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Technical Committee on Electrical Equipment in Chemical Atmospheres

Date: August 6, 2015 To: Technical Committee on Electrical Equipment in Chemical Atmospheres From: Eric Nette, P.E. Staff Liaison/Engineer Re: Agenda Package – NFPA 496/497/499 A2016 Second Draft Meeting – Sept. 30-Oct. 1, 2015

Enclosed is the agenda package for the Sept. 30-Oct. 1, 2015 meeting for the NFPA 496/497/499 Second Draft Meeting. Please ensure that you have reviewed the public input and the other agenda items in advance to prepare for discussion. The agenda and public comments will be posted on the document information pages (www.nfpa.org/496next). Some items to have available during the meeting include:

Agenda package with public comments

A copy of NFPA 496/497/499 (visit the NFPA 496/497/499 Document information pages for your free committee copy)

Any previous copies of the technical committees standard

A laptop

Optional items that are sometimes useful include:

Review of NFPA’s Process, www.nfpa.org/regs If you have any questions or comments, please feel free to reach me at (617) 984-7434 or by e-mail at [email protected]. I look forward to our meeting to begin the revision cycle!

http://www.nfpa.org/496next

http://www.nfpa.org/regs

Technical Committee on Electrical Equipment in Chemical Atmospheres

AGENDA

NFPA 496/497/499 A2016 First Draft Meeting Sept. 30-Oct 1, 2015

Teleconference http://nfpa.adobeconnect.com/nette/

1:00 p.m. to 5:00 p.m. (Eastern Time Zone)

1. Meeting opening, introduction and attendance

2. Approval of First Draft Meeting Minutes of September 16-18, 2014 (Attachment A. September 16-

18, 2014 Meeting Minutes).

3. Chair's remarks, Bill Fiske

4. Staff Liaison update:

a. A2016 Schedule (Attachment B. A2016 Revision Cycle)

b. Committee Membership Update (Attachment C. EEC-AAA Membership)

c. Standards Process Review (Attachment D. NFPA Process – Quick Reference Guide)

5. Old Business

a. 497 Task Group Report.

b. 499 Task Group Report.

6. New Business

a. Public Comments for NFPA 496 (Attachment E. NFPA 496 - A2016 Public Comments)

b. Public Comments for NFPA 497 (Attachment F. NFPA 497 – A2016 Public Comments)

c. Public Comments for NFPA 499 (Attachment G. NFPA 499 – A2016 Public Comments)

d. Development of Second Revisions (Attachment D. NFPA Process – Quick Reference Guide)

7. Other business

8. Date/Location of Next Meeting. (First Draft Meeting for the Annual 2019 Revision Cycle)

9. Adjournment

Attachments:

A. September 16-18, 2014 Meeting Minutes

B. A2016 – Revision Cycle

C. EEC-AAA Committee Membership

D. NFPA Process – Quick Reference Guide

E. NFPA 496 - A2016 Public Comments

F. NFPA 497 – A2016 Public Comments

G. NFPA 499 - A2016 Public Comments

Attachment A:

September 16-18, 2014

Meeting Minutes

TECHNICAL COMMITTEE ON ELECTRICAL EQUIPMENT

IN CHEMICAL ATMOSPHERES

TO: TECHNICAL COMMITTEE ON ELECTRICAL EQUIPMENT IN CHEMICAL ATMOSPHERES

FROM: Eric Nette, Staff Liaison

DATE: September 23, 2014

SUBJ: REVISED--Minutes of September 16-18, 2014, First Draft Meeting (Ithaca, NY)

_________________________________________________________________________________

I. Attendance:

Members, Alternates, and Guests:

William Fiske, Committee Chair, Intertek Testing Services

Donald Ankele, Underwriters Laboratories Inc.

Ronald Brown, PPG Industries, Inc.

Jonathan Cadd, Electrical Systems and Instrumentation, Inc.

John Cawthon, State of Alaska Division of Fire & Life Safety

Paul Chantler, Sherwin Williams

Chris Cirelli, Waters Corporation

Matt Egloff, Montana Tech, University of Montana

William Lawrence, FM Global

Timothy Myers, Exponent, Inc. (via telephone)

Samuel Rodgers, Honeywell Inc.

Joseph Saverino, Air Products and Chemicals, Inc.

Rodolfo Sierra, US Coast Guard

Erdem Ural, Loss Prevention Science & Technologies (via telephone)

David Wechsler, American Chemistry Council (via telephone)

Ryan Parks, Intertek Testing Services (via telephone)

Eric Nette, NFPA, Staff Liaison

Guests:

Michael Sherman, Graco, Inc.

Robert Early, Praxair Distribution, Inc.

Guy Colonna, NFPA

Daniel Gorham, NFPA (via telephone)

EEC-AAA First Draft Meeting Minutes September XX, 2014 – page 2

II. Minutes of Meeting:

1. The Chair opened the meeting at 8:00 a.m., Tuesday September 16, 2014. 2. Attendees introduced themselves and necessary corrections were made to the

Technical Committee roster.

3. The Staff Liaison reported on the current committee roster and member

status.

Distribution Classification

Enforcers: 3, 13%

Insurance: 1, 4%

Manufacturers: 4, 17%

Applied Research/ Testing Laboratory: 2, 8%

Special Expert: 8, 33%

User: 6, 25%

Total Principle Members: 24

4. Staff introduced and reviewed NFPA’s standards development process.

5. A presentation was made by Rob Early from the NFPA Technical Committee

on Industrial and Medical Gases.

i. In response to the presentation, and at the request of Rob Early, CI-1

and CI-2 were created for NFPA 497.

6. The Committee responded to 9 Public Inputs and created 6 First Revisions to

NFPA 496. During the discussion of Public Inputs submitted by William Fiske,

The Committee was temporarily chaired by Matt Egloff.

7. The Committee responded to 18 Public Inputs, provided 3 Committee Inputs,

and created 12 First Revisions to NFPA 497.

8. The Committee responded to 13 Public Inputs, and created 7 First Revisions

to NFPA 499.

9. Next Meeting. The Committee’s next meeting will be NFPA 496, NFPA 497,

and NFPA 499 Second Draft Meeting. The Committee proposed the next

meeting to be in September, 2015. The exact date will be determined later,

but it will be in Ithaca, NY.

10. The Chair thanked everyone for their input. The Committee Meeting was

adjourned at 4:30 p.m., on Wednesday September 17, 2014.

Respectfully submitted,

Eric Nette, NFPA, Staff Liaison

Attachment B:

A2016 Revision Cycle

A2016 Revision Cycle KEY DATES Annual 2016

A2016 [EEC-AAA]

Important Dates for the Cycle:

Public Comment Closing (Paper) April 10, 2015 (DONE)

Public Comment Closing (Digital) May 15, 2015 (DONE)

Posting of Second Draft December 11, 2015

Notice of Intent to Make Motion (NITMAM) February 19, 2016

Issuance of Consent Standard May 13, 2016 (published bit later)

NFPA Annual Meeting with CAMs June 6-9, 2016

Issuance of Standard – with CAMs August 4, 2016 (published bit later)

2016 ANNUAL REVISION CYCLE *Public Input Dates may vary according to standards and schedules for Revision Cycles may change. Please check the NFPA Website for the most up‐to‐date information on Public Input Closing Dates and schedules at

www.nfpa.org/document # (i.e. www.nfpa.org/101) and click on the Next Edition tab.

Process Stage

Process Step

Dates for TC

Dates forTC with

CC Public Input Closing Date for Paper Submittal* 6/6/2014 6/6/2014

Public Input Closing Date for Online Submittal (e‐PI)* 7/7/2014 7/7/2014

Final Date for TC First Draft Meeting 12/12/2014 9/12/2014

Public Input Posting of First Draft and TC Ballot 1/30/2015 10/24/2014

Stage Final date for Receipt of TC First Draft ballot 2/20/2015 11/14/2014

(First Draft) Final date for Receipt of TC First Draft ballot ‐ recirc 2/27/2015 11/21/2014

Posting of First Draft for CC Meeting 11/28/2014

Final date for CC First Draft Meeting 1/9/2015

Posting of First Draft and CC Ballot 1/30/2015

Final date for Receipt of CC First Draft ballot 2/20/2015

Final date for Receipt of CC First Draft ballot ‐ recirc 2/27/2015

Post First Draft Report for Public Comment 3/6/2015 3/6/2015

Public Comment Closing Date for Paper Submittal* 4/10/2015 4/10/2015

Public Comment Closing Date for Online Submittal (e‐PC)* 5/15/2015 5/15/2015

Final Date to Publish Notice of Consent Standards (Standards that received no Comments)

5/29/2015 5/29/2015

Appeal Closing Date for Consent Standards (Standards that received no Comments)

6/12/2015 6/12/2015

Final date for TC Second Draft Meeting 10/30/2015 7/24/2015

Comment Posting of Second Draft and TC Ballot 12/11/2015 9/4/2015

Stage Final date for Receipt of TC Second Draft ballot 1/4/2016 9/25/2015

(Second Final date for receipt of TC Second Draft ballot ‐ recirc 1/11/2016 10/2/2015

Draft) Posting of Second Draft for CC Meeting 10/9/2015

Final date for CC Second Draft Meeting 11/20/2015

Posting of Second Draft for CC Ballot 12/11/2015

Final date for Receipt of CC Second Draft ballot 1/4/2016

Final date for Receipt of CC Second Draft ballot ‐ recirc 1/11/2016

Post Second Draft Report for NITMAM Review 1/18/2016 1/18/2016

Tech Session Notice of Intent to Make a Motion (NITMAM) Closing Date 2/19/2016 2/19/2016

Preparation Posting of Certified Amending Motions (CAMs) and Consent Standards

4/15/2016 4/15/2016

(& Issuance) Appeal Closing Date for Consent Standards 5/3/2016 5/3/2016

SC Issuance Date for Consent Standards 5/13/2016 5/13/2016

Tech Session Association Meeting for Standards with CAMs 6/13‐16/2016 6/13‐16/2016

Appeals and Appeal Closing Date for Standards with CAMs 6/29/2016 6/29/2016

Issuance SC Issuance Date for Standards with CAMs 8/4/2016 8/4/2016

Approved:__October 30, 2012 Revised___December 4, 2013_____________________

Attachment C:

EEC-AAA Committee

Membership

Address List No PhoneElectrical Equipment in Chemical Atmospheres EEC-AAA

Eric Nette08/04/2015

EEC-AAA

William T. Fiske

ChairIntertek Testing Services3933 US Route 11 SouthCortland, NY 13045-9715Alternate: Ryan Parks

RT 10/1/1994EEC-AAA

Donald W. Ankele

PrincipalUL LLC333 Pfingsten RoadNorthbrook, IL 60062-2096Alternate: John Chambers

RT 1/14/2005

EEC-AAA

Babanna Biradar

PrincipalBechtel Corporation3000 Post Oak BoulevardHouston, TX 77056Alternate: Antonino Nicotra

SE 3/2/2010EEC-AAA

Ronald M. Brown

PrincipalPPG Industries, Inc.151 Colfax StreetSpringdale, PA 15144

U 03/07/2013

EEC-AAA

Jonathan L. Cadd

PrincipalElectrical Systems and Instrumentation, Inc.1702 Ward StreetMidland, TX 79705

M 3/5/2012EEC-AAA

John H. Cawthon

PrincipalState of Alaska Division of Fire & Life Safety411 West 4th Street, Suite 2BAnchorage, AK 99501

E 8/9/2011

EEC-AAA

Paul Chantler

PrincipalSherwin Williams333 Republic101 Prospect AvenueCleveland, OH 44023

U 03/07/2013EEC-AAA

Chris Cirelli

PrincipalWaters Corporation177 Robert Treat Paine DriveTaunton, MA 02780

M 07/29/2013

EEC-AAA

Frank C. DeFelice, Jr.

PrincipalAllnex, Inc.528 South Cherry StreetWallingford, CT 06492

U 8/5/2009EEC-AAA

Matt Egloff

PrincipalMontana Tech, University of MontanaGeneral Engineering Department1300 West Park StreetButte, MT 59701

SE 1/10/2008

EEC-AAA

Felix J. Garfunkel

PrincipalParsons Corporation100 High StreetBoston, MA 02110-1713

SE 07/29/2013EEC-AAA

William G. Lawrence, Jr.

