitategraphite pressure equipment inspection,evaluation, and repair include:

1. Cross contamination of either processor service fluids

2. External leakage is observed

3. Flow rate is reduced or excessive pres-sure drop is observed

4. Heat transfer performance is reduced

c. Cracks, bulges, blisters, delaminations,spalling conditions, and excessive erosionare cause for repair or replacement. Anysurface discoloration should be re-cleanedand examined more closely to determineif a delamination or spalling condition ex-ists.

d. Other typical discontinuities include chip-ping, erosion, baffle cutting due to vibra-tion, and cement deterioration. All pas-sage ways are susceptible to fouling.

8-5000 REPAIRS

The requirements provided in Part RC-1020subparagraph (i), RC-1060, RC-1070, RC-1110,RC-1120, RC-1140, RC-1141, RC-2020, RC-2030 and RC-2031 except subparagraph (a)shall apply, insofar as they are applicable tographite pressure equipment. Graphite spe-cific requirements include:

a. Organizations performing repairs shall beaccredited as described in Part RA, as ap-propriate for the scope of work to be per-formed.

b. When the standard governing the origi-nal construction is not the ASME Code,repairs or alterations shall conform to theedition of the original construction stan-dard or specification most applicable tothe work. Where the original code of con-struction is unknown, the edition and ad-denda of the ASME Code most appropri-ate for the work shall be used, providedthe “R” Certificate Holder has the concur-rence of the Inspector and the jurisdictionwhere the pressure retaining item is in-stalled.

c. The materials used in making repairs oralterations shall conform to the require-ments of the original code of constructionexcept as provided in subparagraph (j).The “R” Certificate Holder is responsiblefor verifying identification of existingmaterials from original data, drawings, orunit records and identification of the ma-terials to be installed.

d. When ASME is the original code of con-struction, replacement parts subject to in-ternal or external pressure, which requireshop inspection by an Authorized Inspec-tor, shall be fabricated by an organizationhaving an appropriate ASME Certificateof Authorization. The item shall be in-spected and stamped as required by theapplicable section of the ASME Code. Acompleted ASME Manufacturer’s PartialData Report shall be supplied by themanufacturer.

e. When the original code of construction isother than ASME, replacement parts sub-ject to internal or external pressure shallbe manufactured by an organization cer-tified as required by the original code ofconstruction. The item shall be inspectedand stamped as required by the originalcode of construction. Certification to the

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k. Blind cracks and delaminations may notbe repaired by cement injection only.

l. Cracks and porosity in tubes may not berepaired. Cracked and porous sectionsmay be removed so that the remainder ofthe tube may be used. Individual tubesections shall not be less than 24 in. inlength, and the number of segments in atube shall not exceed the quantity listedin Table 1.

m. Cementing procedure specifications shallbe qualified by the repair organization.The specifications shall be qualified asrequired by the code of construction. Ce-menting procedure qualification shall beverified by the Inspector.

TABLE 1 —Permitted Quantity of Tube Segments

Total Tube Number of Number ofLength, ft. Tube Segments Joints

6 1 09 2 1

12 3 214 3 216 4 318 4 320 4 322 4 324 5 427 5 4

n. Cementing technicians shall be qualifiedby the repair organization. The techni-cians shall be qualified as required by thecode of construction. A cementing tech-nician is any individual who is respon-sible for proper joint preparation, clean-ing parts to be joined, mixing cement, ap-plying cement, securing the joint duringthe curing process, and controlling thecuring process.

o. All records shall be made available to theInspector.

original code of construction as requiredby the original code of construction orequivalent shall be supplied with theitem. When this is not possible or practi-cable, the organization fabricating the partmay have a National Board Certificate ofAuthorization; replacement parts shall bedocumented on Form R-3 and the “R”symbol stamp applied as described in Ap-pendix 2.

f. Organizations performing repairs underan “R” stamp program shall register suchrepairs with the National Board.

g. Before signing the appropriate NBICForm, the Inspector shall review thedrawings, witness any required pressuretest, assure that the required nondestruc-tive examinations have been performedsatisfactorily, and that the other functionsnecessary to assure compliance with therequirement of this Code have been per-formed.

h. Pressure retaining items repaired in ac-cordance with the NBIC shall be markedas required by Appendix 2. The letter “G”shall be applied to the nameplate underthe “R” stamp when graphite repairs aremade.

i. Legible copies of the completed Form R-1, together with attachments, shall be dis-tributed to the owner or user, the Inspec-tor, the jurisdiction if required, and theAuthorized Inspection Agency respon-sible for inservice inspection. Form R-1shall be registered with the NationalBoard. Distribution of Form R-1 and at-tachments shall be the responsibility ofthe organization performing the repair.

j. Graphite parts which have previouslybeen in service in one pressure vesselshould not be used in a second vesselwithout prior approval of the owner.Consideration should be given to the ser-vice condition of the previous process andpossible contamination of the subsequentprocess.

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p. Completed repairs shall be subjected to apressure test. The test pressure shall notbe less than the maximum allowableworking pressure or twice the operatingpressure, whichever is lower. The hydro-static test pressure shall be maintained for30 minutes.

q. Reimpregnation may be used to enhancethe performance and extend the life ofgraphite components. Reimpregnation ofgraphite shall not be considered a meansto restore original strength, nor shall it beconsidered a means to restore the origi-nal depth of impregnation.

8-6000 REPAIRS OF AROUTINE NATURE

The following repairs shall be considered rou-tine, and shall comply with RC-2031 exceptsubparagraph (a).

• MACHINING - routine repair shall notinclude the machining of pressure retain-ing parts with the exception of minor ma-chining for cleaning and joint preparationnot to exceed 1/32 in. of material thick-ness.

• REPAIR OF GASKET SURFACES -remachining of gasket surfaces,reserrating, or flattening is permitted ifthe design thickness is maintained.

• REPLACING INDIVIDUAL TUBES -drilling out and replacing tubes with newtubes or repaired tubes. Only certifiedmaterials shall be used for this repair.

• NOZZLE REPLACEMENT - replacementof nozzles by removing the old nozzle andcementing a new nozzle in place. This isapplicable for nozzles with inside diam-eters not exceeding 18 in.

• PLUGGING TUBES - plugging individualtubes using accepted procedures.

• SURFACE REPAIR - surface repair by in-stallation of plugs or inlay material shallnot exceed 1 cubic inch of total volume.Connected repairs are not to be consid-ered routine.

• REPLACEMENT OR ADDITION OFNON-LOAD BEARING ATTACH-MENTS TO PRESSURE RETAININGITEM - For attachment of non-load bear-ing attachments to pressure retainingitems, the cementing procedure specifica-tion need only be qualified for the pres-sure part and cement to be used.

Complete records of these routine repairsshall be kept for review by the Inspector. Therecords shall include the number of tubes re-placed or plugged and their location withinthe tube bundle.

8-7000 ALTERATIONS

a. The requirements provided in Part RC-3010, RC-3020, RC-3050, RC-3051, andRC-3052 subparagraph (a) shall apply, in-sofar as they are applicable to the materi-als discussed herein. Completed alter-ations shall be subjected to a pressure testnot less than that required by the code ofconstruction. The hydrostatic test pres-sure shall be maintained for a minimumof 30 minutes. The pressure shall be re-duced to MAWP and maintained for in-spection.

b. The nameplate shall be applied in accor-dance with Appendix 2. The letter “G”shall be applied to the nameplate underthe “R” stamp when graphite alterationsare made.

c. Organizations performing alterations un-der an “R” stamp program shall registersuch alterations with the National Board.

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NewReplacementTube

Sleeve

TubesheetOutside Face

Insert

FIGURE 1 — Typical tube-tube sheet joints8-8000 REPAIR GUIDE FORIMPERVIOUS GRAPHITE

8-8100 INTRODUCTION

a. This section is intended to provide sug-gested process and technique details forrepairs. This section is non-mandatory,but should be used as a guide by the re-pair organization in developing specificrepair procedures.

b. Damage to domes (heads), tubesheets, ornozzles is invariably a sign of improperinstallation, operation, or maintenance.Because such damage is random in na-ture, each case must be analyzed sepa-rately to determine the appropriate repairprocedure, and the economics of repairversus replacement.

c. Impervious graphite is a machinable ma-terial. Parts can be modified or repairedin the field, or in a repair shop.

d. Machining operations may be handledwith high-speed steel tools. Extensive ma-chining requires tungsten carbide or dia-mond tooling. No cooling or flushingfluid is required, nor should either beused.

e. Cleanliness is important. Dusty, dirty, andchemically contaminated surfaces pre-vent proper cement adhesion. Poor ce-ment adhesion will result in a lowstrength joint or a joint which leaks. Allsurfaces should be neutralized to a pH of7. Graphite parts should be cleaned andwashed with acetone to remove all mois-ture.

f. All damage should be examined andevaluated to determine the cause. Iden-tification and elimination of the cause isessential in helping to prevent a recur-rence.

g. An acetone wash on the surface of thedamaged part is useful in identifying thefull extent of the cracks. The acetone willquickly evaporate from the surface, leav-ing the cracks damp and clearly visible.

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8-8200 TYPICAL GRAPHITEFRACTURES

8-8210 MAJOR FRACTURE

An extensive fracture, such as shown inFigure 5, is best repaired by completing thebreak and re-cementing the two pieces. Tem-porary steel banding around the circumfer-ence is a method of clamping the repair untilthe cement is cured.


FIGURE 2 — Typical tube-tube joints

FIGURE 3 — Typical edge repairmaterial inlay

FIGURE 4 — Typical nozzle connection

CRACK

STEELBANDING

FIGURE 5 — Example of extensivefracture repair

CRACK

FIGURE 6 — Example of intermediatefracture repair

8-8220 INTERMEDIATE FRACTURE

The break is too minor to warrant complet-ing the fracture. A pie-shaped cut may bemade and the segment re-cemented in place.

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5 plug: An undersized plug will allow the use ofcommon size tooling.

FIGURE 7 — Examples of minorfracture repair

CRACK

PLUGSTITCHING

CRACK

8-8230 MINOR FRACTURE

For minor fractures, such as those shown inFigure 7, plug stitching can be used. Thecrack is removed by drilling and plugging acontinuous chain of overlapping holes alongthe length and depth of fracture.

8-8300 GRAPHITE REPAIR BYPLUG STITCHING

Plug stitching is a form of repair by materialinlaying. In this case, the inlays are small cy-lindrical impervious graphite plugs. Thecrack or fracture is removed by drilling andplugging a continuous series of overlappingholes along its length and depth.

Most plug stitching is done with 7/8 in. di-ameter plugs. The plugs are laid out alongthe fracture line on a pitch of 5/8 in. centers.The overlap of plug material is 1/4 in. alongthe fracture line. A number of plug sizes areavailable and are used in repair, and theamount of overlapping is proportional totheir diameters.

8-8310 PLUG STITCHINGPROCEDURE

a. The following procedure is defined for7/8 in. diameter plugs5. Dimensions forother size plugs shall be adjusted propor-tionally to the diameter.

b. Trace the line of fracture with acetone andmark its length and direction.

c. Beyond the end points of the fracture(crack), one additional plug shall be in-stalled.

d. Starting 5/8 in. beyond the end point ofthe crack, mark drilling centers every5/8 in. along its length. Make sure thereis a plug to be installed outside both endpoints of the line of fracture.

e. Drill a 1/4 in. pilot hole at each location.

f. Redrill a 7/8 in. hole at every other pilothole. Holes must be drilled the full depthof the crack. The depth and direction ofthe crack can be checked with acetone.

g. A 7/8 in. diameter reamer may be usedto true the drilled holes.

h. Dry fit a plug into the holes. There shouldbe 0.005 – 0.010 in. clearance for the ce-ment joint. At no time should there be aforce fit of plugs into any drilled hole.Provisions shall be provided for ventingtrapped air.

i. Sand the O.D. surface of the plugs. Thor-oughly clean all the surfaces of the repairwith acetone; plugs and drilled holes.

j. Apply graphite cement to both plugs andholes. All surfaces of plugs and holes tobe joined are to be wetted with cement.

k. Insert the cemented plugs into the holesallowing 1/16 in. of the plug to extendbeyond the surface of the graphite part.

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Step TwoDrill Pilot Holes

1/4" diameter pilot holes drilled at each location.The dashed lines represent where the fracture line existed.

Step OneLayout Hole Centers

Pattern for 7/8" Diameter Plugs

5/8" 5/8" 5/8" 5/8" 5/8" 5/8"

Line of Fracture

One additional hole location beyond the endpoints of the fracture

FIGURE 8 —

l. Cure the graphite cement according to thecement Manufacturer’s instruction.

m. At this point, half of the plug stitch re-pair is completed. A row of plugs hasbeen installed with 1/4 in. pilot holes be-tween them.

n. Redrill the remaining pilot holes to7/8 in. diameter. The drill will removepart of the plugs which were installed. Itis important to have the plugs replace allof the fracture. If the new holes do notcut into the installed plugs, it will be nec-essary to repeat the procedure betweenthese holes and plug locations, to ensurethat all of the crack has been repaired. Theline of fracture is completely removed bythe overlapping effect of the graphiteplugs.

o. After the second set of holes have beendrilled, repeat the plug cementing proce-dures.

p. Contour the plugs to provide a smoothtransition into the adjoining surface area.The finished repair may be coated with awash coat for appearance.

8-8400 FIGURES - TYPICAL PLUGSTITCHING PROCEDURE

Step one: Layout hole centers.Step two: Drilling pilot holes.Step three: Drilling the first set of holes.Step four: Cementing and curing the first set

of plugs.Step five: Drilling the second set of holes.Step six: Plug stitching repair completed.

190


Drill every other hole to 7/8" diameter

Step FourCement and Cure the First Set of Plugs

Step FiveDrill the Second Set of Holes

The second set of diameter holes is drilled between the installed plugs.The dashed line represents where the fracture line existed.

Step SixPlug Stitch Repair Completed

The dashed line represents where the line existed.It has been completely drilled out and replaced with overlapping

graphite plugs. The fracture no longer exists.

Step ThreeDrill the First Set of Holes

FIGURE 9 — 8-9000 REIMPREGNATIONOF GRAPHITE PARTS(TUBESHEETS,HEADS, ANDBLOCKS)

a. As a function of time, tem-perature, and chemical expo-sure, the resin used to impreg-nate graphite may shrinkand/or degrade. As such, itis possible for voids to de-velop in impregnated graph-ite that has been in chemicalservice for a period of time.The resin loss can vary fromslight to almost complete lossof impregnation. There is nopractical way to determine theamount of resin remaining inthe pores. However, a hydro-static test will determine if thegraphite has continuous po-rosity.

b. Reimpregnation of the graph-ite may be used to enhance theperformance and extend thelife of graphite components. Awritten reimpregnation proce-dure acceptable to the Inspec-tor is required. Thereimpregnation procedureshall include as a minimum:

• Decontamination and dry-ing of the graphite compo-nent

• Subjecting the componentto a vacuum

• Introducing resin underpressure

• Curing the resin at a speci-fied temperature and time

• Leak test

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8-10000 CONTROL OFIMPREGNATION MATERIAL

a. Impregnation material shall be the sameas that specified in the ReimpregnationProcedure. Each impregnation materialshall be traceable by the name of its manu-facturer and the trade name or numberof that manufacturer.

b. The impregnation material manufacturershall supply the Certificate Holder a Cer-tificate of Analysis for each material. Itshall include the following:

• impregnation material identification• batch number(s)• date of manufacture• shelf life• viscosity per ASTM D 2393• specific gravity

c. Prior to reimpregnation, and at subse-quent intervals not to exceed 14 days, theCertificate Holder shall test each batch ofimpregnation material to assure that thecharacteristics of the material have notchanged from values specified in theReimpregnation Procedure. The valuesobtained for viscosity and specific grav-

ity for the impregnation material shall bewithin the limits specified by the manu-facturer and as listed in theReimpregnation Procedure. The test val-ues shall be made available to the Inspec-tor.

8-11000 FINISHING THE REPAIR

a. The parts should be held in place to pre-vent movement while curing the ce-mented joint to achieve a proper repair.The repair firm should take care to ensurethat the cement joint thickness is withinthe range recommended by the cementManufacturer. Care spent in preciselyaligning the parts while clamping willavoid many finishing and machining op-erations later. Particular attention shouldbe given to gasket and other bearing sur-faces.

b. Gasket and bearing surfaces may have tobe machined, filed, or sanded before thejob is completed. Gasket serrations mustbe clean and continuous. Serrations canbe easily re-cut into graphite and any re-pair plugs that cross the gasket surface.

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193

Standard Welding Procedures

Appendix A

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APPENDIX A — STANDARD WELDING PROCEDURES

One or more Standard Welding ProcedureSpecifications (WPSs) from the following listmay be used as an alternative to one or moreWPS documents qualified by the organiza-tion making the repair, provided such an or-ganization accepts by certification (containedtherein) full responsibility for the applicationof the Standard WPS in conformance with theapplication as stated in the Standard WPS.

ANSI/AWS B2.1.001-90 Standard WeldingProcedure Specification (WPS) for ShieldedMetal Arc Welding of Carbon Steel, (M-1/P-1, Group 1 or 2), 3/16 in. (5 mm) through3/4 in. (19 mm), in the As-WeldedCondition, With Backing.

ANSI/AWS B2.1.002-90 Standard WeldingProcedure Specification (WPS) for Gas Tung-sten Arc Welding of Carbon Steel, (M-1/P-1,Group 1 or 2), 3/16 in. (5 mm) through7/8 in. (22 mm), in the As-Welded Condition,With or Without Backing.

ANSI/AWS B2.1-1-016-94 Standard WeldingProcedure Specification (WPS) for ShieldedMetal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in.Thick, E7018, As-Welded or PWHT Condi-tion.

ANSI/AWS B2.1-1-017-94 Standard WeldingProcedure Specification (WPS) for ShieldedMetal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in.Thick, E6010, As-Welded or PWHT Condi-tion.

ANSI/AWS B2.1-1-018-94 Standard WeldingProcedure Specification (WPS) for Self-Shielded Flux Cored Arc Welding of CarbonSteel (M-1/P-1/S-1, Group 1 or 2),1/8 through 1-1/2 in. Thick, E71T-8, As-Welded Condition.

ANSI/AWS B2.1-1-019-94 Standard WeldingProcedure Specification (WPS) for CO2Shielded Flux Cored Arc Welding of Carbon

Steel (M-1/P-1/S-1, Group 1 or 2), 1/8through 1-1/2 in. Thick, E70T-1 and E71T-1,As-Welded Condition.

ANSI/AWS B2.1-1-020-94 Standard WeldingProcedure Specification (WPS) for 75%Ar/25% CO2 Shielded Flux Cored Arc Weld-ing of Carbon Steel (M-1/P-1/S-1, Group 1or 2), 1/8 through 1-1/2 in. Thick, E70T-1 andE71T-1, As-Welded or PWHT Condition.

ANSI/AWS B2.1-1-021-94 Standard WeldingProcedure Specification (WPS) for Gas Tung-sten Arc Welding Followed by Shielded MetalArc Welding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2), 1/8 through 1-1/2 in. Thick,ER70S-2 and E7018, As-Welded or PWHTCondition.

ANSI/AWS B2.1-1-022-94 Standard WeldingProcedure Specification (WPS) for ShieldedMetal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in.Thick, E6010 (Vertical Uphill) Followed byE7018, As-Welded or PWHT Condition.

ANSI/AWS B2.1-8-023-94 Standard WeldingProcedure Specification (WPS) for ShieldedMetal Arc Welding of Austenitic StainlessSteel (M-8/P-8/S-8, Group 1), 1/8 through1-1/2 in. Thick, As-Welded Condition.

ANSI/AWS B2.1-8-024-94 Standard WeldingProcedure Specification (WPS) for Gas Tung-sten Arc Welding of Austenitic Stainless Steel(M-8/P-8/S-8, Group 1), 1/8 through1-1/2 in. Thick, As-Welded Condition.

ANSI/AWS B2.1-8-025-94 Standard WeldingProcedure Specification (WPS) for Gas Tung-sten Arc Welding followed by Shielded MetalArc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in.Thick, As-Welded Condition.

ANSI/AWS B2.1-1-026-94 Standard WeldingProcedure Specification (WPS) for ShieldedMetal Arc Welding of Carbon Steel (M-1/

195

P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in.Thick, E6010 (Vertical Downhill) Followed byE7018, As-Welded or PWHT Condition.

ANSI/AWS B2.1-1-027-98 Standard WeldingProcedure (SWP) for Self-Shielded Flux CoredArc Welding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2), 1/8 through 1/2 in. Thick,E71T-11, As-Welded Condition.

ANSI/AWS B2.1-1-201-96 Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick, E6010(vertical uphill) followed by E7018, As-Welded Condition, Primarily Pipe Applica-tion.

ANSI/AWS B2.1-1-203-96 Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick, E6010(vertical uphill), As-Welded Condition, Pri-marily Pipe Application.

ANSI/AWS B2.1-1-204-96 Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick, E6010(vertical downhill root with balance verticaluphill), As-Welded Condition, Primarily PipeApplication.

ANSI/AWS B2.1-1-205-96 Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick, E6010(vertical uphill) followed by E7018, As-Welded or PWHT Condition, Primarily PipeApplication.

ANSI/AWS B2.1-1-206-96 Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick, E6010(vertical downhill) followed by E7018, As-Welded or PWHT Condition, Primarily PipeApplication.

ANSI/AWS B2.1-1-207-96 Gas Tungsten ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick,ER70S-2, As-Welded or PWHT Condition,Primarily Pipe Application.

ANSI/AWS B2.1-1-208-96 Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick, E7018,As-Welded or PWHT Condition, PrimarilyPipe Application.

ANSI/AWS B2.1-1-209-96 Gas Tungsten ArcWelding followed by Shielded Metal ArcWelding of Carbon Steel (M-1/P-1/S-1,Group 1 or 2) 1/8 through 3/4 in. thick,ER70S-2 and E7018, As-Welded or PWHTCondition, Primarily Pipe Application.

ANSI/AWS B2.1-1-210-96 Gas Tungsten ArcWelding (Consumable Insert) of Carbon Steel(M-1/P-1/S-1, Group 1 or 2) 1/8 through3/4 in. thick, INMs1 and ER70S-2, As-Weldedor PWHT Condition, Primarily Pipe Appli-cation.

ANSI/AWS B2.1-1-211-96 Gas Tungsten ArcWelding (Consumable Insert) Followed byShielded Metal Arc Welding of Carbon Steel(M-1/P-1/S-1, Group 1 or 2) 1/8 through3/4 in. thick, INMs1 and ER70S-2, As-Weldedor PWHT Condition, Primarily Pipe Appli-cation.

ANSI/AWS B2.1-212-97 Gas Tungsten ArcWelding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in.thick, ERF3XX, As-Welded Condition, Prima-rily Pipe Application.

ANSI/AWS B2.1-213-97 Shielded Metal ArcWelding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in.thick, E3XX-XX, As-Welded Condition, Pri-marily Pipe Application.

ANSI/AWS B2.1-214-97 Gas Tungsten ArcWelding Followed by Shielded Metal ArcWelding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in.thick, ER3XX and E3XX-XX, As-Welded Con-dition, Primarily Pipe Application.

ANSI/AWS B2.1-8-215-98 Gas Tungsten ArcWelding With Consumable Insert of Austen-

APPENDIX A - STANDARD WELDING PROCEDURES

196


itic Stainless Steel (M-8/P-8/S-8, Group 1),1/8 through 1-1/2 in. Thick, IN3XX andER3XX As-Welded Condition, Primarily PipeApplication.

ANSI/AWS B2.1-8-216-98 Gas Tungsten ArcWelding With Consumable Insert Followedby Shielded Metal Arc Welding of AusteniticStainless Steel (M-8/P-8/S-8, Group 1), 1/8through 1-1/2 in. Thick, IN3XX, ER3XX, andE3XX-XX As-Welded Condition, PrimarilyPipe Application.

ANSI/AWS B2.1-4-217:1999 Gas TungstenArc Welding of Chromium-MolybdenumSteel (M-4/P-4, Group 1 or 2), ER80S-B2,1/8 through 1/2 in. Thick, As-Welded Con-dition, 1/8 through 3/4 in. Thick, PWHTCondition, Primarily Pipe Applications.

ANSI/AWS B2.1-4-218:1999 Shielded MetalArc Welding of Chromium-MolybdenumSteel (M-4/P-4, Group 1 or 2), E8018-B2,1/8 through 1/2 in. Thick, As-Welded Con-dition, 1/8 through 1-1/2 in. Thick, PWHTCondition, Primarily Pipe Applications.

ANSI/AWS B2.1-4-219:1999 Gas TungstenArc Welding followed by Shielded Metal ArcWelding of Chromium-Molybdenum Steel(M-4/P-4, Group 1 or 2), 1/8 through 1/2 in.Thick, As-Welded Condition, 1/8 through1-1/2 in Thick, PWHT Condition, ER80S-B2and E8018-B2, Primarily Pipe Applications.

ANSI/AWS B2.1-4-220:1999 Gas TungstenArc Welding (Consumable Insert Root) ofChromium-Molybdenum Steel (M-4/P-4,Group 1 or 2), E8018-B2, 1/8 through 1/2 in.Thick, As-Welded Condition, 1/8 through3/4 in. Thick, PWHT Condition, IN515 andER80S-B2, Primarily Pipe Applications.

ANSI/AWS B2.1-4-221:1999 Gas TungstenArc Welding (Consumable Insert Root) fol-

lowed by Shielded Metal Arc Welding ofChromium-Molybdenum Steel (M-4/P-4,Group 1 or 2), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in.Thick, PWHT Condition, IN515, ER80S-B2,and E8018-B2, Primarily Pipe Applications.

ANSI/AWS B2.1-5A-222:1999 Gas TungstenArc Welding of Chromium-MolybdenumSteel (M-5A/P-5A), ER90S-B3, 1/8 through1/2 in. Thick, As-Welded Condition, 1/8through 3/4 in. Thick, PWHT Condition, Pri-marily Pipe Applications.

ANSI/AWS B2.1-5A-223:1999 Shielded MetalArc Welding of Chromium-MolybdenumSteel (M-5A/P-5A), E9018-B3, 1/8 through1/2 in. Thick, As-Welded Condition, 1/8 in.through 1-1/2 in. Thick, PWHT Condition,Primarily Pipe Applications.

ANSI/AWS B2.1-5A-224:1999 Gas TungstenArc Welded followed by Shielded Metal ArcWelding of Chromium-Molybdenum Steel(M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in.Thick, PWHT Condition, ER90S-B3 andE9018-B3, Primarily Pipe Applications.

ANSI/AWS B2.1-5A-225:1999 Gas TungstenArc Welding (Consumable Insert Root) ofChromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-WeldedCondition, 1/8 through 3/4 in. Thick, PWHTCondition, IN521 and ER90S-B3, PrimarilyPipe Applications.

ANSI/AWS B2.1-5A-226:1999 Gas TungstenArc Welding (Consumable Insert Root) fol-lowed by Shielded Metal Arc Welding ofChromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-WeldedCondition, 1/8 through 1-1/2 in. Thick,PWHT Condition, IN521, ER90S-B3, andE9018-B3, Primarily Pipe Applications.

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Recommended Preheat Temperatures

Appendix B

198


APPENDIX B — RECOMMENDED PREHEAT TEMPERATURES

Some minimum temperatures for preheatingare given below as a general guide. It is cau-tioned that the preheating temperatures listeddo not necessarily ensure satisfactory comple-tion of the welded joint. Requirements forindividual materials within the P-Numberlisting may have preheating requirementsmore or less restrictive than this generalguide. When reference is made in this Ap-pendix to materials by the ASME designation,P-Number and Group Number, the sug-gestions of this Appendix apply to theapplicable materials of the original code ofconstruction, either ASME or other, whichconform by chemical composition andmechanical properties to ASME materialshaving the ASME P-Number and GroupNumber designations. (Reference RC-1101)

MINIMUM TEMPERATURES FORPREHEATING

Thicknesses referenced to are nominal at theweld for the parts to be joined.

1. P-No. 1 Group Nos. 1, 2 and 3

a. 175˚F (79˚C) for material which hasboth a specified maximum carboncontent in excess of 0.30% and a thick-ness at the joint in excess of 1 in.

b. 50˚F (10˚C) for all other materials inthis P-Number.


a. 175˚F (79˚C) for material which haseither a specified minimum tensilestrength in excess of 70,000 psi (480MPa) or a thickness at the joint inexcess of 5/8 in. (16 mm).


3. P-No. 4 Group Nos. 1 and 2

a. 250˚F (121˚C) for material which haseither a specified minimum tensilestrength in excess of 60,000 psi (410MPa) or a thickness at the joint inexcess of 1/2 in. (13 mm).

b. 50˚F (10˚C) for all other materialsin this P-Number.

4. P-No. 5A Group 1 and 5B, Group 1

a. 400˚F (204˚C) for material which haseither a specified minimum tensilestrength in excess of 60,000 psi(410 MPa) or has both a specifiedminimum chromium content above6.0% and thickness at the joint in ex-cess of 1/2 in. (13 mm).



400˚F (204˚C)


None


None

8. P-No. 9 Group

a. 250˚F (121˚C) for P-9A Gr. 1 materials

b. 300˚F (149˚C) for P-9B Gr. 1 materials

9. P-No. 10 Group

a. 175˚F (79˚C) for P-10A Gr. 1 materials

b. 250˚F (121˚C) for P-10B Gr. 2 materi-als

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c. 175˚F (79˚C) for P-10C Gr. 3 materials

d. 250˚F (121˚C) for P-10F Gr. 6 materi-als

e. For P-10C Gr. 3 materials, preheat isneither required nor prohibited, andconsideration shall be given to thelimitation of interpass temperature forvarious thicknesses to avoid detri-mental effects on the mechanicalproperties of heat treated material.

f. For P-10D Gr. 4 and P-10E Gr. 5materials, 300˚F (149˚C) withinterpass temperature maintainedbetween 350˚F and 450˚F (177˚C and232˚C).

10. P-No. 11 Group

a. P-11A GroupGroup 1 - None (Note 1)Group 2 - Same as for P-No. 5(Note 1)Group 3 - Same as for P-No. 5(Note 1)Group 4 - 250˚F (121˚C)

APPENDIX B — RECOMMENDED PREHEAT TEMPERATURES

b. P-11B GroupGroup 1 - Same as for P-No. 3(Note 1)Group 2 - Same as for P-No. 3(Note 1)Group 3 - Same as for P-No. 3(Note 1)Group 4 - Same as for P-No. 3(Note 1)Group 5 - Same as for P-No. 3(Note 1)Group 6 - Same as for P-No. 5(Note 1)Group 7 - Same as for P-No. 5(Note 1)

Note 1: Consideration shall be given tothe limitation of interpass temperature forvarious thicknesses to avoid detrimentaleffects on the mechanical properties of heattreated materials.

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201

Historical Boilers

Appendix C

Note:Part PR and excerpts from Part PFT and Appendix Ahave been reprinted from ASME 1971 BPVC Section I,by permission of the American Society of MechanicalEngineers. All rights reserved.

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APPENDIX C — HISTORICAL BOILERS

C-1000 PURPOSE

This section provides recommended require-ments for the inspection and repair of histori-cal steam boilers.

C-2000 SCOPE

Historical steam boilers of riveted construc-tion, preserved, restored, or maintained forhobby or demonstration use.

C-3000 PRE-INSPECTIONREQUIREMENT

See RB-3120 Internal Inspection of Boilers.

C-4000 INITIAL INSPECTION

The results of examinations and tests shall bedocumented by an inspector, acceptable to thejurisdiction, who has demonstrated knowl-edge with historical boilers. The followingexaminations and tests shall be performed:

a. An internal and external visual in-spection (See Boiler Inspection Guide-line).

b. All threaded openings in the boilershall be inspected.

c. Ultrasonic thickness testing andevaluation of all pressure retainingboundaries. Ultrasonic results in ar-eas of generalized thinning (3 in. indiameter or greater) or where groovedthinning is noted (2 in. in length orgreater) are to be used in calculatingMAWP in accordance with C-8000.

d. A hydrostatic pressure test at 1.25times MAWP, but in no case shall thetest pressure be exceeded by morethan 6%.

e. The inspector may require other ex-aminations to be performed, includ-ing but not limited to:

1. An ultrasonic transverse wave ex-amination in two directions at 90°to each other of the longitudinallap seam for cracks located be-tween or adjacent to rivet holes.

2. A magnetic particle examinationof 100% of the longitudinal seamriveted area, and an ultrasonic(longitudinal wave mode) exami-nation of 10% of the rivets forshear failure.

3. An ultrasonic examination (longi-tudinal wave mode) of all fireboxstaybolts and rivets.

4. A liquid penetrant examination.

5. Drilling or treppaning of pressureretaining components.

C-5000 RECURRING INSPECTIONREQUIREMENTS

The following examinations and tests shall beperformed:

a. Annual visual internal and externalinspection (See Boiler InspectionGuideline).

b. Annual visual inspection of the fus-ible plugs to determine the conditionof the threads in the crown sheet andon the fusible plug. The fusible plugsshall be removed, inspected and con-firmed as an ASME Std. plug.

c. Annual hydrostatic test at a pressureat least equal to MAWP up to 1.25times MAWP, but in no case shall thetest pressure exceed 1.25 times MAWPby more than 6%.

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d. Every five years ultrasonic thicknesstesting.

e. Additional testing and examination asdeemed necessary by the inspector.

C- 6000 SAFETY DEVICES ANDCONTROLS

Each boiler shall be equipped with the fol-lowing safety devices and controls. Pressurerelief valve(s), gage glasses, try-cocks, fusibleplugs, and pressure gages shall be tested dur-ing each inspection.

C-6100 PRESSURE RELIEF VALVES

a. Pressure relief valve(s) shall be NationalBoard capacity certified.

b. Pressure relief valve(s) shall be sealed byan ASME “V” Stamp assembler or NB“VR” repair firm.

c. The required pressure relief valve capac-ity in pounds per hour shall be calculatedby boiler heating surface area and type offuel used. Excessive pressure relief valvecapacity should be avoided. (Only heat-ing surface area above the grates to beused.)

