61.40.20.30_spec_2011-02_a01

DEP SPECIFICATION

WELDING OF PIPELINES AND RELATED FACILITIES (AMENDMENTS/SUPPLEMENTS TO ISO 13847:2000)

DEP 61.40.20.30-Gen.

February 2011

(DEP Circular 07/12 has been incorporated)

ECCN EAR99

DESIGN AND ENGINEERING PRACTICE

DEM1

© 2011 Shell Group of companies All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, published or transmitted, in any form or by any means, without the prior

written permission of the copyright owner or Shell Global Solutions International BV.

This document contains information that is classified as EAR99 and, as a consequence, can neither be exported nor re-exported to any country which is under an embargo of the U.S. government pursuant to Part 746 of the Export Administration Regulations (15 C.F.R. Parts 746) nor can be made available to any national of such country. In addition, the information in this document cannot be exported nor re-exported to an end-user or for an end-use that is prohibited by Part 744 of the Export

Administration Regulations (15 C.F.R. Parts 744).

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ECCN EAR99 DEP 61.40.20.30-Gen. February 2011

PREFACE

DEP (Design and Engineering Practice) publications reflect the views, at the time of publication, of Shell Global Solutions International B.V. (Shell GSI) and, in some cases, of other Shell Companies.

These views are based on the experience acquired during involvement with the design, construction, operation and maintenance of processing units and facilities. Where deemed appropriate DEPs are based on, or reference international, regional, national and industry standards.

The objective is to set the recommended standard for good design and engineering practice to be applied by Shell companies in oil and gas production, oil refining, gas handling, gasification, chemical processing, or any other such facility, and thereby to help achieve maximum technical and economic benefit from standardization.

The information set forth in these publications is provided to Shell companies for their consideration and decision to implement. This is of particular importance where DEPs may not cover every requirement or diversity of condition at each locality. The system of DEPs is expected to be sufficiently flexible to allow individual Operating Units to adapt the information set forth in DEPs to their own environment and requirements.

When Contractors or Manufacturers/Suppliers use DEPs, they shall be solely responsible for such use, including the quality of their work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, the Principal will typically expect them to follow those design and engineering practices that will achieve at least the same level of integrity as reflected in the DEPs. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal.

The right to obtain and to use DEPs is restricted, and is typically granted by Shell GSI (and in some cases by other Shell Companies) under a Service Agreement or a License Agreement. This right is granted primarily to Shell companies and other companies receiving technical advice and services from Shell GSI or another Shell Company. Consequently, three categories of users of DEPs can be distinguished:

1) Operating Units having a Service Agreement with Shell GSI or another Shell Company. The use of DEPs by these Operating Units is subject in all respects to the terms and conditions of the relevant Service Agreement.

2) Other parties who are authorised to use DEPs subject to appropriate contractual arrangements (whether as part of a Service Agreement or otherwise).

3) Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) or 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.

Subject to any particular terms and conditions as may be set forth in specific agreements with users, Shell GSI disclaims any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any DEP, combination of DEPs or any part thereof, even if it is wholly or partly caused by negligence on the part of Shell GSI or other Shell Company. The benefit of this disclaimer shall inure in all respects to Shell GSI and/or any Shell Company, or companies affiliated to these companies, that may issue DEPs or advise or require the use of DEPs.

Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, DEPs shall not, without the prior written consent of Shell GSI, be disclosed by users to any company or person whomsoever and the DEPs shall be used exclusively for the purpose for which they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of Shell GSI. The copyright of DEPs vests in Shell Group of companies. Users shall arrange for DEPs to be held in safe custody and Shell GSI may at any time require information satisfactory to them in order to ascertain how users implement this requirement.

All administrative queries should be directed to the DEP Administrator in Shell GSI.



TABLE OF CONTENTS

PART I INTRODUCTION ........................................................................................................4 1.1 SCOPE........................................................................................................................4 1.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS .........4 1.3 DEFINITIONS .............................................................................................................4 1.4 CROSS-REFERENCES .............................................................................................5 1.5 SUMMARY OF CHANGES.........................................................................................5 1.6 COMMENTS ON THIS DEP.......................................................................................5 1.7 DUAL UNITS...............................................................................................................6 PART II GENERAL REQUIREMENTS ....................................................................................7 PART III AMENDMENTS/SUPPLEMENTS TO ISO 13847:2000 (plus Corrigendum

No. 1, 2001) ................................................................................................................8 1. SCOPE........................................................................................................................8 3. TERMS AND DEFINITIONS.......................................................................................8 4. SYMBOLS AND ABBREVIATED TERMS.................................................................8 5. WELDING PROCEDURE SPECIFICATION TESTING AND APPROVAL ...............8 6. APPROVAL AND TESTING OF WELDERS AND WELDING OPERATORS ........19 7. PRODUCTION WELDING........................................................................................19 8. NON-DESTRUCTIVE EXAMINATION .....................................................................22 9. ACCEPTANCE CRITERIA FOR NON-DESTRUCTIVE EXAMINATION ................23 10. REPAIR AND REMOVAL OF DEFECTS.................................................................24 ANNEX A (informative) HYPERBARIC WELDING .................................................................25 ANNEX B (informative) SPECIAL REQUIREMENTS FOR THE WELDING OF CRA-

CLAD STEEL AND CRA PIPELINES......................................................................25 ANNEX C (informative) RECOMMENDATIONS FOR BRAZING AND

ALUMINOTHERMIC WELDING OF ANODE LEADS .............................................25 ANNEX E REQUIREMENTS FOR CRITICAL HIGH-STRAIN PIPELINES..............................25 ANNEX F ADDITONAL REQUIREMENTS FOR THE GIRTH WELDING OF STEEL

CATENARY RISERS................................................................................................28 PART IV REFERENCES .........................................................................................................38



PART I INTRODUCTION

1.1 SCOPE

This DEP specifies requirements and give recommendations for the welding of carbon steel pipeline systems and related facilities.

This DEP is based on ISO 13847:2000 (including Technical Corrigendum 1).

This DEP contains mandatory requirements to mitigate process safety risks in accordance with Design Engineering Manual DEM 1 – Application of Technical Standards.

This is a revision of the DEP with the same number dated January 2010. See [1.5] regarding the changes.

1.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS

Unless otherwise authorised by Shell GSI, the distribution of this DEP is confined to Shell companies and, where necessary, to Contractors and Manufacturers/Suppliers nominated by them. Any authorised access to DEPs does not for that reason constitute an authorization to any documents, data or information to which the DEPs may refer.

This DEP is intended for use in facilities related to oil refineries, chemical plants, gas plants, exploration and production facilities and supply/distribution installations. Application in other facilities may also apply.

When DEPs are applied, a Management of Change (MOC) process should be implemented; this is of particular importance when existing facilities are to be modified.

If national and/or local regulations exist in which some of the requirements could be more stringent than in this DEP, the Contractor shall determine by careful scrutiny which of the requirements are the more stringent and which combination of requirements will be acceptable with regards to the safety, environmental, economic and legal aspects. In all cases the Contractor shall inform the Principal of any deviation from the requirements of this DEP which is considered to be necessary in order to comply with national and/or local regulations. The Principal may then negotiate with the Authorities concerned, the objective being to obtain agreement to follow this DEP as closely as possible.

1.3 DEFINITIONS

1.3.1 General definitions

The Contractor is the party that carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project or operation of a facility. The Principal may undertake all or part of the duties of the Contractor.

The Manufacturer/Supplier is the party that manufactures or supplies equipment and services to perform the duties specified by the Contractor.

The Principal is the party that initiates the project and ultimately pays for it. The Principal may also include an agent or consultant authorised to act for, and on behalf of, the Principal.

The word shall indicates a requirement.

The capitalised term SHALL [PS] indicates a process safety requirement.

The word should indicates a recommendation.

1.3.2 Specific definitions

Pipeline criticality categories:

Term Definition

Non-critical pipelines

Pipelines identified as non-critical in accordance with DEP 31.40.00.10-Gen.



Term Definition

Critical pipelines (a) Pipelines identified as critical in accordance with DEP 31.40.00.10-Gen. and having an operational design maximum axial stress ≤90% SMYS or installation stress ≤100% SMYS.

(b) All offshore pipelines and all pipelines designated for sour service, if not also designated as "critical - high strain"

Critical high-strain pipelines

Critical pipelines having an operational maximum axial stress > 90 % SMYS or installation stress > 100 % SMYS. Such pipelines may also be designated for sour service. The applicable requirements for pipelines in this category, additional to those for critical pipelines, are given in Annex E. Due to the wide range of conditions covered by this category, Annex E is for guidance only – the Principal shall specify the requirements in the Project Specification.

1.3.3 Acronyms

AUT automated ultrasonic testing

AWT all weld tensile

AYS actual yield strength

SCR steel catenary riser

SENT single edged notch tensile (fracture toughness specimen)

SSC sulphide stress cracking

WPQR welding procedure qualification record

1.4 CROSS-REFERENCES

Where cross-references to other parts of this DEP are made, the referenced section number is shown in brackets. Other documents referenced by this DEP are listed in (Part IV).

1.5 SUMMARY OF CHANGES

This DEP is a revision of the DEP of the same number dated January 2010. This DEP has been split into this Specification and a DEP Informative containing background information and the process safety requirements indicated by use of the capitalised term "SHALL [PS]" have been carefully reviewed.

1.6 COMMENTS ON THIS DEP

Comments on this DEP may be sent to the Administrator at [email protected], using the DEP Feedback Form. The DEP Feedback Form can be found on the main page of “DEPs on the Web”, available through the Global Technical Standards web portal http://sww.shell.com/standards and on the main page of the DEPs DVD-ROM.


mailto:[email protected]

http://sww.shell.com/standards


1.7 DUAL UNITS Amended per Circular 07/12 Dual units have been incorporated throughout this DEP.

This DEP contains both the International System (SI) units, as well as the corresponding US Customary (USC) units, which are given following the SI units in brackets. When agreed by the Principal, the indicated USC values/units may be used.



PART II GENERAL REQUIREMENTS

Part III of this DEP is written as amendments and supplements to ISO 13847:2000, including Technical Corrigendum 1. Wherever reference is made to ISO 13847, it shall be understood to mean ISO 13847 (including Technical Corrigendum 1) as amended/supplemented by this DEP.