PrincipalFM Global1151 Boston-Providence TurnpikePO Box 9102Norwood, MA 02062-9102Alternate: Marlon B. Mitchell

I 1/1/1990

EEC-AAA

Robert Malanga

PrincipalFire and Risk Engineering9 Flintlock Drive, Suite 100Long Valley, NJ 07853

SE 4/17/1998EEC-AAA

Adam Morrison

PrincipalFike Corporation704 SW 10th StreetBlue Springs, MO 64015-4263

M 03/03/2014

1



EEC-AAA

Timothy J. Myers

PrincipalExponent, Inc.9 Strathmore RoadNatick, MA 01760-2418

SE 7/26/2007EEC-AAA

Samuel A. Rodgers

PrincipalHoneywell, Inc.15801 Woods Edge RoadColonial Heights, VA 23834-6059

U 4/1/1996

EEC-AAA

Joseph V. Saverino

PrincipalAir Products and Chemicals, Inc.7201 Hamilton BoulevardAllentown, PA 18195-1501

U 10/1/1994EEC-AAA

Rodolfo N. Sierra

PrincipalUS Coast GuardDesign & Engineering StandardsSystems Engineering Division (CG 5213)2100 2nd Street, SWWashington, DC 20593

E 3/4/2009

EEC-AAA

James G. Stallcup

PrincipalGrayboy, Inc.6800 Meadow CreekNorth Richland Hills, TX 76182Alternate: James W. Stallcup, Jr.

SE 1/1/1991EEC-AAA

Erdem A. Ural

PrincipalLoss Prevention Science & Technologies, Inc.2 Canton Street, Suite A2Stoughton, MA 02072

SE 8/5/2009

EEC-AAA

David B. Wechsler

Principal27706 Dalton Bluff CourtKaty, TX 77494American Chemistry Council

U 1/1/1987EEC-AAA

Jack H. Zewe

PrincipalElectrical Consultants Inc.3221 Illinois AvenueKenner, LA 70065-4530

SE 1/1/1992

EEC-AAA

Jack E. Jamison, Jr.

Voting AlternateMiller Engineering, Inc.991 River RoadMorgantown, WV 26501International Association of Electrical InspectorsVoting Alt. to IAEI Rep.

E 03/05/2012EEC-AAA

John Chambers

AlternateUL LLC333 Pfingsten RoadNorthbrook, IL 60062-2096Principal: Donald W. Ankele

RT 04/08/2015

EEC-AAA

Marlon B. Mitchell

AlternateFM Global743 Reynolds RoadWest Glocester, RI 02814Principal: William G. Lawrence, Jr.

I 10/18/2011EEC-AAA

Antonino Nicotra

AlternateBechtel Oil Gas & Chemicals3000 Post Oak BoulevardHouston, TX 77056Principal: Babanna Biradar

SE 10/29/2012

EEC-AAA

Ryan Parks

AlternateIntertek Testing Services1809 10th Street, Suite 400Plano, TX 75074-8009Principal: William T. Fiske

RT 8/5/2009EEC-AAA

James W. Stallcup, Jr.

AlternateGrayboy, Inc.6800 Meadow CreekNorth Richland Hills, TX 76182Principal: James G. Stallcup

SE 1/1/1994

2



EEC-AAA

Eric Nette

Staff LiaisonNational Fire Protection Association1 Batterymarch ParkQuincy, MA 02169-7471

04/16/2014

3

Attachment D:

NFPA Process – Quick

Reference Guide

New Process (Second Draft Stage) – Quick

Reference Guide For additional information on the New Regulations visit: www.nfpa.org/NewRegs

A Technical Committee (TC) can take these actions at the Second Draft

(ROC) meeting: 1. Resolve a Public Comment

Accept

Reject, But See Related Second Revision

Reject

Reject But hold 2. Create a Second Revision

NOTE: All actions require a Committee Statement.

Resolve Public Comment (TC needs to act upon all the Public Comments)

Accept

The TC takes the text exactly as submitted by the public comment and creates a second revision.

Sample Motion: “I move to accept PC#_.”

Approval by meeting vote (simple majority) and final approval through ballot.

Reject but See

The TC agrees with the concept of the PC in whole or part but wants to edit the text to create a second revision.

Sample Motions: i. “I move to reject PC#__, but create a second revision using it as a basis.”

ii. “I move to make a second revision using PC#__ as a basis.”


Reject

The TC disagrees with the proposed changes in the public comment.

Sample Motion: “I move to reject PC#__.”

Approval by meeting vote (simple majority). Not subject to ballot.

Reject, but Hold.

The TC may hold any comment until the public input stage of the next revision cycle meeting any of the following criteria:

i. New concept that has not had any public review ii. The changed text would require the technical committee to restudy the

change iii. The proposed concept cannot be handled in the second draft timeframe

Sample Motion: “I move to hold PC#__.”

Approval by meeting vote (simple majority). Not subject to ballot.

Create a Second Revision (change to the document)

TC must create a Second Revision (SR) for each change they wish to make to the document. The TC can either choose to use a Public Comment for the basis of the change or not.

http://www.nfpa.org/NewRegs

Using Public Comment for basis: i. See above for ACCEPT or REJECT BUT SEE.

Without using Public Comment for basis i. Sample Motion: “I make a motion to revise section __ as follows___.”


Comparison to Previous Process:

PREVIOUS ACTIONS NEW PROCESS ACTIONS Sample Motion

Accept

1) Committee generates a Second

Revision and Substantiation (CS) for

change

2) Committee provides response (CS) to

each PC.

1) “I move to accept PC#__.”

Any variation of Accept (APA, APR,

APP) on a public comment

1) Committee rejects the comment,

but creates a Second Revision

2) Committee provides response (CS) to

each PC that is associated with the

revision

1) “I move to revise section __

using PC#_ as the basis for

change.”

2) “I move to reject PC#__, but

create a second revision using it

as a basis.”

Rejected Public Comment

1) Committee rejects the comment

2) Committee provides response (CS)

to PC

“I make a motion to reject

PC#_ with the following

committee statement__.”

Accepted Committee Comment

Committee generates a Second Revision

and Substantiation (CS) for change

“I make a motion to revise

section __ as follows___.”

Committee generates a

statement for reason for change.

Notes:

1) All meeting actions require a favorable vote of a simple majority of the members present. 2) All Second Revisions will be contained in the ballot and will require a 2/3 affirmative vote

to confirm the meeting action. 3) Only the Second Revisions will be balloted. PCs will be contained in the report but will not

be balloted.

Term Comparison between Current and Old:

CURRENT TERM OLD TERM

Input Stage ROP Stage

Public Input (PI) Proposal

First Draft Meeting ROP Meeting

Committee Input Committee Proposal that Fail

Ballot

Committee Statement

(CS) Committee Statement

First Revision (FR) Committee Proposal or Accepted

Public Proposal

First Draft Report ROP

First Draft ROP Draft

Comment Stage ROC Stage

Public Comment Public Comment

Second Draft Meeting ROC Meeting

Committee Comment Committee Comment that Fail

Ballot

Committee Action Committee Action

Second Revision Committee Comment or Accepted

Public Comment

Second Draft Report ROC

Second Draft ROC Draft

Note: The highlighted terms are the ones that will be most applicable at the Second Draft Meeting.

Attachment E:

NFPA 496 – A2016 Public

Comments

Public Comment No. 1-NFPA 496-2015 [ Section No. 1.1.1 ]

1.1.1

This standard applies to purging and pressurizing for the following:

(1) Electrical equipment located in areas classified as hazardous by Article 500, Article 505, or Article505 of 506 of NFPA 70

(2) Electrical equipment containing sources of flammable vapors or gases and located in either classifiedor unclassified areas

(3) Control rooms or buildings located in areas classified as hazardous by Article 500, Article 505, orArticle 505 506 of NFPA 70

(4) Analyzer rooms containing sources of flammable vapors or gases and located in areas classified ashazardous by Article 500, Article 505, or Article 505 of 506 of NFPA 70

Statement of Problem and Substantiation for Public Comment

Article 506 of NFPA70 references NFPA496-2013 for protection method pressurized.

Note: This is new material that was not issued in the first draft.

Related Item

Public Input No. 1-NFPA 496-2013 [Chapter 7 [Title Only]]

Submitter Information Verification

Submitter Full Name: WILLIAM MILLER

Organization: METTLER TOLEDO

Affilliation: Self

Street Address:

City:

State:

Zip:

Submittal Date: Wed Feb 18 14:18:45 EST 2015

National Fire Protection Association Report http://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentPara...

1 of 2 5/18/2015 11:01 AM

Public Comment No. 2-NFPA 496-2015 [ Section No. 1.2 ]

1.2 Purpose.

This standard provides information on the methods for purging and pressurizing enclosures to preventignition of a flammable atmosphere. Such an atmosphere may be introduced into the enclosure by asurrounding external atmosphere or by an internal source. By these means, electrical equipment that is nototherwise acceptable for a flammable atmosphere may be utilized in accordance with Article 500, Article505, or Article 505 506 of NFPA 70.


Article 506 of NFPA70 references NFPA496-2013 for protection method pressurized.

Note: This is new material that was not issued in the first draft.

Related Item

Public Input No. 1-NFPA 496-2013 [Chapter 7 [Title Only]]


Submitter Full Name: WILLIAM MILLER

Organization: METTLER TOLEDO

Street Address:

City:

State:

Zip:

Submittal Date: Wed Feb 18 19:31:49 EST 2015


2 of 2 5/18/2015 11:01 AM

Attachment F:


Comments

Public Comment No. 1-NFPA 497-2015 [ Chapter 2 ]

Chapter 2 Referenced Publications

2.1 General.

The documents or portions thereof listed in this chapter are referenced within this recommended practice and should beconsidered part of the recommendations of this document.

2.2 NFPA Publications.

National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.

NFPA 30, Flammable and Combustible Liquids Code, 2015 edition.

NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials, 2015 edition.

NFPA 34, Standard for Dipping, Coating, and Printing Processes Using Flammable or Combustible Liquids, 2015 edition.

NFPA 35, Standard for the Manufacture of Organic Coatings, 2016 edition.

NFPA 36, Standard for Solvent Extraction Plants, 2013 edition.

NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals, 2015 edition.

NFPA 55, Compressed Gases and Cryogenic Fluids Code, 2016 edition.

NFPA 58, Liquefied Petroleum Gas Code, 2017 edition.

NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG), 2016 edition.

NFPA 70® , National Electrical Code®, 2017 edition.

2.3 Other Publications.

2.3.1 API Publications.

American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005-4070.

API RP 500, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classifiedas Class I, Division 1 and Division 2, 3rd edition, 2008

API RP 505, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classifiedas Class I, Zone 0, Zone 1, and Zone 2, 2002, reaffirmed 2013.

2.3.2 ASHRAE Publications.

American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc., 1791 Tullie Circle NE, Atlanta, GA30329-2305.

ASHRAE 15 ASHRAE STD 15 & 34 , Safety Standard for Refrigeration Systems, 2013. (This is a combined standard)

2.3.3 ASTM Publications.

ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.

ASTM D323, Standard Method of Test for Vapor Pressure of Petroleum Products (Reid Method), 2008 ( , reapproved 2014 ) .

2.3.4 CGA Publications.

Compressed Gas Association, 14501 George Carter Way, Suite 103, Chantilly, VA 20151-2923.

CGA G2.1, Safety Requirements for the Storage and Handling of Anhydrous Ammonia, 1999 6th edition, 2014 .

2.3.5 IEC Publications.

International Electrotechnical Commission, 3, rue de Varembé, P.O. Box 131, CH-1211 Geneva 20, Switzerland.

IEC 60079-20-1, Explosive atmospheres — Part 20-1: Material characteristics for gas and vapor classification — Test methodsand data, 2012.

2.3.6 ISA Publications.

The International Society of Automation, 67 T.W. Alexander Drive, P.O. Box 12277, Research Triangle Park, NC 27709.

ISA-RP12.12.03, Standard for Portable Electronic Products Suitable for Use in Class I and II, Division 2, Class I Zone 2 andClass III, DIivision 1 and 2 Hazardous (Classified) Locations, 2011.

2.3.7 Other Publications.

Merriam-Webster’s Collegiate Dictionary, 11th edition, Merriam-Webster, Inc., Springfield, MA, 2003.

2.4 References for Extracts in Recommendations Sections.

NFPA 30, Flammable and Combustible Liquids Code, 2015 edition.

NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG),2013 2016 edition.

NFPA 70® , National Electrical Code®,2014 2017 edition.


1 of 18 5/18/2015 11:12 AM


Updated reference to ASHRAE STD 15 & 34 which is now a combined standard. No longer two separate standards.Updated CGA G2.1 year.

Related Public Comments for This Document

Related Comment Relationship

Public Comment No. 2-NFPA 497-2015 [Section No. 4.4.2 [Excluding any Sub-Sections]]

Public Comment No. 3-NFPA 497-2015 [Chapter C]

Related Item

First Revision No. 3-NFPA 497-2014 [Chapter 2]


Submitter Full Name: Aaron Adamczyk

Organization: [ Not Specified ]

Street Address:

City:

State:

Zip:

Submittal Date: Fri Mar 06 20:18:48 EST 2015


2 of 18 5/18/2015 11:12 AM

Public Comment No. 2-NFPA 497-2015 [ Section No. 4.4.2 [Excluding any Sub-Sections] ]


3 of 18 5/18/2015 11:12 AM

An alphabetical listing of selected combustible materials, with their group classification and relevant physical properties, isprovided in Table 4.4.2.