Minimum pounds of steam per hour per squarefoot of heating surface.

Boiler Heating Firetube WatertubeSurface Boiler Boiler

hand fired 5 6

stoker fired 7 8

oil, gas or pulverized fuel fired 8 10

d. Pressure relief valve(s) shall have a testlever.

e. No valve of any description shall beplaced between the required pressure re-lief valve or valves and the boiler, nor onthe discharge pipe between the valve andthe atmosphere.

f. The piping connection between the boilerand the safety valve shall not be less thanthe inlet size of the safety valve, and thedischarge pipe, if used, shall not be re-duced between the safety valve and thepoint of discharge.

C-6200 GAGE GLASS

a. The gage glass shall be fit with a guard toprotect the gage glass.

b. The gage glass shall indicate the mini-mum safe operating water level.

c. The gage glass shall be provided with adrain valve or petcock, piped to a safelocation.

d. The gage glass shall be fully operational.

C-6300 TRY-COCKS

a. Try-cocks shall be correctly located in ref-erence to the minimum required waterlevel.

b. Try-cocks shall be fully operational

C-6400 FUSIBLE PLUG

a. All boilers shall have a fusible plug un-less equipped and operated with auto-matic controls.

b. All fusible plugs shall be constructed tomeet the requirements of the ASME Code,and indicated as such by the ASME mark-ing on the filler material.

c. Fireside fusible plugs must protrude aminimum of one inch into the water.

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d. Waterside fusible plugs may not protrudeinto the fire area more than one inch.

e. Fusible plugs shall not be refilled.

C-6500 PRESSURE GAGE

a. Tested and proven accurate at the time ofthe annual pressure test.

b. Siphon, or water seal, shall be installedbetween pressure gage and boiler.

c. If a valve is installed between the gageand the boiler, the valve shall indicate theopen position or be wired open.

C-7000 APPURTENANCES

C-7100 PIPING AND FITTINGS

All boiler piping and fittings shall meet thefollowing requirements:

a. Threaded openings shall follow ac-cepted standard piping practices.

b. Schedule 80, black pipe (SA-53 B orSA-105 B) shall be used from the boilerto the first valve.

c. All steam piping components shall beused in the manner for which theywere designed and shall not exceedmanufacturer’s pressure rating.

d. The boiler shall be equipped with twomeans of supplying feedwater whilethe boiler is under pressure. Pumpedwater shall be heated.

e. The blowdown line shall be pluggedoff during the time the boiler is oper-ating on display, or piped to a safepoint of discharge.

f. All piping shall be properly sup-ported.

C-7200 REPLACEMENTS

The installation date should be stamped orstenciled on all replaced boiler piping. Al-ternatively, the installation date may be docu-mented in permanent boiler records.

C-8000 MAXIMUM ALLOWABLEWORKING PRESSURE

The maximum allowable working pressureof a boiler shall be determined by computingthe strength of each component to find theweakest point. The strength of the weakestcomponent and the factor of safety allowedby these rules shall determine the maximumallowable working pressure. The followingshall be used to compute the strength of eachboiler component.

C-8100 STRENGTH

a. In calculating the MAWP, when the ten-sile strength of the steel or wrought ironis known, that value shall be used. Whenthe tensile strength of the steel or wroughtiron is not known, the values to be usedare 55,000 psi for steel and 45,000 psi forwrought iron. Original steel stamp marks,original material certifications, or currentlaboratory tests are acceptable sources forverification of tensile strength. Catalogsand advertising literature are not accept-able sources for tensile strength values.

b. In computing the ultimate strength of riv-ets in shear, the following values inpounds per square inch of the cross-sec-tional area of the rivet shanks shall beused:

Iron rivets in single shear 38,000

Iron rivets in double shear 76,000

Steel rivets in single shear 44,000

Steel rivets in double shear 88,000

c. The resistance to crushing of mild steelshall be taken as 95,000 pounds per squareinch of cross-sectional area.

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C-8200 RIVETS

When the diameter of the rivet holes in thelongitudinal joints of a boiler is not known,the diameter of rivets, after driving, may beascertained from the table below.

Sizes of Rivets Based on Plate Thickness

Thickness of 1/4 9/32 5/16 11/32 3/8 13/32Plate, inches

Diameter of 11/16 11/16 3/4 3/4 13/16 13/16Rivet afterDriving,inches

Thickness of 7/16 15/32 1/2 9/16 5/8Plate, inches

Diameter of 15/16 15/16 15/16 1-1/16 1-1/16Rivet afterDriving,inches

C-8300 CYLINDRICALCOMPONENTS

The maximum allowable working pressureof cylindrical components under internalpressure shall be determined by the strengthof weakest course computed from the thick-ness of the plate, the tensile strength of theplate, the efficiency of the longitudinal joint,the inside diameter of weakest course, andthe factor of safety allowed by these rulesusing the following formula:

TS x t x E= maximum allowable working pressure (MAWP), psi

R x FS

C-8400 STAYED SURFACES

The maximum allowable working pressurefor stayed flat plates and those parts which,by these rules, require staying as flat plateswith stays or staybolts of uniform diametersymmetrically spaced, shall be calculatedusing the following formulas:

t2 x TS x C= maximum allowable working pressure (MAWP), psi

FS x p2

C-8500 BRACED AND STAYEDSURFACES (REQUIREDBRACE OR STAYBOLTDIAMETER)

The MAWP based on the net minimum di-ameters of staybolts shall be computed usingthe following formula:

π x d2 x TS = maximum allowable working pressure (MAWP), psi

FS x 4 x p2

C-8600 CONSTRUCTION CODE

In order to address the many pressure-relatedcomponents and features of construction en-countered in firetube boilers, a reprint of the1971 Edition of Section I of ASME Boiler Code,Part PFT is provided.

C-8700 NOMENCLATURE

The nomenclature for the terms used in theabove equations is:

C = 2.1 for welded stays or staysscrewed through plates not over7/16 in. in thickness with ends riv-eted over

C = 2.2 for welded stays or staysscrewed through plates over7/16 in. in thickness with ends riv-eted over

C = 2.5 for stays screwed through platesand fitted with single nuts outsideof plate, or with inside and outsidenuts, omitting washers

C = 2.8 for stays with heads not less than1.3 times the diameter of the staysscrewed through plates, or made ataper fit and having the headsformed on the stays before install-ing them and not riveted over, saidheads being made to have true bear-ing on the plate

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C = 3.2 for stays fitted with inside andoutside nuts and outside washerswhere the diameter of washers isnot less than 0.4p and thickness notless than t.

Note: the ends of stays fitted with nuts shallnot be exposed to the direct radiant heat ofthe fire.

d = diameter of staybolt over thethreads, in.

E = efficiency of the longitudinal joint

The following is a table of efficiencies whichare the average for the different types of joints.

Type of Riveting Lap Butt

single 58double 74 82triple 88quadruple 94

Note: the efficiency of a particular joint de-pends upon the strength of the plate and rivet,thickness of the plates and the diameter ofthe rivets. The 1971 Edition of Section I ofthe ASME Code, Appendix A-1 through A-7,provides a method for calculating a specificjoint efficiency which may be used with theconcurrence of the jurisdiction.

FS = 5 (A jurisdiction may mandate ahigher factor of safety or permit alower factor of safety, but in no casemay the factor of safety be less than4)

p = maximum pitch measured betweenstraight lines passing through thecenters of the staybolts in the differ-ent rows, which lines may be hori-zontal, vertical or inclined, in.

R = inside radius of the weakest courseof shell or drum, in.

TS= ultimate tensile strength of shellplates, psi

t = minimum thickness of shell plate inthe weakest course, in.

C-9000 LIMITATIONS

a. The maximum allowable working pres-sure shall be the lesser of that calculatedby C-8000 or the MAWP established bythe original manufacturer.

b. The shell or drum of a boiler in which atypical “lap seam crack” extending par-allel to the longitudinal joint and locatedeither between or adjacent to rivet holes,is discovered along a longitudinal rivetedjoint for either butt or lap joint shall bepermanently discontinued for use understeam pressure.

C-10000 REPAIRS

Repairs to boilers of historical nature shouldbe performed with consideration towardspreserving the authenticity of original design,while at the same time ensuring that the boileris safe to operate at the pressure allowed byC-8000.

C-10100 CONSTRUCTIONSTANDARDS

Repairs shall conform to the requirements ofthe original construction standard insofar aspossible. If the original construction standardis unknown or unavailable, the boiler shallbe considered a boiler of locomotive designas described in Appendix 3, and subject to theconstruction standard most applicable to theboiler design. The construction standard se-lected for the repair must meet the approvalof the jurisdiction.

C-10200 ACCREDITATION

Organizations performing welded repairsshall be accredited as described in Part RA.Organizations performing non-welded re-pairs shall be otherwise acceptable to the ju-risdiction by having demonstrated compe-tency in the repair of boilers of locomotivedesign.

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C-10300 MATERIALS

Materials used in making repairs shall con-form to the original construction standard, ifknown, or to a construction standard accept-able to the jurisdiction. Carbon or alloy steelshaving a carbon content greater than 0.35%shall not be welded. The repair organizationis responsible for verifying identification ofexisting and replacement materials.

C-10400 REPLACEMENT PARTS

Replacement pressure parts formed by cast-ing, forging, or die forming, and on which nowelding has been performed, shall be sup-plied as material. Such parts shall be markedwith the material identification required bythe construction standard used for the repair.Replacement pressure parts fabricated bywelding shall be manufactured by an organi-zation certified as required by the construc-tion standard used for the repair. Where thereis no manufacturer prepared to supply partsfabricated by welding, an organization ac-credited as described in Part RA may fabri-cate the part with the approval of the juris-diction.

C-10500 WELDED REPAIRINSPECTION

Prior to commencing any welded repairs tothe pressure boundaries of historic boilers, therepair organization shall obtain an Inspector’sapproval of the proposed repair. The Inspec-tor shall be an employee of either a jurisdic-tion, as defined in Appendix 4, or of the Au-thorized Inspection Agency contracted by therepair organization. The Inspector shall as-sure the repairs are performed in accordancewith the approved construction standard, and

shall witness any non-destructive or pressuretesting of the completed repair.

C-10600 WELDING

Welding shall be performed in accordancewith the requirements of the approved con-struction standard in consultation with theinspector identified in C-4000. A repair orga-nization accredited as described in Part RAmay use the Standard Welding ProcedureSpecifications shown in Appendix A, as ap-plicable. Welders shall be qualified for thewelding processes used. Qualification shallbe in accordance with the approved construc-tion standard, or Section IX of the ASMECode.

C-10700 HEAT TREATMENT

Preheating may be used to assist in comple-tion of the welded joint. Consideration shouldbe given to the percentage of carbon contentand to the thickness of the original boilermaterials. Preheat temperatures shall bespecified by the welding procedure specifi-cation being used.

Postweld heat treatment shall be performedas required by the accepted construction stan-dard, in accordance with written procedures.

Welded repairs at or near riveted seams re-quiring preheat or postweld heat treatmentshall be carefully made in order to preventloosening in the riveted seams, especiallywhen localized heat treatment is used.

Alternative postweld heat treatment methodsmay be used with the inspector’s approval.Welding methods which may be used as al-ternatives to postweld heat treatment are de-scribed in Part RD.

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C-10800 NONDESTRUCTIVEEXAMINATION

The Inspector may require nondestructiveexamination (RT, PT, MT, UT, VT) as neces-sary to ensure satisfactory welded repairshave been accomplished.

C-10900 DOCUMENTATION

Organizations performing repairs to historicboilers shall document the repair as requiredby the jurisdiction.

Permanent documentation detailing repairs,inspections, etc. should be retained by theowner.

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BOILER INSPECTION GUIDELINE

Owner

Location

Make

Year

Engine No.

Heating Surface

Design Pressure

Current Operating Pressure

Inspector

Smoke Box

1. Front Tube Sheet

a. Check condition of sheet and thick-ness around handhole openings.

b. Check condition of threaded openingsand plugs.

c. Check condition of rivets betweensheet and shell.

2. Tubesa. Are tubes beaded?

b. Are there signs of leakage?

3. Check condition of smoke box shell(especially around lower surfaces).

4. Check inside condition of barrel and O.D.of tubes.

5. Check back side of tube sheet (especiallyarea in contact with handhole gasket andarea where tube sheet joins barrel).

6. Check tube sheet supports (through stays,supports or strong backs).

7. Check inside rivet heads on lap orbuttstrap joints.

8. Check front bolster (front axle) attach-ment points inside shell.

Barrel (shell)

1. Check front bolster attachment points onoutside of shell.

2. Check condition of tube sheet rivets onoutside of shell.

3. Check condition of threaded openingsand plugs in openings.

4. Check radius rod attachment point.

5. Check attachment points of studs, cast-ings, brackets, accessories, etc.

6. Check plumbing openings on shell(feedwater nozzles, steam take off, watercolumn, etc.).

7. Check handhole openings in shell.

8. Lap seam or buttstrapa. Check for leakage around seams or

joint rivets.

b. Confirm joint efficiency based onnumber of rows of rivets and type ofjoint.

9. Identify and check any external contourthat does not appear normal.

10. Jacketa. Does jacket cover any critical areas or

make them difficult to observe?

b. Is barrel pitted or corroded underjacket?

Wrapper Sheet

1. Check handhole openings (material thick-ness, gasket area, etc.).


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2. Check for seepage around attachmentpoints (wing sheets, axle supports, etc.).

3. Check condition of seams joining wrap-per to throat sheet and rear head.

4. Check condition of seams joining throatsheet to barrel.

5. Check external shapes or contours that donot appear normal.

6. Check for seepage around staybolt heads.

7. Check condition of staybolt heads.

8. Check condition of threaded openings.

9. Check internal surfaces (cracks, pits, ma-terial thickness).

10. Check staybolt thickness and condition.

11. Check for scale and mud buildup inwaterlegs.

12. Check for buildup of dirt and grease be-tween or behind attaching brackets suchas wing sheets.

13. a. Dry bottom boilers1. Check seams at bottom of waterlegs

in ash pan area.

2. Do you need to remove ash pans andgrates to observe above seams?

3. Check condition of grate supportbrackets.

b. Wet bottom boilers1. Check ash pan area for pits and

staybolt head condition.

2. Check inside bottom of wrapper andstaybolt condition.

3. Check condition of lap seam in wrap-per.

4. Check condition of ash pan drain tubeif present.

14. Check for presence and condition of blow-down valve.

Dome

1. Check for presence and condition ofdrainback holes in shell.

2. Check condition of main line shutoffvalve.

3. Check condition of plumbing on main-stream line and on dome.

4. Check condition of dome seams andseams between dome and boiler shell.a. Is seepage present?

b. Can interior seams be observed?

5. Check for presence and condition of pres-sure gage.a. Is there a siphon and what is its con-

dition?

b. Is the gage readable from theoperator’s position?

c. Has the gage been calibrated orchecked against another gage?

d. If a shutoff valve is present, its handleshall indicate open position, or thehandle shall be wired open.

6. Check for presence and condition ofsafety valve.a. Does it have its own inlet/outlet pip-

ing with no possibility of closure?

b. Check that the inlet pipe size is notsmaller than the valve inlet size.

c. Check that the outlet pipe size is notsmaller than the valve outlet size.

211

d. Is it a National Board capacity certi-fied, ASME “V”/NB “VR” stampedvalve of proper pressure and capac-ity rating for the boiler heating sur-face?

e. Does it have a try lever?

f. Is it sealed with a factory seal?

Water Column and Water Glass

1. Is water glass calibrated to level of crownsheet?

2. Check condition of try-cock valves andblowdown valves on column and glass.

3. Check condition of glass (cracks orscratches).

4. Are there leaks around the water glassgaskets?

Firebox

1. Check for bulges or abnormal shapes(What caused them?).

2. Check seams around fire door.

3. Check for sediment buildup over fire dooropening rear head.

4. Check for sediment buildup over peep-hole opening in wrapper sheet (whereapplicable).

5. Check condition of fusible plug. (Mustbe removed for observation.)a. Is it an ASME plug?

b. Check condition of top surface. (Mayneed to brush it off.)

6. When fusible plug is removed, checkcrown sheet thickness at that location andthread condition.

7. Fireside fusible plug must protrude aminimum of one (1) in. into water.

8. Waterside fusible plug may not protrudeinto fire area of more than one (1) in.

9. Water glass calibration can only be donewhen crown sheet and fusible plug canbe seen and measured. (A recommendedminimum water level may be determinedas follows: With engine sitting on levelground and water just observable at thebottom of the glass, the crown sheetshould be covered by a minimum of atleast 2-1/2 in. plus on a full-size boiler.

10. Check staybolt condition, especially neartop surface of crown sheet.

11. Check through stays, strong backs, kneebraces, etc. on rear head.

12. Check handhole openings, threadedopenings and plugs in rear head.

13. Check condition of rear tube sheet, andcheck if rear end of tubes are beaded.

14. Check condition of staybolt heads insidefire box.

15. Check condition or design of crown sheet.Is it flat-topped or able to trap water?

External Plumbing

1. Is black pipe (as opposed to galvanized)used throughout?

2. Check for use of schedule 80 black piperequired between boiler and first valve.

3. Are fittings of proper pressure rating foroperating pressure?

4. Are isolation valves present to shut offindividual system lines?

5. Are two separate feedwater systemspresent and operable?


212


6. Check plumbing for frost damage.

7. Are plumbing support brackets presentwhere needed?

8. Fittings dates are to be stamped, stenciledor recorded on boiler records.

9. 20-year life on piping except for mainsteam line which shall be evaluated as tolife.

Ultrasonic Testing (Every fifth year)

Hydrostatic Pressure Test (Annually)

1. Hydrostatic pressure test should be be-tween maximum allowable working pres-

sure and 1.25 times maximum allowableworking pressure with water temperature@ 60°–120° F.

2. An accurate gage with proven accuracyshall be used when hydrostatically pres-sure testing a boiler. The engine gage shallbe calibrated at this time.

3. Safety valve may be checked against testgage and/or engine gage. (Test shouldonly be performed at a pressure greaterthan 75% of the stamped set pressure ofthe valve or the safety valve or lifting le-ver may be damaged.)

213

PART PR — REQUIREMENTS FOR BOILERS FABRICATED BY RIVETING

pounds per square inch of the cross-sectionalarea of the rivet shank shall be used.

PR-12 CRUSHING STRENGTHOF PLATES

The resistance to crushing of steel plate inpounds per square inch of cross-sectional areashall be taken from Table PG-23.5.

PR-14 THICKNESS OF BUTTSTRAPS

The minimum thickness of buttstraps fordouble-strap joints shall be as given in TablePR-14 in which the required thickness of theshell is that obtained by the rules given in PG-27.2 employing a value of E correspondingto the efficiency of the buttstrap joint. Inter-mediate values shall be determined by inter-polation. Where the required thickness of theplate exceeds 1-1/2 in., the thickness of thebuttstraps shall be not less than two-thirdsof the required thickness of the plate. In nocase shall either of the buttstraps have a lesserthickness than one-half the actual thicknessof the plate.

PR-15 JOINT EFFICIENCY

The efficiency of a joint is the ratio which thestrength of the joint bears to the strength ofthe solid plate. In the case of a riveted jointthis is determined by calculating the break-ing strength of a unit section of the joint, con-sidering each possible mode of failure sepa-rately, and dividing the lowest result by thebreaking strength of the solid plate of a lengthequal to that of the section considered (seeA-1 through A-7 for detailed methods andexamples).

PR-16 LONGITUDINAL JOINTS

16.1 The riveted longitudinal joints of a shellor drum which exceeds 36 in. in diameter

GENERAL

PR-1 SCOPE

The rules in Part PR are applicable to boilersand parts thereof that are fabricated by rivet-ing and shall be used in conjunction with thegeneral requirements in Part PG as well aswith the specific requirements in the appli-cable Parts of this Section that pertain to thetype of boiler under construction.

MATERIALS

PR-5 GENERAL

Materials entering into the construction ofriveted boilers shall comply with the require-ments for materials given in PG-5 throughPG-14.

DESIGN

PR-9 GENERAL

The rules in the following paragraphs applyspecifically to the design of boilers and partsthereof that are fabricated by riveting andshall be used in conjunction with the generalrequirements for Design in Part PG as well aswith the specific requirements for Design inthe applicable Parts of this Section that per-tain to the type of boiler under consideration.

PR-10 STRENGTH OF PLATES

In determining the maximum allowableworking pressure, the maximum allowableworking stress in Table PG-23.1 shall be usedin the computations.

PR-11 STRENGTH OF RIVETS

In computing the ultimate strength of rivetsin shear, the values given in Table PG-23.4 in


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shall be of butt- and double-strap construc-tion. This rule does not apply to the portionof a boiler shell which is staybolted to the fire-box sheet.

16.2 The longitudinal joints of a shell or drumwhich does not exceed 36 in. in diameter maybe of lap-riveted construction, but the maxi-mum allowable working pressure shall notexceed 100 psi.

TABLE PR-14 —Minimum Thickness Of Buttstraps

Required Thickness Minimum Thicknessof Steel Plate, in. of Buttstraps, in.

1/4 1/49/32 1/45/16 1/411/32 1/43/8 5/1613/32 5/16

7/16 3/815/32 3/81/2 7/1617/32 7/169/16 7/165/8 1/2

3/4 1/27/8 5/81 11/161-1/8 3/41-1/4 7/81-1/2 1

PR-17 CIRCUMFERENTIAL JOINTS

17.1 The strength of a riveted circumferen-tial joint of a boiler, the heads of which arenot stayed by tubes or through-stays, shallbe sufficient, considering all methods of fail-ure, to resist the total longitudinal force act-ing on the joint with a factor of safety of 5.The total longitudinal force is determined bythe following formula:

F = 3.14R2Pwhere,

F = total longitudinal force, pounds

R = radius of the circular area acted onby the pressure in producing thetotal longitudinal force on the joint,inches

P = pressure, pounds per square inch

17.2 When 50 percent or more of the totalforce as described in PR-17.1 is relieved bythe effect of tubes or through stays, in conse-quence of the reduction of the area acted onby the pressure and the holding power of thetubes and stays, the strength of the circum-ferential joints shall be at least 70 percent ofthat required by PR-17.1.

PR-20 TRANSVERSE PITCH (BACKPITCH) OF ROWS OF RIVETS

20.1 For longitudinal joints the distance be-tween the centerlines of any two adjacentrows of rivets, or the “back pitch” measuredat right angles to the direction of the joint,shall have the following minimum values:

20.1.1 If P/d is 4 or less, the minimumvalue shall be 2d.

20.1.2 If P/d is over 4, the minimum valueshall be:

2d + 0.1 (P - 4d)

where,P = pitch of rivets in outer row where a

rivet in the inner row comes mid-way between two rivets in the outerrow, inches

P = pitch of rivets in the outer row lesspitch of rivets in the inner rowwhere two rivets in the inner rowcome between two rivets in theouter row, inches (it is here assumedthat the joints are the usual construc-tion where the rivets are symmetri-cally spaced)

d = diameter of the rivet holes, inches

20.2 The back pitch of rivets in circumferen-tial joints may be less than that called for bythe above formulas provided the ligaments

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between rivets in a circumferential direction,as well as those in a diagonal direction asdetermined by the rules in PG-52, are suffi-cient to withstand the stress due to pressure,together with any stress due to weight com-ponents in support of boiler structure, with afactor of safety of 5.

20.3 The back pitch of rivets shall be mea-sured either on the flat plate before rolling,or on the median line after rolling, and theback pitch as there measured shall govern thelocations of rivet holes in the buttstraps.

20.4 The distance between any two rows ofrivets in a circumferential joint or back pitchshall be not less than 1.75d.

PR-21 PREPARATION OFPLATE EDGES

The plate edge shall be beveled to an anglenot sharper than 70 deg. to the plane of theplate and as near thereto as practicable.

PR-22 EDGE DISTANCE

22.1 On longitudinal joints of all types ofboilers and on circumferential joints of drumshaving heads which are not supported bytubes or through-stays, the distance from thecenters of rivet holes to the edges of the plates,except rivet holes in the ends of buttstraps,shall be not less than 1-1/2 and not more than1-3/4 times the diameter of the rivet holes;this distance to be measured from the centerof the rivet holes to the caulking edge of theplate before caulking.

22.2 The distance from the centers of rivetholes of circumferential joints to the edges ofthe plate in boilers having heads which aresupported by tubes or through-stays shall benot less than 1-1/4 times the diameter of therivet holes.

PR-23 RIVETED CONNECTIONS

Attachment by riveting shall be in accordancewith the following requirements:

23.1 Openings for nozzles and other connec-tions shall be far enough away from any mainriveted joint so that the joint and the openingreinforcement plates do not interfere with oneanother.

23.2 Welded connections which requirepostweld heat treatment and which are at-tached to vessels having seams of riveted con-struction shall be fabricated and stress re-lieved prior to the making up or attachmentof the courses by riveting. If they do not re-quire postweld heat treatment and are at-tached after riveting, the welds shall be lo-cated at a distance from the riveted seam atleast equal to the outside diameter of the at-tachment weld plus 4 times the thickness ofthe shell plate.

23.3 Openings for pipe connections to ves-sels having riveted joints may be made by in-serting pipe couplings or similar devices, notexceeding 3 in. pipe size, in the shell or headsand securing them by welding, provided thewelding is performed by welders or weldingoperators who have been qualified under theprovisions of Section IX of the Code for thewelding position and type of joint used.

23.4 For nozzle fittings having a boltingflange and an integral flange for riveting, thethickness of the flange attached to the pres-sure vessel shall not be less than the thick-ness of the neck of the fitting.

23.5 The strength of rivets in tension in aflanged frame or ring riveted to the outsideof a vessel shall be at least equal to that re-quired to resist the load due to the maximumallowable working pressure with a factor ofsafety of 5 computed as follows:


216


Welded

max21”2

FIGURE PR-31 —Allowable Welding Of Plate Edges AtEnds Of Buttstraps

23.5.1 For outside caulking the load shallbe equal to the area bounded by the out-side caulking multiplied by the maximumallowable working pressure.

23.5.2 For inside caulking (and with nooutside caulking) the load shall be equalto the area bounded by the inside caulk-ing multiplied by the maximum allowableworking pressure.

23.6 The rivets attaching nozzles shall be sospaced as to avoid the possibility of the shellplate or the nozzle flange failing by tearingaround through the rivet holes. An exampleillustrating the method of calculations isgiven in A-70.

PR-25 REINFORCEMENT OFOPENINGS

25.1 The area of reinforcement shall be cal-culated by the rules in PG-32 through PG-39.

25.2 In applying reinforcement plates to thedrums of watertube boilers to strengthen theshell where the tubes enter, they shall be riv-eted to the shell, and where outside caulkingis used, the tube shall be expanded into theinner and outer plates so that the rivets andtubes will hold the plates together in accor-dance with the rules for stayed surfaces.Where a reinforcing plate is inside the steamdrum, it is the inner plate; where it is outsideand there is no inner reinforcing plate, theunreinforced shell of the drum is the innerplate.

25.3 The spacing of the rivets with respect tothe tubes shall conform to PG-46 for stayedsurfaces, using a value of 2.5 for C, and shallbe based on a unit pressure equal to the pres-sure that can be carried by the inner plate witha factor of safety of 5.

25.4 The tension in rivets and tubes shall con-form to PFT-27 and PFT-38.

25.5 The combined drum shell and reinforc-ing plate or plates, and riveted connections,

shall have a factor of safety of not less than 5in the ligaments when calculated in accor-dance with PG-52. When reinforcing platesor buttstraps are exposed to flame or gas ofthe equivalent temperature, the joints shallbe protected therefrom.

FABRICATION

PR-30 GENERAL

The rules in the following paragraphs applyspecifically to the fabrication of the boilersand parts thereof that are fabricated by rivet-ing and shall be used in conjunction with thegeneral requirements for Fabrication in PartPG as well as with the specific requirementsfor Fabrication in the applicable Parts of thisSection that pertain to the type of boiler un-der construction.

PR-31 BUTTSTRAPS

31.1 Buttstraps shall be rolled or formed bypressure, not blows to the curvature of theshell with which they are to be used.

31.2 The ends of inner buttstraps of rivetedbuttstrap longitudinal joints may be fusionwelded to the edges of heads or of the ad-joining shell plate, or to circumferentialbuttstraps for tightness, provided the carboncontent in the steel does not exceed 0.35 per-

217

cent. When the buttstrap of a longitudinaljoint does not extend the full length of theshell plates, as shown in Figure PR-31, theabutting edges of the shell plate may bewelded provided the distance from the endof the buttstrap to the edge of the flange ofthe head or adjacent shell plate is not greaterthan 2-1/2 in.

PR-32 RIVET HOLES

All holes for rivets in plates, buttstraps, heads,stays and lugs shall be drilled; or they maybe punched at least 1/8 in. less than full di-ameter for material not over 5/16 in. in thick-ness and at least 1/4 in. less than full diam-eter for material over 5/16 in.

Such holes shall not be punched in materialmore than 5/8 in. in thickness.

For final drilling or reaming the hole to fulldiameter, the parts shall be firmly bolted inposition by tack bolts.

The finished holes must be true, clean andconcentric.

PR-37 ASSEMBLY OF JOINTS

After drilling or reaming rivet holes the platesand buttstraps of longitudinal joints shall beseparated, the burrs and chips removed, theplates and buttstraps reassembled metal-to-metal with barrel pins fitting the holes, andwith tack bolts.

PR-39 RIVETING

39.1 Rivets shall be of sufficient length tocompletely fill the rivet holes and form headsat least equal in strength to the bodies of therivets. Forms of finished rivet heads that willbe acceptable are shown in ANSI B18.4-1966.

39.2 Rivets shall be so driven as to fill theholes preferably by a machine which main-

tains the pressure until no part of the headshows red in the daylight. Barrel pins fittingthe holes and tack bolts to hold the platesfirmly together shall be used. A rivet shall bedriven on each side of each tack bolt beforeremoving the tack bolt.

PR-40 JOINT TIGHTNESS

40.1 The caulking edges of plates, buttstraps,and heads shall be beveled to an angle notsharper than 70 deg. to the plane of the plate,and as near thereof as practicable. Every por-tion of the unfinished surfaces of the caulk-ing edges of plates, buttstrap and heads shallbe planed, milled, or chipped to a depth ofnot less than one-fourth of the thickness ofthe material, but in no case less than 1/8 in.Caulking shall be done with a tool of suchform that there is no danger of scoring ordamaging the plate underneath the caulkingedge, or splitting the caulked sheet.

40.2 Fusion welding may be used to seal thecalking edges of circumferential-riveted lapjoints of power boilers provided the plates donot exceed 0.35 percent carbon and theirthickness is at least 1/8 in. more than thatrequired for a seamless shell of the same di-ameter, same working pressure, and samegrade of material.

40.3 Seal welding may be used on nozzlesand their reinforcing plates under the sameconditions. On unstaying dished heads, sealwelding shall not be applied closer than 1/2in. to the point of tangency of the knuckle ofthe flange. Seal welding may be applied onlywhen the weld metal is deposited in singlelayer having a throat thickness of not less than3/16 in., nor more than 5/16 in. The heat fromwelding shall not distort the plate or loosenthe rivets in such a manner as to break theinitial bond effected in the riveted joint. Af-ter seal welding, the vessel shall beresubjected to the prescribed hydrostatic test.

40.4 The inner buttstraps in locomotive-typeboilers may be seal welded, provided the car-bon content of the plates does not exceed 0.35


218


percent and the weld metal is deposited in asingle layer having a weld size not greaterthan 3/8 in.

INSPECTION AND TESTS

PR-50 GENERAL

At least two inspections shall be made of riv-eted construction (one before reaming rivetholes and one at the hydrostatic test) and, atthe option of the inspector, at such otherstages of the work as he may designate.

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PART PFT — REQUIREMENTS FOR FIRETUBE BOILERS

GENERAL

PFT -1 GENERAL

The rules in Part PFT are applicable to firetubeboilers and parts thereof and shall be used inconjunction with the general requirements inPart PG as well as with the specific require-ments in the applicable Parts of this Sectionwhich apply to the method of fabricationused.

MATERIALS

PFT-5 GENERAL

5.1 Materials used in the construction of pres-sure parts for firetube boilers shall conformto one of the specifications given in Section IIof the Code and shall be limited to those forwhich allowable stress values are given inTable PG-23 or as otherwise specifically per-mitted in Parts PG and PFT.

5.2 Waterleg and doorframe rings of verticalfiretube boilers and of locomotive and othertype boilers shall be of wrought iron or steel,or cast steel as designed in the SpecificationSA-216. The ogee or other flanged construc-tion may be used as a substitute in any case.

DESIGN

PFT-8 GENERAL

The rules in the following paragraphs applyspecifically to the design of firetube boilersand parts thereof and shall be used in con-junction with the general requirements ofDesign in Part PG as well as with the specificrequirements for Design in the applicableParts of this Section which apply to themethod of fabrication used.

PFT-9 MINIMUM THICKNESS

9.1 PlatesThe minimum thicknesses of shell plates, anddome plates after flanging, shall be as follows:

Diameter of Shell Minimum Thickness

36 in. or under 1/4 in.Over 36 to 54 in. 5/16 inOver 54 to 72 in. 3/8 in.Over 72 in. 1/2 in.

9.2.1 Except as otherwise provided inPFT-9.2.2, the minimum thickness of tubesheets for firetube boilers shall be as fol-lows:

Diameter of MinimumTube Sheet Thickness

42 in. or under 3/8 in.Over 42 to 54 in. 7/16 in.Over 54 to 72 in. 1/2 in.Over 72 in. 9/16 in.

9.2.2 Tube sheets with a straight flangelonger than 1-1/2 times the tube sheetthickness, when butt-welded to the shellof a firetube boiler, shall have a minimumthickness as specified in PFT-9.2.1 but inno case shall be less than 0.75 times therequired shell thickness, based on themaximum allowable working pressure.

PFT-10 SHELL JOINTS

10.1 Welded JointsWelded longitudinal and circumferentialjoints of a shell or drum shall comply withthe rules in Part PW.