For ease of reference, the clause numbering of ISO 13847 has been used throughout Part III of this DEP.

Unless specified otherwise in this DEP, all occurrences of the word “should” in ISO 13847 shall be replaced with the word “shall”.

Clauses in ISO 13847, which are not mentioned in this DEP, shall remain valid as written.

Tables and figures in this DEP not replacing the corresponding item in ISO 13847 are numbered in relation to the DEP clause.

The criticality category and all required information, such as upper and lower design temperature, sour service conditions etc., shall be contained in a project specification which shall be applied in conjunction with this DEP and ISO 13847. The project specification shall also contain any technical requirements, in addition to this DEP, necessitated by individual installation or operational conditions. The requirements for critical high-strain pipelines shall be stated in the Project Specification.



PART III AMENDMENTS/SUPPLEMENTS TO ISO 13847:2000 (plus Corrigendum No. 1, 2001)

1. SCOPE

Delete from the second paragraph of this clause:

"and a specified minimum yield strength of 555 MPa (80 ksi) or less."

Add to the second paragraph of this clause:

"and a specified minimum yield strength of 485 MPa (70 ksi) or less."

Add to this clause:

Unless otherwise agreed by the Principal, the following processes shall not be used:

• Self-shielded flux-cored arc welding (SSFCAW)

• Semi-automatic gas metal arc welding (GMAW)

Gas shielded flux cored arc welding (GSFCAW) shall not be used for the root passes of single-sided welds.

Cellulosic SMAW electrodes shall not be used for the welding of fittings, or for pipe-to-pipe welds if the wall thickness is greater than 25 mm (1 in), or for deep water (>240 m (800 ft) water depth) pipelines.

For all tie-in welds employing external clamps, the root pass shall be made using vertical-up welding. Vertical-up welding shall be used for all passes of pipe to fitting welds.

3. TERMS AND DEFINITIONS

Add to this clause:

General and specific definitions in [Part I, 1.3] shall also apply.

3.6 COMPANY

In this term, replace "Company", by "Principal"

Add new term:

3.20 AUTOMATIC WELDING

Welding process in which the welding parameters and torch guidance are controlled electronically without manual intervention.

4. SYMBOLS AND ABBREVIATED TERMS

Add to this clause:

Acronyms in [Part I, 1.3.3] shall also apply.

5. WELDING PROCEDURE SPECIFICATION TESTING AND APPROVAL

In this section replace all references to ISO 9956-1 by ISO 15609 1 and all references to ISO 9956-3 by ISO 15614-1.

5.1 GENERAL

Add to this clause

All welds SHALL [PS] be specified by a WPS and qualified by a WPQ in accordance with the requirements of this DEP.

5.2 WELDING PROCEDURE SPECIFICATION

Add to this clause:

Technical information to be included in the WPS shall be that listed in [Table 5.2-1].



The following, non-technical information shall be included in the WPS:

• WPS number and cross-reference to the WPQR

• Revision number

• Contract number

• Project title

• Contactor's Logo

• Contractor's signature.

• Principal's signature

• Certifying Authorities signature/stamp (where required)

Table 5.2-1 Variables to be specified in the WPS and essential variables

Item Variables to be specified in WPS

Essential variables fornon-critical pipelines

Essential variables for critical pipelines and

critical high-strain pipelines

Process Welding process/combination of welding processes

Any change Any change

Equipment used Any change in equipment type and model for mechanised/automatic welding

Pipe and Fitting material

Steel strength grade Any increase Any change

Heat treatment condition between pipe and pipe or pipe and fitting (TMCP, Q + T, Normalised)


Carbon Equivalent (CE) and/or Pcm of parent material

Any increase in CE > 0.03, or Pcm > 0.02 (Note 1)

(a) for non-sour service: Any increase in CE > 0.03 , or Pcm > 0.02 (b) for sour service: Any increase in CE> 0.02 or Pcm > 0.015 (Note 1)

Manufacturer for pipe or fittings including bends

Any change, unless otherwise agreed by the Principal

Diameter and wall thicknesses

Nominal outside diameter "D" Any decrease more than 0.5 D or increase of more than 1.5 D from that qualified


Nominal wall thickness "t" Any decrease of more than 0.75t or increase of more than 1.5t from that qualified


Joint design Type of bevel Any change Any change







Angle of bevel Any change outside the approved tolerance in the approved WPS For mechanised/automatic GMAW: Restricted to range: 0° to +5° included angle

Any change outside the approved tolerance. in the agreed WPS For mechanised/automatic GMAW: Restricted to range:-0° to +5° included angle

Root gap Any change outside the tolerance in the approved WPS

Any change outside the tolerance in the approved WPS

Root face Any change outside the tolerance in the approved WPS.

Any change outside the tolerance in the approved WPS.

Use of temporary backing Any change Any change Filler metal to be specified for each run

Size Any change Any change

Number of wires used Any change Any change Manufacturer and Trade Name Any change unless

agreed with Principal Any change

Classification and minimum specified yield strength


Flux classification and trade name

Any change unless agreed with Principal

Any change

Drying operation or pre treatment

Any change unless otherwise agreed by the Principal.

Any change unless otherwise agreed by the Principal

Electrical characteristics to be specified for each run

Current type (ac or dc) and Polarity


Arc voltage ±10% ±10% Current ±10% ±10% Arc energy (kJ/mm) (ft-lb/in)

u1,000ampsvolts×

×

where u is the welding speed expressed in mm/s (in/s)

Any change 10% above the maximum arc energy qualified or 10% below the minimum arc energy qualified.

Any change 10% above the maximum arc energy qualified or10% below the minimum arc energy qualified.

Miscellaneous Contact tip to work distance. (SAW, GMAW, GFCAW)

Any change more than 5 mm (0.2 in).

Any change more than 5 mm (0.2 in).

Welding head angle relative to pipe tangent (SAW, mechanised/automatic GMAW:

±5° ±5°







Additional for mechanised/automatic GMAW: • Number of welding heads

for each pass. • Separation of welding

heads • Oscillation (frequency,

width, dwell time on side-wall) .

• Pulsing characteristics (frequency, amplitude, shape, base level, delay and crater fill).


Position Angle of pipe axis to the horizontal

Any change exceeding ±25°

Any change exceeding ±25°

Direction of welding

Vertical-up, Vertical Down Any change Any change

Time between passes

Time between completion of root and start of second pass.

Any increase over the time recorded during qualification testing.

Any increase over the time recorded during qualification testing.

Line-up clamps

The type of line up clamp (if used) i.e. internal or external


Number of passes before removal of line-up clamp

Any reduction Any reduction

Cleaning Method, including inter-run cleaning, final surface cleaning, power or hand tool

No restriction provided consistent results are obtained.

No restriction provided consistent results are obtained

Pre-heat Method of applying heat Any change unless otherwise agreed with Principal.

Method of measuring

temperature Any change unless

otherwise agreed with Principal.

Minimum preheat temperature Any reduction; or an increase > 50ºC (90ºF)

Any reduction; or an increase > 50ºC (90ºF)

Maximum and minimum interpass temperature for each run.

Any increase, over 25°C (45ºF) above that qualified, any reduction below the preheat temperature.

Any increase, over 25°C (45ºF) above that qualified, any reduction below the preheat temperature

Post-weld heat treatment

Temperature range Any change Any change

Hold time Any change Any change Shielding gas Flow rate Any flow greater or less

than that qualified, with ±15 % tolerance.

Any flow greater or less than that qualified, with ±15% tolerance







Composition A change of ±10% in the gas % content.

A change of ±10% in the gas % content

Number and sequence of weld beads formechanised/automatic welding processes

Number of weld beads deposited and sequence of deposition.

Any change (One additional run – "stripper pass" – is permitted in productions)

Any change (One additional run – "stripper pass" – is permitted in productions)

Lay barge move-up (Offshore) or pipe movement (onshore)

Minimum number of passes before lay barge move-up or pipe movement This shall not be less than 2 complete passes unless otherwise agreed with Principal.

N/A Any reduction

Interruption in welding

Number of runs completed before cooling to ambient temperature.

Any reduction from the number of runs recorded during qualification testing

Any reduction from the number of runs recorded during qualification testing

Forced cooling after weld completion

When AUT is employed, the method of forced cooling after completion of welding to facilitate testing. The maximum temperature at the beginning and end of cooling shall be specified.

Any change, unless otherwise agreed with Principal

Any change, unless otherwise agreed with Principal

NOTE: 1. Carbon Equivalent = 1556

NiCuVMoCrMnC ++

++++

Pcm = BVMoNiCrCuMnSiC 51015602030

++++++

++

where elements are expressed in % by weight.

5.3.1 Preliminary WPS

Add to this clause:

The proposed welding procedure specifications (WPSs), for all welding procedures including repair welding, shall be submitted to the Principal for review a minimum of two weeks prior to the proposed date of welding qualification.

• The WPS proposals shall be endorsed and signed by the Contractor's authorised representative prior to submission.

• The Principal shall review, then indicate approval of the WPS proposals after any clarifications by endorsing "APPROVED FOR QUALIFICATION", the contract number, the date, and signature.

• After approval by the Principal, each WPS shall be qualified in accordance with this specification. All qualification testing shall be witnessed by the Principal.

To qualify mechanised/automatic welding procedures, three test welds shall be made for each welding procedure. All three shall be subjected to non-destructive testing and at least one shall be subject to mechanical testing.



5.3.5 Shape and dimensions of test pieces

5.3.5.1 Girth welds

Add to this clause:

If internal clamps are to be used, pipes shall have a length of at least 3 m (10 ft).

5.4 INSPECTION AND TESTING OF TEST PIECES

5.4.1 Scope of inspection and testing

Modify Table 1:

Radiographic examination – See additions to [5.4.2] for additional non-destructive examination requirements.

Three sets of impact tests are required for t ≤ 20 mm (3/4 in) and 6 sets for t > 20 mm (3/4 in). See modifications to [5.4.3.5].

Impact testing is required on all pipe > 6 mm (1/4 in) wall thickness.

Macro-examination and hardness test – Two specimens are required (per Technical Corrigendum 1 to ISO 13847)

All-weld-metal tensile test – Required for critical pipelines and critical high-strain pipelines

Additional fracture toughness and corrosion testing may be required. (5.4.3.9 and 5.4.3.10).