Table 4.4.2 Selected Chemicals

Chemical CAS No.Class I

DivisionGroup

Type aFlashPoint(°C)

AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

Acetaldehyde 75−07−0 C d I −38 175 4.0 60.0 1.5 874.9 IIA 0.37 0.98 0.92

Acetic Acid 64−19−7 D d II 39 426 19.9 2.1 15.6 IIA 2.67 1.76

Acetic Acid- tert-ButylEster

540−88−5 D II 1.7 9.8 4.0 40.6

Acetic Anhydride 108−24−7 D II 49 316 2.7 10.3 3.5 4.9 IIA 1.23

Acetone 67−64−1 D d I –20 465 2.5 12.8 2.0 230.7 IIA 1.15 1.00 1.02

Acetone Cyanohydrin 75−86−5 D IIIA 74 688 2.2 12.0 2.9 0.3

Acetonitrile 75−05−8 D I 6 524 3.0 16.0 1.4 91.1 IIA 1.50

Acetylene 74−86−2 A d GAS 305 2.5 100 0.9 36600 IIC 0.017 0.28 0.25

Acrolein (Inhibited) 107−02−8 B(C) d I 235 2.8 31.0 1.9 274.1 IIB 0.13

Acrylic Acid 79−10−7 D II 54 438 2.4 8.0 2.5 4.3 IIB 0.86

Acrylonitrile 107−13−1 D d I 0 481 3 17 1.8 108.5 IIB 0.16 0.78 0.87

Adiponitrile 111−69−3 D IIIA 93 550 1.0 0.002

Allyl Alcohol 107−18−6 C d I 22 378 2.5 18.0 2.0 25.4 IIB 0.84

Allyl Chloride 107−05−1 D I −32 485 2.9 11.1 2.6 366 IIA 1.33 1.17

Allyl Glycidyl Ether 106−92−3 B(C) e II 57 3.9

Alpha-Methyl Styrene 98−83−9 D II 574 0.8 11.0 4.1 2.7

n-Amyl Acetate 628−63−7 D I 25 360 1.1 7.5 4.5 4.2 IIA 1.02

sec-Amyl Acetate 626−38−0 D I 23 1.1 7.5 4.5 IIA

Ammonia 7664−41−7 D d,f GAS 651 15 28 0.6 7498.0 IIA 680 6.85 3.17

Aniline 62−53−3 D IIIA 70 615 1.2 8.3 3.2 0.7 IIA

Benzene 71−43− D d I −11 498 1.2 7.8 2.8 94.8 IIA 0.20 1.00 0.99

Benzyl Chloride 98−87−3 D IIIA 585 1.1 4.4 0.5

Bromopropyne 106−96−7 D I 10 324 3.0

n-Butane 106−97−8 D d,g GAS 288 1.9 8.5 2.0 IIA 0.25 0.94 1.07

1,3-Butadiene 106−99−0 B(D) d,e GAS 420 2.0 11.5 1.9 IIB 0.13 0.76 0.79

1-Butanol 71−36−3 D d I 36 343 1.4 11.2 2.6 7.0 IIA 0.91

Butyl alcohol (s)(butanol-2)

78−92− D d I 23.8 405 1.7 9.8 2.6 IIA

Butylamine 109−73−9 D GAS −12 312 1.7 9.8 2.5 92.9 IIA 1.13

Butylene 25167−67−3 D I 385 1.6 10.0 1.9 2214.6 IIA 0.94

n-Butyraldehyde 123−72−8 C d I −12 218 1.9 12.5 2.5 112.2 IIA 0.92

n-Butyl Acetate 123−86−4 D d I 22 421 1.7 7.6 4.0 11.5 IIA 1.08 1.04

sec-Butyl Acetate 105−46−4 D II −8 1.7 9.8 4.0 22.2

tert-Butyl Acetate 540−88−5 D II 1.7 9.8 4.0 40.6

n-Butyl Acrylate(Inhibited)

141−32−2 D II 49 293 1.7 9.9 4.4 5.5 IIB 0.88

n-Butyl Glycidyl Ether 2426−08−6 B(C) e II

n-Butyl Formal 110−62−3 C IIIA 34.3

Butyl Mercaptan 109−79−5 C I 2 3.1 46.4

Butyl-2-Propenoate 141−32−2 D II 49 1.7 9.9 4.4 5.5

para tert-Butyl Toluene 98−51−1 D IIIA

n-Butyric Acid 107−92−6 D d IIIA 72 443 2.0 10.0 3.0 0.8


4 of 18 5/18/2015 11:12 AM


DivisionGroup


AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

Carbon Disulfide 75−15−0 d,h I −30 90 1.3 50.0 2.6 358.8 IIC 0.009 0.39 0.20

Carbon Monoxide 630−08−0 C d GAS 609 12.5 74 0.97 IIB 0.54

Chloroacetaldehyde 107−20−0 C IIIA 88 63.1

Chlorobenzene 108−90−7 D I 29 593 1.3 9.6 3.9 11.9

1-Chloro-1-Nitropropane

2425−66−3 C IIIA

Chloroprene 126−99−8 D GAS −20 4.0 20.0 3.0

Cresol 1319−77−3 D IIIA 81 559 1.1 3.7

Crotonaldehyde 4170−30−3 C d I 13 232 2.1 15.5 2.4 33.1 IIB 0.81

Cumene 98−82−8 D I 36 424 0.9 6.5 4.1 4.6 IIA 1.05

Cyclohexane 110−82−7 D I −17 245 1.3 8.0 2.9 98.8 IIA 0.22 1.0 0.94

Cyclohexanol 108−93−0 D IIIA 68 300 3.5 0.7 IIA

Cyclohexanone 108−94−1 D II 44 420 1.1 9.4 3.4 4.3 IIA 0.98

Cyclohexene 110−83−8 D I −6 244 1.2 2.8 89.4 IIA 0.97

Cyclopropane 75−19−4 D d I 503 2.4 10.4 1.5 5430 IIA 0.17 0.84 0.91

p-Cymene 99−87-6 D II 47 436 0.7 5.6 4.6 1.5 IIA

Decene 872−05−9 D II 235 4.8 1.7

n-Decaldehyde 112−31−2 C IIIA 0.09

n-Decanol 112−30−1 D IIIA 82 288 5.3 0.008

Decyl Alcohol 112−30−1 D IIIA 82 288 5.3 0.008

Diacetone Alcohol 123−42−2 D IIIA 64 603 1.8 6.9 4.0 1.4

Di-Isobutylene 25167−70−8 D d I 2 391 0.8 4.8 3.8 0.96

Di-Isobutyl Ketone 108−83−8 D II 60 396 0.8 7.1 4.9 1.7

o-Dichlorobenzene 955−50−1 D IIIA 66 647 2.2 9.2 5.1 IIA

1,4-Dichloro-2,3Epoxybutane

3583−47−9 D d I 1.9 8.5 2.0 IIA 0.25 0.98 1.07

1,1-Dichloroethane 1300−21−6 D I 438 6.2 16.0 3.4 227 IIA 1.82

1,2-Dichloroethylene 156−59−2 D I 97 460 5.6 12.8 3.4 204 IIA 3.91

1,1-Dichloro-1-Nitroethane

594−72−9 C IIIA 76 5.0

1,3-Dichloropropene 10061−02−6 D I 35 5.3 14.5 3.8

Dicyclopentadiene 77−73−6 C I 32 503 2.8 IIA 0.91

Diethylamine 109−87−9 C d I −28 312 1.8 10.1 2.5 IIA 1.15

Diethylaminoethanol 100−37−8 C IIIA 60 320 4.0 1.6 IIA

Diethyl Benzene 25340−17−4 D II 57 395 4.6

Diethyl Ether (EthylEther)

60−29−7 C d I −45 160 1.9 36 2.6 538 IIB 0.19 0.88 0.83

Diethylene GlycolMonobutyl Ether

112−34−5 C IIIA 78 228 0.9 24.6 5.6 0.02

Diethylene GlycolMonomethyl Ether

111−77−3 C IIIA 93 241 0.2

n-n-Dimethyl Aniline 121−69−7 C IIIA 63 371 1.0 4.2 0.7

Dimethyl Formamide 68−12−2 D II 58 455 2.2 15.2 2.5 4.1 IIA 1.08

Dimethyl Sulfate 77−78-1 D IIIA 83 188 4.4 0.7

Dimethylamine 124−40−3 C GAS 400 2.8 14.4 1.6 IIA

2,2-Dimethylbutane 75−83−2 D g I −48 405 319.3

2,3-Dimethylbutane 78−29−8 D g I 396

3,3-Dimethylheptane 1071−26-7 D g I 325 10.8


5 of 18 5/18/2015 11:12 AM


DivisionGroup


AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

2,3-Dimethylhexane 31394−54−4 D g I 438

2,3-Dimethylpentane 107−83−5 D g I 335 211.7

Di-N-Propylamine 142−84−7 C I 17 299 27.1 IIA 0.95

1,4-Dioxane 123−91−1 C d I 12 180 2.0 22.0 3.0 38.2 IIB 0.19 0.70

Dipentene 138−86−3 D II 45 237 0.7 6.1 4.7 IIA 1.18

Dipropylene GlycolMethyl Ether

34590−94−8 C IIIA 85 1.1 3.0 5.1 0.5

Diisopropylamine 108−18−9 C GAS −6 316 1.1 7.1 3.5 IIA 1.02

Dodecene 6842−15−5 D IIIA 100 255

Epichlorohydrin 3132−64−7 C d I 33 411 3.8 21.0 3.2 13.0

Ethane 74−84−0 D d GAS −29 472 3.0 12.5 1.0 IIA 0.24 0.82 0.91

Ethanol 64−17−5 D d I 13 363 3.3 19.0 1.6 59.5 IIA 0.88 0.89

Ethylamine 75−04−7 D d I −18 385 3.5 14.0 1.6 1048 2.4

Ethylene 74−85−1 C d GAS 490 2.7 36.0 1.0 IIB 0.070 0.53 0.65

Ethylenediamine 107−15−3 D d I 33 385 2.5 12.0 2.1 12.5

Ethylenimine 151−56−4 C d I −11 320 3.3 54.8 1.5 211 0.48

Ethylene Chlorohydrin 107−07−3 D IIIA 59 425 4.9 15.9 2.8 7.2

Ethylene Dichloride 107−06−2 D d I 13 413 6.2 16.0 3.4 79.7

Ethylene GlycolMonoethyl EtherAcetate

111−15−9 C II 47 379 1.7 4.7 2.3 IIA 0.53 0.97

Ethylene GlycolMonobutyl EtherAcetate

112−07−2 C IIIA 340 0.9 8.5 0.9

Ethylene GlycolMonobutyl Ether

111−76−2 C IIIA 238 1.1 12.7 4.1 1.0

Ethylene GlycolMonoethyl Ether

110−80−5 C II 235 1.7 15.6 3.0 5.4 0.84

Ethylene GlycolMonomethyl Ether

109−86−4 D II 285 1.8 14.0 2.6 9.2 0.85

Ethylene Oxide 75−21−8 B(C) d,e I −20 429 3 100 1.5 1314 IIB 0.065 0.47 0.59

2-Ethylhexaldehyde 123−05−7 C II 52 191 0.8 7.2 4.4 1.9

2-Ethylhexanol 104−76−7 D IIIA 81 0.9 9.7 4.5 0.2

2-Ethylhexyl Acrylate 103−09−3 D IIIA 88 252 0.3

Ethyl Acetate 141−78−6 D d I −4 427 2.0 11.5 3.0 93.2 IIA 0.46 0.99

Ethyl Acrylate(Inhibited)