220


Not less than 1”

Not less than 1”

9” 16

9” 16

FIGURE PFT-10 — Circumferential JointFor Thick Plates Of Horizontal-ReturnTubular Boilers

6 Primary Furnace gases are those in a zonewhere the design temperature of those gasesexceeds 850°F.

10.2 Riveted Longitudinal Joints

10.2.1 The longitudinal joints of horizon-tal-return tubular boilers shall be locatedabove the fire line of the setting.

10.2.2 In horizontal-return tubular boil-ers of riveted construction, no course shallbe over 12 ft. long.

10.2.3 The inner buttstraps in locomotive-type boilers may be seal welded, providedthe carbon content of the plates does notexceed 0.35 percent and the weld metal isdeposited in a single layer having a weldsize not greater than 3/8 in.

10.3 Riveted Circumferential Joints

10.3.1 In the portion of circumferentialjoints of horizontal-return tubular boilersexposed to the products of combustion,the shearing strength of the rivets shallbe not less than 50 percent of the fullstrength of the plate corresponding to thethickness at the joint.

10.3.2 When shell plates exceed 5/8 in.in thickness in horizontal-return tubularboilers, the portion of the plates formingthe laps of the circumferential joints,where exposed to the fire or products ofcombustion, shall be planed or milleddown as shown in Figure PFT-10 to athickness of not over 9/16 in., providedthe requirements in PR-17 are compliedwith. The entire circumference may beso planed or milled. The radius of the fil-let at the edge of the planing shall be notless than 1 in.

10.3.3 Where the circumferential joints offiretube boilers are to be seal welded, thethickness of the plates at the calking edgesof such seams shall be at least 1/8 in. morethan 60 percent of that required for aseamless shell of the same diameter, thesame working pressure, and the samegrade of material. Such seal welding shallnot be applied until after the boiler ismade tight as evidenced by the regularhydrostatic pressure test prescribed inPG-99.

PFT-11 ATTACHMENT OF HEADSAND TUBE SHEETS

Flat heads and tube sheets of firetube boilersshall be attached by one of the followingmethods:

11.1 By flanging and riveting in accordancewith Part PR.

11.2 By flanging and butt welding in accor-dance with Part PG and Part PW.

11.3 By attaching an outwardly or inwardlyflanged tube sheet to the shell by fillet weld-ing provided the following requirements aremet:

11.3.1 The tube sheet is supported bytubes, or stays, or both;

11.3.2 The joint attaching an outwardlyflanged tube sheet is wholly within theshell and forms no part thereof;

11.3.3 Inwardly flanged tube sheets arefull fillet welded inside and outside;

11.3.4 The throat dimension of the fullfillet weld is equal to, not less than 0.7 ofthe thickness of the head;

11.3.5 The shell at the welds is not in con-tact with primary furnace gases; 6

221

11.3.6 The construction conforms in allother respects to the requirements of thisSection, including welding and postweldheat treating, except that radiographicexamination is not required;

11.3.7 This construction shall not be usedon the rear head of a horizontal-returntubular boiler and inwardly flanged tubesheets shall not be used on a boiler withan extended shell;

11.3.8 On inwardly flanged tube sheets,the length of flange shall conform to therequirements of PW-13 and the distanceof the outside fillet weld to the point oftangency of the knuckle radius shall benot less than 1/4 in.

11.4 By attaching an unflanged tube sheet tothe shell by welding provided the followingrequirements are met:

11.4.1 The tube sheet is supported bytubes, or stays or both;

11.4.2 The welded joint is wholly withinthe shell or wrapper sheet and forms nopart thereof;

11.4.3 The weld is a full penetration weldequal at least to the full thickness of thetube sheet and applied from either or bothsides;

11.4.4 The shell or wrapper sheet, whereexposed to primary furnace gases6 andnot water cooled does not extend morethan 1/8 in. beyond the outside face ofthe tube sheet;

11.4.5 The weld attaching a furnace or alower tube sheet of a vertical firetubeboiler to the furnace sheet is whollywithin the furnace sheet and is groundflush with the upper or waterside of thetube sheet;

11.4.6 The construction conforms in allother aspects to the requirements of this

Section including welding, and postweldheat treatment, except that radiographicexamination is not required;

11.4.7 This construction shall not be usedon the rear head of a horizontal-returntubular boiler.

PFT-12 TUBES

12.1 Allowable Working Pressure

12.1.1 The maximum allowable workingpressure of tubes or flues of firetube boil-ers shall be as given in Table PFT-12.1.

12.1.2 The maximum allowable workingpressure for copper tubes or nipples sub-jected to internal or external pressure shallbe as given in Table PFT-12.2.

The maximum allowable working pres-sure for copper-clad tubes subjected toexternal pressure shall be determined bythe formula in Table PFT 12.1, in which tmay be increased by one-half the thick-ness of the cladding.

12.2 Attachment of Tubes

12.2.1 A firetube boiler shall have the endsof the tubes firmly rolled and beaded, orrolled and welded around the edge of thetube (see Figure PFT-12.1). Tube ends at-tached by rolling and welding are subjectto the following provisions:

12.2.1.1 The tube sheet hole may bebeveled or recessed to a depth at leastequal to the thickness of the tubes.Where the hole is beveled or recessed,the projection of the tube beyond thetube sheet shall not exceed a distanceequal to the tube thickness. The depthof any bevel or recess shall not be lessthan the tube thickness or 1/8 in.whichever is greater, nor more thanone-third of the tube sheet thickness[see Figure PFT-12.1(f) and (g)].


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TABLE PFT-12.1 — Maximum Allowable Working Pressure For Steel Tubes Or FluesFor Firetube Boilers For Different Diameters And Gages Of Tubes Conforming To TheRequirements Of Specifications SA-178, SA-192, SA-209, SA-210, SA-226, OR SA-2501

Wall Nearest Size Outside Diameter, In.Thickness, Bwgin. No. 1 1-1/2 1-3/4 2 2-1/4 2-1/2 3 3-1/4 3-1/2 4 4-1/2 5 5-3/8 5-1/2 6

0.095 13 420 280 240 210 190 170 . . . . . . . . . . . . . . . . . . . . . . . . . . .0.105 12 560 380 320 280 250 230 190 180 160 . . . . . . . . . . . . . . . . . .0.120 11 770 520 440 390 350 310 260 240 220 200 180 . . . . . . . . . . . .

0.135 10+ 980 660 570 490 430 400 330 310 280 250 220 200 . . . . . . . . .0.150 9+ . . . 800 680 600 530 480 400 370 340 300 270 240 230 220 . . .0.165 8 . . . 940 800 700 630 560 470 430 400 350 320 280 270 260 240

0.180 7 . . . . . . 920 810 720 650 540 500 460 410 360 330 300 300 2700.200 6- . . . . . . 1090 950 840 760 630 590 540 480 420 380 360 350 3200.220 5 . . . . . . 1240 1090 970 870 730 670 620 550 490 440 410 400 3700.240 4+ . . . . . . 1410 1230 1090 990 820 760 700 620 550 490 460 450 410

1 These values have been increased to the next higher unit of 10 where the actual values exceed an even unit of 10.

P = 14,000

where P = maximum allowable working pressure, pounds per square incht = minimum wall thickness, inchesD = outside diameter of tubes, inches

For pressures other than those given in the table, the allowable working pressures shall be the next higherunit of 10 above the values given by the formulas.

For pressures below those given in the table, the gage thickness shall be not less than the minimum given inthe table.

(t - 0.065)

D

TABLE PFT-12.2 — Maximum Allowable Working Pressure For Copper Tubes ForFiretube Boilers Conforming To The Requirements Of Specification SB-752 (For use atPressures Not to Exceed 250 psi or Temperatures Not to Exceed 406° F)

Outside Gage — BwgDiameter of Tube in. 12 11 10 9 8 7 6 5 4

2 170 240 250 250 250 250 250 250 2503-1/4 . . . . . . 110 150 220 250 250 250 2504 . . . . . . . . . . . . 130 160 250 250 2505 . . . . . . . . . . . . . . . . . . 150 190 230

2 These values have been rounded out to the next higher unit of 10.

P = 12,000 - 250

where P = maximum allowable working pressure, pounds per square incht = thickness of tube wall, inchesD = outside diameter of tube, inches

(t - 0.039)

D

223

(a)

(b)

(c) (d)

Not over 2 t nor lessthan t but in no casemore than 1/4 in. norless than 1/8 in.

Not less than tand in no caseless than 1/8 in.

Max t

t t(f)(e)

Max t and notmore than T/3 or1/8 in. whicheveris the greater

Not more than T/3nor less than t or1/8 in. whicheveris the greater

(g)

T

t

FIGURE PFT-12.1 — Acceptable FormsOf Tube Attachment On Firetube Boilers

12.2.1.2 Where no bevel or recess isemployed, the tube shall extend be-yond the tube sheet not less than adistance equal to the tube thickness,nor more than twice the tube thick-ness [see Figure PFT-12.1 (e)].

12.2.1.3 On all types of welded attach-ments, the tubes shall be rolled beforewelding and again rolled lightly afterthe welding procedure.

12.2.2 Expanding of tubes by the Prossermethod in lieu of rolling may be em-ployed in combination with any beadedor welded attachment method.

12.2.3 Seal welding is permissible on anytype of beaded attachment. Where sealwelding is employed, a single hydrostatictest of the boiler after seal welding shallsuffice.

12.2.4 The inner surface of the tube holein any form of attachment may begrooved or chamfered.

12.2.5 The sharp edges of tube holes shallbe taken off on both sides of the plate witha file or other tool.

COMBUSTION CHAMBER ANDFURNACES

PFT-13 COMBUSTION CHAMBERTUBE SHEET

13.1 The maximum allowable working pres-sure on a tube sheet of a combustion cham-ber, where the crown sheet is not suspendedfrom the shell of the boiler, shall be deter-mined by the following formula:

t(D - d)P = 27,000

WDwhere,

P = maximum allowable working pres-sure, pounds per square inch

D= least horizontal distance betweentube centers on a horizontal row,inches

d = inside diameter of tubes, inchest = thickness of tube plate, inchesW= distance from the tube sheet to op-

posite combustion chamber sheet,inches

Where tubes are staggered the vertical dis-tance between the centerlines of tube in adja-cent rows must be not less than

1/2 √2dD + d2

Example: Required the minimum allowableworking pressure of a tube sheet supportinga crown sheet stayed by crown bars. Hori-zontal distance between centers, 4-1/8 in.;


224


inside diameter of tubes, 2.782 in.; thicknessof tube sheets 11/16 in; distance from tubesheet to opposite combustion-chamber sheet,34-1/4 in.; measured from outside of tubeplate to outside of back plate; material, steel.Substitution and solving:

(4.125 - 2.782) x 0.6875 x 27,000P= =176 psi

34.25 x 4.125

13.2 Sling stays may be used in place of gird-ers in all cases covered in PFT-13.1, provided,however, that when such sling stays are used,girders or screw stays of the same section areashall be used for securing the bottom of thecombustion chamber to the boiler shell.

13.3 When girders are dispensed with andthe top and bottom of combustion chambersare secured by sling stays, the sectional areaof such stays shall conform to the require-ments of rules for stayed surfaces.

PFT-14 PLAIN CIRCULAR FURNACES

14.1 The shells of unstayed circular furnacesmay be of any length or height and of any ofthe following constructions:

14.1.1 Seamless Construction

14.1.2 Double-welded butt-type construc-tion subject only to the requirements thatthe welds are postweld heat treated in ac-cordance with PW-39, and a bend test ofa sample of the welding for each furnacemeets the requirements of PW-53. Radio-graphic examination is not required.When the longitudinal and circumferen-tial joints have been subjected completelyto radiographic examination, the indi-vidual bend test for each furnace is notrequired.

14.1.3 Riveted construction which meetsthe following requirements:

14.1.3.1 Circumferential and longitu-dinal joints shall have an efficiency

not less than 50 percent nor less thanPD/20,000t percent,

where,P = maximum allowable working pres-

sure, pounds per square inchD = outside diameter, inchest = thickness of furnace walls, inches

14.1.3.2 Buttstrap seams shall be usedonly where they are protected fromcontact with the fire or flame.

14.2 The walls shall not be less than 5/16 in.in thickness.

14.3 The furnace may be of any length orheight.

14.4 The following rules apply specificallyto unstayed circular furnaces 12 in. in diam-eter and over:

14.4.1 Furnaces 12 to 18 in. in Outside Di-ameter, Inclusive. The maximum allowableworking pressure for furnaces not morethan 4-1/2 diameters in length or heightshall be determined by formulas (1) and(2) as follows:

Where the length does not exceed 120times the thickness of the plate:

51.5 (18.75T - 1.03L)P =

D (1)

Where the length exceeds 120 times thethickness of the plate:

4250T2

P = LD (2)


sure, pounds per square inchD= outside diameter of furnace, inchesL = total length of furnace between cen-

ters of head rivet seams (not lengthof a section), inches

T = thickness of furnace walls, sixteenthsof an inch

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14.4.2 The maximum allowable workingpressure for furnaces over 4-1/2 diam-eters in length or height shall be deter-mined in accordance with PFT-15.

14.4.3 Furnaces Over 18 in. in Outside Di-ameter to and Including 30 in. in Inside Di-ameter. The maximum allowable work-ing pressure shall be determined by for-mulas (1) and (2); if over six diameters inlength or height, L in the formula shall betaken as 6 times the diameter.

14.4.4 Furnaces Over 30 in. in Inside Diam-eter to and Including 36 in. in Inside Diam-eter. A riveted longitudinal joint may beof the lap type provided the furnace doesnot exceed 36 in. in length or height.

14.4.5 If the length of a horizontal fur-nace exceeds 36 in. and the joint is riv-eted, a butt- and single- or double-strapconstruction shall be used and shall belocated below the grate.

14.4.6 The maximum allowable workingpressure shall be determined by formu-las (1) and (2); if over six diameters inlength, L in the formula shall be taken as6 times the diameter.

14.4.7 Furnaces Over 36 in. in Inside Diam-eter to and Including 38 in. in Outside Di-ameter. When riveted the longitudinaljoint of a horizontal furnace shall be ofbutt- and single- or double-strap con-struction and shall be located below thegrate.

14.4.8 The maximum allowable workingpressure shall be determined by formu-las (1) and (2); if over six diameters inlength, L in the formula shall be taken as6 times the diameter.

14.4.9 Furnaces Over 38 in. in Diameter.Furnaces over 38 in. in diameter shall befully stayed as flat surfaces in accordancewith requirements of PFT-23.4.

Where it is desired to apply stayboltingto a furnace 38 in. or less in diameter,which is of proper thickness for the re-quired working pressure under the aboverules, the requirements of the Code for thestress allowed upon and the spacing ofthe staybolts may be disregarded.

PFT-15 CIRCULAR FLUES

The maximum allowable working pressurefor seamless or welded flues over 5 in. in di-ameter, and including 18 in. in diameter shallbe determined by one of the following for-mulas:

15.1 Where the thickness of the wall is notgreater than 0.023 times the diameter:

10,000,000t3

P = D3

15.2 Where the thickness of the wall is greaterthan 0.023 times the diameter:

17,300tP = - 275

D


sure, pounds per square inchD= outside diameter of flue, inchest = thickness of wall of flue, inches

15.3 The above formulas may be applied toriveted flues of the size specified providedthe sections are not over 3 ft. in length andthe efficiency of the joint is not less than:

PD

20,000t

Example: Given a flue 14 in. in diameter and5/16 in. in thickness. The thickness of thewall is less than 0.023 times the diameter,hence the formula in (1) applies. Substitut-ing the values in this formula:

10,000,000 x 5/16 x 5/16 x 5/16P= =110 psi

14 x 14 x 14


226


PFT-16 ADAMSON TYPE

When plain horizontal flues are made in sec-tions not less than 18 in. in length and notless than 5/16 in. in thickness:

16.1 They shall be flanged with a radius mea-sured on the fireside of not less than 3 timesthe thickness of the plate, and the flat por-tion of the flange outside of the radius shallbe at least 3 times the diameter of the rivetholes.

16.2 The distance from the edge of the rivetholes to the edge of the flange shall be notless than the diameter of the rivet hole, andthe diameter of the rivets before driving shallbe at least 1/4 in. larger than the thickness ofthe plate.

16.3 The depth of the Adamson ring betweenthe flanges shall be not less than 3 times thediameter of the rivet holes, and the ring shallbe substantially riveted to the flanges. Thefire edge of the ring shall terminate at or aboutthe point of tangency to the curve of theflange, and the thickness of the ring shall benot less than 1/2 in.

16.4 An Adamson furnace may be assembledby welding, provided the outside edges of theflue flanges are attached to Adamson ringsby full fillet welds; inside edges of the ringsare welded to the flat portions of the flueflanges by full fillet welds; and the welds arepostweld heat treated in accordance with PW-39.

The maximum allowable working pressureshall be determined by the following formula:

57.6 (300t - 1.03L)P =

D


sure, pounds per square inchD= outside diameter of furnace, inchesL = length of furnace section, inchest = thickness of plate, inches

Example: Given a furnace 44 in. in diameter,48 in. in length, and 1/2 in. in thickness. Sub-stituting values in formula:

57.6 P = [(300 x 0.5) - (1.03 x 480]

44

= 1.309 (150 - 49.44) = 131 psi

The longitudinal and circumferential jointsmay be of the double-welded butt type, theonly requirements being that the welds arepostweld heat treated in accordance withPW-39 and a bend test of a sample of thewelding for each furnace meets therequirements of PW-53, no radiographic ex-amination being required. When the longi-tudinal and circumferential joints have beensubjected completely to radiographic exami-nation, the individual bend test for each fur-nace is not required.

PFT-17 RING REINFORCED TYPE

Horizontal cylindrical flues or furnaces (Fig-ure PFT-17.2) may be constructed with com-pletely circular stiffening rings provided thefollowing requirements are met:

17.1 The stiffening ring is rectangular in crosssection and is fabricated from one piece ofplate, or from plate sections or bars providedfull penetration welds are used in assembling.

17.2 The stiffening ring after fabrication hasa thickness of not less than 5/16 in. and notmore than 13/16 in. and in no case thickerthan 1-1/4 times the furnace wall thickness.

17.3 The ratio of the height of the stiffeningring to its thickness (Hr /Tr ) is not greaterthan 8 nor less than 3.

17.4 The stiffening ring is attached to the fur-nace by a full penetration weld on each side.

17.5 The thickness of the furnace wall or flueis a minimum of 5/16 in.

227

0.000012 3 4 5 6 78

0.00012 3 4 5 6 78 2 3 4 5 67 8

0.001 0.01 0.12 3 4 5 6 7 8

50

140

100

60708090

120

160180200

250

300350400

500

6007008009001,000

1,2001,4001,6001,8002,000

2,500

3,0003,5004,000

5,000

6,0007,0008,0009,000

10,00012,00014,00016,00018,00020,000

25,000

40,000

50,000

35,00030,000

0.05

0.060.070.080.090.10

0.120.140.16

0.20

0.250.30

0.18

0.35

0.50

0.600.70

0.40

0.901.0

0.80

1.21.4

1.82.0

1.6

2.5

3.03.54.0

5.0

6.07.0

9.08.0

101214161820

25

303540

50

FACTOR A

Leng

th /O

utsi

de D

iam

eter

= L

/D0

UP TO 300 FUP TO 500 F

UP TO 700 FUP TO 800 FUP TO 900 F

FAC

TOR

B =

P(D

/t)

0

o

o

o

o

o

oD /t

=300

oD /t

=250

oD /t

=200

oD /t

=150

oD /t

=60

oD /t

=80

oD /t

=100

oD /t=

125

oD /t

=50

oD /t

=40

oD /t

=30

oD /t

=25

oD /t

=20

oD /t

=15

oD /t

=10

oD /t=300

oD /t=250

oD /t=200

oD /t=60

oD /t=80

oD /t=100

oD /t=125

oD /t=50

oD /t=40

oD /t=30

oD /t=25

oD /t=20

oD /t=15

oD /t=10

oD /t=150

oD /t=400

oD /t=500

oD /t=600

oD /t=800

oD /t=1000

oD /t=400

oD /t=500o

D /t=600o

D /t=800o

D /t=1000

FIGURE PFT-17.1 — Chart for Determining Wall Thickness of Ring Reinforced FurnacesWhen Constructed of Carbon Steel (Specified yield Strength 30,000 to 38,000 psi)


228


Alternate End AssembliesHr

Tr

Hr

Tr

L

D

L

o

L

t

Full PenetrationContinuous WeldBoth Sides of Rings

FIGURE PFT 17.2 — Acceptable Type Of RingReinforced Furnace

7 For immediate temperatures and Do/tratios, interpolations may be made betweenthe lines on the chart in Figure PFT-17.1.

17.6 The spacing, L, of the rings on the fur-nace is not greater than 60t or 36 in., which-ever is smaller.

17.7 The design temperature of the furnaceis taken as 100° F higher than the water tem-perature.

17.8 The boiler design permits replacementof the furnace. A flared or welded OG ring isan acceptable type of assembly.

17.9 The completed furnace assembly ispostweld heat treated but radiographic ex-amination is not required.

17.10 The thickness of the furnace wall anddesign of stiffening rings are determined bythe use of Figure PFT-17.1. The symbols de-fined below, and shown in Figures PFT-17.1and PFT-17.2 are used in the formulas of thisparagraph:

t = minimum required wall thickness offurnace or flue, inches

L = design length of a furnace section,taken as the greatest center-to-cen-ter distance between any two adja-cent stiffening rings, or the distance

from the center of the first stiffen-ing ring to the center of the furnaceweld attachment, inches. In case aflared end assembly is used, the dis-tance shall be measured to the pointof tangency of the flare and the fur-nace and the adjacent stiffeningring.

Do = outside diameter of furnace or flue,inches


The required wall thickness of a ring rein-forced furnace or flue shall not be less thanthat determined by the following procedure:

Step 1: Assume value for t and L. Determinethe ratios L/Do and Do/t;

Step 2: Enter left-hand side of Figure PFT 17.1at the value of L/Do determined in Step 1;

Step 3: Move horizontally to the line repre-senting the value of Do/t determined in Step1; 7

Step 4: From this intersection move verticallyto the material line of the proper temperature; 7

Step 5: From this intersection movehorizontally to the right and read thevalue of B;

Step 6: Compute the allowable work-ing pressure, Pa , by the following for-mula:

BPa =

Do/t

Step 7: Compare Pa with P. If Pa isless than P, select greater value of t ora smaller value of L or some combi-nation of both to increase Pa , so thatit is equal to or greater than P. (Anexample shown in Appendix A-200.)

229

8 For immediate temperatures and Do/t ratios,interpolations may be made between the lineson the chart in Figure PFT-17.1.

The required moment of inertia of a circum-ferential stiffening ring shall not be less thanthat determined by the formula:

AsDo2L (t + ) A

LIs =

14

where,Is = required moment of inertia of the

stiffening ring about its neutral axisparallel to the axis of the furnace,inches

As= cross-sectional area of the stiffeningring, square inches

A= factor determined from Figure PFT17.1

P, Do , L, and t are as defined above

The moment of inertia for a stiffening ringshall be determined by the following proce-dure:

Step 1: Assuming that the furnace has beendesigned and Do , L and t are known, select arectangular member to be used for a stiffen-ing ring and determine its area, As , and itsmoment of inertia, I. Then calculate B by theformula:

PDoB = Ast + L

where B=factor on the right-hand side of Fig-ure PFT-17.1 and P, Do , t, As , and L are asdefined above;

Step 2: Enter the right-hand side of FigurePFT-17.1 at the value of B determined in Step1;

Step 3: Follow horizontally to the materialline for the correct temperature; 8

Step 4: Move down vertically to the bottomof the chart and read the value of A;

Step 5: Compute the value of the requiredmoment of inertia, Is , from the formula givenabove;

Step 6: If the required Is is greater than themoment of inertia, I for this section selectedin Step 1, select a new section with a largermoment of inertia and determine a new valueof Is .

If the required Is is smaller than I for the sec-tion selected in Step 1, that section should besatisfactory. (An example is shown in Appen-dix A-200.)

The longitudinal and circumferential jointsmay be of the double-welded butt type, theonly requirements being that the welds arepostweld heat treated in accordance withPW-39 and a bend test of a sample of thewelding for each furnace meets therequirements of PW-53, no radiographic ex-amination being required. When the longi-tudinal and circumferential joints have beensubjected completely to radiographic exami-nation, the individual bend test for each fur-nace is not required.

PFT-18 COMBINED PLAIN CIRCULARAND CORRUGATED TYPE

Combination-type furnaces for external pres-sure may be constructed by combining a plaincircular section and a corrugated section pro-vided:

18.1 Each type of furnace is designed to beself-supporting, requiring no support fromthe other furnace at their point of connection.

18.2 Paragraphs PFT-14 and PFT-15 are usedfor calculating the maximum allowable work-ing pressure of the plain section. In applyingthe length in the text or L in the formulas, thevalue used shall always be twice the actuallength of the plain section. The actual lengthof the plain section is the distance measured


230


Max 3 t or 1-1/2"(whichever is less)

c3

1

ct

Point of Tangency

FIGURE PFT-18 — Connection BetweenPlain And Corrugated Furnace

from the centerline of the head attachmentweld to the centerline of the full penetrationweld joining the two sections.

18.2.1 Furnaces 12 in. to 18 in. in outsidediameter inclusive. A plain furnace sectionwhose length is such that twice the actuallength does not exceed 4-1/2 diametersshall have its maximum allowable work-ing pressure calculated by Equation (1) or(2) in PFT-14.4. If twice the actual lengthof the plain furnace section does not ex-ceed 120 times the thickness of the plate,Equation (1) shall be used. If twice theactual length of the plain furnace sectionexceeds 120 times the plate thickness,Equation (2) shall be used.

A plain furnace section whose length issuch that twice the actual length exceeds4-1/2 diameters shall have its maximumallowable working pressure determinedin accordance with PFT-15.

18.2.2 Furnaces over 18 in. to and including38 in. in outside diameter. The maximumallowable working pressure of a plainfurnace section shall be determined byEquation (1) and (2) in PFT-14.4. Whentwice the actual length of the plain fur-nace section exceeds 6 times the furnacediameter, L in the formulas shall be takenas 6 times the diameter.

18.3 The maximum allowable working pres-sure of the corrugated section shall be deter-mined from PFT-19.

18.4 The full penetration weld joining a plainself-supporting section to a corrugated self-

supporting section, shall be located as shownin Figure PFT-18.

18.5 The longitudinal and circumferentialjoints may be fusion welded of the double-welded butt type, the only requirements be-ing that the welds are postweld heat treatedin accordance with PW-39 and a bend test ofa sample of the welding for each furnacemeets the requirements of PW-53, no radio-graphic examination being required. Whenthe longitudinal and circumferential jointshave been subjected completely to radio-graphic examination, the individual bend testfor each furnace is not required.

PFT-19 CORRUGATED FURNACES

19.1 The maximum allowable working pres-sure on corrugated furnaces, such as theLeeds suspension bulb, Morison, Fox, Purves,or Brown, having plain portions at the endsnot exceeding 9 in. in length (except flues es-pecially provided for), when new and practi-cally circular, shall be computed as follows:

CtP =

D


sure, pounds per square incht = thickness, inches, not less than 5/16

in. for Leeds, Morison, Fox, andBrown, and not less than 7/16 in. forPurves and other furnaces corru-gated by section not over 18 in. long

D= mean diameter, inchesC= 17,300, a constant for Leeds furnaces,

when corrugations are not morethan 8 in. from center to center andnot less than 2-1/4 in. deep.

C= 15,600, a constant for Morison fur-naces, when corrugations are notmore than 8 in. from center to cen-ter and the radius of the outer cor-rugation is not more than one-halfof the suspension curve.

C= 14,000, a constant for Fox furnaces,when corrugations are not more

231

than 8 in. from center to center andnot less than 1-1/2 in. deep.

C= 14,000, a constant for Purves fur-naces, when rib projections are notmore than 9 in. from center to cen-ter and not less than 1-5/8 in. deep.

C= 14,000 a constant for Brown fur-naces, when corrugations are notmore than 9 in. from center to cen-ter and not less than 1-5/8 in. deep.

C= 10,000, a constant for furnaces cor-rugated by sections not more than18 in. from center to center and notless than 1-1/2 in. deep, measuredfrom the least inside to the greatestoutside diameter of the corruga-tions, and having the ends fitted oneinto the other and substantially riv-eted together, provided that theplain parts at the ends do not exceed12 in. in length.

In calculating the mean diameter of theMorison furnace, the least inside diameterplus 2 in. may be taken as the mean diam-eter.

The longitudinal and circumferential jointsmay be fusion welded of the double-weldedbutt type, the only requirements being thatthe welds are postweld heat treated in accor-dance with PW-39 and a bend test of a sampleof the welding for each furnace meets the re-quirements of PW-53, no radiographic exami-nation being required.

When the longitudinal and circumferentialjoints have been subjected completely to ra-diographic examination, the individual bendtest for each furnace is not required.

19.2 The thickness of a corrugated or ribbedfurnace shall be ascertained by actual mea-surement by the furnace manufacturer, bygaging the thickness of the corrugated por-tions. If a hole is used, the diameter of a holedrilled through the sheet to determine itsthickness shall be 3/8 in. When the furnaceis installed the hole shall be located beneaththe bottom of the grate and closed by a plug.

For the Brown and Purves furnaces, the holesshall be in the center of the second flat; forthe Morison, Fox and other similar types, inthe center of the top corrugation, at least asfar in as the fourth corrugation from the endof the furnace.

PFT-20 ATTACHMENT OF FURNACES

20.1 Riveted Construction

Furnaces may be attached to an inwardly oroutwardly flanged head or tube sheet by riv-eting in accordance with the rules of Part PRand applicable rules in Part PFT.

20.2 Fillet Welded Construction

In a scotch-type boiler, a furnace may be at-tached to an outwardly flanged opening in afront tube sheet by a circumferential filletweld, or a furnace may be attached to eithertube sheet by flaring the end which extendsbeyond the outside face of the head to anangle of 20 to 30 deg. and using a circumfer-ential fillet weld, provided the following re-quirements are met:

20.2.1 The area of the head around thefurnace is stayed by tubes, stays, or bothin accordance with the requirements ofthis Section.

20.2.2 The joint is wholly outside the fur-nace.

20.2.3 The throat dimension of the fullfillet weld is not less than 0.7 times thethickness of the head.

20.2.4 Unless protected by refractory ma-terial, the furnace does not extend beyondthe outside face of the tube sheet, a dis-tance greater than the thickness of thetube sheet. Any excess shall be removedbefore welding.

20.2.5 The construction conforms in allother respects to the requirements of this


232


d (max = 4")d (max) (max)Pitch1

2

FIGURE PFT-20 — Welding Ogee Ring

9 Primary Furnace gases are those in a zonewhere the design temperature of those gasesexceeds 850°F

Section including welding and postweldheat treating, except that radiographicexamination is not required.

20.3 Full Penetration Weld ConstructionA furnace may be attached by a fullpenetration weld, with the furnace extendingat least through the full thickness of the tubesheet but not beyond the toe of the weld, andthe toe shall not project beyond the face ofthe tube sheet by more than 3/8 in. unlessprotected from overheating by refractorymaterial or other means.

20.4 Throat SheetsThroat sheets and inside and outside frontfurnace sheets when fully stayed may beattached as required in PFT-11.4.

20.5 Furnace Sheets Attached by WeldingVertical firetube boilers may be constructedby welding the ogee bottom of the furnacesheet to the outside shell as shown in FigurePFT-20 provided the following requirementsare met:

20.5.1 The tube or crown sheet is fullysupported by tubes, or stays or both.

20.5.2 The joint is wholly within the shelland forms no part thereof.

20.5.3 The weld is not in contact withprimary furnace gases.9

20.5.4 The throat dimension of the fullfillet weld is not less than 0.7 times thethickness of the furnace sheet.

20.5.5 The maximum depth of thewaterleg does not exceed 4 in., and the

radius of the ogee is not greater than theinside width of the waterleg.

20.5.6 The pitch of the lower row ofstaybolts meets the requirements of PFT-26.6.

20.5.7 The construction conforms in allother respects to Code requirementsincluding welding and postweld heattreating, except that radiographicexamination is not required.

PFT-21 FIREBOXES AND WATERLEGS

21.1 Fireboxes and waterlegs may be ofriveted construction provided the rules inPart PR and all applicable rules in Part PFTare followed.

21.2 Welded construction may be used inlieu of riveted joints in the fireboxes ofinternally fired boilers provided the welds arebetween two rows of staybolts, or in the caseof flat surfaces the weld is not less than one-half of a staybolt pitch from the corner. Invertical tubular and firebox types of boilersthe bottom edges of the plates may beattached by fusion welding, provided theload due to internal pressure is carried bystaybolting and the inside width of thewaterleg does not exceed 4 in. An acceptableconstruction is as shown in Figure PWT-12.2with both plates flanged. As an alternativeconstruction one plate only need be flanged,provided the weld joining the flanged plateto the straight plate is a groove weld havingpenetration for its full depth and the weld isoutside of the header. The plates may beconsidered to be fully supported if stayed inaccordance with the requirements of PFT 26.8.

The welds shall be postweld heat treated butradiographic examination is not required.

21.3 Mud rings of plate material permissibleunder this Section of the Code may be used

233

in the construction of waterlegs of verticalfiretube boilers and may be attached as shownin Figure PG-31(g) in compliance with therequirements of Par. PG-31 provided:

21.3.1 The width of the waterleg does notexceed 4 in.

21.3.2 The thickness of the mud ring plateis at least 1/2 in.

The welds shall be postweld heat treated butradiographic examination is not required.

Any crevices between the mud ring and thesheets of the furnace section of a locomotive-type boiler may be made tight with sealwelding when the mud ring is secured byrivets. The abutting ends of mud rings maybe welded.

STAYED SURFACES

PFT-22 GENERAL

The rules of Part PG pertaining to stayedsurfaces which are applicable to firetubeboilers shall be used in conjunction with thefollowing requirements.