5.4.2 Non-destructive examination

Add to this clause:

All qualification welds shall not be subjected to NDE before 24 hours after completion of welding. Any PWHT shall be performed prior to NDE. The required delay of 24 hours is not applicable to welds subject to PWHT.

Radiography shall be by X-ray, using the single wall, single image technique wherever possible. Gamma radiography may be used only as permitted by the Principal and shall be supplemented by ultrasonic examination. Lead intensifying screens shall be used in all cases.

In addition to radiography, ultrasonic examination shall be performed on qualification welds where any part of the weld has been deposited by GMAW, GTAW, or FCAW.

Table 5.4-2 Impact test temperature (for welds not subject to PWHT)

Nominal wall thickness, t Test temperature,

t ≤ 20 mm (3/4 in) T

20 mm (3/4 in) < t ≤ 30 mm (1-3/16 in) T – 10°C (18°F)

t > 30 mm (1-3/16 in) To be advised by Principal T = minimum design temperature

5.4.3 Destructive testing – girth welding

5.4.3.5 Impact testing

Add to this clause:

Alternatively, specimen dimensions and test procedures may be in accordance with ASTM A 370.

For non-critical pipelines:

Add to this clause:

The impact test temperature shall be no higher than 0°C (32°F).

For critical pipelines and critical high-strain pipelines:



Replace fifth paragraph of this clause by:

Impact tests shall be taken from weld centre line, fusion line and fusion line +2 mm (0.08 in), as shown in Figure 3 (as replaced by this DEP). For welds made with the SAW process only, an additional test shall be taken at fusion line +5 mm (0.2 in).. For welds in wall thickness of ≤20 mm (3/4 in) , tests shall be taken at the weld root from 1 mm (0.04 in) to 2 mm (0.08 in) above the inner surface of the pipe. For welds in wall thicknesses >20 mm (3/4 in), tests shall also be taken between 1 mm (0.04 in) and 2 mm (0.08 in) below the outer surface.

The impact test temperature for welds not subject to PWHT shall be as shown in Table 5.4-2 but shall in no case be higher than 0°C (32°F). For welds subject to PWHT the test temperature shall be equal to the minimum design temperature (T°C) (T°F).

The required impact energy for full sized specimens shall be as follows:

• Minimum average energy (of set of three specimens) SMYS/10

• Minimum individual energy (of set of three specimens) SMYS/14

Where SMYS is given in MPa and impact energy in Joules

The required impact energy values for sub-size specimens may be reduced in proportion to the thickness.

5.4.3.6 Macro examination

Add to this clause:

Specimens shall be prepared to a 600 grit finish or better and etched with a solution of 2% to 5% nitric acid in alcohol (Nital). The section surface shall be examined at a minimum of 5x magnification.

5.4.3.7 Hardness testing

Replace second paragraph of this clause by:

Indentation locations shall be as indicated in EN 1043-1 Figures 3 to 7, as appropriate. A photograph shall be taken of each section showing the etched structure of the weld/HAZ and the location of the hardness indentations



Replace Figure 3 by:

Figure 3 Orientation of impact test specimens for procedure qualification of butt welds



Table 2 Permissible maximum hardness values

Modify table as follows (non-sour requirements remain unchanged):

Weld metal

HV10

HAZ

HV10

Hardness Location

Root and mid thickness

Cap Root and mid thickness

Cap

Sour service

t ≤ 9.5 mm (0.37 in) 250 250 250 250

t > 9.5 mm (0.37 in) 250 275 250 275

5.4.3.8 All-weld metal tensile testing

Add to this clause:

All-weld-metal tensile testing is required for critical pipelines and critical high-strain pipelines.

If the design temperature of the pipeline exceeds 75°C (167°F), testing shall be carried out at the upper design temperature.

Testing shall be in accordance with EN 10002-1 or EN 10002-5 as appropriate.

Full stress strain curves shall be provided.

For critical pipelines:

For tests at ambient temperature, the yield strength (Rt0.5) of the weld metal shall exceed the SMYS of the parent material by at least 20 MPa (2900 psi) and the ultimate tensile strength of the weld metal shall exceed that specified for the parent material. For tests at elevated temperature the yield and tensile strengths shall exceed the values required for the parent material as stated in the Project Specification.

For critical high-strain pipelines:

The minimum yield and tensile strength of the weld metal at ambient and elevated temperature shall be as required in the Project Specification. Refer also to Annex E.

In all cases the minimum elongation of the weld metal shall be 18%.

Add new clause:

5.4.3.9 Fracture toughness testing – critical pipelines

For offshore pipelines ≥ 500 mm (20 in) OD, and for other pipelines where required by the Project Specification, CTOD testing shall be performed using single edge notch tension (SENT) or, by agreement with the Principal, single edge notch bend (SENB) specimens.

a) Testing shall be performed on at least three valid specimens from both the weld centre line and from the fusion line/HAZ.

b) Specimen dimensions and testing method shall be carried out in accordance with DNV-OS-F101, Appendix B, Section A900 and DNV-RP-F108 Section 2.3.

c) The precrack depth (notch and fatigue crack) shall be between 0.3 and 0.5 of the pipe thickness.

d) Fusion line/HAZ specimens shall be notched from the outer surface in the weld and the fatigue crack tip shall be positioned in the weld within 0.5 mm (0.02 in) of the fusion line (See DNV-OS-F101, Appendix B, Section 907 and Figure 9).

e) Successful sampling of the fusion line/HAZ by the crack tip shall be verified by



metallography.

f) Weld centreline specimens shall be notched from the inner surface (centre of root) CTOD values shall be reported as δc, δu, or δm, and J values as Jc, Ju or Jm, as defined in BS 7448-2.

Minimum values shall be stated in the Project Specification or as the result of an ECA. NOTE: Fracture toughness testing is not normally required for short sections of offshore pipelines where high

axial stresses are not anticipated, e.g. fixed pipeline risers and onshore sections (of offshore pipelines).

Add new clause:

5.4.3.10 Corrosion testing – sour service

Unless otherwise specified by the Principal, testing for resistance to sulphide stress cracking (SSC) is not required for pipelines in sour service, provided the SMYS of the pipeline material does not exceed 450 MPa (65 ksi) and the maximum axial stress during operation will not exceed 90% of SMYS.

• If required, 4-point bend testing shall be carried out in accordance with EFC 16, Appendix 2.

• The tests shall be performed with the internal surface in tension and in the as-welded condition. at a strain equivalent to 90 % of AYS.

• The strain shall be measured by strain gauges attached directly to the specimen, adjacent to the weld root fusion line.

5.6 ESSENTIAL VARIABLES AND RANGE OF APPROVAL

Replace this clause by:

Essential variables and range of approval for non-critical pipelines, critical pipelines and critical high-strain pipelines are summarised in [Table 5.2-1].

5.7 WELDING PROCEDURE SPECIFICATION FOR REPAIR WELDING

Add to this clause:

5.7.1 General

A repair WPS shall be submitted to the Principal for approval. In addition to the details required in Table 5.2-1, the WPS shall include details on the excavation of defects and preparation of the excavated area for welding.

If a second repair in the same area is permitted by the Principal [see 10.3], the re-repair shall be simulated and shall be subject to the same NDE and destructive testing as required for the first repair, with any additional testing requirements as specified by the Principal.

5.7.2 Non-critical pipelines

If the welding consumables and parameters are within the ranges qualified for the original production weld, no further qualification is required for full and partial depth repairs.

For single pass cap repairs and all internal repairs, simulated repair welds shall be carried out on a joint made to the original weld procedure. The repair welds shall be subject to visual and magnetic particle examination, and one macro-section and hardness survey shall be taken as specified in [5.4.3.6] and [5.4.3.7].

5.7.3 Critical pipelines

5.7.3.1 General

Preheat temperatures for repair welding shall be 50°C (90°F) higher than for the original procedure. Cellulosic electrodes shall not be used for repair welding.

The following repairs shall be qualified by mechanical and, where necessary, corrosion testing of simulated repairs:



• Full depth repair

• Partial depth repair

• Single pass repair - cap

• Single pass repair – root

5.7.3.2 Full penetration repairs

Full penetration repairs shall be qualified by the simulation of such a repair on a weld made to the appropriate, original procedure.

• The excavation shall be at least 100 mm (4 in) in length.

• For welds in the PG/PF or H/J-L045 positions welding shall be carried out between the 6 o'clock and 9 o'clock positions.

• The repaired areas shall be subject to NDE in accordance with the original WPS qualification.

• The following mechanical/corrosion tests, in accordance with [5.4.3], shall be taken from the repaired weld:

o One transverse weld tensile test

o One macro-section and hardness survey

o Three sets of impact tests (for t ≤ 20 mm [3/4 in]) or 6 sets (for t > 20 mm [3/4 in]) in accordance with Figure 3, provided all the original weld metal is removed. Otherwise, the number and location of impact tests shall be agreed with the Principal.

o Fracture toughness testing at weld centre line and fusion line/HAZ (if it was required for the original welding procedure qualification).

o SSC tests of weld root (if they were required for original welding procedure qualification).

• In addition, an AWT shall be taken if the weld metal tensile properties have not been established by qualification of a project welding procedure.

5.7.3.3 Partial penetration repairs – external

Partial penetration repairs shall be qualified by the simulation of the repair of a side wall defect, as shown in Figure 5(b). The repaired area shall be subject to NDE in accordance with the original WPS qualification. Provided the same process, consumables and conditions as qualified for the full depth repair are used for the partial depth repair, the following mechanical tests shall be carried out:

• 1 macro-section and hardness survey

• 2 sets of impact tests taken at the fusion line between the original weld metal and the repair weld, and at this fusion line +2 mm (0.08 in)

• Fracture toughness testing at fusion line/HAZ between the original weld metal and the repair weld (if fracture toughness testing is required for the original procedure)

NOTE: Partial depth repairs from the internal surface shall only be permitted with the agreement of the Principal. Where permitted, internal partial depth repairs shall be qualified as for external repairs and, for sour service, shall also be subjected to SSC testing

5.7.3.4 Partial single pass cap repairs

Single pass cap and root repairs shall be qualified by the simulation of such repairs. The completed weld area shall be subjected to visual and magnetic particle examination and the following mechanical and corrosion tests shall be performed:

• 1 macro-section and hardness survey

• For single pass root repairs – SSC testing (if required for the original procedure)



Internal root repairs on completed welds intended for sour service shall be permitted only with the agreement of the Principal.