140−88−5 D d I 9 372 1.4 14.0 3.5 37.5 IIA 0.86

Ethyl Alcohol 64−17−5 D d I 13 363 3.3 19.0 1.6 59.5 IIA 0.88 0.89

Ethyl Sec-Amyl Ketone 541−85−5 D II 59

Ethyl Benzene 100−41−4 D I 15 432 0.8 6.7 3.7 9.6

Ethyl Butanol 97−95−0 D II 57 1.2 7.7 3.5 1.5

Ethyl Butyl Ketone 106−35−4 D II 46 4.0 3.6

Ethyl Chloride 75−00−3 D GAS −50 519 3.8 15.4 2.2

Ethyl Formate 109−94−4 D GAS −20 455 2.8 16.0 2.6 IIA 0.94

Ethyl Mercaptan 75−08−1 C d I −18 300 2.8 18.0 2.1 527.4 IIB 0.90 0.90

n-Ethyl Morpholine 100−74−3 C I 32 4.0

2-Ethyl-3-PropylAcrolein

645−62−5 C IIIA 68 4.4


6 of 18 5/18/2015 11:12 AM


DivisionGroup


AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

Ethyl Silicate 78−10−4 D II 7.2

Formaldehyde (Gas) 50−00−0 B GAS 430 7 73 1.0 IIB 0.57

Formic Acid 64−18−6 D II 50 434 18.0 57.0 1.6 42.7 IIA 1.86

Fuel Oil 1 8008−20−6 DII or

IIIA k 38−72 k 210 0.7 5.0

Fuel Oil 2II or

IIIA k 52−96 k 257

Fuel Oil 6IIIA or

IIIB k 66–132 k

Furfural 98−01−1 C IIIA 60 316 2.1 19.3 3.3 2.3 0.94

Furfuryl Alcohol 98−00−0 C IIIA 75 490 1.8 16.3 3.4 0.6

Gasoline 8006−61−9 D d I −46 280 1.4 7.6 3.0

n-Heptane 142−82−5 D d I −4 204 1.0 6.7 3.5 45.5 IIA 0.24 0.88 0.91

n-Heptene 81624−04−6 D g I −1 204 3.4 0.97

n-Hexane 110−54−3 D d,g I −23 225 1.1 7.5 3.0 152 IIA 0.24 0.88 0.93

Hexanol 111−27−3 D IIIA 63 3.5 0.8 IIA 0.98

2-Hexanone 591−78−6 D I 35 424 1.2 8.0 3.5 10.6

Hexene 592−41−6 D I −26 245 1.2 6.9 186

sec-Hexyl Acetate 108−84−9 D II 45 5.0

Hydrazine 302−01−2 C II 38 23 98.0 1.1 14.4

Hydrogen 1333−74−0 B d GAS 500 4 75 0.1 IIC 0.019 0.25 0.28

Hydrogen Cyanide 74−90−8 C d GAS −18 538 5.6 40.0 0.9 IIB 0.80

Hydrogen Selenide 7783−07−5 C I 7793

Hydrogen Sulfide 7783−06−4 C d GAS 260 4.0 44.0 1.2 IIB 0.068 0.90

Isoamyl Acetate 123−92−2 D I 25 360 1.0 7.5 4.5 6.1

Isoamyl Alcohol 123−51−3 D II 43 350 1.2 9.0 3.0 3.2 IIA 1.02

Isobutane 75−28−5 D g GAS 460 1.8 8.4 2.0 IIA 0.95

Isobutyl Acetate 110−19−0 D d I 18 421 2.4 10.5 4.0 17.8

Isobutyl Acrylate 106−63−8 D I 427 4.4 7.1

Isobutyl Alcohol 78−83−1 D d I −40 416 1.2 10.9 2.5 10.5 IIA 0.92 0.98

Isobutyraldehyde 78−84−2 C GAS −40 196 1.6 10.6 2.5 IIA 0.92

Isodecaldehyde 112−31−2 C IIIA 5.4 0.09

Isohexane 107−83−5 D g 264 211.7 IIA 1.00

Isopentane 78−78−4 D g 420 688.6

Isooctyl Aldehyde 123−05−7 C II 197 1.9

Isophorone 78−59−1 D 84 460 0.8 3.8 4.8 0.4

Isoprene 78−79−5 D d I −54 220 1.5 8.9 2.4 550.6

Isopropyl Acetate 108−21−4 D I 460 1.8 8.0 3.5 60.4

Isopropyl Ether 108−20−3 D d I −28 443 1.4 7.9 3.5 148.7 IIA 1.14 0.94

Isopropyl GlycidylEther

4016−14−2 C I

Isopropylamine 75−31−0 D GAS −26 402 2.3 10.4 2.0 2.0

Kerosene 8008−20−6 D II 72 210 0.7 5.0 IIA

Liquefied PetroleumGas

68476−8−7 D I 405

Mesityl Oxide 141−97−9 D d I 31 344 1.4 7.2 3.4 47.6


7 of 18 5/18/2015 11:12 AM


DivisionGroup


AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

Methane 74−82−8 D d GAS 600 5 15 0.6 IIA 0.28 1.00 1.12

Methanol 67−56−1 D d I 12 385 6.0 36.0 1.1 126.3 IIA 0.14 0.82 0.92

Methyl Acetate 79−20−9 D GAS −10 454 3.1 16.0 2.6 IIA 1.08 0.99

Methyl Acrylate 96−33−3 D GAS −3 468 2.8 25.0 3.0 IIB 0.98 0.85

Methyl Alcohol 67−56−1 D d I 385 6.0 36 1.1 126.3 IIA 0.91

Methyl Amyl Alcohol 108−11−2 D II 41 1.0 5.5 3.5 5.3 IIA 1.01

Methyl Chloride 74−87−3 D GAS −46 632 8.1 17.4 1.7 IIA 1.00

Methyl Ether 115−10−6 C d GAS −41 350 3.4 27.0 1.6 IIB 0.85 0.84

Methyl Ethyl Ketone 78−93−3 D d I −6 404 1.4 11.4 2.5 92.4 IIB 0.53 0.92 0.84

Methyl Formal 534−15−6 C d I 1 238 3.1

Methyl Formate 107−31−3 D GAS −19 449 4.5 23.0 2.1 IIA 0.94

2-Methylhexane 31394−54−4 D g I 280

Methyl Isobutyl Ketone 108−10−1 D d I 13 440 1.2 8.0 3.5 11

Methyl Isocyanate 624−83−9 D GAS −15 534 5.3 26.0 2.0 IIA 1.21

Methyl Mercaptan 74−93−1 C GAS −18 3.9 21.8 1.7

Methyl Methacrylate 80−62−6 D I 10 422 1.7 8.2 3.6 37.2 IIA 0.95

Methyl N-Amyl Ketone 110−43−0 D II 49 393 1.1 7.9 3.9 3.8

Methyl Tertiary ButylEther

1634−04−4 D I −80 435 1.6 8.4 0.2 250.1

2-Methyloctane 3221−61−2 220 6.3

2-Methylpropane 75−28−5 D g I 460 2639

Methyl-1-Propanol 78−83−1 D d I −40 416 1.2 10.9 2.5 10.1 IIA 0.98

Methyl-2-Propanol 75−65−0 D d I 10 360 2.4 8.0 2.6 42.2

2-Methyl-5-EthylPyridine

104−90−5 D 74 1.1 6.6 4.2

Methylacetylene 74−99−7 C d I 1.7 1.4 4306 0.11

Methylacetylene-Propadiene

27846−30−6 C I IIB 0.74

Methylal 109−87−5 C I −18 237 1.6 17.6 2.6 398

Methylamine 74−89−5 D GAS 430 4.9 20.7 1.0 IIA 1.10

2-Methylbutane 78−78−4 D g −56 420 1.4 8.3 2.6 688.6

Methylcyclohexane 208−87−2 D I −4 250 1.2 6.7 3.4 0.27

Methylcyclohexanol 25630−42−3 D 68 296 3.9

2-Methycyclohexanone 583−60−8 D II 3.9

2-Methylheptane D g 420

3-Methylhexane 589−34−4 D g 280 61.5

3-Methylpentane 94−14−0 D g 278

2-Methylpropane 75−28−5 D g I 460 2639

2-Methyl-1-Propanol 78−83−1 D d I −40 223 1.2 10.9 2.5 10.5

2-Methyl-2-Propanol 75−65−0 D d I 478 2.4 8.0 2.6 42.2

2-Methyloctane 2216−32−2 D g 220

3-Methyloctane 2216−33−3 D g 220 6.3

4-Methyloctane 2216−34−4 D g 225 6.8

Monoethanolamine 141−43−5 D 85 410 2.1 0.4 IIA


8 of 18 5/18/2015 11:12 AM


DivisionGroup


AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

Monoisopropanolamine 78−96−6 D 77 374 2.6 1.1

Monomethyl Aniline 100−61−8 C 482 0.5

Monomethyl Hydrazine 60−34−4 C I 23 194 2.5 92.0 1.6

Morpholine 110−91−8 C d II 35 310 1.4 11.2 3.0 10.1 IIA 0.95

Naphtha (Coal Tar) 8030−30−6 D II 42 277 IIA

Naphtha (Petroleum) 8030−30−6 D d,i I 42 288 1.1 5.9 2.5 IIA

Neopentane 463−82−1 D g −65 450 1.4 8.3 2.6 1286

Nitrobenzene 98−95−3 D 88 482 1.8 4.3 0.3 IIA 0.94

Nitroethane 79−24−3 C I 28 414 3.4 2.6 20.7 IIB 0.87

Nitromethane 75−52−5 C I 35 418 7.3 2.1 36.1 IIA 0.92 1.17

1-Nitropropane 108−03−2 C I 34 421 2.2 3.1 10.1 IIB 0.84

2-Nitropropane 79−46−9 C d I 28 428 2.6 11.0 3.1 17.1

n-Nonane 111−84−2 D g I 31 205 0.8 2.9 4.4 4.4 IIA

Nonene 27214−95−8 D I 0.8 4.4

Nonyl Alcohol 143−08−8 D 0.8 6.1 5.0 0.02 IIA

n-Octane 111−65−9 D d,g I 13 206 1.0 6.5 3.9 14.0 IIA 0.94

Octene 25377−83−7 D I 8 230 0.9 3.9

n-Octyl Alcohol 111−87−5 D 4.5 0.08 IIA 1.05

n-Pentane 109−66−0 D d,g I −40 243 1.5 7.8 2.5 513 IIA 0.28 0.97 0.93

1-Pentanol 71−41−0 D d I 33 300 1.2 10.0 3.0 2.5 IIA 1.30

2-Pentanone 107−87−9 D I 7 452 1.5 8.2 3.0 35.6 IIA 0.99

1-Pentene 109−67−1 D I −18 275 1.5 8.7 2.4 639.7

2-Pentene 109−68−2 D I −18 2.4

2-Pentyl Acetate 626−38−0 D I 23 1.1 7.5 4.5

Phenylhydrazine 100−63−0 D 89 3.7 0.03

Process Gas > 30%H 2

B j GAS 520 4.0 75.0 0.1 0.019 0.45

Propane 74−98−6 D d GAS 450 2.1 9.5 1.6 IIA 0.25 0.82 0.97

1-Propanol 71−23−8 D d I 15 413 2.2 13.7 2.1 20.7 IIA 0.89

2-Propanol 67−63−0 D d I 12 399 2.0 12.7 2.1 45.4 IIA 0.65 1.00

Propiolactone 57−57−8 D 2.9 2.5 2.2

Propionaldehyde 123−38−6 C I −9 207 2.6 17.0 2.0 318.5 IIB 0.86

Propionic Acid 79−09−4 D II 54 466 2.9 12.1 2.5 3.7 IIA 1.10

Propionic Anhydride 123−62−6 D 74 285 1.3 9.5 4.5 1.4

n-Propyl Acetate 109−60−4 D I 14 450 1.7 8.0 3.5 33.4 IIA 1.05

n-Propyl Ether 111−43−3 C d I 21 215 1.3 7.0 3.5 62.3

Propyl Nitrate 627−13−4 B d I 20 175 2.0 100.0

Propylene 115−07−1 D d GAS 460 2.4 10.3 1.5 IIA 0.28 0.91

Propylene Dichloride 78−87−5 D I 16 557 3.4 14.5 3.9 51.7 IIA 1.32

Propylene Oxide 75−56−9 B(C) d,e I −37 449 2.3 36.0 2.0 534.4 IIB 0.13 0.70

Pyridine 110−86−1 D d I 20 482 1.8 12.4 2.7 20.8 IIA

Styrene 100−42−5 D d I 31 490 0.9 6.8 3.6 6.1 IIA 1.21

Tetrahydrofuran 109−99−9 C d I −14 321 2.0 11.8 2.5 161.6 IIB 0.54 0.87

Tetrahydronaphthalene 119−64−2 D IIIA 385 0.8 5.0 4.6 0.4


9 of 18 5/18/2015 11:12 AM


DivisionGroup


AIT(°C)

%LFL %UFL

VaporDensity(Air =

1)

Vapor

Pressure b

(mm Hg)

Class IZone

Group c

MIE(mJ)

MICRatio

MESG(mm)