PFT-23 WORKING PRESSURE FORCURVED SURFACES

23.1 The maximum allowable workingpressure for curved stayed surfaces subjectto internal pressure shall be obtained by thefollowing two methods, and the minimumvalue obtained shall be used:

23.1.1 The maximum allowable workingpressure shall be computed withoutallowing for the holding power of thestays, due allowance being made for theweakening effect of the holes for the staysor riveted longitudinal joint or otherconstruction. To this pressure there shallbe added the pressure obtained by theformula for stayed surfaces given inPG-46 using 1.3 for the value of C.

23.1.2 The maximum allowable workingpressure shall be computed withoutallowing for the holding power of thestays, due allowance being made for theweakening effect of the holes for the staysor riveted longitudinal joint or otherconstruction. To this pressure there shallbe added the pressure corresponding tothe strength of the stays for the allowablestress values in Table PG-23.1, each staybeing assumed to resist the pressureacting on the full area of the externalsurface supported by the stay.

23.2 The maximum allowable workingpressure for a stayed wrapper sheet of alocomotive-type boiler shall be determinedby the two methods given above and by thefollowing formula and the smallest of thethree values obtained shall be used:

11,000tEP =

R - ∑(s sin a)


sure, pounds per square incht = thickness of wrapper sheet, inchesE = minimum efficiency of wrapper

sheet through joints or stay holesR = radius of wrapper sheet, inches

∑(s x sin a)= summated value of transverse spac-ing s x sin a for all crown stays con-sidered in one transverse plane andon one side of the vertical axis of theboiler

s = transverse spacing of crown stays inthe crown sheet, inches

a = angle any crown stay makes withthe vertical axis of boiler

11,000 = allowable stress, pounds per squareinch

The above formula applies to the longitudinalcenter section of the wrapper sheet, and incases where E is reduced at another section,the maximum allowable working pressurebased on the strength at that section may beincreased in the proportion that the distancefrom the wrapper sheet to the top of thecrown sheet at the center bears to the distance


234


( )

90o

FIGURE PFT-23.1 — Stayed WrapperSheet of Locomotive-Type Boiler

FIGURE PFT-23.2 — Proper Location ofStaybolts Adjacent to Longitudinal Jointin Furnace Sheet

measured on a radial line through the othersection, from the wrapper sheet to a linetangent to the crown sheet and at right anglesto the radial lines (see Figure PFT-23.1).

23.3 A furnace for a vertical firetube boiler38 in. or less in outside diameter whichrequires staying shall have the furnace sheetsupported by one or more rows of staybolts,the circumferential pitch not to exceed 1.05times that given by the formula in PG-46.

The longitudinal pitch between the staybolts,or between the nearest row of staybolts andthe row of rivets at the joints between thefurnace sheet and the tube sheet or thefurnace sheet and mud ring, shall not exceedthat given by the following formula:

56,320t2

L = 2PR

where,L = longitudinal pitch of stayboltsP = maximum allowable working

pressure, pounds per square incht = thickness of furnace sheet, inchesR = outside radius of furnace, inches

When values by this formula are less than thecircumferential pitch, the longitudinal pitchmay be as large as the allowablecircumferential pitch.

The stress in the staybolts shall not exceed7500 psi. and shall be determined as specifiedin PFT-23.4.

23.4 In furnaces over 38 in. in outsidediameter and combustion chambers notcovered by special rules in this Section whichhave curved sheets subject to pressure on theconvex side, neither the circumferential norlongitudinal pitches of the staybolts shallexceed 1.05 times that given by the rules inPG-46.

The stress in staybolts shall not exceed 7500psi based on the total load obtained by

multiplying the product of the circumferentialand longitudinal pitches less the minimumcross-sectional area, by the maximumallowable working pressure.

23.5 Furnaces of Vertical Boilers. In a verticalfiretube boiler, the furnace length, for thepurpose of calculating its strength andspacing staybolts over its surface, shall bemeasured from the center of rivets in thebottom of the waterleg to the center of rivetsin the flange of the lower tube sheet.

23.6 When the longitudinal joint of thefurnace sheet of a vertical firetube boiler is oflap-riveted construction and staybolted, astaybolt in each circular row shall be locatednear the longitudinal joint, as shown in FigurePFT-23.2.

235

PFT-24 FLEXIBLE STAYBOLTS

Flexible-type staybolts having a cover capwelded under the provisions of PW-15 to theouter sheet may be used in the constructionof locomotive-type boilers provided the boltsare hollow-drilled from the threaded end intoand partly through the ball head to allow forproper inspection, and so that any breakageis disclosed by leakage at the inner end. Thesewelded joints need not be postweld heattreated nor radiographed.

PFT-25 ATTACHMENT OF STAYS ANDSTAYBOLTS BY WELDING

The attachment of stays and staybolts bywelding shall meet the requirements ofPW-19.

PFT-26 MAXIMUM SPACING

26.1 The maximum distance between centersof rivets, or between the edges of tube holesand the centers of rivets attaching thecrowfeet of stays to the stayed surface, shallbe p as determined in PG-46 using 2.5 for thevalue of C.

26.2 The maximum distance between theedges of tube holes and the centers of othertypes of stays shall be p as determined by theformula in PG-46, using the value of C givenfor the thickness of plate and type of stayused.

26.3 For a flanged head, riveted or welded tothe shell, the maximum distance between theinner surface of the supporting flange andlines parallel to the surface of the shell passingthrough the center of the stay, or the rivetsattaching crowfeet of stays shall be p asdetermined by the formula in PG-46, plus theinside radius of the supporting flanges usingthe following C factors:

For riveted crowfoot stays—Use 2.1 for Cfactor.

For other types of stays—Use the C factorwhich applies to the thickness of the headplate and type of stay used [see Figure A-8(i)and (j)].

26.4 For unflanged heads, the maximumdistance between the inner surface of the shelland the centers of stays, or rivets attachingcrowfeet of stays, shall not be more than one-half the maximum allowable pitch asdetermined by PG-46, using 2.5 for the valueof C, plus 2 in. [see Figure A-8(k)].

26.5 The pitch of diagonal stays attached bywelding between the shells and tube sheetsof horizontal tubular and scotch boilers, andfor other stays when supported plate is notexposed to radiant heat, as determined by PG-46, may be greater than 8-1/2 in., but shallnot exceed 15 times the stay diameter.

26.6 The pitch of the lower row of stayboltsof a vertical firetube boiler, which is requiredto be stayed by the rules in this Section, andwhich is fabricated by welding the ogeebottom of the furnace sheet to the outsideshell, shall not exceed one-half the maximumallowable pitch as determined by PG-46,measured from the center of the staybolt tothe tangent of the ogee (see Figure PFT-20).

26.7 The spacing of staybolts around doorholes fabricated by fusion welding of the fullpenetration type of two-flanged sheets, whichare required to be stayed by the rules of thisSection (see Figure PWT-12.2), shall notexceed one-half the maximum allowablepitch determined by PG-46, measured fromthe center of the staybolt to the points oftangency of the flanges.

26.8 If the furnace sheets are required to bestayed by the rules of this Section, the spacingof staybolts around door holes and thespacing of the first row of staybolts from thebottom of the mud ring fabricated by fusionwelding of the full penetration type wheneither or both sheets are not flanged [seeFigure A-8(l), (m) and (n)] shall not exceedone-half the maximum pitch determined by


236


MAX r = p AS CALULATED BY PAR. PFT-26.2

MIN r = 3 t

p

p

t

β

r

FIGURE PFT-26 — Pitch Of StayboltsAdjacent To Upper Corners Of Fireboxes

If the radius r exceeds the pitch, the curved plateshall be stayed as a flat plate in accordance withPG-46.

PG-46, plus 2 in., measured from the centerof the staybolt to the root of the weld.

26.9 The maximum distance from the firstrow of stays to a full penetration weld incompression applied from either or both sidesof the tube sheet, attaching the crown sheetof a furnace or combustion chamber to astayed head or tube sheet shall not exceed thepitch determined by PG-46, measured fromthe center of the stay to the furnace orcombustion chamber side of the head or tubesheet [see Figures A-8(o) and (p)].

26.10 When a flanged-in manhole openingwith a flange depth of not less than 3 timesthe required thickness of the head, or whenan unflanged manhole ring meeting therequirements of PG-32 through PG-39 isprovided in a flat stayed head of a firetubeboiler, as shown in Figures A-8(q) and (r), thearea to be stayed as required by PFT-31 maybe reduced by 100 sq. in. provided both thefollowing requirements are met:

26.10.1 The distance between themanhole opening and the inside of theshell does not exceed one-half themaximum allowable pitch for anunflanged manhole and one-half themaximum allowable pitch plus the radiusof the head flange for a flanged-inmanhole in a flanged head.

26.10.2 The distance between the centersof the first rows of stays, or the edges oftube holes, and the manhole opening doesnot exceed one-half the maximumallowable pitch as determined by PG-46.

26.11 In applying these rules and those inPG-46 to a head or plate having a manhole orreinforced opening, the spacing applies onlyto the plate around the opening and not acrossthe opening.

26.12 For stays at the upper corners offireboxes, the pitch from the staybolt next tothe corner to the point of tangency to thecorner curve shall be (see Figure PFT-26):

T2

90 √C P

p = Angularity of tangent lines (β)

whereT = thickness of plate in sixteenths of an

inchP = maximum allowable working

pressure, pounds per square inchC = factor for the thickness of plate and

type of stay used as required in PartPG-46.

PFT-27 AREA SUPPORTED BY STAY

27.1 The full pitch dimensions of the staysshall be employed in determining the area tobe supported by a stay, and the area occupiedby the stay shall be deducted therefrom toobtain the net area. The product of the netarea in square inches by the maximumallowable working pressure in pounds persquare inch gives the load to be supportedby the stay.

27.2 Where stays come near the outer edgeof the surfaces to be stayed and specialallowances are made for the spacing, the loadto be carried by such stays shall bedetermined by neglecting the added areaprovided for these special allowances.

Example: If the maximum pitch by PG-46would make a staybolt come 6 in. from theedge of the plate and a special allowance

237

would make it come 7 in., the distance of 6in. shall be used in computing the load to becarried.

PFT-28 STAYBOLTS AND STAYS

28.1 The required area at the point of leastnet cross section of staybolts and stays shallbe as given in PG-49. The maximumallowable stress per square inch at point ofleast net cross-sectional area of staybolts andstays shall be given as in Table PG-23.11. Indetermining the net cross-sectional area ofdrilled or hollow staybolts, the cross-sectionalarea of the hole shall be deducted.

28.2 The length of the stay between supportsshall be measured from the inner faces of thestayed plates. The stresses are based ontension only. For computing stresses indiagonal stays, see PFT-32.

28.3 When stay rods are screwed throughsheets and riveted over, they shall besupported at intervals of not to exceed 6 ft.Stay rods over 6 ft. in length may be usedwithout support if fitted with nuts andwashers or attached by welding under PW-19, provided the least cross-sectional area ofthe stay rod is not less than that of a circle1 in. in diameter.

PFT-29 STRUCTURALREINFORCEMENTS

29.1 When channels or other structuralshapes are riveted to the boiler heads forattaching through stays, the transverse stresson such members shall not exceed 12,500 psi.In computing the stress, the section modulusof the member shall be used without additionfor the strength of the plate. The spacing ofthe rivets over the supported surface shall bedetermined by the formula in PG-46, using2.5 for the value of C.

29.2 Provided the outstanding legs of the twomembers are fastened together so that they

act as one member in resisting the bendingaction produced by the load on the rivetsattaching the members to the head of theboiler, and provided that the spacing of theserivets attaching the members to the head isapproximately uniform, the members may becomputed as a single beam uniformly loadedand supported at the points where thethrough stays are attached.

PFT-30 STAYING SEGMENTSOF HEADS

30.1 A segment of a head shall be stayed byhead-to-head, through, diagonal, crowfoot, orgusset stays, except that a horizontal-returntubular boiler may be stayed as provided inPFT-35.

30.2 Stays shall be used in the tube sheets ofa firetube boiler if the distance between theedges of the tube holes exceeds the maximumpitch of staybolts for the corresponding platethickness and pressure given in PG-46.

Any part of the tube sheet which comesbetween the tube or cylindrical furnace andthe shell need not be stayed if the greatestdistance measured along a radial line fromthe inner surface of the shell to the centerpoint of tangent to any two tube holes or tubehole and cylindrical furnace on the shell sideof such holes does not exceed 1.5 times thevalue of p obtained by applying the formulaof PG-46 with C equal to 2.1 or 2.2 dependingupon the plate thickness. The tube holes, ortube hole and cylindrical furnace (see FigurePFT-30), to which a common tangent may bedrawn in applying this rule, shall not be agreater distance from edge to edge than themaximum pitch referred to.

PFT-31 AREAS OF HEADS TOBE STAYED

31.1 The area of a segment of a flanged headto be stayed shall be the area enclosed by linesdrawn 2 in. from the tubes and a distance d


238


1 p12

1 p121 p1

2

1 p12 1 p1

2

FIGURE PFT-30 — Example of Staying of Heads Adjacent to Cylindrical Furnaces

R

H

d

d 2“

2“

2“

l

L

2“

FIGURE PFT-31.1 — Method ofDetermining Net Area of Segment ofa Head

FIGURE PFT-31.2 — Method ofDetermining Net Area of IrregularSegment of a Head

FIGURE PFT-32 — Measurements forDetermining Stresses in Diagonal Stays

239

√

√

from the shell as shown in Figures PFT-31.1and PFT-31.2. The value of d used may bethe larger of the following values:

d = the outer radius of the flange, notexceeding 8 times the thickness ofthe head

d = 80t/√Pwhere d = unstayed distance from shell, inches

t = thickness of head in inchesP = maximum allowable working pres-

sure, pounds per square inch

31.2 The area of a segment of an unflangedhead to be stayed shall be the area enclosedby the shell and a line drawn 2 in. from thetubes.

31.3 The rules on PFT-30.2 shall be used todetermine if staying is required.

31.3.1 The net area to be stayed in a seg-ment of a flanged head may be deter-mined by the following formula:

4 (H -d - 2)2 2 (R - d)A = - 0.608

3 (H - d - 2)

where,A = area to be stayed, square inchesH = distance from tubes to shell, inchesd = distance determined by formula in

PFT-31.1 for flanged headsd = zero for unflanged headsR = radius of boiler head, inches

31.3.2 The net area to be stayed in asegment of an unflanged head may bedetermined by the following formula:

4 (H - 2)2 2RA = - 0.608

3 (H - 2)

where,A = area to be stayed, square inches

31.4 When stays are required, the portion ofthe heads below the tubes in a horizontal-return tubular boiler shall be supported bythrough stays attached by welding underPW-19 or with nuts inside and outside at the

front head and by attachments whichdistribute the stress at the rear head.

The distance in the clear between the bodiesof the stays or of the inside stays where morethan two are used shall not be less than 10 in.at any point.

When horizontal firetube boilers are set sothat the products of combustion do not comein contact with the lower part of the shell,tubes may be used instead of through staysat the sides of the manhole opening, if used.

PFT-32 STRESSES IN DIAGONALAND GUSSET STAYS

32.1 To determine the required area of adiagonal stay, multiply the area of a directstay required to support the surface by theslant or diagonal length of the stay; anddivide this product by the length of a linedrawn at right angles to surface supportedto center of palm of diagonal stay as follows:

aLA =

l

where,A= sectional area of diagonal stay,

square inchesa = sectional area of direct stay, square

inchesL = length of diagonal stay as indicated

in Figure PFT-32, inchesl = length of line drawn at right angles

to boiler head or surface supportedto center of palm of diagonal stay,as indicated in Figure PFT-32

Example: Given diameter of direct stay=1 in.a=0.7854 sq. in., L=60 in., l=48 in.; substitutingand solving:

Diameter=1.11 in. = 1-1/8 in.

32.2 For staying segments of tube sheets suchas in horizontal-return tubular boilers, whereL is not more than 1.15 times l for any stay,the stays may be calculated as direct stays


240


Not over 3"

Not over 4"

Not over 8"3"

Not lessthan 2"

See

Tab

le

See

Tab

le

β

Α

FIGURE PFT-35 — Staying of Head With SteelAngles in Tubular Boiler

allowing 90 percent of the allowable stressvalue given in Table PG-23.1.

PFT-33 DESIGN OF STAYS AND STAYCONNECTIONS

All rivet holes and pinholes shall conform tothe requirements of PR-32 and the pins shallbe made a neat fit. To determine the sizes thatshall be used, proceed as follows:

33.1 Determine the required cross-sectionalarea of the stay in accordance with PFT-29.

33.2 Design the body of the stay so that thecross-sectional area shall be at least equal tothe required cross-sectional area of the stayfor unwelded stays. Where the stays are forgewelded, the cross-sectional area at the weldshall be at least as great as that computed fora stress of 6,000 psi (see Table PG-23.3).

33.3 Make the area of pins to resist doubleshear at least three-quarters of the requiredcross-sectional area of the stay.

33.4 Make the combined cross section of theeye at the side of the pin (in crowfoot stays)at least 25 percent greater than the requiredcross-sectional area of the stay.

33.5 Make the cross-sectional areas throughthe blades of diagonal stays whereattached to the shell of the boiler atleast equal to the required rivetsection, that is, at least equal to 1-1/4times the required cross-sectional areaof the stay.

33.6 Design each branch of a crowfootto carry two-thirds the total load onthe stay.

33.7 Make the net sectional areasthrough the sides of the crowfoot, teeirons, or similar fastenings at the rivetholes at least equal to the requiredrivet section, that is, at least equal to1-1/4 times the required cross-sectional area of the stay.

33.8 Make the combined cross-sectional areaof the rivets at each end of the stay at least 1-1/4 times the required cross-sectional area ofthe stay.

PFT-34 GUSSET STAYS

Gusset stays when constructed of triangularright-angled web plates secured to single- ordouble-angle bars along the two sides at rightangles shall have a cross-sectional area (in aplane at right angles to the longest side andpassing through the intersection of the twoshorter sides) not less than 10 percent greaterthan would be required for a diagonal stayto support the same surface, calculated by theformula of PFT-32, assuming the diagonalstay is at the same angle as the longest sideof the gusset plate.

PFT-35 STAYING OF UPPERSEGMENTS OF TUBE HEADSBY STEEL STRUCTURALSHAPES

35.1 When the shell of a boiler does notexceed 36 in. in diameter and is designed fora maximum allowable working pressure notexceeding 100 psi, the segment of heads abovethe tubes may be stayed by steel structuralshapes as specified in Table PFT-35 and Figure

241

Height of Segment Dimension β in Fig. PFT-35

10 11 12 13 14 15 16

Thickness, In.

30-in. BoilerAngle 3 by 2-1/2 in. 3/8 7/16 9/16 ... ... ... ...Angle 3-1/2 by 3 in. 5/16 3/8 7/16 9/16 ... ... ...Angle 4 by 3 in. 5/16 5/16 3/8 7/16 1/2 ... ...

34-in. BoilerAngle 3-1/2 by 3 in. ... 7/16 1/2 11/16 ... ... ...Angle 4 by 3 in. ... 5/16 7/16 1/2 5/8 ... ...Angle 5 by 3 in. ... 5/16 5/16 5/16 3/8 1/2 ...

36-in. BoilerAngle 4 by 3 in. ... ... 7/16 9/16 5/8 3/4 ...Angle 5 by 3 in. ... ... 5/16 3/8 7/16 1/2 5/8Angle 6 by 3 in. ... ... ... ... 3/8 3/8 7/16

Dimension A in.Fig. PFT-35 6-1/2 7 7-1/2 8 8-1/2 9 9-1/2

TABLE PFT-35SIZES OF ANGLES REQUIRED FOR STAYING SEGMENTS OF HEAD(With the short legs of the angles attached to the head of the boiler.)

PFT-35, except that structural shapes of equalthickness and greater depth of outstandingleg, or of greater thickness and the same orgreater depth of outstanding leg, may besubstituted for those specified. The legsattached to heads may vary in depth 1/2 in.above or below the dimensions specified inTable PFT-35.

35.2 When this form of staying is to be placedon a boiler, the diameter of which isintermediate to or below the diameters givenin Table PFT-35, the tabular values for the nexthigher diameter shall govern. Rivets of thesame diameter as used in the longitudinaljoints of the boiler shall be used to attach thestructural shapes to the head and to connectthe outstanding legs.

35.3 The rivets attaching structural shapesto heads shall be spaced not over 4 in. apart.The centers of the end rivets shall be not over3 in. from the ends of the structural shape.

The rivets through the outstanding legs shallbe spaced not over 8 in. apart; the centers ofthe end rivets shall be not more than 4 in. fromthe ends of the structural shapes. The endsof the structural shapes shall be consideredthose of the outstanding legs and the lengthsshall be such that their ends overlap a circle3 in. inside the inner surface of the shell asshown in Figure PFT-35.

35.4 The distance from the center of thestructural shapes to the shell of the boiler,marked A in Figure PFT-35, shall not exceedthe values in Table PFT-35, but in no case shallthe leg attached to the head of the lower anglecome closer than 2 in. from the top of thetubes.

35.5 When segments are beyond the rangespecification in Table PFT-35, the heads shallbe stayed in accordance with therequirements in these rules.


242


PFT-36 CROWN BARS ANDGIRDER STAYS

36.1 Crown bars and girder stays for tops ofcombustion chambers and back connectionsor wherever used, shall be proportional toconform to the following formula:

Cd2tP =

(W -p) D1W

where,W = extreme distance between supports

of, in a scotch marine boiler, the dis-tance from the fireside of the tubesheet to the fireside of the back con-nection plate, inches


p = pitch of supporting bolts, inchesD1= distance between girders from cen-

ter to center, inchesd = depth of girder, inchesC= 7,000 when girder is fitted with one

supporting boltC= 10,000 when the girder is fitted with

two or three supporting boltsC= 11,000 when the girder is fitted with

four or five supporting boltsC= 11,500 when the girder is fitted with

six or seven supporting boltsC= 12,000 when the girder is fitted with

eight or more supporting bolts

Example: Given W=34 in., p=7.5 in., D1=7.75in., d=7.5 in., t=2 in., three stays per girder,C=10,000; then substitute the formula:

10,000 x 7.5 x 7.5 x 2P = = 161.1 psi

(34 - 7.5) x 7.75 x 34

Sling stays, if used between crown bars andboiler shell or wrapper sheet, shall beproportioned so as to carry the entire loadwithout considering the strength of the crownbars.

36.2 In a form of reinforcement for crownsheets where the top sheet of the firebox is asemicircle and the top part of the circle not

exceeding 120 deg. in arc is reinforced by archbars extending over the top and down belowthe top row of staybolts at the sides of thefurnace beneath the semicircular crown sheet,these arch bars being riveted to the watersidethrough thimbles, the maximum allowableworking pressure shall be determined byadding to the maximum allowable workingpressure for a plain circular furnace of thesame thickness, diameter, and lengthdetermined by the formula in PFT-14, thepressure P1 determined from the followingformula which is a modification of the firstformula in PFT-15:

bd3

P1 = 10,000,000 D1D

3

where,b = net width of crown bar, inchesd = depth of crown bar, inchesD1= longitudinal spacing of crown bar

which shall not exceed twice themaximum allowable staybolt pitch,inches

D= two times the radius of the crownsheet, inches

provided that the maximum allowableworking pressure must not exceed thatdetermined by the formula for furnaces of theAdamson type, in PFT-16 when L is madeequal to D1 , and also provided that thediameter of the holes for the staybolts in thecrown bars does not exceed 1/3 b, and thecross-sectional areas of the crown bars is notless than 4 sq. in. PG-46 governs the spacingof the staybolts, rivets, or bolts attaching thesheet to the bars, and PFT-23.4, the size of thestaybolts, rivets or bolts.

For constructions in which the crown sheetis not semicircular, or in which other featuresdiffer from those specified above, a test shallbe made in accordance with PG-101 and theworking pressure shall be based thereon.

36.3 Cast iron supporting lugs, legs, or endsshall not be used.

243

TABLE PFT-38 — Values of C For Determining Pitchof Stay Tubes

Pitch of Stay When Tubes When Tubes AreTubes in the Have No Nuts Fitted With NutsBounding Rows Outside of Plates Outside of Plates

Where there aretwo plain tubesbetween two stay 2.2 2.4tubes

Where there is oneplain tube between 2.6 2.8two stay tubes

Where every tube inthe bounding rowsis a stay tube andeach alternate tubehas a nut . . . 3.2

PFT-37 TRUNCATED CONESHAPED COMBUS-TION CHAMBERS OFVERTICAL TUBULARBOILERS

37.1 Upper combustion chambersof vertical submerged tubularboilers made in the shape of afrustrum of a cone when not over38 in. diameter at the large end maybe used without stays if computedby the rule of plain cylindricalfurnaces in PFT-14, making D in theformula equal to the diameter atthe large end, provided that thelongitudinal joint conforms to therequirements of PFT-14.

37.2 When over 38 in. in diameterat the large end, that portion whichis over 30 in. in diameter shall be fullysupported by staybolts or gussets. Ifsupported by staybolts, PFT-23.4 shall apply.If supported by gussets the spacing of therivets attaching the gussets to the cone sheetshall not exceed the staybolt spacing givenin PFT-23.4. The top row of staybolts or rivetsshall be at a point where the cone top is 30 in.or less in diameter.

In calculating the pressure permissible on theunstayed portion of the cone, the verticaldistance between the horizontal planespassing through the centers of the rivets atthe cone top and through the center of thetop row of staybolts shall be as L in PFT-14.4and D in that paragraph shall be the insidediameter at the center of the top row ofstaybolts.

PFT-38 STAY TUBES

38.1 When stay tubes are used inmultitubular boilers to give support to thetube plates, the sectional area of such staytubes may be determined as follows:

(A - a) PTotal section of stay tubes, sq. in. =

S

where,A= area of that portion of tube plate

containing the tubes, square inchesa = aggregate area of holes in the tube

plate, square inchesP = maximum allowable working pres-

sure, pounds per square inchS = maximum allowable stress value in

the tubes, pounds per square inch(not to exceed 7,000 psi).

38.2 The pitch of stay tubes shall conform tothe formula in PG-46, using the values of Cas given in Table PFT-38.

When the ends of tubes are not shielded fromthe action of flame or radiant heat, the valuesof C shall be reduced 20 percent. The tubesshall project about 1/4 in. at each end and beslightly flared. Stay tubes when threadedshall be not less than 3/16 in. in thickness atbottom of thread; nuts on stay tubes are notadvised. For nest of tubes, C shall be takenas 2.5 and p as the mean pitch of stay tubes.For spaces between nests of tubes, p shall betaken as the horizontal distance from centerto center of the bounding rows of tubes andC as given in Table PFT-38.


244


DOORS AND OPENINGS

PFT-39 RIVETED DOOR OPENINGS

Doors in waterlegs may be attached byriveting provided the rules for riveting in PartPR and the rules for stayed surfaces in thisPart are complied with.

PFT-40 WELDED DOOR OPENINGS

Arc or gas welding may be used in thefabrication of door holes provided the sheetsare stayed around the opening in accordancewith the requirements of PFT-26.7 and 26.8.

The fit-up of the several parts of an arc or gaswelded door opening shall be such that themaximum gap between the two plates to bejoined by welding does not exceed 1/8 in.

PFT-41 OPENINGS IN WRAPPERSHEETS

Openings located in the curved portion of thewrapper sheet of a locomotive-type boilershall be designed in accordance with the rulesin PG-32.

PFT-42 ACCESS AND FIRING DOORS

The minimum size of an access door to beplaced in a boiler setting shall be 12 in. x 16in., or equivalent area; 11 in. to be the leastdimension in any case. The minimum size ofa fire door opening in an internally firedboiler in which the minimum furnacedimension is 24 in. or over shall be not lessthan 11 in. x 15 in. or 10 in. x 16 in. in size. Acircular opening shall be not less than 15 in.in diameter.

The bonnet or smoke hood of a vertical flueor tubular boiler shall be provided with anaccess opening at least 6 x 8 in. for the purposeof inspection and cleaning the top head of theboiler.

PFT-43 LOCATION OF MANHOLESAND HANDHOLES

43.1 The manhole shall be located in the fronthead below the tubes of a horizontal-returntubular boiler 48 in. or over in diameter.Smaller boilers shall have either a manholeor a handhole below the tubes. There shallbe a manhole in the upper part of the shell orhead of a firetube boiler over 40 in. indiameter, except on a vertical firetube boiler,or except on internally fired boilers not over48 in. in diameter. The manhole may beplaced in the head of the dome. Smallerboilers shall have either a manhole or ahandhole above the tubes.

Where plugs are used the minimum size shallbe 1-1/2 in. and the requirements of PG-32through PG-44 shall apply.

43.2 A traction, portable, or stationary boilerof the locomotive type shall have not less thansix handholes or washout plugs located asfollows: One in the rear head below the tubes;one in the front head at or about the line ofthe crown sheet; four in the lower part of thewaterleg; also, where possible, one near thethroat sheet. If the front head is obstructedby a smokebox, the handhole may be insertedin either side sheet at or about the line of thecrown sheet.

43.3 A vertical boiler, except watertube typeand boilers of steam fire engines and boilersless than 24 in. in diameter, shall have not lessthan four handhole openings in the shelllocated as follows: One at or about thewaterline or opposite the fusible plug whenused; three at or about the line of the crownsheet or lower tube sheet, and if internallyfired not less than three additional handholeopenings at the lower part of the waterleg.

A submerged-tube type of vertical firetubeboiler 24 in. or more in diameter shall havetwo or more additional handhole openingsin the shell, in line with the underside of theupper tube sheet.

245

43.4 A vertical boiler, except of the watertubetype, less than 24 in. in diameter, shall havein the shell a handhole opening at thewaterline and two washout openings near thebottom in addition to the blowoff for washingout the boiler, except:

43.4.1 If of the internally fired type, it shallhave a handhole opening in the shell inline with the crown sheet or lower tubesheet, in which case the handhole openingat the waterline may be omitted.

43.4.2 If of the submerged-tube type, itshall also have a handhole opening in theshell in line with the upper tube sheet inwhich case the handhole opening at thewaterline may be omitted.

43.5 If a vertical-type boiler is equipped withmanholes or other access openings, throughwhich adequate inspection may be made, therequired handhole and/or inspectionopenings at the waterline and for the tubesheets may be omitted.

43.6 A vertical firetube boiler of a steam fireengine shall have at least three washoutopenings located as follows: One at or aboutthe line of the crown sheet, two at the lowerpart of the waterleg.

43.7 A boiler of the scotch type shall have ahandhole or washout plug in the front headbelow or on each side of the furnace, or oneach side of the shell near the front head, ahandhole or a washout plug on the bottomof the shell, an opening to inspect the top ofthe furnace, and an inspection opening abovethe top row of tubes. Scotch marine boilers(wet-back type) shall also have an openingfor inspection of the water space at the rearof the combustion chamber.

PFT-44 OPENING BETWEEN BOILERAND SAFETY VALVE

The opening or connection between the boilerand the safety valve shall have at least the

area of the valve inlet. In the case of firetubeboilers, the openings in the boilers for safetyvalves or safety relief valves shall be not lessthan given in Table PFT-44, except firetubeboilers used for waste heat purposes only, notequipped for direct firing, need not meet therequirements of Table PFT-44 provided therated steaming capacity is stamped on theboiler and safety valves or safety relief valvesof the required relieving capacity are suppliedsuch that the provisions of PG-67.2 aresatisfied. No valve of any description shallbe placed between the required safety valveor safety relief valve or valves and the boiler,nor on the discharge pipe between the safetyvalve or safety relief valve and theatmosphere. When a discharge pipe is used,the cross-sectional area shall be not less thanthe full area of the valve outlet or of the totalof the areas of the valve outlets dischargingthereinto and shall be as short and straightas possible and so arranged as to avoid unduestresses on the valve or valves.

DOMES

PFT-45 REQUIREMENTS FOR DOMES

45.1 The longitudinal joint of a riveted dome24 in. or over in inside diameter shall be ofbutt- and double-strap construction, or thedome may be made without a seam of onepiece of steel pressed into shape; and itsflange shall be double-riveted to the shell. Inthe case of a dome less than 24 in. in diameter,for which the product of the inside diameterin inches and the maximum allowableworking pressure in pounds per square inchdoes not exceed 4,000, its flange may besingle-riveted to the shell and thelongitudinal joint may be of the lap type,provided it is computed with a factor of safetyof not less than 8.

The longitudinal joint of a dome may be butt-welded and the dome flange may be doublefull fillet lap-welded to the shell, in place ofriveting if the welding complies fully with therequirements for welding in Part PW.


246


TAB

LE

PFT

-44

— M

inim

um

Tot

al A

reas

of

Op

enin

gs (S

qu

are

Inch

es) i

n F

iret

ub

e B

oile

rs f

or S

afet

y V

alve

Con

nec

tion

s

Gag

eB

oile

r H

eati

ng S

urf

ace,

sq.

ft.

Pre

ssu

re,

psi

100

200

300

400

500

600

800

1000

1200

1400

1600

1800

2000

2500

3000

V

163.

174

6.34

89.

522

12.6

9515

.869

19.0

4325

.392

31.7

3938

.086

44.4

3550

.738

57.1

3063

.478

79.3

4795

.216

13.3

3025

2.50

05.

000

7.49

910

.000

12.4

9815

.000

20.0

0024

.996

30.0

0035

.000

40.0

0044

.992

49.9

9262

.489

74.9

8710

.498

501.

584

3.16

84.

752

6.33

87.

920

9.50

412

.677

15.8

3919

.007

22.1

7525

.354

28.5

1031

.678

39.5

9947

.517

6.65

5

751.

166

2.33

13.

497

4.66

35.

828

6.99

59.

326

11.6

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247

FIGURE PFT-46.1 — Spacing of Support-ing Lugs in Pairs on Horizontal-ReturnTubular Boiler

2" Maximum

Radiographic examination of the fillet weldsmay be omitted. The opening shall bereinforced in accordance with PG-32 throughPG-44.

45.2 The joints of a dome may be welded andthe dome welded to the shell if the weldingcomplies fully with the requirements forwelding in Part PW. The opening shall bereinforced in accordance with PG-32 throughPG-44.