Testing conditions and acceptance criteria shall be the same as for the original procedure.

6. APPROVAL AND TESTING OF WELDERS AND WELDING OPERATORS

6.1 APPROVAL FOR MANUAL AND PARTLY-MECHANIZED WELDING

Add to this clause:

Existing welder and welding operator qualifications meeting the requirements of ISO 13847 may be accepted if agreed by the Principal.

6.4 TEST WELDING

6.4.1 Positional welding

6.4.1.1 Girth welds

Add to this clause:

For manual welding other than that of the main pipeline, including pipe to fitting welds, risers, spools, and associated pipework within the pipeline scope, qualification in the H-L045 position shall qualify for all positions.

6.5 INSPECTION AND TESTING OF TEST WELDS

6.5.1 Non-destructive examination

Add to this clause:

Radiography shall be by X-ray, using the single wall, single image technique wherever possible, in accordance with clause [8.5]. Gamma radiography may be used only as permitted by the Principal and shall be supplemented by ultrasonic examination in accordance with clause [8.6].

In addition to radiography, ultrasonic examination shall be performed on qualification welds where any part of the weld has been deposited by GMAW, GTAW or FCAW.

The mechanical test requirements of clause 6.5.2 shall also apply.

7. PRODUCTION WELDING

7.1 GENERAL

Modify this clause:

The minimum allowable distance between girth welds shall be the external pipe diameter or 500 mm (20 in), whichever is larger. The minimum distance between the weld toe of any branch or attachment weld and that of a similar weld or a girth weld shall be 100 mm (4 in) or 4 t, whichever is larger.

7.5 PIPE END PREPARATION

Replace third paragraph of this clause by:

The principal means of weld bevelling shall be by machining. Manual preparation methods shall be used only in individual cases with the permission of the Principal. If thermal cutting is employed, all heat-affected material shall be removed by machining or grinding to a depth of 1 mm (0.04 in).

Add to fifth paragraph of this clause:

If more than 6 mm (1/4 in) is removed from the original, as-delivered pipe end, the bevel shall be subject to MPE. No through-thickness defect of any length, or any circumferential



defect > 6 mm (1/4 in), is permitted. If AUT is to be subsequently carried out on the completed butt weld, no through-thickness defects or circumferential defects are permitted.

7.7 LINE-UP

Replace first paragraph of this clause by:

Longitudinal and/or spiral weld seams shall be separated by at least half a pipe diameter at the girth weld. Longitudinal weld seams shall be positioned in the top of the pipe between the 9 o'clock and the 3 o'clock positions.

Add to third paragraph of this clause:

For critical pipelines and critical high-strain pipelines, the internal misalignment shall not exceed 1.6 mm (0.06 in) at any location around the circumference. A smaller tolerance may be required by the Project Specification.

Add to fourth paragraph of this clause:

The line-up procedure for fittings, flanges, and pipe joints shall be approved by the Principal

7.8 TACK WELDING

Add to this clause:

If tack welding is necessary, bridge tacks (made by welding a carbon steel bar to the faces of the weld preparation) shall be used. The use of root tacks shall be permitted only with the agreement of the Principal.

7.10 ELECTRODES AND FILLER MATERIALS

Add to this clause:

The selection of electrodes and filler materials shall be approved by the Principal.

If low-hydrogen SMAW electrodes are selected, it shall be demonstrated to the satisfaction of the Principal that the diffusible hydrogen content shall not exceed 5 ml (0.013 gal) per 100 g (0.22 lbm) of the resulting deposited weld metal

For critical pipelines and critical high-strain pipelines, batch testing of consumables shall be performed in accordance with AWS A5.01, with the following classification:

• SMAW consumables: C2

• Solid electrodes: S2

• Flux cored electrodes: T2

• SAW fluxes: F2

All batch tests shall be documented by an inspection certificate in accordance with ISO 10474, Type 31.B.

For sour service, all consumables shall result in deposited weld metal complying with the requirements of ISO 15156-2.

Additional weld chemistry requirements for resistance to preferential corrosion in hydrocarbon and water service shall be stated in the Project Specification.

7.11 SHIELDING GASES

Add to this clause:

Purity and (for gas mixtures) the compositional tolerances shall be in accordance with ISO 14175.



7.12 PREHEATING

Add to this clause:

The minimum preheat temperature shall not be less than that calculated in accordance with EN 1011-2. For tack welding and repairs, the preheat temperature shall be at least 50°C (90°F) above that established for the relevant main procedure.

Preheat temperatures may also be measured by contact thermocouples.

If induction coils are used, they shall be switched off before welding.

7.13 STRAY ARCS

Add to this clause:

MPE and ultrasonic wall thickness measurement shall be performed on areas where arc strikes have been removed. The wall thickness shall not be reduced below the minimum specified for the line pipe.

7.16 WELD METAL DEPOSITION

7.16.2 Other welding

Add to this clause:

For set-on nozzles an area of pipe 25 mm (1 in) greater in diameter than that of the footprint of the nozzle connection weld shall be inspected by compression wave ultrasonic examination in accordance with ISO 11496. Defects with an area greater than 100 mm2 (0.16 in2) are unacceptable. Adjacent defects separated by a distance less than the largest dimension of the smallest defect shall be assessed as one defect.

7.18 PARTIALLY COMPLETED WELDS

Add to this clause:

The weld shall not be interrupted (i.e. allowed to cool to ambient temperature) before completion of the third pass. In the event of such an interruption, the weld shall be removed from the line.

If sections of pipeline containing uncompleted welds are moved, the Contractor shall submit calculations to demonstrate that the stress in the partially completed welds does not exceed 80% of SMYS. Refer to [Table 5.2-1] and clause 7.6.

7.19 POST WELD HEAT TREATMENT

7.19.3 Post weld heat-treatment procedure

Replace second sentence of this clause by:

The minimum holding temperature shall be 580°C (1076°F), unless otherwise agreed with the Principal.

Add to this clause:

A post weld heat-treatment procedure shall be submitted to the Principal for approval. This procedure shall contain details on the holding temperature range, heating and cooling rates, temperature measurement, control, and recording temperature measurement.

Add new clause:

7.21 PRODUCTION TESTING

The Principal shall have the right to request a test weld to be made at any stage during normal production welding to allow a metallurgical examination of the deposited weld. Similarly, when NDT cannot be carried out or gives inconclusive results, the Principal shall have the right to have a pipe section, including the weld, cut out and removed for testing.



Subsequent mechanical testing shall be carried out in accordance with [5.4.3] and as directed by the Principal.

If production testing is required as part of the Project, the frequency and extent of testing shall be as specified in the Project Specification.

8. NON-DESTRUCTIVE EXAMINATION

8.1 GENERAL

Add to this clause

All butt welds SHALL [PS] be subject to either 100% radiography or 100% mechanised / automatic ultrasonic examination.

• Manual ultrasonic examination shall be substituted for radiography only with the agreement of the Principal.

• If radiography is used to inspect GMAW welds, the first 50 welds shall also be subject to automated or manual ultrasonic examination.

• If a significantly higher number of unacceptable defects are found by ultrasonic examination, ultrasonic examination shall be continued at the discretion of the Principal.

Welds on offshore pipelines made using GMAW shall be inspected with automated ultrasonic testing (AUT) if the total included angle of the weld preparation is less than 30° or the thickness is greater than 25 mm (1 in), unless agreed otherwise by the Principal.

For welds that will not be subjected to hydrotesting i.e. “golden” welds, both radiography and ultrasonic examination shall be carried out. With the agreement of the Principal, radiography may be waived if AUT is used.

All attachment welds to the pipe surface and all set-on branch fitting connection welds shall be subjected to 100% MPE (which means the complete length of every weld).

For offsite fabrication of pipeline spool pieces and the welding of fittings, there shall be a minimum delay between completion of welding and NDE of 24 hours. For all onshore welding with cellulosic electrodes, there shall be a minimum delay between completion of welding and NDE of 12 hours.

8.2 QUALIFICATION OF NDE PERSONNEL

Add to this clause:

General

NDE personnel shall hold a valid qualification to EN 473 or ISO 9712 for the relevant technique (or to an equivalent standard approved by the Principal)

Only personnel qualified to Level 2 or Level 3 shall interpret the test results. A Level 3 qualified inspector shall be available to give supervision and assist in the interpretation of ambiguous indications.

If, in the opinion of the Principal, welding examination or NDE personnel fail to perform to a satisfactory standard, they shall be disqualified from the works until such time that it can be demonstrated by the Contractor that they have achieved a satisfactory standard by undertaking a test by a third party agency approved by the Principal.

The procedure for qualification of AUT personnel shall be agreed with the Principal.

8.5 RADIOGRAPHIC EXAMINATION

8.5.1 Technique


Delete reference to ISO 1106-3 and substitute ISO 17636 (for which Class B shall apply).



Gamma radiography may be substituted for X-radiography only with the agreement of the Principal. For critical pipelines and non-critical pipelines, gamma radiography shall be supplemented by manual ultrasonic examination.

For pipe ≥500 mm (20 in) OD where the double wall, single image technique is employed, radiography shall be supplemented with manual ultrasonic examination.

8.5.3 Procedure qualification

In the second paragraph of this clause replace ISO 1106-3 by ISO 17636

8.5.6 Screens

Add to this clause:

Lead screens shall be used for welds in off-site fabrication.

8.6 ULTRASONIC EXAMINATION

8.6.5 Mechanised examination

Replace this clause with:

8.6.5 Automated ultrasonic testing (AUT)

The procedure for qualification of the AUT system, and the interpretation of results, shall be agreed with the Principal and shall generally be in accordance with the requirements of DNV OSF101, Appendix E.

9. ACCEPTANCE CRITERIA FOR NON-DESTRUCTIVE EXAMINATION

9.5 ULTRASONIC EXAMINATION

Add new clause:

9.5.4 Acceptance criteria – AUT

9.5.4.1 General

The general (workmanship) AUT acceptance criteria in [9.5.4.2 and 9.5.4.3] apply to pipelines of wall thickness ≥12 mm (1/2 in) and are equivalent to the radiographic acceptance criteria given in 9.4. The indication sizes are stated as measured dimensions and are based on a measurement uncertainty of 1.5 mm (0.06 in) (for both height and length). This uncertainty is the maximum permitted for any AUT system, which shall be established by historical data and performance trials and accepted by the Principal.