Tetramethyl Lead 75−74−1 C II 38 9.2

Toluene 108−88−3 D d I 4 480 1.1 7.1 3.1 28.53 IIA 0.24

n-Tridecene 2437−56−1 D IIIA 0.6 6.4 593.4

Triethylamine 121−44−8 C d I −9 249 1.2 8.0 3.5 68.5 IIA 0.75 1.05

Triethylbenzene 25340−18−5 D 83 56.0 5.6

2,2,3-Trimethylbutane D g 442

2,2,4-Trimethylbutane D g 407

2,2,3-Trimethylpentane D g 396

2,2,4-Trimethylpentane D g 415 IIA 1.04

2,3,3-Trimethylpentane D g 425

Tripropylamine 102−69−2 D II 41 4.9 1.5 IIA 1.13

Turpentine 8006−64−2 D I 35 253 0.8 4.8

n-Undecene 28761−27−5 D IIIA 0.7 5.5

UnsymmetricalDimethyl Hydrazine

57−14−7 C d I −15 249 2.0 95.0 1.9 IIB 0.85

Valeraldehyde 110−62−3 C I 280 222 3.0 34.3

Vinyl Acetate 108−05−4 D d I −6 402 2.6 13.4 3.0 113.4 IIA 0.70 0.94

Vinyl Chloride 75−01−4 D d GAS −78 472 3.6 33.0 2.2 IIA 0.96

Vinyl Toluene 25013−15−4 D 52 494 0.8 11.0 4.1

Vinylidene Chloride 75−35−4 D I 570 6.5 15.5 3.4 599.4 IIA 3.91

Xylene 1330−20-7 D d I 25 464 0.9 7.0 3.7 IIA 0.2 1.09

Xylidine 121−69−7 C IIIA 63 371 1.0 4.2 0.7

aType is used to designate if the material is a gas, flammable liquid, or combustible liquid. (See 4.2.6 and 4.2.7.)

bVapor pressure reflected in units of mm Hg at 77°F (25°C) unless stated otherwise.

cClass I, Zone Groups are based on 1996 IEC TR3 60079-20-1, Explosive atmospheres — Part 20-1:Material characteristicsfor gas and vapor classification — Test methods and data, which contains additional data on MESG and group classifications.

dMaterial has been classified by test.

eWhere all conduit runs into explosionproof equipment are provided with explosionproof seals installed within 18 in. (450 mm)of the enclosure, equipment for the group classification shown in parentheses is permitted.

fFor classification of areas involving ammonia, see ASHRAE 15, Safety Standard for Refrigeration Systems, and CGA G2.1,Safety Requirements for the Storage and Handling of Anhydrous Ammonia.

gCommercial grades of aliphatic hydrocarbon solvents are mixtures of several isomers of the same chemical formula (ormolecular weight). The autoignition temperatures (AIT) of the individual isomers are significantly different. The electricalequipment should be suitable for the AIT of the solvent mixture. (See A.4.4.2.)

hCertain chemicals have characteristics that require safeguards beyond those required for any of the above groups. Carbondisulfide is one of these chemicals because of its low autoignition temperature and the small joint clearance necessary to arrestits flame propagation.

iPetroleum naphtha is a saturated hydrocarbon mixture whose boiling range is 68°F to 275°F (20°C to 135°C). It is also knownas benzine, ligroin, petroleum ether, and naphtha.

jFuel and process gas mixtures found by test not to present hazards similar to those of hydrogen may be grouped based on thetest results.

k Liquid type and flash point vary due to regional blending differences.



10 of 18 5/18/2015 11:12 AM

Updated Table 4.4.2 note c by updating reference to IEC 60079-20-1.



Public Comment No. 1-NFPA 497-2015 [Chapter 2] Referenced current standard names and years

Public Comment No. 3-NFPA 497-2015 [Chapter C]

Related Item

First Revision No. 4-NFPA 497-2014 [Section No. 4.4.2]




Street Address:

City:

State:

Zip:



11 of 18 5/18/2015 11:12 AM

Public Comment No. 7-NFPA 497-2015 [ New Section after 5.10 ]

(new) Figure Compressed Gas Cylinders

Insert new figure 9.5.x and 10.5.x for Heavier than Air

Insert new figure 9.5.x1 and 10.5.x2 for Lighter than Air

See attached graphic.

Additional Proposed Changes

File Name Description Approved

Compressed_gas_cylinders.docx Compressed gas figures for Division and Zone, Heavier than air and lighter than air


As discussed there was a need to address gas cylinder storage classification

Related Item

First Revision No. 11-NFPA 497-2014 [Section No. 5.9 [Excluding any Sub-Sections]]


Submitter Full Name: DAVID WECHSLER


Street Address:

City:

State:

Zip:

Submittal Date: Thu May 14 14:45:45 EDT 2015


12 of 18 5/18/2015 11:12 AM


5.10.8 Storage of Liquid or Gaseous Hydrogen. Replace drawings with attached figures

[See Figure 5.10.8(a) and Figure 5.10.8(b).]

Figure 5.10.8(a) Liquid Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. Thisdiagram applies to liquid hydrogen only.

Figure 5.10.8(b) Gaseous Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. Thisdiagram applies to gaseous hydrogen only.



CYLINDERS_Division.pdf Gas storage in cylinders - divisions

FILL_CONNECTION_LIQUID_Division.pdf Liquid hydrogen storage fill connection - divisions

RECEIVERS_Division.pdf Gas hydrogen storage in receivers - divisions

TANK_AND_VAPORIZER_LIQUID_Division.pdf Liquid hydrogen storage - tank and vaporizer - divisions

VENT_STACK_GAS_Division.pdf Gas hydrogen vent stack - divisions

VENT_STACK_LIQUID_Division.pdf Liquid hydrogen vent stack - divisions

section_5.10.8_figures_-_divisions.docx Complete set of figures and figure numbers for divisions


Updates drawings to match material in 2016 edition of NFPA 55

Related Item

Committee Input No. 1-NFPA 497-2014 [Section No. 5.9.8]


Submitter Full Name: ROB EARLY

Organization: PRAXAIR

Affilliation: NFPA Industrial and Medical Gases Committee

Street Address:

City:

State:

Zip:

Submittal Date: Mon May 11 16:21:00 EDT 2015


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1

Figure 5.10.8(a) – liquid hydrogen storage – tank and vaporizer (part of system containing liquid hydrogen)

2

Figure 5.10.8(b) – liquid hydrogen tank fill connection

3

Figure 5.10.8(c) – liquid hydrogen vent stack

4

Figure 5.10.8(d) – gas hydrogen storage – receivers

5

Figure 5.10.8(e) – gas hydrogen storage – cylinders

6

Figure 5.10.8(f) – gas hydrogen vent stack


5.10.8 Storage of Liquid or Gaseous Hydrogen. Update figures with attachments - alternate updates



Figure 5.10.8(b) Gaseous Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. Thisdiagram applies to gaseous hydrogen only.



section_5.10.8_figures_-_divisions_-_alternate.pdf figures for divisions - alternate


Updating to match NFPA 55 classified area requirements

Related Item






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14 of 18 5/18/2015 11:12 AM


5.11.8 Storage of Liquid or Gaseous Hydrogen. Replace drawings with attached figures.



Figure 5.11.8(b) Gaseous Hydrogen Storage Located Outdoors, or Indoors in an Adequately Ventilated Building. Thisdiagram applies to gaseous hydrogen only.



CYLINDERS_Zone.pdf Gas hydrogen storage in cylinders - zones

FILL_CONNECTION_LIQUID_Zone.pdf Liquid hydrogen fill connection - zone

RECEIVERS_Zone.pdf Gas hydrogen storage in receivers - zones

TANK_AND_VAPORIZER_LIQUID_Zone.pdf Liquid hydrogen storage - tank and vaporizer - zones

VENT_STACK_GAS_Zone.pdf Gas hydrogen vent stack - zones

VENT_STACK_LIQUID_Zone.pdf Liquid hydrogen vent stack - zones

section_5.11.8_figures_-_zones.docx complete set of figures and figure numbers for zones


Harmonizes figures with updates in NFPA 55, 2016 edition

Related Item





Affilliation: NFPA Industrial and Medical Gases committee

Street Address:

City:

State:

Zip:

Submittal Date: Mon May 11 16:30:44 EDT 2015


15 of 18 5/18/2015 11:12 AM

1

Figure 5.11.8(a) – liquid hydrogen storage – tank and vaporizer (part of system containing liquid hydrogen)

2

Figure 5.11.8(b) – liquid hydrogen tank fill connection

3

Figure 5.11.8(c) – liquid hydrogen vent stack

4

Figure 5.11.8(d) – gas hydrogen storage – receivers

5

Figure 5.11.8(e) – gas hydrogen storage – cylinders

6

Figure 5.11.8(f) – gas hydrogen vent stack


5.11.8 Storage of Liquid or Gaseous Hydrogen. Update with attached drawings - alternate



Figure 5.11.8(b) Gaseous Hydrogen Storage Located Outdoors, or Indoors in an Adequately Ventilated Building. Thisdiagram applies to gaseous hydrogen only.



section_5.11.8_figures_-_zones_-_alternate.pdf updated figures - alternate


updates figures to match NFPA 55

Related Item






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Public Comment No. 3-NFPA 497-2015 [ Chapter C ]

Annex C Informational References

C.1 Reference Publications.

The documents or portions thereof listed in this annex are referenced within the informational sections of this recommendedpractice and are not part of the recommendations of this document unless also listed in Chapter 2 for other reasons.

C.1.1 NFPA Publications.

National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.

NFPA 70 ®, National Electrical Code ®, 2014.

NFPA Fire Protection Guide to Hazardous Materials, 2010.

C.1.2 Other Publications.

C.1.2.1 ASTM Publications.

ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428–2959.

ASTM E659, Standard Test Method for Autoignition Temperature of Liquid Chemicals, 2014.

C.1.2.2 IEC Publications.

International Electrotechnical Commission, 3, rue de Varembé, P.O. Box 131, CH-1211 Geneva 20, Switzerland.

IEC 60079-1-1, Electrical apparatus for explosive gas atmospheres, Part 1-1: Flameproof enclosures “d”— Method of test forascertainment of maximum experimental safe gap , 2002 (Superseded by IEC 60079-20-1) .

IEC 60079-11, Explosive atmospheres — Part 11: Equipment protection by intrinsic safety “I,” 2012.

IEC 60079-20, - 1, Explosive atmospheres —Part 20-1: Material characteristics of gas and vapor classification — Testmethods and data, .2012.

C.1.2.3 NAS Publications.

National Materials Advisory Board of the National Academy of Sciences, 500 Fifth Street, NW, Washington, DC 20055.

NMAB 353-1, Matrix of Combustion-Relevant Properties and Classification of Gases, Vapors and Selected Solids, 1979.

C.1.2.4 UL Publications.

Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.

Technical Report No. 58 (TR 58), An Investigation of Flammable Gases or Vapors with Respect to Explosion-Proof ElectricalEquipment, 1993. (Withdrawn)

C.1.2.5 Other Publications.

Brandes, E. and Redeker, T. “Maximum Experimental Safe Gap of Binary and Ternary Mixtures.” Journal de Physique IVFrance, Vol. 12, No. 7, 2002.

Lunn, G. A., “Maximum Experimental Safe Gap: The Effects of Oxygen Enrichment and the Influence of Reaction Kinetics,”Journal of Hazardous Materials, 261–270, 1984.

Phillips, H. “Differences Between Determinations of Maximum Experimental Safe Gaps in Europe and U.S.A.” Journal ofHazardous Materials, 1981.

Thomas, G., “Pipeline Explosions I: An Evaluation of MESG as a Relative Measure of Potential Explosion Severity and theGenesis of a Mimic Gas Concept for Explosion Hazard Testing,” 5th Int. Seminar on Fire and Explosion Hazards, Edinburgh,Scotland, 2007.

C.2 Informational References.

The following documents or portions thereof are listed here as informational resources only. They are not a part of therecommendations of this document.

C.2.1 ASHRAE Publications.

American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc., 1791 Tullie Circle, NE, Atlanta, GA30329-2305.

ASHRAE STD 15 & 34, Designation and Safety Classification of Refrigerants Saftey Standard for Refrigeration Systems ,2013, Errata, 2015 . (This is now a combined standard.)

C.2.2 ASTM Publications.

ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.

ASTM D56, Standard Method of Test for Flash Point by the Tag Closed Tester, 2005, reapproved 2010 .

ASTM D93, Standard Test Method for Flash Point by Pensky-Martens Closed Cup Tester, 2013.

ASTM D3278, Standard Method of Tests for Flash Point of Liquids by Small Scale Closed-Cup Apparatus, 1996, reapproved2011 .

ASTM E681, Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases), 2009.


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C.2.3 Bureau of Mines Publications.

U.S. Government Printing Office, Washington, DC 20402.

RI 7009, Minimum Ignition Energy and Quenching Distance in Gaseous Mixture.

C.2.4 Other Publications.

Energy Institute (Institute of Petroleum), Model Code of Safe Practice for the Petroleum Industry, Part 15: Area ClassificationCode for Installations Handling Flammable Fluids, 2008.

Hilado, C. J., and S. W. Clark. “Autoignition Temperatures of Organic Chemicals.” Chemical Engineering, September 4, 1972.

Rodgers, S. A., “Fuel Ratio Method for Estimating the MESG of Nitrogen-Diluted and Oxygen-Enriched Fuels, Including theBrandes-Redeker Method to Estimate the MESG of Mixed Fuels,” AIChE 6th Global Congress on Process Safety, 44th AnnualLoss Prevention Symposium, San Antonio, TX March 22–24, 2010.

C.3 References for Extracts in Informational Sections.