45.3 When a dome is located on the barrel ofa locomotive-type boiler or on the shell of ahorizontal-return tubular boiler, the diameterof the dome shall not exceed six-tenths thediameter of the shell or barrel of the boilerunless the portion of the barrel or shell underthe dome (the neutral sheet) is stayed to thehead or shell of the dome by stays whichconform in spacing and size to therequirements given in PG-46 and Table PG-23.1. With such stayed construction thediameter of a dome located on the barrel orshell of a boiler is limited to eight-tenths ofthe barrel or shell diameter.

45.4 All domes shall be so arranged that anywater can drain back into the boiler.

45.5 Flanges of domes shall be formed witha corner radius, measured on the inside, of atleast twice the thickness of the plate for plates1 in. in thickness or less, and at least 3 timesthe thickness of the plate for plates over 1 in.in thickness.

45.6 Domes and manhole frames attached toshells or heads of boilers shall be designed inaccordance with PG-32 through PG-44, withthe additional requirement that the maximumallowable stress value in tension of rivets inmanhole frames having a thickness of 7/8 in.or less and of rivets in domes flanges shallnot exceed 7,200 psi.

45.7 In a locomotive-type boiler with a domeon a tapered course, the maximum allowablediameter of the dome shall be based on thatdiameter of the tapered course whichintersects the axis or centerline of the dome.

SETTING

PFT-46 METHOD OF SUPPORT

46.1 The design and attachment of lugs,hangers, saddles, and other supports shallmeet the requirements of PG-22.1 and PG-55.

46.2 In applying the requirements of 46.1,localized stresses due to concentrated supportloads, temperature changes, and restraintagainst dilation of the boiler due to pressureshall be provided for. Lugs, brackets, saddles,and pads shall conform satisfactorily to theshape of the shell or surface to which theyare attached or with which they are in contact.

46.3 A horizontal-return tubular boiler over72 in. in diameter shall be supported fromsteel hangers by the outside-suspension typeof setting, independent of the furnace sidewalls. The hangers shall be so designed thatthe load is properly distributed between therivets attaching them to the shell and so thatno more than two of these rivets come in thesame longitudinal line on each hanger. Thedistance girthwise of the boiler from thecenters of the bottom rivets to the centers ofthe top rivets attaching the hangers shall benot less than 12 in. The other rivets used shallbe spaced evenly between these points.

46.4 The horizontal-return tubular boiler, 14ft. or more in length, or over 54 in. and up toand including 72 in. in diameter, shall besupported by the outside-suspension type of


248


FIGURE PFT-46.2 — Welded Bracket Connec-tion for Horizontal-Return Tubular Boilers

Section B-B

T T T34

34

34

122

“T” “T”min.

Dimension “T” notless than 1% ofBoiler Diameter

20m

ax.

20m

ax.

Dimension “R” not less than 1-1/2 x Diameter of Hole

“R”

B

B

setting as specified in PFT-46.3, or at fourpoints by not less than eight steel or cast ironlugs set in pairs. A horizontal-return tubularboiler up to and including 54 in. in diametershall be supported by the outside-suspensiontype of setting as specified in PFT-46.3, or bynot less than two steel or cast iron lugs oneach side. The distance girthwise of the boilerfrom the centers of the bottom rivets to thecenters of the top rivets attaching the hangersshall be not less than the square of the shelldiameter divided by 675. If more than fourlugs are used they shall be set in four pairs,the lugs of each pair to be spaced not over 2in. apart and the load to be equalized betweenthem (see Figure PFT-46.1). If the boiler issupported on structural steel work, the steelsupporting members shall be so located orinsulated that heat from the furnace cannotimpair their strength.

46.5 Figure PFT-46.2 illustrates an acceptabledesign of hanger bracket for weldedattachment to welded horizontal-returntubular boilers with the additionalrequirement that the hanger pin be located atthe vertical center line over the center of awelded contact surface. The bracket platesshall be spaced at least 2-1/2 in. apart, butthis dimension shall be increased if necessaryto permit access for the welding operation.

46.6 Wet-bottom stationary boilers shall besupported so as to have a minimum clearanceof 12 in. between the underside of the wet-bottom and the floor to facilitate inspection.Other types of firetube boilers set horizontallyshall be supported so that they have aminimum clearance of 12 in. between themetal surface of the shell and the floor. Boilerinsulation, saddles, or other supports shall bearranged so that inspection openings arereadily accessible.

PIPING, FITTINGS, AND APPLIANCES

PFT-47 WATER GLASSES

Boilers of the horizontal firetube type shallbe so set that when the water is at the lowest

reading in the water gage glass there shall beat least 3 in. of water over the highest pointof the tubes, flues or crown sheet.

PFT-48 FEED PIPING

48.1 When a horizontal-return tubular boilerexceeds 40 in. in diameter, the feedwater shalldischarge at about three-fifths the length fromthe end of the boiler which is subjected to thehottest gases of the furnace (except ahorizontal-return tubular boiler equippedwith an auxiliary feedwater heating andcirculating device), above the central row oftubes. The feed pipe shall be carried throughthe head or shell farthest from the point ofdischarge of the feedwater in the mannerspecified for a surface blowoff in PG-59.3.2,and be securely fastened inside the shellabove the tubes.

48.2 In vertical tubular boilers having tubes4 ft. or less in length, the feedwater shall beintroduced at a point not less than 12 in. abovethe crown sheet. When the boiler is underpressure, feedwater shall not be introducedthrough the openings or connections used for

249

the water column, the water gage glass, orthe gage cocks. In closed systems the watermay be introduced through any openingwhen the boiler is not under pressure.

PFT-49 BLOWOFF PIPING

49.1 Blowoff piping of firetube boilers whichare exposed to products of combustion shallbe attached by screwing into a tappedopening with a screw fitting or valve at theother end.

49.2 Blowoff piping of firetube boilers whichare not exposed to products of combustionmay be attached by any method provided inthis Section except by expanding into groovedholes.

49.3 The bottom blowoff pipes of traction andportable boilers shall have at least one slowor quick-opening blowoff valve or cockconforming to the requirements of PG-59.5.3.3.


250


FIGURE A-1 — Example of Lap Joint,Longitudinal or Circumferential, SingleRiveted

P

APPENDIX — EXPLANATORY OF THE CODE AND CONTAINING MATTERWHICH IS NOT MANDATORY UNLESS SPECIFICALLY REFERRED

TO IN THE RULES OF THE CODE

EFFICIENCY OF JOINTS

A-1 EFFICIENCY OF RIVETEDJOINTS

The ratio which the strength of a unit lengthof a riveted joint has to the same unit lengthof the solid plate is known as the efficiencyof the joint and shall be calculated by thegeneral method illustrated in the followingexamples:

TS =tensile strength stamped on plate,pounds per square inch

t = thickness of plate, inchesb = thickness of buttstrap, inchesP = pitch of rivets, inches, on row hav-

ing greatest pitchd = diameter of rivet after driving,

inches= diameter of rivet hole

a = cross-sectional area of rivet afterdriving, square inches

s = shearing strength of rivet in singleshear, pounds per square inch, asgiven in PG-23.2

S = shearing strength of rivet in doubleshear, pounds per square inch, asgiven in PG-23.2

c = crushing strength of mild steel,pounds per square inch, as given inPG-23.3

n = number of rivets in single shear in aunit length of joint

N = number of rivets in double shear ina unit length of joint

A-2 EXAMPLE

Lap joint, longitudinal or circumferential,single riveted.

A= strength of solid plate = P x t x TSB = strength of plate between rivet holes

(P - d) t x TS

C= shearing strength of one rivet insingle shear = n x s x a

D= crushing strength of plate in frontof a rivet = d x t x c

Divide B, C, or D (whichever is the least) byA, and the quotient will be the efficiency of asingle-riveted lap joint as shown in FigureA-1.

TS= 55,000 psit = 1/4 in. = 0.25 in.P = 1-5/8 in. = 1.625 in.d = 11/16 in. = 0.6875 in.a = 0.3712 sq. in.s = 44,000 psic = 95,000 psiA = 1.625 x 0.25 x 55,000 = 22,343B = (1.625 - 0.6875)0.25 x 55,000 = 12,890C = 1 x 44,000 x 0.3712 = 16,332D = 0.6875 x 0.25 x 95,000 = 16,328

12,890(B) = 0.576 = efficiency of joint

22,343(A)

A-3 EXAMPLE

Lap joint, longitudinal or circumferential,double riveted.

251

FIGURE A-2 — Example of Lap Joint,Longitudinal or Circumferential, DoubleRiveted

P

FIGURE A-3 — Example of Butt- andDouble-Strap Joint, Double Riveted

P


(P - d) t x TSC= shearing strength of two rivets in

single shear = n x s x aD= crushing strength of plate in front

of two rivets = n x d x t x c

Divide B, C, or D (whichever is the least) byA, and the quotient will be the efficiency of adouble-riveted lap joint as shown in FigureA-2.

TS= 55,000 psit = 5/16 in. = 0.3125 in.P = 2 7/8 in. = 2.875 in.d = 3/4 in. = 0.75 in.a = 0.4418 sq. in.s = 44,000 psic = 95,000 psiA = 2.875 x 0.3125 x 55,000 = 49,414B = (2.875 - 0.75) 0.3125 x 55,000 = 36,523C = 2 x 44,000 x 0.4418 = 38,878D = 2 x 0.75 x 0.3125 x 95,000 = 44,531


49,414(A)

A-4 EXAMPLE

Butt- and double-strap joint, double riveted.

A= strength of solid plate = P x t x TS

B = strength of plate between rivet holesin the outer row = (P - d) t x TS

C= shearing strength of two rivets indouble shear, plus the shearingstrength of one rivet in single shear= N x S x a + n x s x a

D= strength of plate between rivet holesin the second row, plus the shear-ing strength of one rivet in singleshear in the outer row = (P - 2d) t xTS + n x s x a

E = strength of plate between rivetholes in the second row, plus thecrushing strength of buttstrap infront of one rivet in the outer row =(P - 2d) t x TS + d x b x c

F = crushing strength of plate in frontof two rivets, plus the crushingstrength of buttstrap in front of onerivet = N x d x t x c + n x d x b x c

G= crushing strength of plate in frontof two rivets, plus the shearingstrength of one rivet in single shear= N x d x t x c + n x s x a

H = strength of buttstraps between rivetholes in the inner row = (P - 2d) 2b xTS. This method of failure is notpossible for thicknesses ofbuttstraps required by these rulesand the computation need only bemade for old boilers in which thinbuttstraps have been used. For thisreason this method of failure willnot be considered in other joints.


252


FIGURE A-4 — Example of Butt- andDouble-Strap Joint, Triple Riveted

P

Divide B, C, D, E, F, G, or H (whichever isthe least) by A, and the quotient will be theefficiency of a butt- and double-strap joint,double riveted, as shown in Figure A-3.

TS= 55,000 psit = 3/8 in. = 0.375 in.b = 5/16 in. = 0.3125 in.P = 4-7/8 in. = 4.875 in.d = 7/8 in. = 0.875 in.a = 0.6013 sq. in.s = 44,000 psiS = 88,000 psic = 95,000 psi

Number of rivets in single shear in a unitlength of joint = 1.

Number of rivets in double shear in a unitlength of joint = 2.

A= 4.875 x 0.375 x 55,000 = 100,547B = (4.875 - 0.875)0.375 x 55,000 = 82,500C= 2 x 88,000 x 0.6103 + 1 x 44,000 x

0.6013 = 132,286D= (4.875 - 2 x 0.857) 0.375 x 55,000 + 1 x

44,000 x 0.6013 = 90,910E = (4.875 - 2 x 0.875) 0.375 x 55,000 +

0.875 x 0.3125 x 95,000 = 90,499F = 2 x 0.875 x 0.375 x 95,000 + 1 x 0.875

x 0.3125 x 95,000 = 88,320G= 2 x 0.875 x 0.375 x 95,000 + 1 x 44,000

x 0.6013 = 88,800


100,547(A)

A-5 EXAMPLE

Butt- and double-strap joint, triple riveted.

A = strength of solid plate = P x t x TSB = strength of plate between rivet holes

in the outer row = (P - d)t x TSC = shearing strength of four rivets in

double shear, plus the shearingstrength of one rivet in single shear= N x S x a + n x s x a

D = strength of plate between rivet holesin the second row, plus the shear-

ing strength of one rivet in singleshear in the outer row = (P - 2d)t xTS + n x s x a

E = strength of plate between rivetholes in the second row, plus thecrushing strength of buttstrap infront of one rivet in the outer row =(P - 2d)t x TS + d x b x c

F = crushing strength of plate in frontof four rivets, plus the crushingstrength of buttstrap in front of onerivet = N x d x t x c + n x d x b x c

G = crushing strength of plate in frontof four rivets, plus the shearingstrength of one rivet in single shear= N x d x t x c + n x s x a

Divide B, C, D, E, F, or G (whichever is theleast) by A, and the quotient will be the

253

FIGURE A-5 — Example of Butt- and Double-Strap, Quadruple Riveted

P

efficiency of a butt- and double-strap joint,triple riveted as shown in Figure A-4.

TS= 55,000 psit = 3/8 in. = 0.375 in.b = 5/16 in. = 0.3125 in.P = 6-1/2 in. = 6.5 in.d = 13/16 in. = 0.8125 in.a = 0.5185 sq. in.s = 44,000 psiS = 88,000 psic = 95,000 psi



A= 6.5 x 0.375 x 55,000 = 134,062B = (6.5 - 0.8125) 0.375 x 55,000 = 117,304C= 4 x 88,000 x 0.5185 + 1 x 44,000 x

0.5185 = 205,326D= (6.5 - 2 x 0.8125) 0.375 x 55,000 + 1 x

44,000 x 0.5185 = 123,360E = (6.5 - 2 x 0.8125)0.375 x 55,000 +

0.8125 x 0.3125 x 95,000 = 124,667F = 4 x 0.8125 x 0.375 x 95,000 + 1 x

0.8125 x 0.3125 x 95,000 = 139,902G= 4 x 0.8125 x 0.375 x 95,000 + 1 x

44,000 x 0.5185 = 138,595


134,062(A)

A-6 EXAMPLE

Butt- and double-strap joint, quadrupleriveted.


in the outer row = (P - d)t x TSC= shearing strength of eight rivets in

double shear, plus the shearingstrength of three rivets in singleshear = N x S x a + n x s x a

D= strength of plate between rivet holesin the second row, plus the shear-ing strength of one rivet in single

shear in the outer row = (P - 2d)t xTS + 1 x s x a

E = strength of plate between rivet holesin the third row, plus the shearingstrength of two rivets in the secondrow in single shear and one rivet insingle shear in the outer row = (P -4d)t x TS + n x s x a

F = strength of plate between rivet holesin the second row, plus the crush-ing strength of buttstrap in front ofone rivet in the outer row = (P - 2d)tx TS + d x b x c

G= strength of plate between rivet holesin the third row, plus the crushingstrength of buttstrap in front of tworivets in the second row and onerivet in the outer row = (P - 4d)t xTS + n x d x b x c


254


H = crushing strength of plate in frontof eight rivets, plus the crushingstrength of buttstrap in front of threerivets = N x d x t x c + n x d x b x c

I = crushing strength of plate in frontof eight rivets, plus the shearingstrength of two rivets in the secondrow and one rivet in the outer row,in single shear = N x d x t x c + n x sx a

Divide B, C, D, E, F, G, H, or I (whichever isthe least) by A, and the quotient will be theefficiency of a butt- and double-strap joint,quadruple riveted, as shown in Figure A-5.

TS= 55,000 psit = 1/2 in. = 0.5 in.b = 7/16 in. = 0.4375 in.P = 15 in.d = 15/16 in. = 0.9375 in.a = 0.6903 sq. in.s = 44,000 psiS = 88,000 psic = 95,000 psi



A= 15 x 0.5 x 55,000 = 412,500B = (15 - 0.9375)0.5 x 55,000 = 386,718C= 8 x 88,000 x 0.6903 + 3 x 44,000 x

0.6903 = 577,090D= (15 - 2 x 0.9375)0.5 x 55,000 + 1 x

44,000 x 0.6903 = 391,310E = (15 - 4 x 0.9375)0.5 x 55,000 + 3 x

44,000 x 0.6903 = 400,494F = (15 - 2 x 0.9375)0.5 x 55,000 + 0.9375

x 0.4375 x 95,000 = 399,902G= (15 - 4 x 0.9375) 0.5 x 55,000 + 3 x

0.9375 x 0.4375 x 95,000 = 426,269H = 8 x 0.9375 x 0.5 x 95,000 + 3 x 0.9375

x 0.4375 x 95,000 = 473,145I = 8 x 0.9375 x 0.5 x 95,000 + 3 x 44,000

x 0.6903 = 447,369


412,500(A)

A-7

Figure A-6 and A-7 illustrate other joints thatmay be used in which eccentric stresses areavoided. The butt- and double-strap jointwith straps of equal width shown in FigureA-6 may be so designed that it will have anefficiency of from 82 to 84 percent and thesawtooth joint shown in Figure A-7 so that itwill have an efficiency of from 92 to 94percent.

BRACED AND STAYED SURFACES

A-8

The allowable loads based on the net cross-sectional area of staybolts with V-threads arecomputed from the following formulas. Theuse of Whitworth threads with other pitchesis permissible.

The formula for the diameter of a staybolt atthe bottom of a V-thread is:

D - (P x 1.732) = d

where,D = diameter of staybolt over the

threads, inchesP = pitch of threads, inches = 1/number

of threads per inchd = diameter of staybolt at bottom of

threads, inches1.732 = a constant

When ANSI Standard threads are used theformula becomes

D - (P x 1.732) = d

Tables A-1 and A-2 give the allowable loadson net cross-sectional areas for staybolts withV-threads having 12 and 10 threads per in.

A-9

Table A-3 shows the allowable loads on netcross-sectional areas of round stays or braces.

255

FIGURE A-7 — Illustration of Butt- andDouble-Strap Joint of the Sawtooth Type

FIGURE A-6 — Illustration of Butt- andDouble-Strap Joint with Straps of EqualWidth

TABLE A-1 — Allowable Loads on Staybolts with V Threads, 12 ThreadsPer Inch

Outside diameter Diameter at Net Cross-Sectional Allowable Loadof Staybolts, in. Bottom of Area (at Bottom at 7500 lb

Thread, in. of Thread). sq. in. Stress per sq. in.

3/4 0.7500 0.6057 0.288 216013/16 0.8125 0.6682 0.351 26327/8 0.8750 0.7307 0.419 3142

15/16 0.9375 0.7932 0.494 37051 1.0000 0.8557 0.575 43121-1/16 1.0625 0.9182 0.662 4965

1-1/8 1.1250 0.9807 0.755 56621-3/16 1.1875 1.0432 0.855 61421-1/4 1.2500 1.1057 0.960 7200

1-5/16 1.3125 1.1682 1.072 80401-3/8 1.3750 1.2307 1.190 89251-7/16 1.4375 1.2932 1.313 98491-1/2 1.5000 1.3557 1.444 10830


256


TABLE A-2 — Allowable Loads on Staybolts with V Threads, 10 ThreadsPer Inch

Outside diameter Diameter at Net Cross-Sectional Allowable Loadof Staybolts, in. Bottom of Area (at Bottom at 7500 lb

Thread, in. of Thread). sq. in. Stress per sq. in.

1-1/4 1.2500 1.0768 0.911 68321-5/16 1.3125 1.1393 1.019 76421-3/8 1.3750 1.2018 1.134 85051-7/16 1.4375 1.2643 1.255 94121-1/2 1.5000 1.3268 1.382 103651-9/16 1.5625 1.3893 1.515 113621-5/8 1.6250 1.4518 1.655 12412

TABLE A-3 — Allowable Loads on Round Braces or Stay Rods

Allowable stress, in psi, on Net Cross-Sectional Area

Minimum Diameter of Net Cross-Sectional 6000 8500 9500Circular Stay, in. Area of Stay, sq. in.

Allowable load, in lb., on Net Cross-Sectional Area

1 1.0000 0.7854 4712 6676 74621-1/16 1.0625 0.8866 5320 7536 84231-1/8 1.1250 0.9940 5964 8449 9443

1-3/16 1.1875 1.1075 6645 9414 105211-1/4 1.2500 1.2272 7363 10431 116581-5/16 1.3125 1.3530 8118 11501 12854

1-3/8 1.3750 1.4849 8909 12622 141071-7/16 1.4375 1.6230 9738 13796 154191-1/2 1.5000 1.7671 10603 15020 16787

1-9/16 1.5625 1.9175 11505 16298 182161-5/8 1.6250 2.0739 12443 17628 197021-11/16 1.6875 2.2365 13419 19010 21247

1-3/4 1.7500 2.4053 14432 20445 228521-13/16 1.8125 2.5802 15481 21932 245121-7/8 1.8750 2.7612 16567 23470 26231

1-15/16 1.9375 2.9483 17690 25061 280092 2.0000 3.1416 18850 26704 298452-1/8 2.1250 3.5466 21280 30147 33693

2-1/4 2.2500 3.9761 23857 33797 377732-3/8 2.3750 4.4301 26580 37656 420862-1/2 2.500 4.9087 29452 41724 46632

2-5/8 2.6250 5.4119 32471 46001 514132-3/4 2.7500 5.9396 35638 50487 564262-7/8 2.8750 6.4918 38951 55181 616733 3.0000 7.0686 42412 60083 67152

257

TABLE A-4 — Net Areas of Segments of Heads Where d, as Given in PFT-31.1 andPFT-31.3 is Equal t0o 3 inches

Height From Diameter of Boiler, in.Tubes to Shell, 24 30 36 42 48 54 60 66 72 78 84 90 96in. Area to Be Stayed, sq. in.

8 28 33 37 40 43 47 51 53 55 58 60 63 658-1/2 35 41 46 51 55 59 63 66 70 74 76 80 829 42 49 56 62 67 72 76 82 86 90 92 95 989-1/2 50 58 66 70 80 86 91 96 101 105 111 116 11910 57 68 77 85 93 99 106 112 117 123 129 132 137

10-1/2 66 78 89 98 107 114 123 131 135 142 147 153 16011 74 88 100 111 121 130 138 147 155 161 169 174 18311-1/2 83 99 112 124 137 146 156 165 173 181 189 196 20412 91 109 125 139 151 163 174 184 194 203 213 219 23012-1/2 ... 120 138 153 167 180 193 204 216 224 234 243 252

13 ... 132 151 168 183 197 211 224 235 247 256 267 27913-1/2 ... 143 164 183 200 216 230 246 258 270 282 293 30214 ... 155 178 199 217 234 250 266 280 294 305 319 33114-1/2 ... 167 192 215 235 254 271 287 303 318 333 345 36015 ... 178 206 231 252 273 291 309 326 343 357 372 386

15-1/2 ... ... 220 247 271 291 312 332 350 368 382 400 41716 ... ... 235 263 289 312 334 355 374 394 411 423 44316-1/2 ... ... 249 281 308 332 357 380 399 420 436 457 47517 ... ... 264 297 326 353 378 402 425 447 467 486 50217-1/2 ... ... ... 314 345 374 400 426 449 471 494 516 536

18 ... ... ... 331 365 396 424 450 476 500 520 543 56418-1/2 ... ... ... 349 384 417 448 476 501 526 552 577 59819 ... ... ... 366 404 439 470 500 529 555 580 604 63119-1/2 ... ... ... 384 424 461 496 528 558 584 613 641 66320 ... ... ... 401 444 483 519 552 583 613 642 667 699

20-1/2 ... ... ... ... 464 505 543 578 613 643 675 706 72921 ... ... ... ... 485 528 568 604 640 673 705 733 76621-1/2 ... ... ... ... 505 551 594 632 669 703 739 766 79722 ... ... ... ... 526 574 618 658 697 734 769 800 83522-1/2 ... ... ... ... ... 597 643 687 726 765 800 835 867

23 ... ... ... ... ... 620 668 713 754 796 830 869 90623-1/2 ... ... ... ... ... 642 695 740 784 827 866 904 94524 ... ... ... ... ... 667 719 768 814 859 897 939 97824-1/2 ... ... ... ... ... 689 745 797 843 892 934 975 101825 ... ... ... ... ... 714 771 825 875 922 966 1010 1051

25-1/2 ... ... ... ... ... 737 798 855 907 956 1003 1047 109226 ... ... ... ... ... 761 824 882 936 987 1035 1083 112626-1/2 ... ... ... ... ... ... 850 909 968 1024 1073 1120 116727 ... ... ... ... ... ... 877 939 998 1053 1106 1157 120227-1/2 ... ... ... ... ... ... 904 968 1030 1089 1145 1195 1243

28 ... ... ... ... ... ... 930 997 1060 1120 1177 1232 127928-1/2 ... ... ... ... ... ... ... 1028 1092 1157 1211 1270 132129 ... ... ... ... ... ... ... 1056 1123 1187 1248 1305 136029-1/2 ... ... ... ... ... ... ... 1084 1155 1221 1284 1347 140030 ... ... ... ... ... ... ... 1115 1187 1255 1321 1382 1442

30-1/2 ... ... ... ... ... ... ... ... 1218 1290 1358 1424 148031 ... ... ... ... ... ... ... ... 1252 1324 1394 1459 152331-1/2 ... ... ... ... ... ... ... ... 1286 1359 1433 1496 156132 ... ... ... ... ... ... ... ... 1317 1394 1467 1538 165032-1/2 ... ... ... ... ... ... ... ... ... 1430 1508 1575 1650

33 ... ... ... ... ... ... ... ... ... 1465 1542 1617 168733-1/2 ... ... ... ... ... ... ... ... ... 1500 1578 1655 173334 ... ... ... ... ... ... ... ... ... 1536 1617 1695 177034-1/2 ... ... ... ... ... ... ... ... ... ... 1654 1735 181635 ... ... ... ... ... ... ... ... ... ... 1692 1775 1856

35-1/2 ... ... ... ... ... ... ... ... ... ... ... 1810 190036 ... ... ... ... ... ... ... ... ... ... ... 1857 194136-1/2 ... ... ... ... ... ... ... ... ... ... ... ... 198437 ... ... ... ... ... ... ... ... ... ... ... ... 2026


258


A-10

Table A-4 gives the net areas of segments ofheads for use in computing stays.

259

Appendix D

Recommended Guide for the Designof a Test System for Pressure Relief Devicesin Compressible Fluid Service

260


APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OFA TEST SYSTEM FOR PRESSURE RELIEF DEVICES IN

COMPRESSIBLE FLUID SERVICE

INTRODUCTION

This non-mandatory appendix providesguidance for the design of a test system us-ing compressible fluids (i.e., steam or air/gas)and permits the determination of pressurerelief valve set pressure and valve operatingcharacteristics such as blowdown. The sizeof the test vessel needed depends on the sizeof the valve, its set pressure, the design of thetest system, and whether blowdown must bedemonstrated. A repair organization may usethe information provided in this appendix todetermine the minimum size test vesselneeded so that the measured performance ischaracteristic of the valve and not the testsystem.

PART I GENERAL

1. The National Board administrative rulesand procedures for the “VR” Certificateof Authorization and symbol stamprequire that pressure relief valves, afterrepair, be tested in accordance with themanufacturer’s recommendations andthe applicable ASME Code section. Thepurpose of this testing is to providereasonable assurance that valves willperform according to design when theyare returned to service.

2. It is recognized that a full evaluationof the performance of some pressurerelief valve designs requires testing atmaximum allowable overpressure.However, it is beyond the scope of thisappendix to define test equipment orfacilities for such testing.

3. Part II below provides a glossary, Part IIIdescribes typical test equipment, and PartIV provides data for estimating the sizeof test vessels required.

PART II GLOSSARY

1. Accumulator: A vessel in which the testmedium is stored or accumulated priorto its use for testing.

2. Transient: A very short time, occurringover a brief time interval, maintained onlyfor a short time interval as opposed to asteady state.

3. Velocity distortion: The pressure decreasethat occurs when fluid flows past theopening of a pressure sensing line. Thisis a distortion of the pressure that wouldbe measured under the same conditionsfor a non or slowly moving fluid.

4. Intervening: Coming between or insertedbetween, as between the test vessel andthe valve being tested.

5. Water head: The pressure adjustment thatmust be taken into account due to theweight of test media (in this case, steam)that is .433 psi per foot added (subtracted)from the gage pressure for each foot thegage is below (above) the point at whichthe pressure is to be measured.

PART III TEST SYSTEMDESCRIPTION

1. An optimum configuration, particularlywhen the test medium source is of smallcapacity, is shown in Figure 1. The testmedium flows from the pressure source,usually a compressor or boiler, to anaccumulator. It then flows through apressure-controlling valve into the testvessel, from which it is discharged,through the pressure relief valve mountedon the test vessel. The pressure control-ling valve is usually a globe valve,

261

APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FORPRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE

although any throttling valve isacceptable. If the pressure controllingvalve is of adequate size and can openquickly, large transient flows can begenerated, increasing the pressure abovethe pressure relief valve set pressure,causing it to lift, and be sustained in itslifted condition.

2. Figure 2 shows a simpler test system inwhich the test vessel is pressurizeddirectly from the pressure source withoutthe use of an accumulator. In this configu-ration, flow-rates through the pressurerelief valve and any consequent over-pressure are dependent on the flowgenerating capacity of the pressuresource.

3. In a test facility, the pressure relief valveis usually mounted on an isolating valvewhich should be of sufficient size that itwill not choke flow to the pressure reliefvalve. There should be no interveningpiping between the two (2) valves toavoid any unnecessary pressure drop be-tween the test vessel and the pressure re-lief valve.

4. The isolating valve and any adapterflanges or valve test nozzles must bedesigned to sustain pressure relief valvedischarge forces, and so secured that theseforces cannot be transmitted to the testvessel. This is especially important forlarger valves set at pressures greater than100 psig.

5. The vessel should have a length-to-diam-eter ratio as low as is practical, and shouldbe suitably anchored.

6. Pressure sensing lines should beconnected to the test vessel well awayfrom any inlet or outlet connections wheretransient flow velocity during testingcould cause erroneous pressure readings.When testing with steam, any water headwhich develops in the gage line must betaken into consideration.

7. Any intervening piping between thetest vessel and the pressure relief valveshould be as short and as straight as pos-sible and be of adequate size to minimizeinlet pressure drop.

8. In the case of steam, the equipmentshould be insulated and steam trapsshould be installed, as appropriate, toensure that the test steam is dry, saturatedsteam with a minimum quality of 98%.

9. Safety valves should be used to protectthe test vessel and the accumulator.

PART IV TEST VESSEL SIZING DATA

1. Recommended test vessel sizes are givenin Figures 3 and 4 for a configurationusing one vessel fed directly from thesource of the test medium. Figure 3 givesthe test vessel size in cubic feet vs. thevalve orifice area in square inches for dry,saturated steam. Curves are shown for setpressures up to 500 psig for three (3) dif-ferent blowdowns: 4%, 7% and 10%. Thesource is assumed to be capable of feed-ing the test vessel at 2500 lbs/hr.Figure 4 gives similar curves for air witha source capable of feeding the test vesselat 200 SCFM.

2. For smaller valves, with effective orificesless than 1.28 square inches, the size ofthe test vessel needed becomes less de-pendent on the flow capacity of thesource. For these valves, a 15 cubic feetminimum size test vessel is recom-mended. This should allow the accuratemeasurement and setting of blowdownfor small valves. This minimum sizeshould also be adequate for determiningset pressures of larger valves; however,larger test vessels must be used ifblowdown is to be set accurately. It is rec-ognized that there are practical limits onthe size and maximum pressure of a testvessel used to demonstrate pressure re-lief valve operational characteristics. In

262


such cases, determination of valve setpressure remains the only viable produc-tion and repair test option. The recom-mended minimum size test vessel(15 cubic feet) should be adequate for thispurpose.

263

Test Vessel

TestMediumSource

GagesBlock Valveand Bypass

Control Valveand Bypass

Drain Trap

Test Valve

FIGURE 2 — Schematic of Test Equipment without Accumulator

TestMediumSource

Accumulator

Test Vessel

FIGURE 1 — Schematic of Test Equipment with Accumulator

GagesBlock Valveand Bypass

Test Valve

TrapDrain

Control Valveand Bypass

TrapDrain

APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FORPRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE

264


300

250

200

150

100

50

00 5 10 15 20 25 30 35

VALVE FLOW AREA (SQ. IN.)

VALVE FLOW AREA (SQ. IN.)

250

200

150

100

50

00 5 10 15 20 25 30 35

VE

SSE

L SI

ZE

(CU

. FT.

)V

ESS

EL

SIZ

E (C

U. F

T.)

FIGURE 3 — Recommended Test Vessel SizeTest Medium: Steam

FIGURE 4 — Recommended Test Vessel SizeTest Medium: Air or Gas

•■

4% B

lowdown

10% Blowdown7% Blowdown

7% Blowdown

10% Blowdown

▼

■

•

▼

■

•

•■

265

Recommended Procedures forRepairing Pressure Relief Valves

Appendix E

266


APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRINGPRESSURE RELIEF VALVES

INTRODUCTIONIt is essential that the repair organizationestablish basic, specific procedures for therepair of pressure relief valves. The purposeof these recommended procedures is to pro-vide the repair organization with guidelinesfor this important aspect of valve repair. It isrealized that there are many various types ofvalves and conditions under which they arerepaired and, for this reason, the specificitems in these recommended procedures maynot apply, or they may be inadequate for eachof those types or to the detailed repairs whichmay be required for each valve. SeeRA-2256(i).

Part I contains recommended procedures forthe repair of spring loaded pressure reliefvalves and Part II contains recommendedprocedures for the repair of pilot operatedtypes of safety relief valves.

PART I SPRING LOADEDPRESSURE RELIEF VALVES

Note 1: Prior to removal of a valve from a sys-tem for a repair or any disassembly, ensurethat all sources of pressure have been re-moved from the valve.

1. Visual Inspection as ReceivedThis information is to be recorded:

a. Record user (customer) identificationnumber.

b. Complete nameplate data, plus anyimportant information received fromcustomer.

c. Check external adjustment seals forwarranty repair.

d. Check bonnet for venting on bellowtype valves.

e. Check appearance for any unusualdamage, missing or misapplied parts.