9.5.4.2 Linear indications

If any part of the indication lies within 2 mm (0.08 in) of the inner or outer surface:

Height < 3.0 mm (0.12 in): Wall thickness or 25 mm (1 in), whichever is less.

Height > 3.0 mm (0.12 in): Not acceptable.

For indications not within 2 mm (0.08 in) of the inner or outer surface:

Height < 3.0 mm (0.12 in): 50 mm (2 in) or 2 x wall thickness, whichever is less.

Height > 3.0 mm (0.12 in) ≤ 5 mm (0.20 in) or 0.25 t, whichever is less: 12.5 mm (1/2 in)

Height > 5 mm (0.20 in) or 0.25t, whichever is less: Not acceptable.

The maximum allowable accumulated length of reportable indications in any 300 mm (12 in) of weld shall be 100 mm (4 in) or 3 x wall thickness, whichever is less.

The maximum allowable accumulated length of reportable indications in any weld is 12% of weld length.

Any indication signifying a crack or copper inclusion is not acceptable



Visually apparent linear defects (i.e. lack of fusion) on, or adjacent to, the external weld cap of a depth greater than 1 mm (0.04 in) are unacceptable.

9.5.4.3 Gas clusters:

Height > 3 mm (0.12 in) or length > 25 mm (1 in) is not acceptable

The interaction rules for defects shall apply in accordance with BS 7910 Figure 9.

For pipelines with wall thickness <12 mm (1/2 in), the AUT acceptance criteria shall be subject to the agreement of the Principal

Add new clause:

9.5.5 Acceptance criteria based on ECA

For non-critical pipelines and critical pipelines, AUT defect acceptance criteria based on an ECA may only be applied if agreed by the Principal. Such an assessment shall be carried out in accordance with BS 7910 Level 2 (or other assessment method acceptable to the Principal) and shall only be carried out when all pipeline stresses and other design factors are known and when the fracture toughness of the weld and HAZ have been established for all welding procedures and materials. NOTE: It is therefore unlikely that such acceptance criteria could be accepted pre-contract.

Such defect acceptance criteria shall be based on the critical defect sizes, as determined by the ECA, plus the AUT uncertainty in flaw sizing.

10. REPAIR AND REMOVAL OF DEFECTS

10.2 AUTHORISATION FOR REPAIR


Internal partial depth repair shall not be carried out unless agreed with the Principal. For sour service, single pass internal repairs on completed welds shall not be carried out unless agreed with the Principal and qualified by additional corrosion testing. See [5.7].

Solidification cracks in the weld metal may be repaired, if they are not longer than 4 mm (0.16 in). All other cracks, in weld or HAZ, may not be repaired and the affected weld shall be removed from the line.

10.3 SECOND REPAIRS

Replace this clause by.

Second repairs shall be permitted only on an individual basis with the agreement of the Principal and shall be carried out to a qualified, repeat repair procedure. See [5.7]. No more than two repair attempts are permitted. If the second repair is unacceptable, the complete weld shall be removed.

10.4 DEFECT REMOVAL AND PREPARATION FOR REPAIR

Add to this clause:

For offshore welding, the maximum safe depth and length of repair for each repair location relative to the tensioners shall be calculated and submitted to the Principal for approval.



ANNEX A (informative) HYPERBARIC WELDING

Add to this annex:

The requirements for hyperbaric welding, if applicable, shall be as specified by the Principal.

ANNEX B (informative) SPECIAL REQUIREMENTS FOR THE WELDING OF CRA-CLAD STEEL AND CRA PIPELINES

Replace this annex by:

The specification for welding of CRA-clad steel and CRA pipelines shall be agreed with the Principal.

ANNEX C (informative) RECOMMENDATIONS FOR BRAZING AND ALUMINOTHERMIC WELDING OF ANODE LEADS

Add to this annex:

The qualification of procedures for the brazing and aluminothermic welding of anode leads to line pipe shall be as specified in clause C.2.

Add this annex:

ANNEX E REQUIREMENTS FOR CRITICAL HIGH-STRAIN PIPELINES

E.1 GENERAL

This annex shall apply to critical high-strain pipelines in addition to the requirements for critical pipelines specified in Part II of this DEP. These pipelines may also be designated for sour service. Examples include pipelines installed by reeling or other high strain methods and those which will experience high operational strains due to thermal buckling, ground movement or free spanning.

Due to the wide range of conditions covered by this category, it is not possible to specify normative requirements for all possible cases. Such requirements for qualification, installation, inspection and acceptance shall be detailed in the Project Specification. The following sections are therefore informative and intended to form a framework on which a Project Specification may be based.

E.2 WELDING PROCEDURE QUALIFICATION AND MECHANICAL/CORROSION TESTING

E.2.1 All-weld-metal tensile testing.

The measured yield strength of the weld metal at room temperature shall be higher than the maximum permitted yield strength of the pipeline material. The minimum weld-metal yield strength at elevated temperature shall be specified in the Project Specification.

E.2.2 Fracture toughness testing

Fracture toughness testing requirements for critical high-strain pipelines shall be specified on an individual basis, but will consist of some, or all, of the following:

• CTOD or J R-curves generated by the testing of at least six SENT specimens in both weld centreline and fusion line/HAZ (Refer to DNV-RP-F 108 Section 2.3).

NOTE: Where previous testing has given confidence in the tearing behaviour of the weld joint, the number of tests to establish the R-curve may be reduced to a minimum of three.



• Segment testing (refer to DNV-RP-F 108 Section 4).

• "Wide plate" testing using transweld tensile specimens of at least 300 mm (12 in) width, containing simulated weld defects.

The required values shall be specified on an individual basis. For R-curves a lower bound curve shall be defined by an equation of the type: δ or J = x∆am (where ∆a is crack extension, x and m are constants). For wide plate tests, a minimum strain level shall be attained without propagation of specified, simulated defects.

The fracture toughness testing requirements for pipelines subject to total installation strains of ≥ 1.0% (e.g. reeling) shall be in accordance with DNV-RP-F108 and the Project specification. For these pipelines validation of the ECA shall be either by segment testing (in accordance with DNV-RP-F108 Section 4) or by full scale testing. Validation testing may be waived by the Principal where there is an adequate historical record of previous testing validating the ECA methodology.

E.2.3 Strain-aged testing

For pipelines where the installation strain exceeds 0.4%, a section from each procedure qualification weld (including full depth repair welds) shall be strained in tension to the maximum total accumulated strain equal to that experienced by the pipeline. After straining, the section shall be heat treated at 250°C (482°F) for a minimum period of one hour. The following tests shall be taken from the aged weld:

• Three or six sets of Charpy impact tests (depending on the thickness) as required by (5.4.3.5). Testing and energy requirements shall be as specified in (5.4.3.5).

• 1 all-weld metal tensile test in accordance with (5.4.3.5). The measured yield strength of the weld metal shall be greater than the maximum specified yield strength of the pipe material.

If an ECA is to be applied to the operational case after straining, (i.e. after high-strain installation), fracture toughness testing in the strain aged condition may be required unless there is sufficient evidence that the fracture toughness properties are not reduced by strain aging.

E.2.4 Sour service

For pipelines in sour service subject to operational axial strains corresponding to more than 90 % of SMYS, testing for resistance to SSC shall be required by the Project Specification. This may include of some, or all of the following tests:

• Four-point bend testing (refer to EFC 16, Appendix 2).

• Determination of K1ssc by the double cantilever beam method (Refer to EFC 16, Appendix 3) or by testing of fracture toughness specimens (e.g. SENB, SENT) in sour environment.

• "Full ring" testing of whole weld under sour conditions and design stress.

Where an ECA is required for an operational case involving sour conditions, values of K1ssc for weld and fusion line/HAZ will be required for the assessment of root defects exposed to the sour environment. In addition, CTOD values for hydrogen charged specimens (but not directly exposed to the sour test environment) may be required to assess non-surface breaking defects.

For pipelines where the installation stress exceeds 100% SMYS and is exposed to sour conditions in operation, but where the operational axial stress is ≤ 90% SMYS, 4-point bend SSC testing shall be carried out on weld samples that have been subjected to strain cycles equivalent to the maximum anticipated in installation. Testing shall be in accordance with EFC 16, Appendix 2.

The testing conditions, including applied strains, H2S level, test solution pH and duration of test shall be stated in the Project Specification. Other forms of testing, applicable to particular pipeline conditions, may be required by the Project Specification.



E.2.5 Fatigue

Fatigue crack growth tests may be required in the case of cyclic, operational strain. In assessing the growth of flaws exposed to corrosive (sour and non-sour) environments, testing shall be carried out in a similar environment

E.2.6 Qualification of repair welding procedures

The qualification of repair welding for critical high-strain pipelines shall be as required for critical pipelines. However, further testing of weld metal tensile properties and fracture toughness shall be performed. The type and extent of the additional testing shall be stated in the Project Specification.

E.3 NON-DESTRUCTIVE EXAMINATION

AUT shall be used on all critical high-strain pipelines. The procedure for qualification of the AUT system, and the interpretation of results, shall be agreed with the Principal and shall be in general accordance with the requirements of DNV OSF101, Appendix E.

E.4 ACCEPTANCE CRITERIA FOR NON-DESTRUCTIVE EXAMINATION

The maximum permitted flaw dimensions for acceptance criteria shall be determined by an ECA. Unless otherwise agreed or required by the Project Specification, the method of assessment shall be in general accordance with BS 7910 Level 3B and DNV-RP-F-108 Section 3, using R-curves obtained in accordance with (E.2). Alternative methods, including those making use of finite element analysis, may also be used if agreed with the Principal. ECAs of operational cases shall include the effect of internal pressure.

The maximum fracture toughness value used in ECAs shall be that corresponding to a crack extension (∆a) of 1 mm (0.04 in), unless otherwise agreed with the Principal. Where the ECA is carried out by the Contractor, the ECA methodology shall be agreed with the Principal.