(Reserved)


IEC 60079-1-1 superseded by IEC 60079-20-1.UL TR 58 has been withdrawn.



Public Comment No. 1-NFPA 497-2015 [Chapter 2]Referenced current standard names, andyears.

Public Comment No. 2-NFPA 497-2015 [Section No. 4.4.2 [Excluding anySub-Sections]]

Referenced current standard name in notec.

Related Item

First Revision No. 12-NFPA 497-2014 [Chapter C]




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Attachment G:


Comments


1.2 Purpose.

1.2.1

The purpose of this recommended practice is to provide the user with a basic understanding of theparameters that determine the degree and the extent of the hazardous (classified) location. Thisrecommended practice also provides the user with examples of the applications of these parameters.

1.2.2

This recommended practice is intended as a guide and should be applied with sound engineeringjudgment. Where all factors are properly evaluated, a consistent area classification scheme can bedeveloped.

1.2.3

This recommended practice is based on the criteria established by Articles 500 and 502 of NFPA 70.

1.2.4

The application of this recommended practice does not address all potential hazards associated with solidparticulate materials, including, but not limited to, the possible need for explosion venting or explosionsuppression addressed in other NFPA standards.

1.2.5

This recommended practice does not address the criteria for classifying locations in accordance with Article506 of NFPA 70 .


Note: for Clarification - This comment only applies to the deletion of 1.2.5 and not all 1.2.

It had been suggested by Public Input to include dust zones within NFPA 499. During this session, the Committee received apparently incorrect information that having more than one ANSI standard dealing with Hazardous Area Classification for Zones for combustible dusts would violate ANSI regulations. Precedent already exists for ANSI supported standards dealing with HAC zone methodology. These include NFPA 497, API 505, ISA 60079-10, just to name a few. Additionally since the US National Electrical Code provides a method in which Division equipment may be used in Zones and vice versa (in some cases), there should be no reasonable rational for not permitting Zone methodology to be applied with combustilble dusts as outlined with the repeated public input now Public comments made in support of adding Zones for combustible dusts in 499.



Public Comment No. 2-NFPA 499-2015 [New Section after 4.3]

Public Comment No. 3-NFPA 499-2015 [New Section after 5.1.4]


Public Comment No. 5-NFPA 499-2015 [Section No. 5.2.2]

Public Comment No. 6-NFPA 499-2015 [Section No. 6.10]


Public Comment No. 10-NFPA 499-2015 [Section No. A.6.3.2]

Public Comment No. 11-NFPA 499-2015 [Section No. A.6.7]




Public Comment No. 15-NFPA 499-2015 [Chapter 6]


1 of 51 5/18/2015 11:33 AM

Related Item

Public Input No. 28-NFPA 499-2014 [New Section after 4.3]


Submitter Full Name: David Wechsler


Street Address:

City:

State:

Zip:

Submittal Date: Thu Mar 05 10:20:07 EST 2015


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Public Comment No. 2-NFPA 499-2015 [ New Section after 4.3 ]

TITLE OF NEW CONTENT

Type your content here ...

Renumber existing 4.3 to 4.4 Additional Potential Combustible Dust Hazards and add the following

new section 4.3 as shown:

4.3 Classification of Combustible Dusts

4.3.1 Combustible Dust Groups. Combustible dusts are addressed in the National Electrical Code,

in Articles 500, 502, and 506.

4.3.2 In Class II- Divisions, hazardous (classified) location the combustible dust are divided into Groups E,F,

and G.

4.3.2.1 Group E. Atmospheres containing combustible metal dusts, including aluminum, magnesium, and

their commercial alloys, or other combustible dusts whose particle size, abrasiveness, and conductivity

present similar hazards in the use of electrical equipment.

4.3.2.2 (retain appendix material 3.3.4.2*) Group F. Atmospheres containing combustible

carbonaceous dusts that have more than 8 percent total entrapped volatiles (see ASTM D 3175,

Standard Test Method for Volatile Matter in the Analysis Sample of Coal and Coke, for coal and

coke dusts) or that have been sensitized by other materials so that they present an explosion

hazard.

4.3.2.3 (retain appendix material 3.3.4.3*) Group G. Atmospheres containing combustible dusts notincluded

in Group E or Group F, including flour, grain, wood, plastic, and chemicals.

4.3.3 In Class II- Zones, hazardous (classified) location the combustible dust are divided into Zone Groups

IIIC and IIIB.

4.3.3.1 Zone Group IIIC. Atmospheres containing combustible metal dusts, including aluminum,magnesium,

and their commercial alloys, or other combustible dusts whose particle size, abrasiveness, and conductivity


4.3.3.2 Zone Group IIIB. Atmospheres containing 1) combustible carbonaceous dusts that have more than8

percent total entrapped volatiles (see ASTM D 3175, Standard Test Method for Volatile Matter in the

Analysis Sample of Coal and Coke, for coal and coke dusts) or that have been sensitized by othermaterials

so that they present an explosion hazard or 2) combustible dusts not included in Zone Group IIIC including

flour, grain, wood, plastic, and chemicals.

Informational Note No. 1: Ignitible fibers and flyings addressed in NEC Article 506 are not considered

combustible dusts under the scope of this recommended practice.

4.3.4 5.2.2* A listing of selected combustible dusts with their group classification and relevant physical

properties is provided in Table 4.x.x (former Table 5.2.2). The chemicals are listed alphabetically.

Revise this table to include new column showing Zone Groups and editing this information in this new

column by adding IIIB across from each G and F entry, and IIIC across each E entry

4.3.5 5.2.3 Table 4.x.x (former Table 5.2.3) provides a cross-reference of selected chemicals sorted by their

Chemical Abstract Service (CAS) numbers.

4.3.6 5.2.4 References that deal with the testing of various characteristics of combustible materials arelisted

in B.2.1, B.2.2, and B.2.4.


Added material is needed to support the inclusion of the Zone methodolgy for combustible dusts as shown in the


3 of 51 5/18/2015 11:33 AM

earlier Public Input 28.



Public Comment No. 1-NFPA 499-2015[Section No. 1.2]

Supports the addition of Zone methodology which was notpermitted by clause 1.2.5

Public Comment No. 3-NFPA 499-2015 [NewSection after 5.1.4]

Public Comment No. 4-NFPA 499-2015 [NewSection after 5.2.1]

Public Comment No. 5-NFPA 499-2015[Section No. 5.2.2]



Related Item

Public Input No. 28-NFPA 499-2014 [New Section after 4.3]




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4 of 51 5/18/2015 11:33 AM

Public Comment No. 3-NFPA 499-2015 [ New Section after 5.1.4 ]



Add new section 5.1.4 as shown below:

5.1.4 Class II –Zone hazardous (classified) location is further subdivided into either Class II, Zone 20, Zone

21 or Zone 22, in which combustible dust are or may be present in the air or in layers, in quantities

sufficient to produce explosive or ignitible mixtures.

5.1.4.1 Zone 20. A Zone 20 location is a location in which (a) Ignitible concentrations of combustible dust

are present continuously.

(b) Ignitible concentrations of combustible dust are present for long periods of time.

5.1.4.2 Zone 21. A Zone 21 location is a location (a) In which ignitible concentrations of combustible dustare

likely to exist occasionally under normal operating conditions; or (b) In which ignitible concentrations of

combustible dust may exist frequently because of repair or maintenance operations or because of leakage;

or (c) In which equipment is operated or processes are carried on, of such a nature that equipment

breakdown or faulty operations could result in the release of ignitable concentrations of combustible dust

and also cause simultaneous failure of electrical equipment in a mode to cause the electrical equipment to

become a source of ignition; or (d) That is adjacent to a Zone 20 location from which ignitible

concentrations of dust could be communicated, unless communication is prevented by adequate

positive pressure ventilation from a source of clean air and effective safeguards against ventilation.

5.1.4.3 Zone 22. A Zone 22 location is a location (a) In which ignitible concentrations of combustible dustare

not likely to occur in normal operation and, if they do occur, will only persist for a short period; or (b) Inwhich

combustible dust are handled, processed, or used but in which the dust are normally confined within closed

containers of closed systems from which they can escape only as a result of the abnormal operation of the

equipment with which the dust are handled, processed, or used; or (c) That is adjacent to a Zone 21

location, from which ignitible concentrations of dust could be communicated, unless such communication is

prevented by adequate positive pressure ventilation from a source of clean air and effective safeguards

against ventilation failure are provided.


With the inclusion of Combustible Dust Zones, the relavent document texts required revision based upon NECArticle 506 addressing Zone 20, 21, and 22, combustible Dust locations based upon the NEC



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2]Action supports inclusion of Zonemethodology

Public Comment No. 2-NFPA 499-2015 [New Section after4.3]

Action supports inclusion of Zonemethodology

Public Comment No. 4-NFPA 499-2015 [New Section after5.2.1]



Related Item

Public Input No. 30-NFPA 499-2014 [New Section after 5.1.4]


5 of 51 5/18/2015 11:33 AM




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6 of 51 5/18/2015 11:33 AM


5.1.9*

Where Group E dusts are present in hazardous quantities, there are only Division 1 locations.


This material is more correctly addressed in 5.1.3.1 (3) which follows the NEC.




Related Item





Street Address:

City:

State:

Zip:

Submittal Date: Tue Mar 10 08:58:29 EDT 2015


7 of 51 5/18/2015 11:33 AM

Public Comment No. 4-NFPA 499-2015 [ New Section after 5.2.1 ]



Add new section 5.2.2 and renumber accordingly:

New 5.2.2 Combustible Zone Dust Groups. Combustible Zone dusts are addressed

in the National Electrical Code , in Article 506 and are divided into Groups IIIC, and IIIB.

5.2.2.1 Group IIIC. Atmospheres containing combustible metal dusts, including aluminum, magnesium, and

their commercial alloys, or other combustible dusts whose particle size, abrasiveness, and conductivity


5.2.2.2 Group IIIB. Atmospheres containing combustible carbonaceous dusts that have more than 8

percent total entrapped volatiles (see ASTM D 3175, Standard Test Method for Volatile Matter in the

Analysis Sample of Coal and Coke , for coal and coke dusts) or that have been sensitized by other

materials so that they present an explosion hazard, or atmospheres containing combustible dusts not

included in Group IIIC, including flour, grain, wood, plastic, and chemicals.


Texts support the inclusion of these material groups for Combustible Zone dust groups



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2] Deals with Zone methodology

Public Comment No. 2-NFPA 499-2015 [New Section after 4.3] Deals with Zone methodology

Public Comment No. 3-NFPA 499-2015 [New Section after 5.1.4] Deals with Zone methodology




Related Item





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8 of 51 5/18/2015 11:33 AM



9 of 51 5/18/2015 11:33 AM

5.2.2*


10 of 51 5/18/2015 11:33 AM

A listing of selected combustible dusts with their group classification and relevant physical properties isprovided in Table 5.2.2. The chemicals are listed alphabetically.

Table 5.2.2 Selected Combustible Dusts

Chemical Name CAS No.

NEC

Group CodeLayer or Cloud Ignition

Temperature (°C)

Acetal, linear G NL 440

Acetoacet-p-phenetidide 122-82-7 G NL 560

Acetoacetanilide 102-01-2 G M 440

Acetylamino-t-nitrothiazole G 450

Acrylamide polymer G 240

Acrylonitrile polymer G 460

Acrylonitrile-vinyl chloride-vinylidenechloridecopolymer (70-20-10)

G 210

Acrylonitrile-vinyl pyridine copolymer G 240

Adipic acid 124-04-9 G M 550

Alfalfa meal G 200

Alkyl ketone dimer sizing compound G 160

Allyl alcohol derivative (CR-39) G NL 500

Almond shell G 200

Aluminum, A422 flake 7429-90-5 E 320

Aluminum, atomized collector fines E CL 550

Aluminum—cobalt alloy (60-40) E 570

Aluminum—copper alloy (50-50) E 830

Aluminum—lithium alloy (15% Li) E 400

Aluminum—magnesium alloy (dowmetal) E CL 430

Aluminum—nickel alloy (58-42) E 540

Aluminum—silicon alloy (12% Si) E NL 670

Amino-5-nitrothiazole 121-66-4 G 460

Anthranilic acid 118-92-3 G M 580

Apricot pit G 230

Aryl-nitrosomethylamide G NL 490

Asphalt 8052-42-4 F 510

Aspirin [acetol (2)] 50-78-2 G M 660

Azelaic acid 109-31-9 G M 610

Azo-bis-butyronitrile 78-67-1 G 350

Benzethonium chloride G CL 380

Benzoic acid 65-85-0 G M 620

Benzotriazole 95-14-7 G M 440

Beta-naphthalene-axo-

dimethylanilineG 175

Bis(2-hydroxy-

5-chlorophenyl) methane97-23-4 G NL 570

Bisphenol-A 80-05-7 G M 570

Boron, commercial amorphous (85% B) 7440-42-8 E 400

Calcium silicide E 540


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NEC


Temperature (°C)