Note 2: If sufficient damage or other unusualconditions are detected that may pose a safetyrisk during preliminary testing, then proceeddirectly to step three.

Note 3: Valves which are to be repaired inplace proceed to step 3, unless preliminarytesting has been authorized by the owner.

2. Preliminary Test as ReceivedInformation from the recommended prelimi-nary performance test and subsequent disas-sembly and inspections will provide a basisfor any repair interval change which may benecessary to ensure that the valve will func-tion as intended.

a. Determine set pressure or Cold Dif-ferential Test Pressure (CDTP) in ac-cordance with manufacturer’s recom-mendations and appropriate ASMECode Section. Do not allow test pres-sure to exceed 116% of set pressureunless otherwise specified by theowner. A minimum of three tests isusually required to obtain consistentresults.

Note 4: If results do not correlate with fieldperformance, then steps to duplicate fieldconditions (fluid and temperature) may benecessary.

b. Record preliminary test results andtest bench identification data.

3. Disassembly

a. Remove cap and lever assembly, ifapplicable.

b. Remove release nut assembly, if ap-plicable.

267

APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES

c. Loosen jam nut on adjusting (com-pression) screw.

d. Record measurement and removeadjusting (compression) screw.

e. Remove bonnet or yoke.

f. Remove spring and washers, and tag(identify) including upper and lowerwashers, as appropriate.

g. Remove spindle and disk assembly.

h. Remove ring pins.

i. Record measurement and removeadjusting rings, nozzle and guide, asapplicable.

4. Cleaninga. Wire all small parts together and clean

by means of an abrasive (caution: donot use a cleaning method that willdamage the parts.)

b. Do not clean in a chemical solutionexcept under acceptable circum-stances.

c. Protect seating surfaces and name-plates prior to cleaning.

5. Inspectiona. Check spring for damage such as

erosion, corrosion, cracking, breakageor compression below free height.

b. Check nozzle for cracks (NDE asapplicable) or unusual wear.

c. Check disk assembly for cracks (NDEas applicable) or unusual wear.

d. Check spindle for trueness, bearingareas and thread condition.

e. Check guide for wear and galling.

f. Check adjusting ring(s) for wornthreads and wear.

g. Check ring pins for bent or broken pinand thread condition.

h. Check bellows, if provided, for pin-holes and corrosion.

i. Check flange gasket facings for wearand cuts.

6. MachiningMachine nozzle and disk as necessary tothe manufacturer’s critical dimensioncharts.

7. Lappinga. Machine or hand lap disk and nozzle

to be sure of flatness.

b. Lap bevel seats to a grey finish; thenremachine disk or plug to the manu-facturer’s critical dimension.

8. Adjusting RingsInstall lower ring and guide ring to thesame position they were when removed,or to manufacturer’s specifications.

9. Bearing PointsGrind all bearing areas with grindingcompound to make sure they are roundand true.

10. TestingAll test data is to be recorded. Testing willbe done in accordance with manu-facturer’s recommendations and appro-priate ASME Code section. To precludeunsafe and unstable valve operations orerroneous performance test results, it isrecommended that low volume testingequipment (e.g., gas cylinders without atest vessel, hand pumps, tubing, etc.)should be avoided.

11. SealingAfter final adjusting and acceptance byquality control inspection, all externaladjustments will be sealed with a safety

268


seal providing a means of identificationof the organization performing the repair.

12. NameplateThe repairer will place a repair nameplateon each repaired valve. The nameplateshall, as a minimum, meet the require-ments of RA-2260.

PART II PILOT OPERATED SAFETYRELIEF VALVES

1. Visual Inspection as ReceivedThis information is to be recorded:

a. Complete nameplate data, plus anyother important information receivedfrom the customer.

b. User identification number, if appli-cable.

c. Seals on external adjustment (yes/no).

d. Identification on seal.

e. Obvious damage and external condi-tion including missing or misappliedparts.

2. Disassemblya. Remove pilot and disassemble per

manufacturer’s maintenance instruc-tion.

b. Disassemble main valve. Where liftadjustments are provided, do notremove the locking device or changethe lift.

c. Remove the nozzle if recommendedby the manufacturer’s maintenanceinstructions.

3. Cleaninga. Pilot – Components of pilot are small

and must be handled carefully to pre-vent damage or loss. Clean parts and

nameplates with solvents which willnot affect the parent metal and/orpolish with 500 grit paper.

b. Main Valve – Clean by appropriatemeans such as abrasive blast. Finishesof machined surfaces must not beaffected. (Caution: Do not use a clean-ing method that will damage the partsor nameplates.)

4. Inspectiona. Pilot

1. Check spring for damage such ascorrosion, cracks, out of squareends, etc.

2. Inspect all parts for damage. Smallburrs or scratches may be removedby polishing. Severely damagedparts should be replaced. (Internalcomponents or pilots should not berepaired by machining as the func-tions of the pilot could easily beimpaired.)

3. Check strainers on inlet and outletlines.

4. Replace all soft goods per manu-facturer’s recommendation.

b. Main Valve

1. Check nozzle seating surface fornicks. These can be removed bymachining or lapping as required.

2. Check the piston and liner (orother moving member) for gallingor excessive wear. The pistonshould move freely in the liner.

3. Replace soft goods or relap diskas required.

5. TestingAll test data is to be recorded. Testingwill be done in accordance with the

269

APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES

manufacturer’s recommendation andin accordance with the applicable ASMECode section. To preclude unsafe andunstable valve operations or erroneousperformance test results, it is recom-mended that low volume testing equip-ment (e.g., gas cylinders without a testvessel, hand pumps, tubing, etc.) shouldbe avoided.

6. SealingAfter final adjustment and acceptance byquality control, all external adjustmentswill be sealed by means assuring positiveidentification of the organization per-forming the repair.

7. NameplateThe repairer will place a repair nameplateon each repaired valve. The nameplate,as a minimum, shall meet the require-ments of RA-2260.

270


271

Appendix F

Pressure Differential Between Safety orSafety Relief Valve Setting and Boiler orPressure Vessel Operating Pressure

272


APPENDIX F — PRESSURE DIFFERENTIAL BETWEEN SAFETY ORSAFETY RELIEF VALVE SETTING AND BOILER OR

PRESSURE VESSEL OPERATING PRESSURE

SCOPE

If a safety valve or safety relief valve issubjected to pressure at or near its set pres-sure, it will tend to weep or simmer, anddeposits may accumulate in the seat and diskarea. Eventually, this can cause the valve tofreeze close and thereafter the valve could failto open at the set pressure. Unless the sourceof pressure to the boiler or pressure vessel isinterrupted, the pressure could exceed therupture pressure of the vessel.

It is important that the pressure differentialbetween the valve set pressure and the boileror pressure vessel operating pressure is suf-ficiently large to prevent the valve from weep-ing or simmering.

I. HOT WATER HEATINGBOILERS

For hot water heating boilers, the recom-mended pressure differential between thepressure relief valve set pressure and theboiler operating pressure should be at least10 psi (0.69 bar), or 25% of the boiler operat-ing pressure, whichever is greater.

Two examples follow:a. If the safety relief valve of a hot water

heating boiler is set to open at 30 psi (2.07bar), the boiler operating pressure shouldnot exceed 20 psi (1.34 bar).

b. If the safety relief valve of a hot waterheating boiler is set to open at 100 psi (6.90

bar), the boiler operating pressure shouldnot exceed 75 psi (5.17 bar).

Section IV of the ASME Code does not requirethat safety relief valves used on hot waterheating boilers have a specified blowdown.Therefore, to help ensure that the safety re-lief valve will close tightly after opening andwhen the boiler pressure is reduced to thenormal operating pressure, the pressure atwhich the valve closes should be well abovethe operating pressure of the boiler.

II. STEAM HEATING BOILERS

For steam heating boilers, the recommendedpressure differential between the safety valveset pressure and boiler operating pressureshould be at least 5 psi (0.35 bar), i.e., theboiler operating pressure should not exceed10 psi (0.69 bar).

Since some absorption-type refrigeration sys-tems use the steam heating boiler for their op-eration, the boiler operating pressure mayexceed 10 psi (0.69 bar). If, the boiler operat-ing pressure is greater than 10 psi (0.69 bar),it should not exceed 15 psi (1.03 bar), minusthe blowdown pressure of the safety valve.

This recommendation can be verified byincreasing the steam pressure in the boileruntil the safety valve pops, then slowlyreducing the pressure until it closes, to en-sure that this closing pressure is above theoperating pressure.

273

APPENDIX F — PRESSURE DIFFERENTIAL BETWEEN SAFETY OR SAFETY RELIEF VALVE SETTINGAND BOILER OR PRESSURE VESSEL OPERATING PRESSURE

III. POWER BOILERS

For power boilers (steam), the recommended pressure differentials between the safety valveset pressure and the boiler operating pressure are as follows:

MINIMUM PRESSURE DIFFERENTIAL ASPERCENTAGE OF BOILER DESIGN PRESSURE

DESIGN PRESSURE: over 15 psi to 300 psi (10 bar to 21 bar)10% but not less than 7 psi (0.5 bar)

over 300 psi to 1000 psi (21 bar to 69 bar)7% but not less than 30 psi (2.1 bar)

over 1000 psi to 2000 psi (69 bar to 138 bar)5% but not less than 70 psi (5 bar)

over 2000 psi (137.90 bar)per designer’s judgement

Notes: 1. Above 2000 psi (137.90 bar) the pressure differential between operating pressureand the maximum allowable working pressure is a matter for the designer’s judge-ment, taking into consideration such factors as satisfactory operating experience andthe intended service conditions .

2. Safety relief valves in hot water service are more susceptible to damage and sub-sequent leakage, than safety valves relieving steam. It is recommended that themaximum allowable working pressure of the boiler and safety relief valve setting forhigh-temperature hot water boilers be selected substantially higher than the desiredoperating pressure, so as to minimize the times the safety relief valve must lift.

IV. PRESSURE VESSELS

Due to the variety of service conditions andthe various designs of pressure relief valves,only general guidelines can be given regard-ing differentials between the set pressure ofthe valve and the operating pressure of thevessel. Operating difficulty will be minimizedby providing an adequate differential for theapplication. The following is general advisoryinformation on the characteristics of theintended service and of the pressure reliefvalves which may bear on the proper pres-sure differential selection for a given appli-cation. These considerations should be re-viewed early in the system design since theymay dictate the maximum allowable work-ing pressure of the system.

To minimize operational problems it isimperative that the user consider not onlynormal operating conditions of the fluids(liquids or gases), pressures, and tempera-tures but also start-up and shutdown condi-tions, process upsets, anticipated ambientconditions, instrument response time, pres-sure surges due to quick-closing valves, etc.When such conditions are not considered, thepressure relief devices may become, in effect,a pressure controller, a duty for which it wasnot designed. Additional considerationshould be given to the hazard and pollutionassociated with the release of the fluid. Largerdifferentials may be appropriate for fluidswhich are toxic, corrosive, or exceptionallyvaluable.

274


The blowdown characteristics and capabilityare the first consideration in selecting acompatible valve and operating margin.After a self-actuated release of pressure, thevalve must be capable of reclosing above thenormal operating pressure. For example: ifthe valve is set at 100 psi (6.89 bar) with a 7%blowdown, it will close at 93 psi (6.41 bar).The operating pressure must be maintainedbelow 93 psi (6.41 bar) in order to preventleakage or flow from a partially open valve.Users should exercise caution regarding theblowdown adjustment of large, spring-loaded valves. Test facilities, whether ownedby the manufacturer, repair house, or user,may not have sufficient capacity to accuratelyverify the blowdown setting. The setting can-not be considered accurate unless made in thefield on an actual installation.

Pilot operated valves represent a special casefrom the standpoint of both blowdown andtightness. The pilot portion of some pilotoperated valves can be set at blowdowns asshort as 2%. This characteristic is not, how-ever, reflected in the operation of the mainvalve in all cases. The main valve can varyconsiderably from the pilot depending on thelocation of the two components in the sys-tem. If the pilot is installed remotely from themain valve, significant time and pressure lagscan occur, but reseating of the pilot assuresreseating of the main valve. The pressure dropin connecting piping between the pilot andthe main valve must not be excessive, other-wise the operation of the main valve will beadversely affected.

Tightness capability is another factor affect-ing valve selection, whether spring-loaded orpilot operated. Tightness varies somewhat de-pending on whether metal or resilient seatsare specified and also on such factors as cor-rosion and temperature. The required tight-ness and test method should be specified tocomply at a pressure not lower than the nor-mal operating pressure of the process. Itshould be remembered that any degree oftightness obtained should not be consideredpermanent. Service operation of a valve al-most invariably reduces the degree of tight-ness.

The following minimum pressure differen-tials are recommended unless the safety orsafety relief valve has been designed or testedin a specific or similar service and a smallerdifferential has been recommended by themanufacturer:

a. for set pressures up to 70 psi (4.83 bar),the recommended pressure differential is5 psi (0.34 bar);

b. for set pressure between 70 and 1000 psi(4.83 and 68.95 bar), the recommendedpressure differential is 10% of set pres-sure;

c. for set pressures above 1000 psi (68.95bar), the recommended pressure differen-tial is 7% of set pressure.

275

Safety Valves on the Low-Pressure Sideof Steam Pressure Reducing Valves

Appendix G

276


APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDEOF STEAM PRESSURE REDUCING VALVES

I. SCOPE

The subject of protection of vessels in steamservice connected to the low pressure side ofa steam pressure reducing valve is of consid-erable importance to proper operation ofauxiliary equipment such as pressure cook-ers, hot water heating systems, etc., operat-ing at pressures below that which the primaryboiler generating unit is operating.

To automatically reduce the primary boilerpressure for such processing equipment, pres-sure reducing valves are used. The manufac-turers of such equipment have data availablelisting the volume of flow through reducingvalves manufactured by them, but such dataare not compiled in a form that the resultscan be deduced readily. To protect the equip-ment operating on the low pressure side of apressure reducing valve, safety valves of arelieving capacity sufficient to prevent anunsafe pressure rise in case of failure of thepressure reducing valve, should be installed.

The pressure reducing valve is a throttlingdevice, the design of which is based on cer-tain diaphragm pressures opposed by springpressure which, in turn, controls the openingthrough the valve. If the spring, thediaphragm, or any part of the pressure reduc-ing valve fails, steam will flow directlythrough the valve and the low pressure equip-ment will be subjected to the boiler pressure.To protect the equipment operating on thelow pressure side of the pressure reducingvalve, safety valve(s) should be installed onthe low pressure side of the pressure reduc-ing valve which will provide a relieving ca-pacity sufficient to prevent the pressure fromrising above the system design pressure.

In most cases pressure reducing valves usedfor the reduction of steam pressures have thesame pipe size on the inlet and outlet. In caseof failure of a pressure reducing valve, thesafety valve on the low pressure side musthave a capacity to take care of the volume of

steam determined by the high pressure sideand the area of the pipe.

II. INSTALLATION OF SAFETYVALVES

In most cases it is necessary to install morethan one safety valve on the low pressure sideof the pressure reducing valve. It is advisable,if the safety valves are connected to the pipeattached to the pressure reducing valve, thateach safety valve have a separate connectionto the pipe. It is not important that all thesafety valves be mounted on the pipelineconnecting the pressure reducing valve to theauxiliaries. Safety valves will be equallyeffective if they are attached to some of theauxiliaries provided the piping between thepressure reducing valve and the safety valveis of a size adequate for the maximum pres-sure, and there are no intervening stop valves.

III. SAFETY VALVE CAPACITY

a. The capacity of the safety valve(s) on thelow pressure side of the pressure reduc-ing valve should be based on the capac-ity of the pressure reducing valve whenwide open or under maximum flow con-ditions or the flow capacity through thebypass valve.

By using the formula in IV below, Inspec-tors may calculate the required relievingcapacities of the safety valve(s) installedon the low pressure side of the pressurereducing valve.

b. Usually a pressure reducing valve has abypass arrangement so that in case of fail-ure of the pressure reducing valve theboiler pressure may be short circuited intothe low pressure line without passingthrough the pressure reducing valve.When determining the required relievingcapacity of safety valves for the low pres-

277

APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE REDUCING VALVES

sure side of the pressure reducing valve,the steam flow through the bypass mustbe taken into consideration.

IV. CALCULATION OF SAFETYVALVE RELIEVING CAPACITY

When a pressure reducing valve is installed,there are two possibilities of introducingboiler pressure into the low pressure system:

a. the failure of the pressure reducing valveso that it remains wide open;

b. the possibility of the bypass valve beingopen.

It is necessary therefore, to determine the flowunder both circumstances (a) and (b) andcheck that the size of the safety valve undereither condition will be adequate. The follow-ing formula should be used:

a. steam flow, W in lbs/hr through thepressure reducing valve

W = AKCwhere,

A = internal area in sq. in. of the inlet pipesize of the pressure reducing valve(ref. Table 2)

K = flow coefficient for the pressurereducing valve (see V)

C = flow of saturated steam through a1 sq. in. pipe at various pressuredifferentials from Table 1.

b. steam flow, W in lbs/hr through theby-pass valve

W = A1 K1 C1where,

A1 = internal area in sq. in. of the pipe sizeof the bypass around the pressurereducing valve

K1 = flow coefficient for the bypass valves(see V)

C1 = flow of saturated steam through a1 sq. in. pipe at various pressuredifferentials from Table 1, below.

V. STEAM FLOW WHEN FLOWCOEFFICIENTS ARE NOTKNOWN

It is possible that the flow coefficients K andK1 may not be known and in such instancesfor approximating the flow, a factor of 1/3may be substituted for K and 1/2 for K1.

The formulas in IV above then become:

W = 1/3 AC for the capacity through thepressure reducing valve and

W = 1/2 A1 C1 for the capacity throughthe bypass valve.

Caution should be exercised when substitut-ing these factors for the actual coefficientssince this method will provide approximatevalues only and the capacities so obtainedmay in fact be lower than actual. It is recom-mended that the actual flow coefficient beobtained from the pressure reducing valvemanufacturer and reference books beconsulted for the flow coefficient of thebypass valve.

VI. TWO-STAGE PRESSUREREDUCING VALVE STATIONS

The safety relief valve for two-stage pressurereducing valve stations shall be sized on thebasis of the high side pressure and the inletsize of the first pressure reducing valve in theline. If an intermediate pressure line is takenoff between the pressure reducing valves thenthis line and the final low side shall beprotected by safety relief valves sized on thebasis of the high side pressure and the inletsize of the first pressure reducing valve.

278


TABLE 1 — Capacity of Saturated Steam, in lb./hr., per sq. in. of Pipe Area

850 800 750 700 650 600 550 500 450 400 350 300 250

1000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .950 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .900 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .850 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .800 22550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .750 30600 21800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .700 35730 29420 21020 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .650 39200 34250 28260 20190 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .600 41500 37470 32800 27090 19480 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .550 42840 39850 35730 31310 25940 18620 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .500 43330 40530 37610 33880 29760 24630 17720 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .450 43330 40730 38150 35260 31980 28080 23290 16680 . . . . . . . . . . . . . . . . . . . . . . . . .400 . . . . . 40760 38220 35680 33050 29980 26380 21870 15760 . . . . . . . . . . . . . . . . . . . .350 . . . . . . . . . . . . . . . . . . . . 33120 30690 27910 24570 20460 14790 . . . . . . . . . . . . . . .300 . . . . . . . . . . . . . . . . . . . . 33240 . . . . . 28140 25610 22620 18860 13630 . . . . . . . . . .250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28150 25650 23200 21000 17100 10800 . . . . .200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21350 18250 15350 10900175 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18250 16000 12600150 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18250 16200 13400125 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18780 . . . . . 13600110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13600100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13600

85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1360075 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1360060 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1363050 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Outletpres.,psi

Pressure reducing valve inlet pressure, psi

Where capacities are not shown for inlet and outlet conditions, use the highest capacity shown under the applicable inlet pressure column.


1500 1450 1400 1350 1300 1250 1200 1150 1100 1050 1000 950 900

1000 76560 72970 69170 64950 60540 55570 49930 43930 35230 25500 . . . . . . . . . . . . . . .950 77430 74180 70760 67000 63100 58770 53920 48610 42380 34890 24910 . . . . . . . . . .900 77750 74810 71720 68340 64870 61040 56820 52260 47050 41050 33490 23960 . . . . .850 77830 74950 72160 69130 66020 62610 58900 54930 50480 45470 39660 29080 23190800 . . . . . 75070 72330 69490 66700 63680 60390 56910 53060 48800 43980 38340 31610750 . . . . . . . . . . . . . . . 69610 66880 64270 61260 58200 54840 51170 47080 42420 37110700 . . . . . . . . . . . . . . . . . . . . 66900 64270 61520 58820 55870 52670 49170 45230 40860650 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61550 58860 56260 53480 50440 47070 43400600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58980 56270 53660 51020 48470 45010550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53810 51040 48470 45800500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45850450 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45870400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .350 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Outletpres.,psi



279

200 175 150 125 100 85 75 60 50 40 30 25

1000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .950 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .900 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .850 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .700 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .650 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .450 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .350 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175 7250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150 9540 6750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125 10800 8780 6220 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110 11000 9460 7420 4550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 11000 9760 7970 5630 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 11000 . . . . . 8480 6640 4070 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 11000 . . . . . . . . . . 7050 4980 3150 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 11000 . . . . . . . . . . 7200 5750 4540 3520 . . . . . . . . . . . . . . . . . . . . . . . . .50 11000 . . . . . . . . . . . . . . . 5920 5000 4230 2680 . . . . . . . . . . . . . . . . . . . .40 11000 . . . . . . . . . . . . . . . . . . . . 5140 4630 3480 2470 . . . . . . . . . . . . . . .30 11050 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3860 3140 2210 . . . . . . . . . .25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3340 2580 1485 . . . . .15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2830 2320 180010 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2060

5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Outletpres.,psi




TABLE 2 — Pipe Data

Nominal Approx.pipe size, Actual external Approx. internal internal area

inches diameter, inches diameter, inches square inches

3/8 0.675 0.49 0.191/2 0.840 0.62 0.303/4 1.050 0.82 0.53

1 1.315 1.05 0.861-1/4 1.660 1.38 1.501-1/2 1.900 1.61 2.04

2 2.375 2.07 3.362-1/2 2.875 2.47 4.78

3 3.500 3.07 7.393-1/3 4.000 3.55 9.89

4 4.500 4.03 12.735 5.563 5.05 19.996 6.625 6.07 28.898 8.625 8.07 51.1510 10.750 10.19 81.5512 12.750 12.09 114.80

Note: In applying these rules, the area of the pipe is always based upon standard weightpipe and the inlet size of the pressure reducing valve.

APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE REDUCING VALVES

280


281

Recommended Guide for the Inspection ofPressure Vessels in LP Gas Service —Nonmandatory

Appendix H

282


APPENDIX H — RECOMMENDED GUIDE FOR THE INSPECTION OFPRESSURE VESSELS IN LP GAS SERVICE

H-1000 GENERAL CONDITIONS

a. Pressure vessels designed for storing LPgas can be stationary or can be mountedon skids. LP gases are generally consid-ered to be noncorrosive to the interior ofthe vessel. This part is provided for guid-ance of a general nature for the owner,user, or jurisdictional authority. Theremay be occasions where more detailedprocedures will be required.

b. The application of this section to under-ground vessels will only be necessarywhen evidence of structural damage tothe vessel has been observed, leakage hasbeen determined, or the tank has beendug up and is to be reinstalled.

H-2000 PRE-INSPECTIONACTIVITIES

A review of the known history of the pres-sure vessel should be performed. This shouldinclude a review of information, such as:

a. Operating conditions

b. Normal contents of the vessel

c. Results of any previous inspection

d. Current jurisdictional inspection certifi-cate, if required

e. ASME Code Symbol Stamping or markof code of construction, if required

f. National Board and/or jurisdictional reg-istration number, if required

The vessel should be sufficiently cleaned toallow for visual inspection.

H-3000 ASSESSMENT OFINSTALLATION

The type of inspection given to pressure ves-sels should take into consideration the con-dition of the vessel and the environment inwhich it operates. The inspection may be ex-ternal or internal, and use a variety of non-destructive examination methods. Wherethere is no reason to suspect an unsafe condi-tion or where there are no inspection open-ings, internal inspections need not be per-formed. The external inspection may be per-formed when the vessel is pressurized or de-pressurized, but shall provide the necessaryinformation that the essential sections of thevessel are of a condition to operate.

H-3100 DEFINITIONS

DENTS — Deformations caused by a bluntobject coming in contact with the vessel insuch a way that the thickness of the metal isnot materially reduced.

CUTS OR GOUGES — Deformations causedby a sharp object coming in contact with thevessel in such a way as to cut into or upsetthe metal reducing the thickness of the metalat that point.

CORROSION OR PITTING — The loss ofwall thickness by corrosive media, for ex-ample:

ISOLATED PITTING — Small diametervoids separated from other pits or corro-sion that do not effectively weaken thevessel.

LINE CORROSION — A loss of wallthickness (corrosion) in a continuous pat-tern or pitting connected in a narrow bandor line.

283

APPENDIX H — RECOMMENDED GUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE

CREVICE CORROSION — A loss of metalin the area of the intersection of skirts(footrings), collars (headrings), saddlebands and other attachments with thevessel.

GENERAL CORROSION — A loss ofmetal over a considerable surface area ofthe vessel.

CRACK — Any surface or subsurface sepa-ration of base metal or weld material whoseextent must be determined by nondestructiveexamination methods (see H-3510).

DISTORTION — Any change in the originalshape of the vessel, for example:

BULGES — Permanent deformationscaused by excessive internal pressure thatresults in the pressure vessel’s surfacebeing outside its original symmetry.

H-3200 EXTERNAL INSPECTION

All parts of the vessel shall be inspected forcorrosion, distortion, cracking or other con-ditions as described in this section. In addi-tion, the following should be reviewed, whereapplicable:

a. InsulationIf the insulation is in good condition andthere is no reason to suspect an unsafecondition behind it, then it is not neces-sary to remove the insulation in order toinspect the vessel. However, it may beadvisable to remove a small portion of theinsulation in order to determine its con-dition and the condition of the vessel sur-face.

b. Evidence of LeakageAny leakage of vapor or liquid shall beinvestigated. Leakage coming from be-hind insulation, supports, or evidence ofpast leakage shall be thoroughly investi-gated by removing any insulation neces-sary until the source is established.

c. Structural AttachmentsThe pressure vessel mountings should bechecked for adequate allowance for ex-pansion and contraction, such as pro-vided by slotted bolt holes or unob-structed saddle mountings. Attachmentsof legs, saddles, skirts or other supportsshould be examined for distortion orcracks at welds.

d. Vessel ConnectionsComponents which are exterior to the ves-sel and are accessible without disassem-bly shall be inspected as described in thisparagraph. Manholes, reinforcing plates,nozzles, or other connections shall be ex-amined for cracks, deformation or otherdefects. Bolts or nuts should be examinedfor corrosion or defects. Weep holes inreinforcing plates shall remain open toprovide visual evidence of leakage as wellas to prevent pressure build up betweenthe vessel and the reinforcing plate. Ac-cessible flange faces should be examinedfor distortion. It is not intended thatflanges or other connections be openedunless there is evidence of corrosion tojustify opening the connection.

e. Fire DamagePressure vessels shall be carefully in-spected for evidence of fire damage. Theextent of fire damage determines the re-pair that is necessary, if any.

H-3300 INTERNAL INSPECTION

When there is a reason to suspect an unsafecondition, the suspect parts of the vessel shallbe inspected and evaluated (See NBIC,RB-2030).

H-3400 NONDESTRUCTIVEEXAMINATION (NDE)

Listed below are a variety of methods thatmay be employed to assess the condition ofthe pressure vessel. These examination meth-

284


ods should be implemented by experiencedand qualified individuals. Generally, someform of surface preparation will be requiredprior to the use of these examination meth-ods: visual, magnetic particle, liquid pen-etrant, ultrasonic, radiography, radioscopy,eddy current, metallographic examination,and acoustic emission. When there is doubtas to the extent of a defect or detrimental con-dition found in a pressure vessel, additionalNDE may be required.

H-3500 ACCEPTANCE CRITERIA

H-3510 CRACKS

Cracks in the pressure boundary (heads,shells, nozzles, welds joining parts, andattachment welds) are unacceptable.When a crack is identified, the vessel shallbe removed from service until the crackis repaired by a qualified repair organi-zation or permanently retired from ser-vice (See NBIC, Part RC).

H-3520 DENTS

a. ShellsThe maximum mean dent diameter inshells shall not exceed 10% of the shelldiameter, and the maximum depth of thedent shall not exceed 10% of the meandent diameter. The mean dent diameteris defined as the average of the maximumdent diameter and the minimum dent di-ameter. If any portion of the dent is closerto a weld than 5% of the shell diameter,the dent shall be treated as a dent in aweld area, see paragraph H-3520(b).

b. WeldsThe maximum mean dent diameter onwelds (i.e., part of the deformation in-cludes a weld) shall not exceed 10% of theshell diameter. The maximum depth shall

not exceed one twentieth of the mean dentdiameter.

c. HeadsThe maximum mean dent diameter onheads shall not exceed 10% of the shelldiameter. The maximum depth shall notexceed one twentieth of the mean dent di-ameter. The use of a template may be re-quired to measure dents on heads.

When dents are identified which exceed thelimits set forth in these paragraphs, the ves-sel shall be removed from service until thedents are repaired by a qualified repair orga-nization or permanently retired from service.

H-3530 BULGES

a. ShellsIf a bulge is suspected, the circumferenceshall be measured at the suspect locationand several places remote from the sus-pect location. The variation between mea-surements shall not exceed 1%.

b. HeadsIf a bulge is suspected, the radius of cur-vature shall be measured by the use oftemplates. At any point the radius of cur-vature shall not exceed 1.25% of the di-ameter for the specified shape of the head.

When bulges are identified which exceed thelimits set forth in these paragraphs, the ves-sel shall be removed from service until thebulges are repaired by a qualified repair or-ganization or permanently retired from ser-vice.

H-3540 CUTS OR GOUGES

When a cut or a gouge exceeds 1/4 of thethickness of the vessel, the vessel shall be re-moved from service until it is repaired by aqualified repair organization or permanentlyretired from service.

285

APPENDIX H — RECOMMENDED GUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE

H-3550 CORROSION

a. Line and Crevice CorrosionFor line and crevice corrosion, the depthof the corrosion shall not exceed 1/4 ofthe original wall thickness.

b. Isolated PittingIsolated pits may be disregarded pro-vided that:

1. Their depth is not more than one-halfthe required thickness of the pressurevessel wall (exclusive of corrosion al-lowance);

2. The total area of the pits does not ex-ceed 7 sq. in. within any 8 in. diam-eter circle; and

3. The sum of their dimensions alongany straight line within this circle doesnot exceed 2 in.

c. General CorrosionFor a corroded area of considerable sizethe thickness along the most critical planeof such area may be averaged over alength not exceeding 20 in. The thicknessat the thinnest point shall not be less than50% of the required wall thickness and theaverage shall not be less than 75% of therequired wall thickness. When generalcorrosion is identified which exceeds thelimits set forth in this paragraph, the pres-sure vessel shall be removed from serviceuntil it is repaired by a qualified organi-zation or permanently retired from ser-vice.

H-3560 LEAKS

Leakage is unacceptable. When leaks areidentified, the vessel shall be removed fromservice until repaired by a qualified repairorganization or permanently retired from ser-vice.

H-3570 FIRE DAMAGE

a. Vessels in which bulging exceeds the lim-its of H-3530(a) or distortion which ex-ceeds the limits of the original code of con-struction (e.g., Section VIII, Division 1 ofthe ASME Boiler and Pressure VesselCode) shall be removed from service un-til repaired by a qualified organization orpermanently retired from service.

b. Common evidence of exposure to fire is:

1. charring or burning of the paint orother protective coat,

2. burning or scarring of the metal,

3. distortion, or

4. burning or melting of the valves.

c. A pressure vessel which has been sub-jected to the action of fire shall be re-moved from service until it has been prop-erly evaluated. The general intent of thisrequirement is to remove from servicepressure vessels which have been subjectto the action of fire which has changedthe metallurgical structure or the strengthproperties of the steel. This is normallydetermined by visual examination as de-scribed above with particular emphasisgiven to the condition of the protectivecoating. If there is evidence that the pro-tective coating has been burned off anyportion of the pressure vessel surface, orif the pressure vessel is burned, warped,or distorted, it is assumed that the pres-sure vessel has been overheated. If, how-ever, the protective coating is onlysmudged, discolored, or blistered and isfound by examination to be intact under-neath, the pressure vessel shall not be con-sidered affected within the scope of thisrequirement. Vessels that have been in-volved in a fire and show no distortionshall be requalified for continued service

286


by retesting using the hydrostatic test pro-cedure applicable at the time of originalfabrication.

H-4000 RECORDS

A permanent record shall be maintained foreach vessel repaired by a qualified organiza-tion. The record shall include the following:

a. An ASME Manufacturer’s Data Report or,if the vessel is not ASME Code stamped,other equivalent specifications.

b. Form R-1 Report of Welded Repair orother equivalent document describing theextent of all repairs to the vessel.

H-5000 CONCLUSIONS

Any defect or deficiency in the condition,operating, and maintenance practices of thepressure vessel should be evaluated at thetime of inspection and decision made for thecorrection of such defect or deficiency.

287

INTERPRETATIONS

Interpretations

These interpretations are not part of the NBIC and are providedfor information only.

Indices are provided for Interpretations of the 1995 and latereditions/addenda of the NBIC.

Previously issued interpretations are included for convenience.Users of the Code are cautioned to check the validity of theseinterpretations prior to use.