Cases are possible where both installation and operational stresses involve high strains, e.g. where installation is by reeling and where the pipeline is subject to lateral buckling in operation. In this situation ECAs shall be required for both cases, the fracture toughness testing requirements and weld defect acceptance criteria being determined by the most stringent of the two cases. The effect of strain-aging shall be taken into account in carrying out the ECA for the operational case (see E.2.3).

Where an ECA is required for an operational case involving sour service, the maximum permitted size of flaws exposed to the sour environment shall be assessed by a linear elastic method using measured K1ssc values. The maximum size for buried flaws shall be assessed using fracture toughness obtained from hydrogen charged specimens.

For operational cases involving cyclic loading, allowance shall be made for fatigue crack growth.

Validation of the ECA may be required using segment or wide plate tests, unless there is sufficient historical data to validate the ECA methodology to the satisfaction of the Principal. For operational cases, the selection of the artificial defect size used in such tests shall make allowance for the effect of internal pressure in reducing the critical defect size.

Flaw acceptance criteria shall be based on the dimensions of the critical defect sizes determined by the ECA, minus the uncertainly in sizing of the AUT method and equipment to be used, as established by testing specified by the Principal. Acceptance criteria shall be clearly and simply defined, and agreed by the Principal.

Add this annex:



ANNEX F ADDITONAL REQUIREMENTS FOR THE GIRTH WELDING OF STEEL CATENARY RISERS

F.1 GENERAL

This annex specifies requirements and gives recommendations for steel catenary risers. CAUTION: The use of this annex, or parts of this annex, might not be acceptable under the regulations in some

countries (for example, the use of the API X' S-N curve is not permitted in the UK or Norway). Before using this annex, the Principal shall check if its use is permitted by the applicable regulations.

F.2 WELDING PROCEDURE QUALIFICATION

The use of mechanised/automatic welding processes shall be approved by the Principal before qualifying weld procedures. Approval of mechanised/automatic welding processes shall be based on pipeline construction, proven track records and/or a test program to prove the process capabilities for pipeline or flowline welds. A test program shall be successfully conducted whenever mechanised/automatic welding is proposed for SCR welds.

This test program shall be successfully conducted whenever mechanised/automatic welding is proposed for Steel Catenary Riser welds, unless specifically waived by the Principal in the Contract. As part of the process capabilities test program, the Contractor shall produce fifty (50) consecutive welds with no less than forty five (45) meeting the nondestructive testing acceptance standards as specified in (F.7). Nondestructive testing shall be performed using both x-ray radiography as specified in (8.5) and the selected AUT system for production welding. Mechanical properties, including fracture toughness, of at least one of the fifty welds shall also be determined. Sectioning of a weld or welds may be required based on the nondestructive examination results.

The process capabilities test program described above shall also be completed whenever the gas metal arc welding process using the surface tension transfer (STT) welding technique is proposed for SCR welds. This applies to all Contractors including those that have used this technique during installation of previous SCRs.

Selection of SCR welding processes shall consider all associated processes; for example, pipe cutting, bevelling, and alignment. SCR welding processes shall not be selected solely in order to enhance welding speed, as SCR weld quality is paramount.

F.3 QUALIFICATION BY FATIGUE TESTING

F.3.1 General

All offshore (and onshore if applicable) girth weld processes shall be qualified for cyclic service (i.e. fatigue testing) unless previously qualified for the Principal’s previous SCRs. The Contractor shall clearly state in his bid documents whether he proposes weld processes that he considers to have been previously qualified by the Principal. The default assumption is that the weld process has not been qualified. Unless specifically approved otherwise by the Principal, the Contractor shall conduct fatigue tests for each qualified welding process. In bidding, the Contractor shall assume that fatigue testing is required for separate diameters if the nominal pipe diameter sizes differ by more than two sizes or if pipe wall thickness for the two different diameters differs by more than 3.2 mm (0.126 in)

Any riser weld process that has not been qualified previously for use on a project for the Principal, shall be qualified. This shall involve full scale fatigue testing of at least 3 welds each at three stress ranges by means of rotating bending tests. To allow sufficient time for the testing the qualification programme shall commence at least 6 (six) months prior to riser installation.

F.3.2 Scope of work of qualification by fatigue testing

The Contractor shall be responsible for performing, or subcontracting, full-scale resonant fatigue tests of nine full-scale samples in air. The scope of work for the fatigue test shall include:

a) Develop fatigue test procedures.



b) Receipt of sample and sample preparation.

c) Coordination and arrangement of witnessing by the Principal at any subcontractors' premises.

d) Fatigue test of nine samples at predetermined stress ranges.

e) Post – mortem investigation.

f) Test Report.

The development of the WPS, including weld consumable selection, welding process, etc. is the responsibility of the Contractor. The Principal will monitor the development of the procedures and sample preparation. All welds shall be made and inspected as if they are production SCR quality welds.

The test welds shall be prepared in a continuous sequence, as they would be in production. All welds shall either be accepted, or rejected and cut-out and re-welded on the basis of AUT and other inspection procedures. The Contractor shall attempt to include some welds with deliberate root defects within the range of the acceptable ECA values. The Principal shall have final approval of all welds to be tested.

Should the SCR be reeled, the test welds shall first be subjected to at least four complete strain cycles at a strain that corresponds to the minimum reel or aligner radius, prior to fatigue testing.

F.3.3 Sample preparation

All riser weld fatigue qualification testing shall be completed using resonance machines. Full scale fatigue test specimens shall be fabricated using a specimen as described below:

A

B

Figure F.2

Piece 1 Piece 2

Test Weld

Figure F.1 Resonance machine test specimen (pipe OD varies per project)

Table F.1 Specimen description

Specimen Size Overall Length “A” (m)

Weld Position “B” (m)

Riser Pipe OD, Wall, Grade as in the Contract, unless specifically defined otherwise

To be decided by Testing Subcontractor, but approximately 6 m (20 ft)

To be decided by Testing Subcontractor, but Approximately 3 m (10 ft)

NOTE: Dimensions A and B are shown on Figure F.1.

Also, reference markers shall be placed at 0°, 90°, 180°, and 270° positions at both ends of the specimen so that a consistent reference plane is maintained for identifying hi-lo/flaws/specimen orientation.



Ideally, Piece 1 and Piece 2 should be of contrasting yield and tensile strengths within the range of project pipe supplied by the Principal (i.e. If Piece 1 is a high yield and tensile strength sample, then Piece 2 should be of a low yield and tensile strength).

Prior to shipment of test specimens to the third party test facility the following shall be recorded:

a) Actual specimen length;

b) End measurements before welding (including wall thickness);

c) Location of weld;

d) Hi-lo information on weld, at circumferential positions, taken at 30°;

e) Any defect information (e.g. AUT reports).

Every attempt should be made to make pipe welds with the maximum allowable hi-lo tolerance. If the production pipe ends are to be counter bored or ID-trued by machining for fit-up within the specified hi-lo tolerances, the test pipe ends shall also be counter bored or ID-trued by machining.

F.3.4 Test preparation

All specimens shall be strain-gauged in the weld area, with strain gauges placed circumferentially at 90° intervals on both sides of the weld as detailed in Figure F.2 below. All strain gauge locations shall be referenced to orientation marks on each end of the specimen. Unless otherwise specified by the test contractor the strain gauge distance to the weld cap shall be 50 mm (2 in). The weld cap shall not be sanded or sanded flush unless such sanding will also be executed during production welding.

TBD

Strain Gauge

TBD

Strain Gauge

NOTE: TBD = To be decided

Figure F.2 Test weld detail

Specimens shall be tested in a high frequency test machine at a third party testing facility. If no failure occurs, run-out data can be used if they comfortably exceed API-X’. Data shall be compared to the pool of existing full-scale and small-scale data.

The third party testing contractor shall provide comprehensive procedures including but not limited to sample details, test preparations (including application of “mean stress”), loading and stress calculations, actual test procedures, and measurement details.

The third party testing contractor shall be responsible for designing and welding end caps as necessary to develop required mean stress in the test sample.

A representative of the Principal shall be present during sample preparation, test preparation, loading of sample, initiation of fatigue testing, and unloading of sample, unless this privilege is waived.

F.3.5 Test samples

Full scale fatigue testing shall be performed on at least three (3) welds each at three (3) stress ranges for each welding procedure/pipe combination to be qualified.

Table F.2 Riser pipe test samples

Specimen Stress range



Number MPa (psi)

1A, 1B, 1C 170 (25,000)

2A, 2B, 2C 120 (17,500)

3A, 3B, 3C 80 (11,500)

The mean stress for all the above is 140 MPa (20,000 psi)

The nominal or design stress range is based on the nominal outside diameter and wall thickness of the pipe and calculated directly from strain gauge readings obtained by gauges mounted on the outer surface of the pipe. The strain gauges shall be located close to the weld, but outside the area where the wall thickness may have been reduced by pipe end counterboring or ID-truing. No corrections shall be made to the nominal or design stress values for reductions in wall thickness near the weld, failure location (inner or outer surface of the pipe) or any strain concentrations produced by pipe end mismatch or the weld profile.

F.3.6 Requirements for qualification

Specimen Numbers 1A, 1B, 1C (Test Series 1)

The mean of the data (failures and run-outs, if any) shall achieve 477,243 cycles (i.e. 4.5X API-X’). At least one failure shall be achieved, with no single failure before 106,053 cycles (i.e. 1X API-X).

Specimen Numbers 2A, 2B, 2C (Test Series 2)

The mean of the data (failures and run-outs, if any) shall achieve 1,811,643 cycles (i.e. 4.5X API-X’). At least one failure shall be achieved, with no single failure before 402,587 cycles (i.e. 1X API-X’). In addition, lower bound failure shall, when connected to the lower bound failure from the Test Series 1 welds, achieve a log ∆S vs. log N slope no steeper than –3.74 (API-X’ slope). Specimen Numbers 3A, 3B, 3C (Test Series 3)

The mean of the data (failures and run-outs, if any) shall achieve 8,710,138 cycles (i.e. 4.5X API-X’), with no single failure below 1,935,586 cycles (i.e. 1X API-X’). In addition, lower bound failure (or shortest runout if no failures are obtained) shall, when connected to the lower bound failure point from the Test Series 2 welds, achieve a log ∆S vs. log N slope no steeper than –3.74 (API-X’ slope).