Carbon black (more than 8% total entrappedvolatiles)

F

Carboxymethyl cellulose 9000-11-7 G 290

Carboxypolymethylene G NL 520

Cashew oil, phenolic, hard G 180

Cellulose G 260

Cellulose acetate G 340

Cellulose acetate butyrate G NL 370

Cellulose triacetate G NL 430

Charcoal (activated) 64365-11-3 F 180

Charcoal (more than 8% total entrappedvolatiles)

F

Cherry pit G 220

Chlorinated phenol G NL 570

Chlorinated polyether alcohol G 460

Chloroacetoacetanilide 101-92-8 G M 640

Chromium (97%) electrolytic, milled 7440-47-3 E 400

Cinnamon G 230

Citrus peel G 270

Coal, Kentucky bituminous F 180

Coal, Pittsburgh experimental F 170

Coal, Wyoming F 180

Cocoa bean shell G 370

Cocoa, natural, 19% fat G 240

Coconut shell G 220

Coke (more than 8% total entrapped volatiles) F

Cork G 210

Corn G 250

Corn dextrine G 370

Corncob grit G 240

Cornstarch, commercial G 330

Cornstarch, modified G 200

Cottonseed meal G 200

Coumarone-indene, hard G NL 520

Crag No. 974 533-74-4 G CL 310

Cube root, South America 83-79-4 G 230

Di-alphacumyl peroxide, 40-60 on CA 80-43-3 G 180

Diallyl phthalate 131-17-9 G M 480

Dicyclopentadiene dioxide G NL 420

Dieldrin (20%) 60-57-1 G NL 550

Dihydroacetic acid G NL 430

Dimethyl isophthalate 1459-93-4 G M 580

Dimethyl terephthalate 120-61-6 G M 570

Dinitro-o-toluamide 148-01-6 G NL 500


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NEC


Temperature (°C)

Dinitrobenzoic acid G NL 460

Diphenyl 92-52-4 G M 630

Ditertiary-butyl-paracresol 128-37-0 G NL 420

Dithane m-45 8018-01-7 G 180

Epoxy G NL 540

Epoxy-bisphenol A G NL 510

Ethyl cellulose G CL 320

Ethyl hydroxyethyl cellulose G NL 390

Ethylene oxide polymer G NL 350

Ethylene-maleic anhydride copolymer G NL 540

Ferbam™ 14484-64-1 G 150

Ferromanganese, medium carbon 12604-53-4 E 290

Ferrosilicon (88% Si, 9% Fe) 8049-17-0 E 800

Ferrotitanium (19% Ti, 74.1% Fe, 0.06% C) E CL 380

Flax shive G 230

Fumaric acid 110-17-8 G M 520

Garlic, dehydrated G NL 360

Gilsonite 12002-43-6 F 500

Green base harmon dye G 175

Guar seed G NL 500

Gulasonic acid, diacetone G NL 420

Gum, arabic G 260

Gum, karaya G 240

Gum, manila G CL 360

Gum, tragacanth 9000-65-1 G 260

Hemp hurd G 220

Hexamethylene tetramine 100-97-0 G S 410

Hydroxyethyl cellulose G NL 410

Iron, 98% H2 reduced E 290

Iron, 99% carbonyl 13463-40-6 E 310

Isotoic anhydride G NL 700

L-sorbose G M 370

Lignin, hydrolized, wood-type, fine G NL 450

Lignite, California F 180

Lycopodium G 190

Malt barley G 250

Manganese 7439-96-5 E 240

Magnesium, grade B, milled E 430

Manganese vancide G 120

Mannitol 69-65-8 G M 460

Methacrylic acid polymer G 290

Methionine (l-methionine) 63-68-3 G 360

Methyl cellulose G 340

Methyl methacrylate polymer 9011-14-7 G NL 440


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NEC


Temperature (°C)

Methyl methacrylate-ethyl acrylate G NL 440

Methyl methacrylate-styrene-

butadieneG NL 480

Milk, skimmed G 200

N,N-dimethylthio-

formamideG 230

Nitropyridone 100703-82-0 G M 430

Nitrosamine G NL 270

Nylon polymer 63428-84-2 G 430

Para-oxy-benzaldehyde 123-08-0 G CL 380

Paraphenylene diamine 106-50-3 G M 620

Paratertiary butyl benzoic acid 98-73-7 G M 560

Pea flour G 260

Peach pit shell G 210

Peanut hull G 210

Peat, sphagnum 94114-14-4 G 240

Pecan nut shell 8002-03-7 G 210

Pectin 5328-37-0 G 200

Pentaerythritol 115-77-5 G M 400

Petrin acrylate monomer 7659-34-9 G NL 220

Petroleum coke (more than 8% total entrappedvolatiles)

F

Petroleum resin 64742-16-1 G 500

Phenol formaldehyde 9003-35-4 G NL 580

Phenol formaldehyde, polyalkylene-p 9003-35-4 G 290

Phenol furfural 26338-61-4 G 310

Phenylbetanaphthylamine 135-88-6 G NL 680

Phthalic anydride 85-44-9 G M 650

Phthalimide 85-41-6 G M 630

Pitch, coal tar 65996-93-2 F NL 710

Pitch, petroleum 68187-58-6 F NL 630

Polycarbonate G NL 710

Polyethylene, high pressure process 9002-88-4 G 380

Polyethylene, low pressure process 9002-88-4 G NL 420

Polyethylene terephthalate 25038-59-9 G NL 500

Polyethylene wax 68441-04-8 G NL 400

Polypropylene (no antioxidant) 9003-07-0 G NL 420

Polystyrene latex 9003-53-6 G 500

Polystyrene molding compound 9003-53-6 G NL 560

Polyurethane foam, fire retardant 9009-54-5 G 390

Polyurethane foam, no fire retardant 9009-54-5 G 440

Polyvinyl acetate 9003-20-7 G NL 550

Polyvinyl acetate/alcohol 9002-89-5 G 440

Polyvinyl butyral 63148-65-2 G 390


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NEC


Temperature (°C)

Polyvinyl chloride-dioctyl phthalate G NL 320

Potato starch, dextrinated 9005-25-8 G NL 440

Pyrethrum 8003-34-7 G 210

Rayon (viscose) flock 61788-77-0 G 250

Red dye intermediate G 175

Rice G 220

Rice bran G NL 490

Rice hull G 220

Rosin, DK 8050-09-7 G NL 390

Rubber, crude, hard 9006-04-6 G NL 350

Rubber, synthetic, hard (33% S) 64706-29-2 G NL 320

Safflower meal G 210

Salicylanilide 87-17-2 G M 610

Sevin 63-25-2 G 140

Shale, oil 68308-34-9 F

Shellac 9000-59-3 G NL 400

Sodium resinate 61790-51-0 G 220

Sorbic acid (copper sorbate or potash) 110-44-1 G 460

Soy flour 68513-95-1 G 190

Soy protein 9010-10-0 G 260

Stearic acid, aluminum salt 637-12-7 G 300

Stearic acid, zinc salt 557-05-1 G M 510

Styrene modified polyester-glass fiber 100-42-5 G 360

Styrene-acrylonitrile (70-30) 9003-54-7 G NL 500

Styrene-butadiene latex (>75% styrene) 903-55-8 G NL 440

Styrene-maleic anhydride copolymer 9011-13-6 G CL 470

Sucrose 57-50-1 G CL 350

Sugar, powdered 57-50-1 G CL 370

Sulfur 7704-34-9 G 220

Tantalum 7440-25-7 E 300

Terephthalic acid 100-21-0 G NL 680

Thorium (contains 1.2% O) 7440-29-1 E CL 270

Tin, 96%, atomized (2% Pb) 7440-31-5 E 430

Titanium, 99% Ti 7440-32-6 E CL 330

Titanium hydride (95% Ti, 3.8% H) 7704-98-5 E CL 480

Trithiobisdimethylthio-

formamideG 230

Tung, kernels, oil-free 8001-20-5 G 240

Urea formaldehyde molding compound 9011-05-6 G NL 460

Urea formaldehyde-phenol formaldehyde 25104-55-6 G 240

Vanadium, 86.4% 7440-62-2 E 490

Vinyl chloride-acrylonitrile copolymer 9003-00-3 G 470

Vinyl toluene-acrylonitrile butadiene 76404-69-8 G NL 530

Violet 200 dye G 175


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NEC


Temperature (°C)

Vitamin B1, mononitrate 59-43-8 G NL 360

Vitamin C 50-81-7 G 280

Walnut shell, black G 220

Wheat G 220

Wheat flour 130498-22-5 G 360

Wheat gluten, gum 100684-25-1 G NL 520

Wheat starch G NL 380

Wheat straw G 220

Wood flour G 260

Woodbark, ground G 250

Yeast, torula 68602-94-8 G 260

Zirconium hydride 7704-99-6 E 270

Zirconium (contains 0.3% O) 7440-67-7 E CL 330

Notes:

(1) Normally, the minimum ignition temperature of a layer of a specific dust is lower than the minimumignition temperature of a cloud of that dust. Since this is not universally true, the lower of the two minimumignition temperatures is listed. If no symbol appears in the “Code” column, then the layer ignitiontemperature is shown. “CL” means the cloud ignition temperature is shown. “NL” means that no layerignition temperature is available, and the cloud ignition temperature is shown. “M” signifies that the dustlayer melts before it ignites; the cloud ignition temperature is shown. “S” signifies that the dust layersublimes before it ignites; the cloud ignition temperature is shown.

(2) Certain metal dusts might have characteristics that require safeguards beyond those required foratmospheres containing the dusts of aluminum, magnesium, and their commercial alloys. For example,zirconium and thorium dusts can ignite spontaneously in air, especially at elevated temperatures.

(3) Due to the impurities found in coal, its ignition temperatures vary regionally, and ignition temperaturesare not available for all regions in which coal is mined.



499_table_4.5.2_revised.rtfReplace existing table with this revised table reflecting Combustible Zone Dust Groups.


Table needs to be revised to reflect the Combustible Zone dusts, added with Section 5.2.2



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2] Supports Zone methodology

Public Comment No. 2-NFPA 499-2015 [New Section after 4.3] Supports Zone methodology

Public Comment No. 3-NFPA 499-2015 [New Section after 5.1.4] Supports Zone methodology

Public Comment No. 4-NFPA 499-2015 [New Section after 5.2.1] Supports Zone methodology




Related Item


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Public Input No. 25-NFPA 499-2014 [Section No. 5.2.2]




Street Address:

City:

State:

Zip:



17 of 51 5/18/2015 11:33 AM

Table 4.5.2 Selected Combustible Materials

Chemical Name CAS No. Division Grp/

Zone Group

Code Layer or Cloud

Ignition Temp.

(°C)

Acetal, Linear G/IIIB NL 440

Acetoacet-p-phenetidide 122-82-7 G//IIIB NL 560

Acetoacetanilide 102-01-2 G//IIIB M 440

Acetylamino-t-nitrothiazole G//IIIB 450

Acrylamide Polymer G/IIIB 240

Acrylonitrile Polymer G//IIIB 460

Acrylonitrile-Vinyl Chloride-Vinylidenechloride copolymer

(70-20-10)