288


PARAGRAPH INDEX

Foreword ............................................................................................................................. 95-20

Code Cases 1923 ......................................................................................................... 98-2498-56

1945 ......................................................................................................... 98-2498-56

2203 ......................................................................................................... 98-12

RA-2130 Procedure for Obtaining or Renewing a National BoardCertificate of Authorization ................................................................ 98-21

RA-2151 Outline of Requirements for a Quality Systemfor Qualification for the National Board “R” Symbol Stamp ........ 98-13

RA-2231 Condition of Use .................................................................................. 98-2RA-2262 Nameplate Contents ............................................................................ 98-25

98-2695-26

RA-2281 Test Medium and Testing Equipment ............................................... 98-17RA-2330 Procedure for Obtaining or Renewing a National Board

“NR” Certificate of Authorization..................................................... 98-798-41

RA-3020 Prerequisites for Accreditation........................................................... 96-16RA-3050 General Conditions .............................................................................. 98-11

RB-3234 Pressure Testing .................................................................................... 95-38RB-3237 Inspection Interval ............................................................................... 98-19RB-3238 Conditions that Affect Remaining Life Evaluation......................... 95-57

98-3RB-3550 Operational Inspection ........................................................................ 95-55RB-3640 Inspection of Parts and Appurtenances ........................................... 98-9RB-4000 Restamping or Replacement of Nameplates.................................... 98-35

95-47

RC-1000 General Requirements ......................................................................... 95-19RC-1010 Scope ...................................................................................................... 98-22RC-1020 Construction Standard ........................................................................ 95-36

95-48RC-1050 Replacement Parts ................................................................................ 98-14

98-2798-2898-3795-48

RC-1090 Welding .................................................................................................. 98-695-51

RC-1110 Nondestructive Examination ............................................................. 98-1095-41

RC-2031 Routine Repairs .................................................................................... 98-198-498-1898-3198-4295-27

289

INTERPRETATIONS

RC-2031 Routine Repairs (continued) .............................................................. 95-2895-3195-3395-53

RC-2050 Examination and Test .......................................................................... 98-2798-3398-3695-2795-3295-3995-54

RC-2070 Documentation ..................................................................................... 95-50RC-3020 Design .................................................................................................... 98-14

95-22RC-3022 Re-rating ................................................................................................ 98-14

98-1598-2098-32

RC-3030 Examination and Test .......................................................................... 98-1598-3498-38

RC-3050 Documentation ..................................................................................... 95-50

RD-1010 Scope ...................................................................................................... 98-6RD-2020 Scope ...................................................................................................... 98-8RD-2030 Wasted Areas ........................................................................................ 98-42RD-2050 Re-Ending or Piecing Pipes or Tubes ................................................ 98-36RD-2060 Patches ................................................................................................... 95-52RD-2070 Stays ....................................................................................................... 98-40

Appendix 2 Stamping and Nameplate Information ............................................. 95-24

Appendix 4 Glossary of Terms................................................................................. 95-2195-2995-3495-4395-45

Appendix 5 National Board Forms ......................................................................... 98-3995-2595-3095-4095-42

Appendix 6 Examples of Repairs and Alterations ................................................ 98-2398-2998-3095-4495-4695-4895-49

290


SUBJECT INDEX

alternatives to PWHT........................................................................................................ 98-6attachments......................................................................................................................... 98-1blisters, repair of ................................................................................................................ 98-9deaerators, inspection of .................................................................................................. 98-9definition of repair ............................................................................................................ 98-23

98-2998-3095-4395-4595-4695-49

definition of alteration ...................................................................................................... 95-2195-3695-4495-45

definition of inspector ....................................................................................................... 95-29definition of non-load bearing......................................................................................... 95-33demonstration requirements ........................................................................................... 98-41derating ............................................................................................................................... 98-20inspection interval ............................................................................................................. 98-19inspection interval ............................................................................................................. 95-57joint review demonstration requirements ..................................................................... 98-21material thickness .............................................................................................................. 98-36MTR ..................................................................................................................................... 98-37nameplates .......................................................................................................................... 95-24non “U” stamped vessels ................................................................................................. 95-23nondestructive examination ............................................................................................ 98-10nuclear components .......................................................................................................... 98-7original code of construction ........................................................................................... 95-19out-of-service ...................................................................................................................... 98-3owner-user inspection ...................................................................................................... 98-11

98-16piping .................................................................................................................................. 98-22pressure relief valves......................................................................................................... 98-2

98-1398-1798-2498-2598-2695-2695-5595-56

pressure testing .................................................................................................................. 98-1598-2798-3398-3498-3895-2795-3295-3995-38

291

INTERPRETATIONS

qualification of welders/welding procedures .............................................................. 95-51quality system manual ...................................................................................................... 98-13“R” forms ............................................................................................................................ 98-39

95-2795-2895-3095-4095-4295-4895-50

reclassification .................................................................................................................... 95-22replacement parts .............................................................................................................. 98-14

98-2798-28

replacement nameplates ................................................................................................... 98-3595-47

re-rating ............................................................................................................................... 98-1498-1598-32

routing repairs .................................................................................................................... 98-198-498-1898-3198-4295-2595-2795-2895-3195-5395-54

stays ..................................................................................................................................... 95-40timing of repairs ................................................................................................................ 98-5

95-41use of editions/addenda .................................................................................................. 95-20window patch .................................................................................................................... 95-52

292


INTERPRETATION NBI 92-4Question: Is it the intent of Chapter III, Supplement 1 that boiler or pressure vessel tube

replacement using tubes of an equal or greater allowable stress value be considered arepair when the replacement material satisfies the original ASME Code requirementsand such replacement has been accepted by an ASME Code stamp holder or a registeredprofessional engineer?

Reply: No. However, a revision to the 1989 Edition of the National Board Inspection Code,published in the January 1990 BULLETIN, revised these requirements.

INTERPRETATION NBI 92-5Question: In some instances, the National Board Inspection Code provides alternative

requirements that may be applied when accepted by the jurisdiction. How mayalternative requirements be applied at an installation located in an area where there isno jurisdiction?

Reply: It is the intent of the National Board Inspection Code that where there is no jurisdiction,alternative requirements may be accepted by the Authorized Inspection Agencyresponsible for signing the R-1 form.

INTERPRETATION NBI 92-6Question: When a jurisdiction adopts the National Board Inspection Code, does the jurisdiction

adopt any other jurisdiction’s authorization for an out of state organization to performrepairs?

Reply: No.

INTERPRETATION NBI 92-7Question: When an alteration/re-rating is performed where one organization performs the

required design calculation and a second organization performs the necessary physicalwork, how may alteration/re-rating be performed by the two organizations?

Reply:: It is the intent of the National Board Inspection Code that the certification of thealteration/re-rating performed by the two organizations may be accomplished inaccordance with the following procedure:

1. The “R” Certificate Holder performing the design function shall complete an R-1Form certifying the design change. The following statement shall be included underremarks on the R-1 form: Design Only.

2. The “R” Certificate Holder performing the field activities, including the pressuretesting and stamping, shall complete a second R-1 Form certifying the field activities.The “R” Certificate Holder performing the field activities shall be responsible forcollecting and distributing all data report forms.

293

INTERPRETATIONS

INTERPRETATION NBI 93-1Question: Is it a requirement of the Code that the Inspector who performs the acceptance

inspection and certifies the R-1 Form be the same Inspector who authorized the initiationof the repair or alteration?

Reply: No. However, the Inspector who performs the acceptance inspection and certifies theR-1 Form must be employed by the same Authorized Inspection Agency as the Inspectorwho authorized the repair or alteration.

INTERPRETATION NBI 93-2Question 1: May a fillet welded patch plate be installed as an alteration?

Reply: No.

Question 2: May a reinforced opening through the shell be added to a pressure vessel as analteration?

Reply: Yes, provided the reinforcing pad meets all the applicable requirements of SectionVIII, Division 1 of the ASME Boiler and Pressure Vessel Code, including the provisionof weep holes in the reinforcing pad.

INTERPRETATION NBI 93-4Subject: Chapter III, R-301.2 Acceptance of Repairs and Alterations, 1992 editionQuestion: May an Owner-User Commissioned Inspector perform acceptance inspections and

sign an R-1 Form for alterations performed by the Owner-User Inspector’s employerwhen the employer holds a valid “R” Certificate of Authorization?

Reply: No.

INTERPRETATION NBI 93-5Subject: Chapter III, R-503(d), 1992 edition

Question: If a pressure test required for a re-rated vessel is less than or equal to the hydrostatictest performed during construction, is a new pressure test required after the reratingis completed?

Reply: No, provided no physical work is performed.

INTERPRETATION NBI 93-6Subject: Chapter III, Rerating, 1992 editionQuestion: Do the rules of the National Board Inspection Code permit the re-rating of a completed

boiler or pressure vessel to a higher MAWP by performing radiography andrecalculating the pressure using a higher joint efficiency?

Reply: No.

294


INTERPRETATION NBI 94-1Subject: Chapter III, 1989 editionQuestion: For repair of valves, other than safety, safety relief and relief valves, covered and

required by B31.1 as part of the boiler external piping, is it a requirement of the NationalBoard Inspection Code that an organization repairing such valves have a valid “R”Certificate of Authorization?

Reply: No.

INTERPRETATION NBI 94-2Subject: Chapter III, Paragraph R-301.1, 1992 editionQuestion: Is it a requirement of the Code the inspector give prior approval for a repair of a routine

nature?

Reply: Yes (Chapter III, R-301.1, page 33).

INTERPRETATION NBI 95-1Subject: Application of the National Board Inspection Code All EditionsQuestion: In applying the rules of the National Board Inspection Code, what edition of the National

Board Inspection Code governs the inspection of a pressure vessel that was built priorto the latest edition of the Code?

Reply: The laws/regulations of the jurisdiction in which the object is located specify whichedition of the Code applies to the object. If there is no jurisdiction, the latest edition isapplicable.

INTERPRETATION NBI 95-2Subject: R-307 Replacement Parts

1992 Edition with the 1993 AddendaQuestion: When a material change has been specified by the owner for a replacement tube bundle,

altered to upgrade the performance, which will be installed into an existing heatexchanger shell by mechanical means (no welding), is Form R1, Report of WeldedRepair or Alteration, required by R-307.1(c) necessary in addition to the manufacturer’spartial data report supplied by the parts manufacturer?

Reply: Yes. The organization, in possession of a valid Certificate of Authorization for the useof the “R” symbol stamp, that installs the part and affixes the nameplate is responsiblefor completing the R-1 form.

295

INTERPRETATIONS

INTERPRETATION NBI 95-3Subject: R-200 Definition of Terms

R-404 Authorization of Organizations Making RepairsR-505 Authorization of Organizations Making Alterations1992 Edition with the 1993 Addenda

Question 1: An inservice ASME stamped pressure vessel manufactured to the ASME Boiler andPressure Vessel Code, Section VIII, Division 1, has its shell diameter turned downbelow original tolerances. The diameter is then built back up by fusion welding usingweld metal having a chemical composition and tensile strength similar to that of thebase metal, only to be remachined back to its original tolerances. This is done to providemore wear resistance and also to extend the useful life of the vessel. Is this procedureconsidered a repair?

Reply 1: Yes.

Question 2: Is the procedure specified in Question (1) considered an alteration if the weld metalhas a chemical composition and tensile strength that are not similar to that of the basemetal?

Reply 2: Yes.

Question 3: In order to perform the procedures specified in Questions 1 and 2 above to ASMECode vessels and maintain their integrity, in accordance with the NBIC is it requiredthat the organization performing the work hold an “R” Certificate?

Reply 3: Yes.

INTERPRETATION NBI 95-4Subject: U-107 Inspection for Corrosion and Other Deterioration

1992 Edition with the 1993 AddendaQuestion: Is U-107(b) applicable to areas that have wall loss resulting from grinding?

Reply: Yes.

INTERPRETATION NBI 95-5Subject: Purpose and Scope of the National Board Inspection Code

1992 Edition with the 1993 AddendaQuestion: At what point following the completion of a new power boiler, heating boiler or pressure

vessel may the National Board Inspection Code be used?

Reply: When all requirements of the construction code have been met.

INTERPRETATION NBI 95-6Subject: R-401.2.2 Access Openings

1992 Edition with the 1993 AddendaQuestion: May a fillet welded patch plate be installed as a repair?

Reply: No.

296


INTERPRETATION NBI 95-7Subject: Appendix C-R, 3.0 Administrative Procedures

1992 Edition with the 1994 AddendaQuestion: May a renewed “R” Certificate of Authorization be issued based upon a manual review

of an “N” type Certificate of Authorization?

Reply: Yes.

INTERPRETATION NBI 95-8Subject: Appendix C-R, Guide for Completing Form R-1, Report of

Welded Repair or Alteration1992 Edition with the 1994 Addenda

Question: For instruction 13 of the guide for completing Form R-1, is a manufacturer’s serialnumber acceptable for “stamped identification?”

Reply: Noting the manufacturer’s serial number is one acceptable method to address “stampedidentification.”

INTERPRETATION NBI 95-9Subject: Chapter III, Supplement 3 Welding Methods as an

Alternative to Postweld Heat Treatment1992 Edition with the 1994 Addenda

Question: Is it the intent of the 1994 Addendum to the National Board Inspection Code to prohibitthe use of “controlled preheat” as an alternative method of postweld heat treatment inthe repair of pressure vessels?

Reply: Method 1 as shown in the 1992 Edition was inadvertently omitted from the 1994addendum. The omission should be considered an errata.

INTERPRETATION NBI 95-10Subject: R-301.2.2 Owner-User Acceptance Inspection of Repairs

1992 Edition with the 1994 AddendaQuestion 1: May an Owner-User obtain an “R” Certificate of Authorization?

Reply 1: Yes.

Question 2: May repairs performed by the Owner-User holding an”R” Certificate of Authorizationbe inspected by Owner-User Commissioned Inspectors?

Reply 2: Yes.

Question 3: May acceptance inspections of alterations be performed by Owner-User CommissionedInspectors?

Reply 3: No. Acceptance inspections for alterations must be performed by an Inspector employedby an Authorized Inspection Agency (insurance company or jurisdiction).

297

INTERPRETATIONS

INTERPRETATION NBI 95-11Subject: R-503 Re-rating a Boiler or Pressure Vessel

1992 Edition with the 1994 AddendaQuestion: Do the rules of the National Board Inspection Code permit the re-rating of a complete

boiler or pressure vessel to a higher MAWP by removing existing weld seams, re-weldseams, performing radiography and recalculating using a higher joint efficiency?

Reply: No.

INTERPRETATION NBI 95-12Subject: U-107 Inspection for Corrosion and Other Deterioration

1992 Edition with the 1994 AddendaQuestion 1: May the provisions of U-107 Inspection for Corrosion and Other Deterioration of the

1992 Edition, 1994 Addenda of the National Board Inspection Code be applied to a vesselof any size?

Reply 1: Yes, provided the owner-user’s inspection program has been approved by thejurisdiction.

Question 2: When applying U-107(b) in question 1, may any of the readings taken along the lengthof the properly oriented line (circumferential or longitudinal) be less than the requiredthickness for pressure?

Reply 2: Yes, as long as the average of the readings taken along the line is equal to or greaterthan the required thickness for pressure.

INTERPRETATION NBI 95-13Subject: U-106 Maximum Period Between Inspections

1992 Edition with the 1994 AddendaQuestion 1: Does Chapter V mandate the type of inspection to be performed?

Reply 1: No. The type of inspection (internal, external, NDE, etc.) is established by the owner-user and the Inspector provided the inspection method provides sufficient informationto determine if the vessel can be safely operated.

Question 2: In accordance with paragraph U-106, may a “complete on-stream evaluation of pressurevessels” be performed in lieu of an internal inspection?

Reply 2: Yes.

Question 3: U-106(c) states that under specific circumstances and when the corrosion rate is knownto be zero a vessel need not be internally inspected. Does this mean that an internalinspection is required when the corrosion rate is not zero?

Reply 3: U-106(c) provides guidance for a specific situation. The requirements ofU-106(c) are not related to the requirements of U-106(b).

298


INTERPRETATION NBI 95-14Subject: R-202 Alteration

1992 Edition with the 1994 AddendaQuestion: May a welded repair to a pressure vessel be performed without postweld heat treatment

or acceptable alternative to postweld heat treatment, when the pressure vessel asreported on the data report was postweld heat treated during construction?

Reply: No.

INTERPRETATION NBI 95-15Subject: R-307 Replacement of Pressure Parts

1992 Edition with the 1994 AddendaQuestion: Is it permissible to use an assembly from an inservice pressure vessel as a replacement

part for the repair/alteration of a second vessel?

Reply: Yes, provided the intended repair/alteration has the concurrence of the jurisdictionand the Authorized Inspection Agency.

INTERPRETATION NBI 95-16Subject: R-302.1 Welding Procedure Specifications

1992 Edition with the 1994 AddendaQuestion: Is it permissible for a repair organization to carry out repairs using qualified weld

procedure specifications supplied by an owner-user of the boiler, pressure vessel orpiping to be repaired?

Reply: No.

INTERPRETATION NBI 95-17Subject: R-404 Authorization of Organizations Making Repairs

1992 Edition with the 1994 AddendaQuestion 1: Is it the intent of the National Board Inspection Code to permit documented repairs (Form

R-1) regardless of whether documented or undocumented repairs have been performedin the past?

Reply 1: Yes, provided the original construction was to the ASME Code.

Question 2: When an “R” Certificate Holder performs a repair on a vessel, does the CertificateHolder assume responsibility for the work performed by others on the vessel?

Reply 2: No.

299

INTERPRETATIONS

INTERPRETATION NBI 95-18Subject: Appendix C-NR, NR-1000 Scope and Applicability

1992 Edition with the 1994 AddendaQuestion 1: Is it a requirement of the NBIC that the rules of Appendix C-NR be applied to any

repair or modification performed on an ASME Section III N-Stamped item, even thoughthe installed item is not located in a Class 1, 2, or 3 system within the ASME Section XIProgram boundaries established by the Owner in accordance with regulatory safetysystem classification so as to maintain its ASME Section III Code integrity?

Reply 1: No. The rules of Appendix C-NR are not required for repairs or modifications to ASMESection III items installed outside of ASME Section XI system boundaries.

Question 2: Is it a requirement of the NBIC that any work performed on an item prior to itsinstallation in a Class 1, 2, or 3 system within the ASME Section XI Program beperformed under the rules of Appendix C-NR?

Reply 2: Yes. Upon completion of the construction Code, any repairs or modifications of anitem intended for service in an ASME Section XI system must be performed under therules of Appendix C-NR to maintain the Code integrity of the item.

Question 3: Is it permissible for the owner to reuse an ASME Section III N-Stamped item that wasinstalled in a location not within the ASME Section XI Class 1, 2, or 3 system, providedall work performed on the item was in accordance with the rules of Appendix C-NR?

Reply 3: Yes. Under the described conditions, the Code integrity would be maintained forpossible reuse of the item in an ASME Section XI Class 1, 2, or 3 system application.

Question 4: Under the requirements of Appendix C-NR, is it permissible for the owner to reuse anASME Section III N-Stamped item that was installed in a location not within the ASMESection XI Class 1, 2, or 3 system even though work had been performed on the itemoutside the rules of Appendix C-NR?

Reply 4: No. An item on which repair or modification activities have been performed outsideof the rules of Appendix C-NR may not be subsequently used in an application whichrequires compliance with the rules of Appendix C-NR.

INTERPRETATION NBI 95-19Subject: RC-1000 General Requirements

1995 EditionQuestion: When the National Board Inspection Code references “the original code of construction,”

is it required to use the edition and addenda of that code as used for construction?

Reply: No. The term “original code of construction” refers to the document itself, not theedition/addenda of the document. Repairs and alterations may be performed to theedition/addenda used for the original construction or a later edition/addenda mostapplicable to the work.

300


INTERPRETATION NBI 95-20Subject: Foreword, 1995 EditionQuestion: May the requirements of an earlier Edition and Addenda of the National Board

Inspection Code be used when performing a repair or alteration?

Reply: Yes.

INTERPRETATION NBI 95-21Subject: Appendix 4, Definition of Alteration,

1995 EditionQuestion: May an ASME Section VIII, Division 1 pressure vessel that has postweld heat treatment

reported on an ASME Manufacturer’s Data Report, be repaired by welding withoutsubsequent postweld heat treatment or postweld heat treatment alternatives?

Reply: No. This is an alteration.

INTERPRETATION NBI 95-22Subject: RC-3020 Design, RC-3021 Calculations,

1995 EditionQuestion: May the rules of RC-3020 and RC-3021 be followed to reclassify a vessel originally

constructed to ASME, Section III, to ASME, Section VIII?

Reply: No. The National Board Inspection Code does not provide rules for reclassification ofpressure retaining items.

INTERPRETATION NBI 95-23Subject: RC-1010 Scope,

1995 EditionQuestion: May repairs to cargo containers that are designed to ASME Section VIII, Division 1,

but are not stamped with the “U” Symbol be documented on the form R-1, if the repairfacility maintains the National Board “R” Symbol?

Reply: Yes.

INTERPRETATION NBI 95-24Subject: Appendix 2,

1995 EditionQuestion 1: Are nameplates required to have the same layout as the figures shown in Appendix 2?

Reply 1: No. However, all information shown in the figures must be included on the stampingor nameplate and the National Board Certificate number must appear directly belowthe symbol stamp.

Question 2: Are the instructions (MAWP, ° F, etc.) shown in the figures in Appendix 2 required tobe included on the stamping or nameplate?

Reply 2: Yes. However, the words “Certificate Holder” and “National Board “R” CertificateNumber” may be omitted.

301

INTERPRETATIONS

INTERPRETATION NBI 95-25Subject: Appendix 5, Form R-1,

1995 EditionQuestion: Is it required that the Inspector perform a physical inspection of routine repairs to

enable completion of the Certificate of Inspection block on Form R-1?

Reply: No. When the Remarks section of Form R-1 includes the Statement “Routine Repairs”in accordance with RC-2031(d), it is understood that the inspection signed for by theInspector is a document review and that a physical inspection may not have beenperformed.

INTERPRETATION NBI 95-26Subject: RA-2262 Nameplate Contents,

1995 Edition, 1995 AddendumQuestion 1: Is it the intent of RA-2262 (NB-65, paragraph 9.2(a)) that the capacity and type model

number be included on the valve repair nameplate only when this information hasbeen changed?

Reply 1: Yes.

INTERPRETATION NBI 95-27Subject: RC-2031 Routing Repairs

RC-2050 Pressure TestingRC-2060 StampingRC-2072 Distribution1995 Edition

Question 1: May the repair of cracks or pinholes be considered a routine repair?

Reply 1: The scope of routine repairs are defined in RC-2031. The nature of the defect is not acriteria for determining whether the repair is routine.

Question 2: Is the registration of R-1 forms an option?

Reply 2: Yes, see RC-2072. However, the jurisdiction may require registration (RC-1150).

Question 3: May the “R” Symbol Stamp be applied to a repaired item whether or not the R1 formis registered with the National Board?

Reply 3: Yes, provided all of the requirements of the NBIC are met. See RC-2060.

Question 4: Who is responsible for determining whether or not it is practical to perform a pressuretest of a repaired item?

Reply 4: The “R” Certificate Holder. See RC-2050(a).

302


INTERPRETATION NBI 95-28Subject: RC-2031 Routine Repairs

1995 EditionQuestion: Do the provisions in RC-2031(a) for waiving the inprocess involvement of the Inspector

on routine repairs include waiving the requirement for the Inspector to sign the FormR-1 as addressed in RC-2071(b)?

Reply: No. The requirements of RC-2071(b) are applicable for all repairs, including routinerepairs. See RC-2031(d).

INTERPRETATION NBI 95-29Subject: RC-1070 Inspector

1995 EditionQuestion: Is it the intent of the NBIC that a jurisdiction as defined in Appendix 4 which is not a

member of the National Board, employ Inspectors for inspection of repairs andalterations as referenced in RC-1070(a)?

Reply: Yes, RC-1070(a) does not restrict the jurisdiction to only National Board Members.

INTERPRETATION NBI 95-30Subject: Data Report Forms

1995 EditionQuestion 1: May repairs or alterations performed in accordance with the requirements of API-510

be documented on NBIC forms R-1 or R-2?

Reply 1: No.

Question 2: May repairs or alterations performed in accordance with the requirements of API-510be accepted by the Inspector?

Reply 2: This is outside the scope of the NBIC.

INTERPRETATION NBI 95-31Subject: RC-2031 Routine Repairs

1995 Edition, 1995 AddendumQuestion: Do the provisions in RC-2031(b) for waiving the inprocess involvement of the

Inspector on routine repairs include waiving the requirement for the Inspector towitness a pressure test as addressed in RC-1130?

Reply: Yes.

INTERPRETATION NBI 95-32Subject: RC-2050 Pressure Testing

1995 Edition, 1995 AddendumQuestion: In RC-2050(a), does the expression “shall be pressure tested at 80% of the maximum

allowable working pressure stamped on the pressure retaining item or operatingpressure, whichever is greater” mean not less than the greater of 80% of the maximumallowable working pressure or the operating pressure?

Reply: Yes.

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INTERPRETATION NBI 95-33Subject: RC-2031(a)(2) Definition of “non-load bearing”

1995 EditionQuestion: Does the NBIC specify a quantitative value below which an attachment is considered

non-load bearing?

Reply: No, “non-load bearing attachment” is a generally accepted design term referring toitems that transmit an inconsequential load onto the pressure retaining boundary.

INTERPRETATION NBI 95-33(a)Subject: Appendix C-R, 4.0 (f)

1992 Edition with the 1994 AddendumQuestion: May an “R” Certificate of Authorization holder with field repair in the scope of its “R”

Certificate perform repairs and alterations in other shops owned by the CertificateHolder?

Reply: No. Each shop must have its own certificate.

INTERPRETATION NBI 95-34Subject: Appendix 4, Definition of an Authorized Inspection Agency

1995 EditionQuestion 1: In Appendix 4, the definition of an Authorized Inspection Agency refers to the National

Board Rules and Regulations. If an Inspector is assigned to a shop that only holds an“R” Certificate of Authorization and performs inspections of repairs and alterations topressure retaining items, is the Authorized Inspector Supervisor required to audit theperformance of the Inspector as specified in 3.4.3.(d) of the National Board Rules andRegulations?

Reply 1: No.

Question 2: In Appendix 4, the definition of an Authorized Inspection Agency refers to the NationalBoard Rules and Regulations. If an Inspector is assigned to a shop that only holds an“R” Certificate of Authorization and performs inspections of repairs and alterationsto pressure retaining items, is the Inspector required to monitor the quality program?

Reply 2: No; however, the Inspector shall assure compliance with the requirements of the NBIC.See RC-1130.

INTERPRETATION NBI 95-35Subject: R-200 Definition of Terms

1992 Edition with the 1994 AddendumQuestion 1: Is the welding in of a plug to seal tubes in a boiler or pressure vessel considered a

repair?

Reply 1: Yes.

Question 2: Does the NBIC apply to plugging tubes by welding plugs to tubes and/or their jointsto tube sheets of tubes that have leaked, tubes that have corroded to an unacceptablethin wall thickness, and tubes required to be removed from service for operating reasonsin boilers and pressure vessels?

Reply 2: Yes.

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INTERPRETATION NBI 95-36Subject: RC-1020 Construction Standards

1995 Edition with the 1995 AddendumQuestion: When work is performed under the NBIC to a code other than the original code of

construction, is it required that the work be classified as an alteration?

Reply: No, see RC-1020. The use of a different design basis code does not necessarily requirework to be classified as an alteration; however, the concurrence of the Inspector andthe jurisdiction is required for this determination.

INTERPRETATION NBI 95-37Withdrawn

INTERPRETATION NBI 95-38Subject: RB-3234 Pressure Testing

1995 Edition with the 1995 AddendumQuestion: Does RB-3234 allow for an in-service pressure test in excess of 1-1/2 times the MAWP

adjusted for temperature?

Reply: No, where any provision of the National Board Inspection Code presents a direct orimplied conflict with any regulation, the jurisdictional regulation shall govern.However, in these circumstances, the activity cannot be documented as meeting therequirements of the National Board Inspection Code.


1995 Edition with the 1995 AddendumQuestion: Is the performance of a pressure test in accordance with RC-2050(a) required after a

routine repair?

Reply: Yes, except as permitted by RC-2050(g).

INTERPRETATION NBI 95-40Subject: Appendix 5, Form R-2 Report of Alteration

1995 Edition with the 1995 AddendumQuestion 1: Does the NBIC require that the Data Report Forms used to report repairs and alterations

be identical to the forms shown in Appendix 5?

Reply 1: Yes.

Question 2: May the Data Report Forms used for repairs and alterations be computer generated?

Reply 2: Yes, provided they are identical to the forms shown in Appendix 5.

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INTERPRETATION NBI 95-41Subject: RC-1110 Nondestructive Examination

1995 Edition with the 1995 AddendumQuestion 1: When performing in-service inspection, radiographic examination uncovers indications

in welds made by the original manufacturer that are in excess of that allowed by theoriginal code of construction. Is it a requirement that these welds be repaired?

Reply 1: The decision as to whether or not to perform a repair of deficiencies discovered duringin-service inspection is outside the scope of the Code. See RB-3280.

Question 2: When nondestructive examination of a repair weld reveals indications in excess ofthat allowed by the original code of construction, must the indication be removed orreduced to an acceptable size?

Reply 2: Yes.

INTERPRETATION NBI 95-42Subject: RC-2070 Documentation

RC-3050 Documentation1995 Edition with the 1995 Addendum

Question: When work classified as an alteration is performed in conjunction with work on thesame pressure retaining item classified as a repair, do both Form R-1 and Form R-2need to be prepared?

Reply: No, as long as the repair work is identified on Form R-2 along with the alterationwork.

INTERPRETATION NBI 95-43Subject: Appendix 5, Definition of Repair

1995 Edition with the 1995 AddendumQuestion: May the welding of a new circumferential seam in a completed, code stamped and

certified ASME Code pressure vessel be classified as a repair?

Reply: Yes.

INTERPRETATION NBI 95-44Subject: Appendix 6, Item C-5

Examples of Alterations1995 Edition with the 1995 Addendum

Question: For a boiler stamped in accordance with the ASME Code, Section I, is it the intent ofAppendix 6, paragraph C.5 that an increase in heating surface be considered analteration only when the resulting change requires an increase in the relieving capacityof the safety valves?

Reply: Yes.

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INTERPRETATION NBI 95-45Subject: Appendix 4

Definition of Repair1995 Edition with the 1995 Addendum

Question 1: Providing there is no work performed on pressure retaining items, is the removal of acoal grate, installation of new burners, brick wall modifications, and concrete andrefractory work outside the scope of the NBIC?

Reply 1: Yes, provided the required safety or safety relief valve relieving capacity is not increased.

Question 2: In a high temperature water boiler, is an increase in the maximum design output inBtu/hr, which requires an increase in the safety relief valve relieving capacity consideredan alteration in accordance with the NBIC?

Reply 2: Yes.

INTERPRETATION NBI 95-46Subject: Appendix 6, B-7

1995 Edition with the 1995 AddendumQuestion 1: May the example of a repair given in Appendix 6, paragraph B-7 apply to a nozzle or

an opening for which the axis is not perpendicular to the wall or head of a pressureretaining item?

Reply 1: Yes, provided calculations to determine availability of reinforcement (compensation)for such construction is not a consideration of the original code of construction.

Question 2: May the example of a repair given in Appendix 6, paragraph B-7 apply to nozzles andopenings larger than NPS 3?

Reply 2: Yes, provided calculations to determine availability of reinforcement (compensation)for such construction is not a consideration of the original code of construction.

INTERPRETATION NBI 95-47Subject: RB-4020

1995 Edition with the 1995 AddendumQuestion: When replacing a nameplate, may the National Board number be stamped on the

replacement nameplate by the original manufacturer when the manufacturer no longerholds an ASME Certificate of Authorization?

Reply: Yes, provided the requirements of RB-4000 are met.

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INTERPRETATION NBI 95-48Subject: RC-1020, RB-1050(a) & Appendix 6, B-6

1995 Edition with the 1995 AddendumQuestion 1: May retubing and testing a boiler whose original code of construction is ASME Section

IV be documented on an R-1 if the replacement tubes are expanded as permitted inASME Section IV, HG-360.2?

Reply 1: Yes, provided all applicable requirements of the NBIC are met.

Question 2: May repairs to saddles, frames or supports of pressure vessels be documented on anR-1?

Reply 2: Yes, provided all applicable requirements of the NBIC are met.

INTERPRETATION NBI 95-49Subject: Appendix 6, B-17

1995 Edition with the 1995 AddendumQuestion: Does the example of a repair given in Appendix 6, paragraph B-17 apply only to material

changes within a single P number?

Reply: No.

INTERPRETATION NBI 95-50Subject: RC-2072 and RC-3052

1995 Edition with the 1996 AddendumQuestion: Does the term “attachment” as used in RC-2072 and RC-3052 refer to Material Test

Reports?

Reply: No, the term applies to R-3, R-4 and Manufacturer’s Partial Data Reports.

INTERPRETATION NBI 95-51Subject: RC-1090

1995 Edition with the 1996 AddendumQuestion: May an “R” Certificate Holder use weld procedures and welders qualified by a

technically competent group or agency?

Reply: Yes, as permitted by RC-1092 or when allowed by the original code of construction.

INTERPRETATION NBI 95-52Subject: RD-2060 Patches, Figure 8

1995 Edition with the 1996 AddendumQuestion 1: Is there a maximum length to width ratio for the tube window patch configuration?

Reply 1: No, the NBIC does not specify dimensions for the patch.

Question 2: Is there a maximum dimension allowed for the tube window patch?

Reply 2: No, the NBIC does not specify dimensions for the patch.

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INTERPRETATION NBI 95-53Subject: RD-2031 Routine Repairs

1995 Edition with the 1995 AddendumQuestion 1: Is the addition of a nozzle penetrating through a head or shell considered a routine

repair?

Reply 1: No.

Question 2: Is a pipe nozzle that penetrates a head or shell considered a section of pipe used inRC-2031?

Reply 2: No.


1995 Edition with the 1996 AddendumQuestion: In accordance with RC-1130 is it required that the Inspector witness any pressure test

of a repair or alteration?

Reply: Yes, except as provided by RC-2031 (b).