F.3.7 Post-mortem investigation

All weld failures shall be sectioned and subjected to a post-mortem examination to determine, to the extent possible, what initiated the crack that led to the weld failure. A full test report shall be prepared upon completion of the test and furnished to the Principal.

F.4 FIELD BEVELS

The Contractor shall develop a QC procedure for the Principal’s approval for checking the dimension of each bevel and ensuring that the bevel dimensions are within the required tolerance before the pipe is moved to the production welding line.

The ID of the ends of each piece of pipe supplied by the Principal will generally be within +/- 1.6 mm (0.063 in) of the average specified nominal ID of the pipe order. The Contractor shall arrange for a pipe joint end dimensional survey at the Contractor’s cost and shall supply the Principal with a recommended assembly sequence for approval.

The Contractor shall develop for the Principal’s approval procedures for sorting the pipe and measuring hi-lo during production assembly. Hi-lo measurements shall be verified by the Contractor’s designated QC personnel and the Principal’s representative and recorded for as many locations around the pipe ends circumference as are required, but no less than six (6). Care shall be taken that such measurements are taken as close as practical to the actual weld ends.



The Contractor shall assemble the riser pipe with internal hi-lo mismatch limited to ±0.5 mm (0.020 in) except as allowed below. Should the Principal provide fully assembled quadruple joints to the Contractor ready for offshore installation, the Principal will take responsibility for the matching of quadruple joint ends and provide the Contractor with a record of measurements.

If the internal hi-lo criteria cannot be met by selection alone, the Contractor shall ID-true individual joints as required to meet the hi-lo criteria for the total circumference of the joint. Such work shall take place and be completed with sufficient time for inspection before the start of production welding.

The following deviations from the maximum hi-lo mismatch are allowed:

• On heavy wall DSAW or other seam welded line pipe [generally 400 mm (16 in) and larger in nominal diameter], some peaking at the seam may result in not being able to meet the maximum hi-lo tolerance. The Contractor is allowed to rotate the seams of adjacent pipe joints to the optimum position to minimize hi-lo (even if this means placing seam to seam). Should the Contractor still not be able to achieve the maximum allowable hi-lo tolerance, the maximum hi-lo tolerance at the seam may be increased to 0.9 mm (0.035 in).

• If separate ECA criteria have been developed for “critical” and “non-critical” riser welds, the hi-lo tolerance for non-critical welds may be increased to +/- 0.75 mm (0.030 in)

• While no specific external specific hi-lo criteria are specified, external hi-lo shall be measured after achieving the required internal hi-lo tolerance. If external hi-lo exceeds 1.5 mm (0.060 in) on any weld, the Principal’s welding inspector shall be consulted to decide whether a hi-lo slightly higher than specified can be accepted, or whether the joint shall be rejected.

• The Contractor shall alert AUT personnel of any unusual hi-lo conditions and mark them on the pipe. Before the AUT technician designates that a weld shall be cut out, the welding supervisor shall ensure that the AUT technician has the appropriate hi-lo information for this evaluation.

F.5 WELDING PERSONNEL

All welding personnel shall be subject to approval by the Principal. Welder qualification shall include AUT and riser weld flaw acceptance criteria.

F.6 NON-DESTRUCTIVE EXAMINATION

All welds shall be examined by means of AUT in accordance with a procedure and acceptance criteria agreed by the Principal. The Contractor may be required to supply up to 10 welds, including up to 5 welds with seeded defects, for development of NDE procedures.

F.7 WELD ACCEPTANCE CRITERIA

F.7.1 Surface defects

Acceptance criteria shall be in accordance with (F.7.3).

Burn through and arc burns within 100 mm (4 in) of the weld shall be unacceptable and the weld shall be cut-out and re-welded.

Undercut at the ID weld edge is unacceptable unless the ECA based approach has determined an acceptable length for undercut. Undercut shall be treated as a linear defect and, if accepted, AUT operator shall consider this in defect evaluation. External undercut shall also be considered a defect and shall not exceed 0.4 mm (1/64 in). The AUT operator shall be notified of any external undercut that can be measured and the position relative to the zero position for the AUT scan and shall consider the existence of undercut in the weld evaluation.

Any internal concavity shall blend smoothly into the pipe surface.



If using the ECA based approach, the height and length of internal undercut or internal root concavity shall be treated as if they were a linear defect.

Because the depth of undercut or internal root concavity cannot be reliably measured by means of the ultrasonic pulse echo technique, they shall be measured by means of Time of Flight Diffraction (TOFD).

F.7.2 ECA Weld acceptance criteria

F.7.2.1 Applicability

This clause applies to single sided butt welds in SCRs. SCRs may also include Lazy Wave SCRs, which are SCRs with a section of the riser supported by buoyancy. All welds shall be examined by AUT in accordance with procedures agreed by the Principal. Welds in an SCR may be divided into “critical” welds and “non-critical” welds. Critical welds include at least those welds in the section that is characterized as the “touchdown zone”, usually a pipe section at least 300 m (1000 ft) long, and a few welds near the top hang-off point. In some cases, other regions for critical welds may be identified, for example welds near the mouth of a pull-tube of a SPAR if the flowlines are pulled into a pull-tube rather than supported by a stress joint or flex joint, or welds in the belly section of a Lazy Wave or Shaped SCR.

Unless the requirement is specifically waived by the Principal, critical weld procedures shall be qualified in a full scale fatigue testing program (see F.3) and shall meet the minimum requirements of the API-X’ S-N Curve as specified in (F.3).

Typically, non-critical welds shall be made using the same welding procedure as used for the critical welds, but with slightly relaxed criteria for joint alignment (see F.4). If this is the case, such welds are typically classified to meet the minimum requirements of the BS 7608-E S-N curve. The transition point from “critical” to “non-critical” welds shall be defined as the point where the fatigue spectrum will result in the weld meeting the required minimum fatigue life of the BS 7608-E curve with appropriate allowance for movement of the touchdown point, but shall not be less than 150 m (500 ft) from the nominal touchdown point unless specifically approved by the Principal.

In some cases, non-critical welds are made using different welding procedures than the procedures used for critical welds, for example in a riser with a clad welded touchdown section, and carbon steel upper section. If the Principal has waived full scale fatigue qualification for such welds, the transition point of the critical section to the non-critical section shall be defined as the point where the fatigue spectrum will result in the weld meeting the required minimum fatigue life of the BS 7608-F2 curve with appropriate allowance for movement of the touchdown point, but shall not be less than 150 m (500 ft) from the nominal touchdown point unless specifically approved by the Principal. Non-critical welds shall still meet the general construction requirements of (5.).

F.7.2.2 Analysis

The Principal will usually provide default acceptance criteria as part of the Invitation to Tender document, but detailed ECA shall be carried out prior to start of construction. The Principal will normally conduct this detailed ECA, but the Contractor in that case is still responsible for a simplified fatigue analysis for construction cyclic loading.

Should the Contractor be responsible for both detailed design and construction, the Contractor shall conduct the ECA and develop weld acceptance criteria for the Principal’s approval.

F.7.3 Acceptance criteria

Because weld acceptance criteria may not be available to the Contractor at the time of bidding the work, the Contractor may use the default weld acceptance criteria in Tables F.3 through F.6 for the purposes of bid preparation. These criteria are only preliminary and shall be validated by ECA. The overall length of “critical” joints may be assumed to be at least 300 m (1000 ft) of each riser and the weld between the stress joint or flex joints and first pipe weld is also considered a “critical” weld. (These tables include an allowance for AUT under sizing error and thus can be considered to present AUT acceptance criteria):



Table F.3 Critical (touchdown joints) – ID and OD surface breaking defects

Height (mm) Height (in) Length (mm) Length (in) 0 ≤ 0.5 0 ≤ 0.02 25.4 1.0 > 0.5 ≤ 1.0 > 0.02 ≤ 0.04 12.7 0.5 > 1.0 > 0.04 0 0

Table F.4 Non-critical joints – ID and OD surface breaking defects

Height (mm) Height (in) Length (mm) Length (in) 0 ≤1.0 0 ≤ 0.04 25.4 1.0 > 1.01 ≤ 2.0 > 0.04 ≤ 0.08 12.7 0.5 > 2.0 > 0.08 0 0

Table F.5 Critical (touchdown) joints – buried defects

Height (mm) Height (in) Length (mm) Length (in) 0 ≤1.5 0 ≤ 0.06 50 (*) 2 > 1.5 ≤ 2.5 > 0.06 ≤ 0.10 12.5 0.5 > 2.5 > 0.10 0 0

(*) Aggregate length shall not exceed 8 % of total weld length

Table F.6 Non-critical joints – buried defects

Height (mm) Height (in) Length (mm) Length (in) 0 ≤ 2.0 0 ≤ 0.08 50 (*) 2 > 2.0 ≤ 3.0 > 0.08 ≤ 0.12 25 1 > 3.0 > 0.12 0 0

(*) Aggregate length shall not exceed 8 % of total weld length

F.8 PIPE AND FORGED FITTING HANDLING

Although this clause is primarily concerned with the Contractor’s handling of individual or multiple joints for S-lay, J-Lay or reeling, appropriate requirements shall also apply to the Contractor’s handling of the riser stress joints and other forged or specialty fittings supplied by the Principal.

The Contractor shall develop and present to the Principal for approval procedures for the handling and storage of individual joints and fittings to minimise damage and sorting problems. The Contractor shall demonstrate how joints will be handled throughout the entire load-out, transportation and production sequence. Particular attention shall be given to handling of the stress joints: the curved areas of the fittings are prone to fatigue failure if even the slightest gouge damages them. The Contractor shall set aside a riser pipe storage area which will allow him to load out the riser joints in the proper installation sequence.

None of the riser pipes shall be stored anywhere onshore or offshore in a nested configuration. Pipe joints, coated and uncoated, shall be stacked with intermediate timber layers. Uncoated pipes shall be stacked so that an internal joint end ID measurement tool can be inserted without the pipes having to be moved.

Handling and lifting procedures shall be designed to limit the maximum bending strain to a value of 0.001. Procedures shall be verified by engineering calculations. Padded pipe supports shall be provided by the Contractor for riser pipe, including insulated riser pipe. Padded supports shall be in good condition, with all hardware recessed to prevent contact with the pipe. Padded supports shall be sufficiently wide and resilient to leave the pipe coating unmarked.



F.9 GENERAL INSPECTION

The Principal’s and Contractor's Inspection/QC/QA efforts shall be coordinated to ensure all requirements are satisfied. No assembly work shall be started until the required procedures have been developed by the Contractor and approved by the Principal.

No welding or field joint installation shall take place without an inspector representing the Principal being present in the work area. No root bead welding shall take place without the continuous presence of the Principal’s welding inspector at the weld location itself. Prior to any welding, hi-lo shall be measured and recorded and if excessive, another joint shall be found with a better ID match. Any weld that is found to have been made without the inspector representing the Principal being present shall be cut out and re-welded.

F.10 MISCELLANEOUS REQUIREMENTS

F.10.1 General

The Principal shall make bare pipe and forged fitting weld test spools available for the qualification of welding and NDE procedures and welders, as well as practice welding. The following supplements the general requirements for pipeline and flowline welding.

F.10.2 Weld repairs

No weld repairs are allowed unless specific approval is obtained from the inspector representing the Principal. This rule applies regardless of whether the weld has been subjected to NDE or not. Flapper wheel sanding of the root pass internal bead is permitted provided the sanding does not impinge on the internal pipe wall. Any cutting of pipe shall be done by mechanical means.

F.10.3 SCR cap pass re-welding

The re-welding of SCR cap passes before visual inspection shall be done before the element temperature falls below the preheat temperature. Reheating to bring the weldment back to the minimum preheat temperature shall not be performed. For non-critical riser welds, as defined in (F.6.3), the Contractor may propose a minor cap repair procedure for the Principal’s approval. Such a procedure shall not penetrate deeper than 3 mm (0.12 in) into the base metal thickness. Such a procedure shall be fully qualified as a separate procedure.

F.10.4 Cap pass profile

Cap pass valleys (both internal and external) shall be less than 0.5 mm (0.020 in) in depth between ripple ridges or between adjacent beads for weld surfaces not specified to be ground flush. The weld groove shall be completely filled (no concavities allowed) and the maximum reinforcement height anywhere along the weld surface, shall be no more than 1.6 mm (1/16 in) on the ID and 2 mm (5/64 in) on the OD. At no point shall the weld surface lie below the adjacent base metal surface. Weld reinforcement shall be free from undercut and internal concavity and shall blend smoothly into the base metal so as to result in a re-entrant angle at the toe of the weld of no less than 160°. The Contractor shall develop a suitable method/template for such measurement for the Principal’s approval.

F.10.5 CTOD tests

CTOD tests as defined in API Std 1104 Appendix A shall be conducted in the HAZ and the weld metal (3 tests each) for each pipe diameter. The lowest CTOD value shall exceed 0.38 mm (1.5 in) and the average shall exceed 0.5 mm (0.02 in). The Test temperature shall be -18°C (0°F) unless otherwise specified by the Principal.

F.10.6 Root pass profile

A smooth and uniform root pass is the single most important requirement for these welds. Each production weld shall be started with a fresh machine bevel. Small angle grinders (i.e. with a wheel no larger than 13 cm [5 in] diameter) with fine abrasive wheels may be used to touch up the weld bevel and even up the root gap as part of the final lineup process. The only personnel permitted to operate touch-up grinders are procedure-qualified welders. Root touch-up procedures, equipment and abrasives shall be tried out and qualified as an



integral part of the WPQs. The maximum depth of root pass penetration shall be 1.6 mm (0.06 in).

F.10.7 External clamps

The Contractor shall use an external clamp if the inspector representing the Principal judges it to be required.

F.10.8 Weld cap sanding

Weld caps shall be sanded after welding if this facilitates NDE interpretation. If the weld procedure qualified with fatigue testing requires the cap to be sanded flush, this shall be done after NDE. Sanding with a 60 to 80 grit sanding pad is permitted but grinding with a disc is not permitted unless approved by the Principal. If the fatigue testing program is based on using welds that are “sanded flush” to improve fatigue testing performance, the following shall apply: Weld surfaces specified to be sanded flush shall be sanded so that there is no more than 1 mm (0.04 in) weld reinforcement remaining, no undercut, and no remaining concavity (i.e. suck-back), with all specified surfaces receiving some degree of grinding and all visible signs (cap lines) of the weld toe being eliminated, i.e. sanded to “white” metal. Grinding of the toe shall be limited to 1 mm (0.04 in) or to the specified minimum wall thickness, whichever amount is less. Unless otherwise specified by the Principal, the minimum specified wall thickness is 5 % less than the nominal wall thickness. Cap line removal shall be verified with MPI. Base metal surfaces within 13 mm (½ in) of welds specified to be sanded flush shall also be sanded to “white” metal. The local wall thickness of the base metals and weld shall not be less than the minimum specified wall thickness after grinding, as verified by straight-beam ultrasonic examination scans parallel to the longitudinal axis of the pieces being welded. Straight-beam ultrasonic (i.e. ultrasonic thickness gauge) scans shall extend a minimum of 50 mm (2 in) into the base metal on both sides of the weld and shall be made every 50 mm (2 in) of weld length. AUT shall be performed before there is any sanding on the pipe body to blend in sanding of the toe. The surface roughness of the sanded region shall not exceed 6.3 µm (0.25 mils) RMS. Grinding marks shall be parallel (to within 30°) to the longitudinal axis of the pieces being welded, unless the surface roughness of the sanded region is less than 6.3 µm (0.25 mils) RMS, in which case grinding marks may be in any direction. The transition from sanded regions into base metal shall be contoured so that stress concentration effects are minimized. Sanded surfaces, particularly weld toes, shall have a radius of at least 75 mm (3 in). The slope of the transition into base metal from sanded regions shall be no steeper than 4-to-1.

F.10.9 De-magnetisation

The Contractor shall assume that all joint ends may need to be demagnetized before welding. Either joint-by-joint or batch demagnetization is acceptable. The maximum permissible Gaussian magnetic flux density shall be 20 Gs, as measured at the pipe ends with a Hall effect gauss meter.

F.11 WELDER QUALIFICATION

Once personnel are qualified, no substitution shall be made without the Principal's approval.

F.12 JOINT STRAIGHTNESS AND CLEANLINESS

All joints shall be blown out with compressed air prior to welding and a foam pig shall be sent through each multiple stand joints to remove loose material.

The straightness of multiple spool assemblies and bevel end squareness is of utmost importance. Alignment shall be verified by means of a square, a straight edge or optical instruments. The end preparation for a tie-in weld (for both onshore and offshore pipelines) shall be square within 0.25 mm (0.01 in) (which is the maximum gap between the non-contacting bevel and the leg of the square with the long leg of the 0.60 m (2 ft) square along the outside of the spool being checked).



F.13 FIELD JOINT COATING

No field joint coating shall be done prior to approval and acceptance of the weld by the Principal.



PART IV REFERENCES

In this DEP Specification, reference is made to the following publications: NOTES: 1. Unless specifically designated by date, the latest edition of each publication shall be used,

together with any amendments/supplements/revisions thereto.

2. The DEPs and most referenced external standards are available to Shell staff on the SWW (Shell Wide Web) at http://sww.shell.com/standards/.

SHELL STANDARDS

Pipeline Engineering (amendments/supplements to ISO 13623) DEP 31.40.00.10-Gen.

AMERICAN STANDARDS

Standard test methods and definitions for the mechanical testing of steel products

ASTM A 370

Issued by: American Society for Testing and Materials 100 Barr Harbor Drive, West Conshohocken PA 19428-2959 USA

Procurement guidelines for consumables – Welding and allied processes – Flux and gas shielded electrical welding processes

AWS A5.01

Issued by: American Welding Society 550 North LeJeune Road PO Box 351040, Miami, FL 33136 USA

BRITISH STANDARDS

Fracture mechanics toughness tests - Part 2 : Method for determination of Kic, critical CTOD and critical J values of welds in metallic materials

BS 7448-2

Guide to methods for assessing the acceptability of flaws in metallic structures

BS 7910

Issued by: British Standards Institution 389 Chiswick High Road London W4 4AL UK

EUROPEAN STANDARDS

Non-destructive testing – Qualification and certification of NDT personnel – General principles

EN 473

Welding – Recommendations for welding of metallic materials – Part 2 – Arc welding of ferritic steels

EN 1011-2

Metallic materials – Tensile testing: Part 1 Method of testing at ambient temperatures

EN 10002-1

Metallic materials – Tensile testing: Part 5 Method of testing at elevated temperatures

EN 10002-5

Destructive tests on welds in metallic materials – Part 1: Hardness test on arc welding joints

EN 1043-1



Issued by: CEN Rue de Stassart 36 B-1050 Brussels Belgium

Copies can also be obtained from national standards organizations

European Federation of Corrosion – Guidelines on materials requirements for carbon steel and low alloy steels for H2S-containing environments in oil and gas environments

EFC 16

Issued by: Institute of Materials, 1 Carlton House Terrace London SW1Y 5DB United Kingdom

INTERNATIONAL STANDARDS

Non-destructive testing — Qualification and certification of personnel

ISO 9712

Steel and steel products – Inspection documents ISO 10474

Seamless and welded steel tubes for pressure purposes – Ultrasonic testing of tube ends for the detection of laminar imperfections

ISO 11496

Petroleum and natural gas industries – Pipeline transportation systems – Welding of pipelines

ISO 13847:2000 (plus Corrigendum No. 1, 2001)

Welding consumables – Gases and gas mixtures for fusion welding and allied processes

ISO 14175

Materials for use in H2S-containing environments in oils and gas production facilities – Part 2: Cracking resistant and low alloy steels

ISO 15156-2

Specification and qualification of welding procedures for metallic materials – Part 1: Arc Welding

ISO 15609

Specification and qualification of welding procedures for metallic materials- Welding procedure test – Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys

ISO 15614-1

Non-destructive testing of welds: Radiographic testing of fusion joints

ISO 17636

Issued by: ISO Central Secretariat 1, ch. de la Voie-Creuse Case postale 56 CH-1211 Genève 20 Switzerland

Copies can also be obtained from national standards organizations.

NORWEGIAN STANDARDS

Submarine pipeline systems DNV OS-F101

Fracture control for pipeline installation methods introducing cyclic plastic strain

DNV RP-F108



Issued by: Det Norske Veritas Industri Norge AS Veritasveien 1 1322 Høvik Norway


61.40.20.30_spec_2011-02_a01

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