INTERPRETATION NBI 95-55Subject: RB-3550 Operational Inspection

1995 Edition with the 1996 AddendumQuestion: Under the provisions of paragraph RB-3550, may a repair organization that meets the

requirements of RA-2220 act as the designee of a pressure vessel user to makeadjustments to a steam service pressure relief valve with air as the test media, providedthat:a) the jurisdiction has authorized such adjustments;b) no “VR” Symbol is applied to the pressure relief valve?

Reply: Yes.

INTERPRETATION NBI 95-56Subject: RA-2231 (b)(1) Acceptance of Code Cases 1923 and 1945 when used in

Original Construction1995 Edition with the 1996 Addendum

Question: Under the provisions of paragraph RA-2231 (b)(1) is it permissible for a “VR”stampholder to repair a restricted lift valve when ASME Code Case 1923-2 or 1945-3was used in the original construction?

Reply: Yes, provided no change is made in valve lift.

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INTERPRETATION NBI 95-57Subject: RB-3238(e) Above Ground Vessels

1995 Edition with the 1996 AddendumQuestion 1: Does the interval of the lesser of five (5) years or 1/4 life refer only to an initial external

inspection?

Reply 1: No.

Question 2: Does the National Board Inspection Code establish an inspection interval for periodicexternal examinations?

Reply 2: Yes. The external inspection interval is defined in RB-3238 (e) & (f) with remaining lifecalculated as per RB-3236.

INTERPRETATION VR86-10Question: May a pressure relief valve repair organization be qualified for a “VR” certificate of

authorization utilizing mobile test facilities for shop and field use provided therequirements of NB-65 (NBIC)are met and the repair organization applies andsuccessfully surveys for a “VR” certificate of authorization?

Reply: Yes

INTERPRETATION VR-1-1986Question: It is permissible to apply the “VR” stamp to a valve repaired under an ASME Code

section other than that for which it was originally stamped and National Board capacitycertified?

Reply: No

INTERPRETATION VR-87-2Question: Under the provisions of NB-65, paragraph 11.1.3, (NBIC RA-2283) is it permissible to

use an auxiliary lifting device in shop to establish the valves set pressure?

Reply: Yes, provided this procedure is addressed in the quality control manual and also coveredin the scope.

INTERPRETATION VR-88-1Question: May a “VR” applicant, who also submits liquid valves for and successfully acquires

capacity certification as an assembler in accordance with Section VIII of the ASMEBoiler and Pressure Vessel Code, qualify for a scope of work which includes liquid astest medium without submitting a repaired valve as required by NB-65, revision 7,paragraph 2.2.1(b) (NBIC RA-2224(b))?

Reply: No

310


INTERPRETATION VR-88-2Question 1: Is it permissible to apply the “VR” stamp to a repaired “UV” stamped valve to be

tested and set on air or steam while the manufacturer’s nameplate indicates capacitycertification in steam or air respectively?

Answer 1: Yes, provided:1. The valve holds National Board capacity certification for both media;

2. The original manufacturer’s specifications are checked and required modificationsare made for the medium to be changed to;

3. The spring is verified for the application;

4. The Owner-User specifically requests the change;

5. The original capacity is lined through, yet left legible on the original nameplate, andthe new capacity indicated on the repair nameplate.

Question 2: May a repair organization change the Code status (e.g. change a “V” symbol stampedvalve to a “UV”,”HV” or “NV” symbol stamped valve or vice-versa) of a repairedpressure relief valve?

Answer 2: No

INTERPRETATION VR-88-04Question: Is it a requirement before issuance or renewal of Certificates of Authorization that

annual audits be performed under paragraph 10.2(d) of NB-65 (NBIC RA-2273) if nofield work was performed?

Answer: No

INTERPRETATION VR-89-01Question: In accordance with Appendix B, Part II, item 2 of NB-65 (NBIC Appendix 7, Part II,

item 2), is it permissible to apply the “NR” - “VR” stamp to “NV” stamped NationalBoard certified pressure relief valves that were manufactured prior to 1971 ASME Code,Section III, which did not specify Class 1, 2 or 3?

Answer: Yes

INTERPRETATION VR89-05Question: In accordance with NB-65 paragraph 11.1(a) (NBIC RA-2281), is it permissible to apply

the “VR” stamp without conducting the performance testing of a Pilot OperatedPressure Relief Valve in their final combined configuration?

Answer: No

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INTERPRETATION VR-90-01Question: May one of the valves which is submitted for replacement testing in accordance with

paragraph 2.3.1(c) of NB-65 (NBIC-2228(c))be considered to meet one of the two valveminimum as required in paragraph 2.2.1(b) of NB-65 (NBIC RA-2224(b))?

Answer: No

INTERPRETATION VR91-03Question: Is it permissible for a manufacturer to apply the “VR” symbol to valves repaired at

one location in accordance with NB-65, paragraph 8.3.1(a) (NBIC RA-2258(a)), to valvesof identical design manufactured by the same organization at a different location whosecapacity certifications were in accordance with ASME Code Interpretations I-86-23,IV-86-11 and VIII-1-86-52?

Answer: Yes, provided that the following conditions are met:1. Each “VR” certificate holder has met the requiremetns of NB-65, paragraph 8.3.1(a)(NBIC RA-2258(a))and holds a valid ASME Certificate of Authorization, as appropriatefor Code Symbol stamps “V”, “HV”, or “UV”.

2. The “VR” certificate holder may only apply the “VR” symbol to repaired valves ofthe same design as covered by his ASME Certificate of Authorization.

3. The “VR” certificate holder maintains an approved quality control system to ensurethat all NB-65 (NBIC)requirements are met.

INTERPRETATION VR-92-01Question: For the repair of pressure relief valves at an owner-user’s facility, for the owner-user’s

own use, may temporary contract personnel be considered the owner-user’s personnelfor the purpose of assisting a “VR” certificate holder in the performance of pressurerelief valve repairs, provided the requirements of paragraph 10.3 of NB-65 (NBIC RA-2274) are met?

Answer: Yes

INTERPRETATION VR92-02Question: May Code Case 2071 be applied to a “VR” production valve being tested in accordance

with paragraph 11.1.1(a) of NB-65 (NBIC RA-2281)when it is marked with the CodeCase number?

Answer: Yes

INTERPRETATION VR92-03Question: May Code Case 2071 be applied to a “VR” production valve being tested in accordance

with 11.1.1(a) of NB-65 (NBIC RA-2281) when it is not marked with the Code Casenumber?

Answer: No

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INTERPRETATION VR92-04Question: May Code Case 2071 be applied to a “VR” verification valve submitted in accordance

with paragraph 2.3 of NB-65 (NBIC RA-2224(b))when it is not marked with the CodeCase number?

Answer: No

INTERPRETATION VR92-05Question: May Code Case 2071 be applied to a “VR” verification valve submitted in accordance

with paragraph 2.3 of NB-65 (NBIC RA-2224(b))when it is marked with the CodeCase number?

Answer: No

INTERPRETATION VR93-02Question: Is it permissible for a manufacturer who has obtained a “VR” Certificate of

Authorization under the provisions of Paragraph 8.3.1(a) of NB-65 (NBIC RA-2258(a))to apply a “VR” Stamp to valves they had previously ASME Code stamped as anassembler or to valves manufactured by the organization they were an assembler for?

Answer: No

INTERPRETATION VR93-08Question: May a pressure relief valve used at a location other than that of the certificate holder

be tested in accordance with NB-65 paragraph 11.2 (NBIC RA-2282)?

Answer: Yes, provided the repair activities are within the scope stated on the certificate, bothlocations are within the same metropolitan area and owned and operated by the sameuser, and the quality control manual addresses provisions for using only qualifiedpersonnel for final adjustments.

INTERPRETATION VR94-01Question: Does paragraph 3.4 of NB-65 (NBIC RA-2242) permit steam test facilities which are

not located at the address of record?

Answer: Yes, provided the steam test facility, location and control of all aspects of the testingare described in the quality control manual and verification testing of required valve(s)is performed in accordance with NB-65, paragraph 2.2.1(b) and 2.3 (NBIC pars. RA-2224(b) and RA-2228) . These controls shall include the measures used to ensure onlyemployees of the certificate holder perform any adjustments to the valves being testedas required by paragraphs 11.0 and 12.0 (NBIC RA-2281 and RA-2290). The address oftesting shall be recorded on the document required by NB-65 paragraph 8.2.1(i)(2)(NBIC RA-2258(i)(1)) for each steam valve.

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INTERPRETATION VR94-02Question: May an applicant who has shop equipment (including test equipment for air and/ or

water) extend their “VR” Certificate of Authorization to include field-only repairs ofASME Section I pressure relief valves in accordance with NB-65 paragraph 2.2.4 (NBICRA-2242)?

Answer: No. Paragraph 10.2 (NBIC RA-2272) permits only a “VR” Certificate of Authorizationfor field repair both as an extension of their in-shop/plant scope or as a field-repair-only scope.

INTERPRETATION 98-1Subject: RC-2031(a)(1)

1995 Edition with the 1997 AddendumQuestion: In RC-2031(a)(1), does the phrase “and their attachments” refer to such items as:

(a) joining of pipe to pipe and tube to tube;(b) attachments such as clips, lugs, rings, devices, skirts, etc.;(c) nozzles and other connections welded to shells, drums and headers?

Reply: (a) No.(b) Yes, provided postweld heat treatment is not required by the original code ofconstruction for the attachment weld.(c) No.

INTERPRETATION 98-2Subject: RA-2231 Conditions of Use

1995 Edition with the 1996 AddendumQuestion: Does RA-2231(b) require that the “VR” stamp be applied only to pressure relief valves

which meet the following conditions:(a) the valves are stamped with an ASME “V”, “UV”, or “NV” Code Symbol or markedwith an ASME “HV” Symbol and have been capacity certified on the applicable fluidby the National Board; andb) have been dissembled, inspected and repaired such that the valve’s condition andperformance are equivalent to the standards for new valves in the year they weremanufactured?

Reply: Yes.

INTERPRETATION 98-3Subject: RB-3238 Interrupted Service

1995 Edition with the 1995 AddendumQuestion 1: Does paragraph RB-3238(f) of the National Board Inspection Code define when a

pressure vessel is inservice or out-of-service?

Reply 1: No, the NBIC does not define out-of-service or in-service. This is subject to jurisdictionalrequirements.

Question 2: When returning a pressure vessel to service, do the requirements of paragraph RB-3238(f) apply even if the pressure vessel was inspected to other requirements whilenot inservice?

Reply 2: Yes.

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INTERPRETATION 98-4Subject: RC-2031 Routine Repair

1995 Edition with the 1996 AddendumQuestion 1: Does RC-2031(a)(1) limit routine repairs to a single tube or pipe?

Reply 1: No.

Question 2: May the repair of more than one tube or pipe be classified as a routine repair?

Reply 2: Yes, subject to the acceptance of the jurisdiction and the Inspector.

INTERPRETATION 98-5Subject: Foreward

1995 Edition with the 1996 AddendumQuestion: Do the rules of the National Board Inspection Code require the repair of a pressure

retaining item when the pressure retaining item no longer complies with the originalcode of construction?

Reply: No, the National Board Inspection Code does not provide rules for determining whena repair must be performed. (See RB-3180 and RB-3280).

INTERPRETATION 98-6Subject: RC-1090 Welding

RD-1010 Scope1995 Edition with the 1996 Addendum

Question 1: May the rules of the original code of construction be used for welding non-pressureparts to a pressure retaining item?

Reply 1: Yes.

Question 2: Is it required that the alternative methods shown in RD-1000 be applied to repairs andalterations?

Reply 2: No. RD-1000 includes alternatives that may be used in lieu of the original code ofconstruction. When an alternative method is used, all requirements of the alternativemust be met.

INTERPRETATION 98-7Subject: RA-2330(d)

1995 Edition with the 1996 AddendumQuestion 1: If an ASME Section III component is installed in a location outside the ASME Section

XI program boundary, is it a requirement of RA-2330(d) that ASME Section XI activities(e.g., VT-2 examination) be performed as part of an “NR” repair or replacement activity?

Reply 1: Yes.

Question 2: Is it permissible for an Owner to use an ASME Section III component previouslyinstalled in a location outside of the Section XI program boundary in a location withinthe ASME Section XI boundary as long as all previous work performed on the itemwas performed in accordance with NBIC requirements?

Reply 2: Yes, provided the component is examined in accordance with the appropriate ASMESection XI requirements for its intended use.

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INTERPRETATIONS

INTERPRETATION 98-8Subject: RD-2010 Scope

1995 Edition with the 1996 AddendumQuestion: May a “blister” in a pressure retaining item be repaired by the drilling of a hole in the

center of the blister, hammering the blister flat, and rewelding the hole?

Reply: When the NBIC does not specify or otherwise limit the repair technique to be used, itis the responsibility of the “R” Certificate Holder with the concurrence of the Inspectorto choose the appropriate technique. However, the chosen technique must remove thedefect.

INTERPRETATION 98-9Subject: RB-3640

1995 EditionQuestion: Does the National Board Inspection Code (NBIC) require an atmospheric deaerator

vessel to be inspected in accordance with part RB-3640?

Reply: No. Part RB provides recommendations for the conduct of inspections; however, thejurisdiction may mandate the use of RB-3600.

INTERPRETATION 98-10Subject: RC-1110

1995 EditionQuestion 1: Do the buttwelded joints used to replace a portion of a tube sheet in an ASME Section

I firetube boiler require the same nondestructive examination as longitudinalbuttwelded joints in an ASME Section I boiler?

Reply 1: Yes.

Question 2: If the answer to question #1 above is “Yes” and the NDE requirements of the originalcode of construction are not possible or practicable, may alternative NDE methods beused?

Reply 2: Yes, RC-1110 permits the use of alternative NDE methods that are acceptable to theInspector and, where required, the jurisdiction.

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INTERPRETATION 98-11Subject: RA-3050

1995 Edition with the 1996 AddendumQuestion 1: Are inservice inspections performed under the Owner-User accreditation program valid

when the inspected items are intended for lease or rent, or installed for use at otherlocations?

Reply 1: No.

Question 2: Are repair inspections performed by an Owner-User inspection organization validwhen the item(s) repaired are intended for lease or rent, or installed for use at anotherorganization’s location?

Reply 2: No.

Question 3: May an inspector who is employed by an accredited Owner-User inspectionorganization perform repair authorization and acceptance inspections for pressureretaining items not owned or used by the Owner-User accredited inspectionorganization?

Reply 3: No.

INTERPRETATION 98-12Subject: Use of Code Case 2203 in Repairs

1995 Edition with the 1996 AddendumQuestion: Under the provisions of paragraph RA-2231(b)(1), is it permissible to apply ASME

Code Case 2203 and convert a pressure relief valve by removing the lifting device thatis required by Section VIII, Division 1, paragraph UG-136(a)(3) and Section VIII,Division 2, paragraph I-101?

Reply: Yes, provided that the “VR” Certificate Holder verifies that:1. All of the requirements of ASME Code Case 2203 are met, and2. That all of the requirements of the NBIC concerning conversions, and specifically,paragraphs R-2231(b)(2) and RA-2262(b)(3) are met.

INTERPRETATION 98-13Subject: RA-2151r

1995 Edition with the 1996 AddendumQuestion: Does RA-2151r require an “R” Certificate Holder to list or reference, in the Quality

System Manual, the specific Construction Codes that may be used while performingrepairs or alterations?

Reply: No; however, the Quality System Manual must include provisions for addressingrequirements imposed by specific Construction Codes used for repairs and alterations.

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INTERPRETATION 98-14Subject: Appendix 6, Examples of Repairs and Alterations

RC-1050 Replacement PartsRC-3022 Re-ratingRC-3020 Design1998 Edition

Question 1: Does the example of an alteration given in Appendix 6, paragraph C.7, for replacementof a pressure retaining part with a material of different allowable stress from that usedin the original design, apply to use of the same material when later editions/addendaof the original code of construction permit higher allowable stresses for that material?

Reply 1: Yes, when use of the higher allowable stress value results in a reduction in materialthickness.

Question 2: Does the example of a repair given in Appendix 6, paragraph B.17, for replacement ofa pressure retaining part with a material of different nominal composition and equalor greater allowable stress from that used in the original design, apply to use of thesame material when later editions/addenda of the original code of construction permithigher allowable stresses for that material?

Reply 2: Yes, provided there is no reduction in material thickness.

Question 3: When a replacement part is constructed using higher allowable stress values permittedby a later edition/addenda of the original code of construction and the replacementpart is thinner than the part being replaced, is it required that an “R” Certificate Holderperform calculations and inspections to verify that the connecting welds and the affectedportions of the pressure retaining items are in compliance with the original code ofconstruction?

Reply 3: Yes.

Question 4: May a pressure retaining item be re-rated using a later edition/addenda of the originalcode of construction which permits higher allowable stress values for the materialthan was used in the original construction?

Reply 4: Yes, in compliance with the following minimum criteria:(a) The “R” Certificate Holder verifies (by calculations and other means) that the re-rated item can be satisfactorily operated at the new service conditions (e.g., stiffness,buckling, external mechanical loadings, etc.),(b) The pressure retaining item is not used for lethal service,(c) The pressure retaining item is not in high-cycle operation or fatigue service (i.e.,loadings other than primary membrane stress are controlling design considerations.),(d) The pressure retaining item was constructed to the 1968 Edition or later edition/addenda of the original code of construction,(e) The pressure retaining item is shown to comply with all relevant requirements ofthe edition/addenda of the code of construction which permits the higher allowablestress values (e.g., reinforcement, toughness, examination, pressure testing, etc.),(f) The pressure retaining item has a satisfactory operating history and currentinspection of the pressure retaining item verifies that the item exhibits no unrepaireddamage (e.g., cracks, corrosion, erosion, etc.),(g) The rerating is acceptable to the Inspector and, where required, the jurisdiction,(h) All other requirements of Part RC are met, and(i) Use of this Interpretation is documented in the Remarks Section of Form R2.

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Question 5: May a new minimum required wall thickness be calculated for a pressure retainingitem by using a later edition/addenda of the original code of construction which permitshigher allowable stress values for the material than was used in the originalconstruction?

Reply 5: Yes, in compliance with the following minimum criteria:(a) The “R” Certificate Holder verifies (by calculations and other means) that the affectedportions of the pressure retaining item can be satisfactorily operated (e.g., stiffness,buckling, external mechanical loadings, etc.),(b) The pressure retaining item is not used for lethal service,(c) The pressure retaining item is not in high-cycle operation or fatigue service(i.e., loadings other than primary membrane stress are controlling designconsiderations.),(d) The pressure retaining item was constructed to the 1968 Edition or later edition/addenda of the original code of construction,(e) The pressure retaining item is shown to comply with all relevant requirements ofthe edition/addenda of the code of construction which permits the higher allowablestress values (e.g., reinforcement, toughness, examination, pressure testing, etc.),(f) The pressure retaining item has a satisfactory operating history and currentinspection of the pressure retaining item verifies that the item exhibits nounrepaired damage (e.g., cracks, etc.). Areas of corrosion or erosion may be left inplace provided the remaining wall thickness is greater than the new minimumthickness,(g) The design change is acceptable to the Inspector and, where required, thejurisdiction,(h) All other requirements of Part RC are met, and(i) Use of this Interpretation is documented in the Remarks Section of Form R2.

INTERPRETATION 98-15Subject: RC-3022 & RC-3030(h) Pressure Testing Requirements Related to

Re-rating Activities1995 Edition with the 1996 Addendum

Question 1: If calculations and current thickness measurements indicate that a pressure retainingitem may be altered by re-rating only (no physical work being done), may the originalpressure test as recorded on the manufacturer’s data report be used to satisfy RC-3022(d), if the pressure test is at least equal to the calculated test pressure required toverify the integrity of said alteration, subject to the approval of the Inspector and therequirements of the jurisdiction?

Reply 1: Yes.

Question 2: If the maximum allowable working pressure (MAWP) of a pressure retaining itemmust be reduced, due to wall thinning below the minimum wall thickness required tocontain the MAWP stated on the manufacturer’s data report and on the ASME stampednameplate, but the maximum allowable temperature is increased, is it the intent ofthe NBIC that this be considered a re-rate?

Reply 2: Yes. Any increase in pressure or temperature is considered a re-rate in accordancewith RC-3022.

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Question 3: If the maximum allowable working pressure (MAWP) of a pressure retaining itemmust be reduced, due to wall thinning below the minimum wall thickness required tocontain the MAWP stated on the manufacturer’s data report and on the ASME stampednameplate, but the maximum allowable temperature is increased, is it the intent of theNBIC that this is, in effect, a derate and outside the scope of the NBIC?

Reply 3: No. Any increase in pressure or temperature is considered a re-rate in accordance withRC-3022.

INTERPRETATION 98-16Subject: RA-3020 Prerequisites for Accreditation

1998 EditionQuestion: May an Inspector, holding a National Board Owner-User Commission and employed

by an Owner-User Inspection Organization, perform inspections at more than one ofhis/her employer’s facilities which are National Board accredited Owner-UserOrganizations?

Reply: Yes, provided this is described in each Quality System Manual and is acceptable to thejurisdiction(s) where the inspections will be performed.

INTERPRETATION 98-17Subject: RA-2281 Testing Medium and Testing Equipment

1998 EditionQuestion: For testing in accordance with paragraph RA-2281(a), is it permissible to use the 1998

ASME Code Section I blowdown requirements for valves built to earlier Code editions?

Reply: Yes.

INTERPRETATION 98-18Subject: RC-2031 (a)(1) Routine Repairs

1998 Edition with the 1998 AddendumQuestion: In RC-2031 (a)(1), does the phrase "and their attachments" refer to items such as: flanges,

welded couplings, welded fittings for thermometers or pressure gages, or other typesof pressure retaining items?

Reply: No.

INTERPRETATION 98-19Subject: RB-3237 Inspection Interval

1998 Edition with the 1998 AddendumQuestion: Where there are services in which pressure retaining items are used which restrict

human access due to radiological or toxicological concerns, is it permissible to utilizedegradation analysis to extend the interval, or exempt the vessel from internal or on-stream evaluation?

Reply: Yes, provided it is acceptable to the jurisdiction (see RB-1000). The NBIC providesguidance only in establishing inspection intervals or exemptions (see RB-3237 andRB-3238). The jurisdiction is the final authority on inspection intervals or exemptions.

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INTERPRETATION 98-20Subject: RC-3022 Re-rating

1998 Edition with the 1998 AddendaQuestion 1: Is derating a vessel to a lower MAWP considered an alteration or a re-rating?

Reply 1: Neither. The NBIC does not address derating. See RC-3022, footnote 1.

Question 2: In lieu of derating a corroded vessel and affixing nameplates with the new MAWP,may the pressure relief device set pressure be reduced to less than the calculated MAWPbased upon actual remaining wall thickness, if the calculations are conducted in ac-cordance with RC-3020 and RC-3021?

Reply 2: This is outside the scope of the NBIC. The jurisdiction in which the pressure vessel islocated should be contacted to determine the specific procedures to be followed.

INTERPRETATION 98-21Subject: RA-2130 (f)

1998 Edition with the 1998 AddendaQuestion: Is it required that an applicant for an "R" Certificate of Authorization, whose program

includes repair of ASME Section VIII, Division 2 pressure vessels, demonstrate thecapability to comply with the applicable requirements of RC- 2080 to ensure the pro-gram satisfies RA-2130 (f)?

Reply: Yes.

INTERPRETATION 98-22Subject: RC-1010 Scope

1998 EditionQuestion 1: Does the NBIC address ASME B31 piping codes?

Reply 1: Yes. See the definition of "pressure retaining item" in Appendix 4.

Question 2: Is a nameplate required for piping system repairs/alterations performed in accordancewith the NBIC?

Reply 2: Yes.

Question 3: When multiple repairs or alterations are described on a single "R" data report form,may a single nameplate be used?

Reply 3: Yes.

INTERPRETATION 98-23Subject: Appendix 6, B-7

1995 Edition with the 1995 AddendumQuestion: Is the head or shell thickness limited to 3/8 in. in thickness when installing a new NPS

3 nozzle as stated in Appendix 6, paragraph B-7?

Reply: No. The example is correct for a vessel constructed in accordance with ASME Code,Section VIII, Division 1.

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INTERPRETATION 98-24Subject: Restricted Lift per Code Case 1923 & 1945

1998 Edition with the 1998 AddendaQuestion: May a "VR" Certificate holder perform a conversion, as defined in RA-2242(c), of a

pressure relief valve from one certified design type to another certified type whichwas certified by the manufacturer in accordance with ASME Code Cases 1923 or 1945?

Reply: Yes, provided all NBIC requirements pertaining to conversions are met and the certifi-cate holder receives from the valve manufacturer specifications and instructions whichinclude the additional marking requirements of the applicable code case.

INTERPRETATION 98-25Subject: RA-2262(b)(3)

1998 Edition with the 1998 AddendaQuestion: Does RA-2262(b)(3) require the repair organization to mark out the type/model num-

ber if the type/model number was changed prior to the implementation ofRA-2262(b)(3)?

Reply: Yes, and the new type or model number shall be stamped on the repair nameplate inaccordance with paragraph RA-2262-(a)(7).

INTERPRETATION 98-26Subject: RA-2262(b)(1)

1998 Edition with the 1998 AddendaQuestion: May the spring on a pressure relief valve be reset within the guidelines of ASME Sec-

tion 1, PG-72.3 or Section VIII, Div. 1, UG-126(c), as applicable, provided the repairactivities are within the scope stated on the "VR" holder's certificate and the require-ments of paragraph RA-2262(b)(1) are met?

Reply: Yes, provided the set pressure is within the manufacturer's spring range.

INTERPRETATION 98-27Subject: RC-2050(b) Pressure Testing

RC-1050 Replacement Parts1995 Edition with the 1996 Addendum

Question 1: Does the term replacement parts, as used in RC-2050(b), include replacement parts asdefined in RC-1050(a)?

Reply 1: No. RC-1050(a) describes parts supplied as material on which no fabrication weldingis performed.

Question 2: Is it the intent of the 1995 Edition with the 1996 Addendum that the term replacementparts, as used in RC-2050(b), include replacement parts as defined in RC-1050(b)?

Reply 2: No. The 1997 Addendum clarifies these requirements.

Question 3: Does the term replacement parts, as used in RC-2050(b), include replacement parts asdefined in RC-1050(c) and RC-1050(d)?

Reply 3: Yes.

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INTERPRETATION 98-28Subject: RC-1050(c) Replacement Parts Fabricated by an "R" Certificate Holder

Appendix 6 Pressure Retaining Replacement ItemsRC-1050 Definition of New Replacement Parts1998 Edition

Question 1: Does RC-1050(c) of the NBIC permit the holder of an "R" Certificate to fabricate bywelding new and exact pressure retaining replacement parts for an ASME stampeditem that the "R" stamp holder is repairing?

Reply 1: No. ASME replacement parts fabricated by welding that require shop inspection byan Authorized Inspector shall be fabricated by an organization having an appropriateASME Certificate of Authorization.

Question 2: An ASME stamped item is determined to be corroded beyond repair and the onlysalvageable part is the ASME Code stamping or nameplate. Is it the intent of the NBICto permit a holder of an "R" Certificate only to build a complete new and exact pres-sure retaining replacement item using the original ASME construction Code, Section,Edition and Addenda and same materials, transfer and document the transfer of theASME stamping or nameplate on an R-1 Form to the new pressure retaining item andstamp the repair with the "R" stamp?

Reply 2: No.

Question 3: Does the NBIC define the point at which a repair becomes new construction?

Reply 3: No.

INTERPRETATION 98-29Subject: Appendix 6 Tube Placement

1998 Edition with the 1998 AddendumQuestion 1: Is the replacement of heat exchanger tube material with a material that has a different

nominal composition and an allowable stress equal to or greater than the originalmaterial considered a repair?

Reply 1: Yes, provided that the thickness of the replacement material is equal to or greater thanthe original material thickness, and provided the replacement material satisfies thematerial and design requirements of the original code of construction under which thevessel was built.

Question 2: Is the replacement of heat exchanger tube material with a material that has a differentnominal composition and an allowable stress less than the original material consid-ered an alteration?

Reply 2: Yes. See Appendix 6, C7.

Question 3: May tube replacement(s) be considered a routine repair if authorization is obtained inaccordance with RC-2030?

Reply 3: Yes, provided the tube material is NPS 5 or less.

Question 4: Does the NBIC require a tube replacement, which is considered to be a repair, to bedocumented on an R-1 Form when no welding is performed?

Reply 4: No. The NBIC does not address the documentation of non-welded repairs.

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INTERPRETATION 98-30Subject: Appendix 6C Example of Alteration Due to Grinding or Machining

1998 EditionQuestion 1: A pressure retaining item has its surface ground or machined to remove imperfections

caused during operation. Is the resulting reduction in outside diameter, length, andthickness caused by such grinding or machining considered an alteration as describedin Appendix 6, Item C4?

Reply 1: No, unless the changes affect the pressure-containing capability of the pressure retain-ing item.

Question 2: A pressure retaining item has its surface ground or machined to remove imperfectionscaused during operation. The grinding and machining reduces the item's thickness,length and outside diameter. Must such grinding or machining be performed by aholder of an "R" Certificate of Authorization?

Reply 2: No.

INTERPRETATION 98-31Subject: RC-2031 Replacement of a Nozzle as Routine Repair

1998 Edition with the 1998 AddendaQuestion: Is the replacement of a nozzle which is NPS 5 or less considered a routine repair re-

gardless of weld thickness?

Reply: No, RC-2031 (a)(1) does not address nozzles.

INTERPRETATION 98-32Subject: RC-3022 Re-rating Using Higher Joint Efficiency

Allowed by Later Edition of Original Code of Construction1998 Edition

Question: Is it permissible to re-rate a pressure vessel using an increased joint efficiency of 1.0 inaccordance with a later edition/addenda of the original code of construction if all ofthe butt joints were 100% radiographed in the original construction?

Reply: No.

INTERPRETATION 98-33Subject: RC-2051 Liquid Pressure Test of Repairs

1998 EditionQuestion: Is it a requirement of the NBIC that a liquid pressure test be applied after a repair?

Reply: No. The "R" Certificate Holder is required to verify the integrity of the repair. Thecombination of tests and/or examinations to be performed is subject to the acceptanceof the Inspector and, where required, the jurisdiction.

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INTERPRETATION 98-34Subject: RC-3030 Examination and Testing

1995 Edition with the 1996 AddendumQuestion: When the design rated capacity of a boiler is increased without physical work such

that the design pressure and temperature are unaffected, is it required to perform apressure test in accordance with the NBIC?

Reply: No.

INTERPRETATION 98-35Subject: RB-4000 Restamping or Replacement of Nameplate

1998 Edition with the 1999 AddendumQuestion 1: Do the requirements of RB-4020 apply to vessels that are removed from a plant site or

manufacturer's facility and are repaired or altered by an "R" Certificate Holder?

Reply 1: Yes.

Question 2: May an "R" Certificate Holder attach a replacement nameplate supplied by the origi-nal manufacturer, after proper identification has been established and in the presenceof an Inspector, on an ASME vessel?

Reply 2: Yes, provided all requirements of RB-4000 are met.

Question 3: When a nameplate is to be placed on an ASME vessel, which jurisdiction must ap-prove the attachment of the replacement nameplate?

Reply 3: The jurisdiction where the vessel is located.

Question 4: When the original manufacturer is no longer in business, may an "R" Certificate Holderprovide a replacement nameplate describing the design conditions of the ASME ves-sel?

Reply 4: No. The jurisdiction should be contacted when the original manufacturer is no longerin business.

INTERPRETATION 98-36Subject: RD-2050

1998 Edition with the 1999 AddendumQuestion: In RD-2050, does the thickness required by the original code of construction refer to

the material thickness originally supplied?

Reply: Yes.

INTERPRETATION 98-37Subject: RC-1050(a) Material Requirements

1998 Edition with the 1999 AddendumQuestion: If a repair or alteration requires the use of material in accordance with RC-1050(a), are

material test reports that include actual mechanical test properties required to be fur-nished?

Reply: Unless otherwise specifically addressed in the NBIC, all materials, including markingand test reports, shall comply with the original code of construction.

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INTERPRETATION 98-38Subject: RC-3031(c) NDE in lieu of Pressure Testing

1998 Edition with the 1999 AddendumQuestion: Would the desire to save time and/or expense constitute pressure testing as not being

practicable?

Reply: No. The determination of "practicable" is based on technical consideration of the na-ture and scope of the alteration activity.

INTERPRETATION 98-39Subject: R-1 and R-2 Forms

1998 Edition with the 1999 AddendumQuestion: A pressure retaining item is repaired or altered in accordance with the National Board

Inspection Code. The pressure retaining item and its Manufacturer's Data Report arenot registered with the National Board. Is it required that the Inspector list his/herNational Board Commission Number (including endorsements) in the "Certificate ofDesign Change Review" and "Certificate of Inspection" blocks of the appropriate FormR-1 and R-2?

Reply: Yes. See Appendix 5, instruction 28 in the Guide for Completing National Board RForms.

INTERPRETATION 98-40Subject: RD-2070 Stays

1998 Edition with the 1998 AddendumQuestion: Is the replacement of a threaded stay with a welded stay always classified as a repair?

Reply: No. In some cases, the design of threaded stays and welded stays will differ, whichmay change the MAWP. In such cases, the work shall be performed as an alteration.

INTERPRETATION 98-41Subject: RA-2330(g)

1998 Edition with the 1998 AddendumQuestion: May a holder of an ASME Certificate of Accreditation use documentation of the ASME

survey to demonstrate compliance with Part RA-2330(g) of the NBIC?

Reply: No. RA-2330(g) provides the alternative to demonstration for an ASME "N" type Cer-tificate of Authorization.

INTERPRETATION 98-42Subject: RC-2031, RD-2030(d) Weld Buildup of Boiler Tubes' Wasted Areas

1998 Edition with the 1999 AddendumQuestion: May weld buildup of wasted areas on boiler tubes addressed by RD-2030(d) be con-

sidered a routine repair in accordance with RC-2031(a)(1)?

Reply: Yes, provided all requirements of RC-2031 are met.

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