G//IIIB 210

Acrylonitrile-Vinyl Pyridine Copolymer G//IIIB 240

Adipic Acid 124-04-9 G//IIIB M 550

Alfalfa Meal G//IIIB 200

Alkyl Ketone Dimer Sizing Compound G//IIIB 160

Allyl Alcohol Derivative (CR-39) G//IIIB NL 500

Almond Shell G//IIIB 200

Aluminum, A422 Flake 7429-90-5 E/IIIC 320

Aluminum, Atomized Collector Fines E/IIIC CL 550

Aluminum—cobalt alloy (60-40) E/IIIC 570

Aluminum—copper alloy (50-50) E/IIIC 830

Aluminum—lithium alloy (15% Li) E/IIIC 400

Aluminum—magnesium alloy (Dowmetal) E/IIIC CL 430

Aluminum—nickel alloy (58-42) E/IIIC 540

Aluminum—silicon alloy (12% Si) E/IIIC NL 670

Amino-5-nitrothiazole 121-66-4 G/IIIB 460

Anthranilic Acid 118-92-3 G/IIIB M 580

Apricot Pit G/IIIB 230

Aryl-nitrosomethylamide G/IIIB NL 490

Asphalt 8052-42-4 F/IIIB 510

Aspirin [acetol (2)] 50-78-2 G/IIIB M 660

Azelaic Acid 109-31-9 G/IIIB M 610

Azo-bis-butyronitrile 78-67-1 G/IIIB 350

Benzethonium Chloride G/IIIB CL 380

Benzoic Acid 65-85-0 G/IIIB M 440

Benzotriazole 95-14-7 G/IIIB M 440

Beta-naphthalene-axo-dimethylaniline G/IIIB 175

Bis(2-hydroxy-5-chlorophenyl) Methane 97-23-4 G/IIIB NL 570

Bisphenol-A 80-05-7 G/IIIB M 570

Boron, Commercial Amorphous (85% B) 7440-42-8 E/IIIC 400

Calcium Silicide E/IIIC 540

Carbon Black (More Than 8% Total Entrapped Volatiles) F/IIIB

Carboxymethyl Cellulose 9000-11-7 G/IIIB 290

Carboxypolymethylene G/IIIB NL 520

Cashew Oil, Phenolic, Hard G/IIIB 180

Cellulose G/IIIB 260

Cellulose Acetate G/IIIB 340

Cellulose Acetate Butyrate G/IIIB NL 370

Cellulose Triacetate G/IIIB NL 430

Charcoal (Activated) 64365-11-3 F/IIIB 180

Charcoal (More Than 8% Total Entrapped Volatiles) F/IIIB

Cherry Pit G/IIIB 220

Chlorinated Phenol G/IIIB NL 570

Chlorinated Polyether Alcohol G/IIIB 460

Chloroacetoacetanilide 101-92-8 G/IIIB M 640

Chromium (97%) Electrolytic, Milled 7440-47-3 E/IIIC 400

Cinnamon G/IIIB 230

Citrus Peel G/IIIB 270

Coal, Kentucky Bituminous F/IIIB 180

Coal, Pittsburgh Experimental F/IIIB 170

Coal, Wyoming F/IIIB 180

Cocoa Bean Shell G/IIIB 370

Cocoa, Natural, 19% Fat G/IIIB 240

Coconut Shell G/IIIB 220

Coke (More Than 8% Total Entrapped Volatiles) F/IIIB

Cork G/IIIB 210

Corn G/IIIB 250

Corn Dextrine G/IIIB 370

Corncob Grit G/IIIB 240

Cornstarch, Commercial G/IIIB 330

Cornstarch, Modified G/IIIB 200

Cottonseed Meal G/IIIB 200

Coumarone-Indene, Hard G/IIIB NL 520

Crag No. 974 533-74-4 G/IIIB CL 310

Cube Root, South America 83-79-4 G/IIIB 230

Di-alphacumyl Peroxide, 40-60 on CA 80-43-3 G/IIIB 180

Diallyl Phthalate 131-17-9 G/IIIB M 480

Dicyclopentadiene Dioxide G/IIIB NL 420

Dieldrin (20%) 60-57-1 G/IIIB NL 550

Dihydroacetic Acid G/IIIB NL 430

Dimethyl Isophthalate 1459-93-4 G/IIIB M 580

Dimethyl Terephthalate 120-61-6 G/IIIB M 570

Dinitro-o-toluamide 148-01-6 G/IIIB NL 500

Dinitrobenzoic Acid G/IIIB NL 460

Diphenyl 92-52-4 G/IIIB M 630

Ditertiary-butyl-paracresol 128-37-0 G/IIIB NL 420

Dithane m-45 8018-01-7 G/IIIB 180

Epoxy G/IIIB NL 540

Epoxy-bisphenol A G/IIIB NL 510

Ethyl Cellulose G/IIIB CL 320

Ethyl Hydroxyethyl Cellulose G/IIIB NL 390

Ethylene Oxide Polymer G/IIIB NL 350

Ethylene-maleic Anhydride Copolymer G/IIIB NL 540

Ferbam™ 14484-64-1 G/IIIB 150

Ferromanganese, Medium Carbon 12604-53-4 E/IIIC 290

Ferrosilicon (88% Si, 9% Fe) 8049-17-0 E/IIIC 800

Ferrotitanium (19% Ti, 74.1% Fe, 0.06% C) E/IIIC CL 380

Flax Shive G/IIIB 230

Fumaric Acid 110-17-8 G/IIIB M 520

Garlic, Dehydrated G/IIIB NL 360

Gilsonite 12002-43-6 F/IIIB 500

Green Base Harmon Dye G/IIIB 175

Guar Seed G/IIIB NL 500

Gulasonic Acid, Diacetone G/IIIB NL 420

Gum, Arabic G/IIIB 260

Gum, Karaya G/IIIB 240

Gum, Manila G/IIIB CL 360

Gum, Tragacanth 9000-65-1 G/IIIB 260

Hemp Hurd G/IIIB 220

Hexamethylene Tetramine 100-97-0 G/IIIB S 410

Hydroxyethyl Cellulose G/IIIB NL 410

Iron, 98% H2 Reduced E/IIIC 290

Iron, 99% Carbonyl 13463-40-6 E/IIIC 310

Isotoic Anhydride G/IIIB NL 700

L-sorbose G/IIIB M 370

Lignin, Hydrolized, Wood-type, Fine G/IIIB NL 450

Lignite, California F/IIIB 180

Lycopodium G/IIIB 190

Malt Barley G/IIIB 250

Manganese 7439-96-5 E/IIIC 240

Magnesium, Grade B, Milled E/IIIC 430

Manganese Vancide G/IIIB 120

Mannitol 69-65-8 G/IIIB M 460

Methacrylic Acid Polymer G/IIIB 290

Methionine (l-methionine) 63-68-3 G/IIIB 360

Methyl Cellulose G/IIIB 340

Methyl Methacrylate Polymer 9011-14-7 G/IIIB NL 440

Methyl Methacrylate-ethyl Acrylate G/IIIB NL 440

Methyl Methacrylate-styrene-butadiene G/IIIB NL 480

Milk, Skimmed G/IIIB 200

N,N-Dimethylthio-formamide G/IIIB 230

Nitropyridone 100703-82-0 G/IIIB M 430

Nitrosamine G/IIIB NL 270

Nylon Polymer 63428-84-2 G/IIIB 430

Para-oxy-benzaldehyde 123-08-0 G/IIIB CL 380

Paraphenylene Diamine 106-50-3 G/IIIB M 620

Paratertiary Butyl Benzoic Acid 98-73-7 G/IIIB M 560

Pea Flour G/IIIB 260

Peach Pit Shell G/IIIB 210

Peanut Hull G/IIIB 210

Peat, Sphagnum 94114-14-4 G/IIIB 240

Pecan Nut Shell 8002-03-7 G/IIIB 210

Pectin 5328-37-0 G/IIIB 200

Pentaerythritol 115-77-5 G/IIIB M 400

Petrin Acrylate Monomer 7659-34-9 G/IIIB NL 220

Petroleum Coke (More Than 8% Total Entrapped Volatiles) F/IIIB

Petroleum Resin 64742-16-1 G/IIIB 500

Phenol Formaldehyde 9003-35-4 G/IIIB NL 580

Phenol Formaldehyde, Polyalkylene-p 9003-35-4 G/IIIB 290

Phenol Furfural 26338-61-4 G/IIIB 310

Phenylbetanaphthylamine 135-88-6 G/IIIB NL 680

Phthalic Anydride 85-44-9 G/IIIB M 650

Phthalimide 85-41-6 G/IIIB M 630

Pitch, Coal Tar 65996-93-2 F/IIIB NL 710

Pitch, Petroleum 68187-58-6 F/IIIB NL 630

Polycarbonate G/IIIB NL 710

Polyethylene, High Pressure Process 9002-88-4 G/IIIB 380

Polyethylene, Low Pressure Process 9002-88-4 G/IIIB NL 420

Polyethylene Terephthalate 25038-59-9 G/IIIB NL 500

Polyethylene Wax 68441-04-8 G/IIIB NL 400

Polypropylene (no antioxidant) 9003-07-0 G/IIIB NL 420

Polystyrene Latex 9003-53-6 G/IIIB 500

Polystyrene Molding Compound 9003-53-6 G/IIIB NL 560

Polyurethane Foam, Fire Retardant 9009-54-5 G/IIIB 390

Polyurethane Foam, No Fire Retardant 9009-54-5 G/IIIB 440

Polyvinyl Acetate 9003-20-7 G/IIIB NL 550

Polyvinyl Acetate/Alcohol 9002-89-5 G/IIIB 440

Polyvinyl Butyral 63148-65-2 G/IIIB 390

Polyvinyl Chloride-dioctyl Phthalate G/IIIB NL 320

Potato Starch, Dextrinated 9005-25-8 G/IIIB NL 440

Pyrethrum 8003-34-7 G/IIIB 210

Rayon (Viscose) Flock 61788-77-0 G/IIIB 250

Red Dye Intermediate G/IIIB 175

Rice G/IIIB 220

Rice Bran G/IIIB NL 490

Rice Hull G/IIIB 220

Rosin, DK 8050-09-7 G/IIIB NL 390

Rubber, Crude, Hard 9006-04-6 G/IIIB NL 350

Rubber, Synthetic, Hard (33% S) 64706-29-2 G/IIIB NL 320

Safflower Meal G/IIIB 210

Salicylanilide 87-17-2 G/IIIB M 610

Sevin 63-25-2 G/IIIB 140

Shale, Oil 68308-34-9 F/IIIB

Shellac 9000-59-3 G/IIIB NL 400

Sodium Resinate 61790-51-0 G/IIIB 220

Sorbic Acid (Copper Sorbate or Potash) 110-44-1 G/IIIB 460

Soy Flour 68513-95-1 G/IIIB 190

Soy Protein 9010-10-0 G/IIIB 260

Stearic Acid, Aluminum Salt 637-12-7 G/IIIB 300

Stearic Acid, Zinc Salt 557-05-1 G/IIIB M 510

Styrene Modified Polyester-Glass Fiber 100-42-5 G/IIIB 360

Styrene-acrylonitrile (70-30) 9003-54-7 G/IIIB NL 500

Styrene-butadiene Latex (>75% styrene) 903-55-8 G/IIIB NL 440

Styrene-maleic Anhydride Copolymer 9011-13-6 G/IIIB CL 470

Sucrose 57-50-1 G/IIIB CL 350

Sugar, Powdered 57-50-1 G/IIIB CL 370

Sulfur 7704-34-9 G/IIIB 220

Tantalum 7440-25-7 E/IIIC 300

Terephthalic Acid 100-21-0 G/IIIB NL 680

Thorium (contains 1.2% O) 7440-29-1 E/IIIC CL 270

Tin, 96%, Atomized (2% Pb) 7440-31-5 E/IIIC 430

Titanium, 99% Ti 7440-32-6 E/IIIC CL 330

Titanium Hydride (95% Ti, 3.8% H) 7704-98-5 E/IIIC CL 480

Trithiobisdimethylthio-formamide G/IIIB 230

Tung, Kernels, Oil-free 8001-20-5 G/IIIB 240

Urea Formaldehyde Molding Compound 9011-05-6 G/IIIB NL 460

Urea Formaldehyde-phenol Formaldehyde 25104-55-6 G/IIIB 240

Vanadium, 86.4% 7440-62-2 E/IIIC 490

Vinyl Chloride-acrylonitrile Copolymer 9003-00-3 G/IIIB 470

Vinyl Toluene-acrylonitrile Butadiene 76404-69-8 G/IIIB NL 530

Violet 200 Dye G/IIIB 175

Vitamin B1, Mononitrate 59-43-8 G/IIIB NL 360

Vitamin C 50-81-7 G/IIIB 280

Walnut Shell, Black G/IIIB 220

Wheat G/IIIB 220

Wheat Flour 130498-22-5 G/IIIB 360

Wheat Gluten, Gum 100684-25-1 G/IIIB NL 520

Wheat Starch G/IIIB NL 380

Wheat Straw G/IIIB 220

Wood Flour G/IIIB 260

Woodbark, Ground G/IIIB 250

Yeast, Torula 68602-94-8 G/IIIB 260

Zirconium Hydride 7704-99-6 E/IIIC 270

Zirconium (contains 0.3% O) 7440-67-7 E/IIIC CL 330

Notes:

1. Normally, the minimum ignition temperature of a layer of a specific dust is lower than the minimum ignition temperature

of a cloud of that dust. Since this is not universally true, the lower of the two minimum ignition temperatures is listed. If no

symbol appears in the “Code” column, then the layer ignition temperature is shown. “CL” means the cloud ignition

temperature is shown. “NL” means that no layer ignition temperature is available, and the cloud ignition temperature is

shown. “M” signifies that the dust layer melts before it ignites; the cloud ignition temperature is shown. “S” signifies that the

dust layer sublimes before it ignites; the cloud ignition temperature is shown.

2. Certain metal dusts may have characteristics that require safeguards beyond those required for atmospheres containing the

dusts of aluminum, magnesium, and their commercial alloys. For example, zirconium and thorium dusts may ignite

spontaneously in air, especially at elevated temperatures.

3. Due to the impurities found in coal, its ignition temperatures vary regionally and ignition temperatures are not available for

all regions in which coal is mined.

Public Comment No. 15-NFPA 499-2015 [ Chapter 6 ]

Chapter 6 Classification of Combustible Dust Class II (Combustible Dust) or Zone 20, Zone 21, andZone 22 Locations

6.1 General.

6.1.1

The decision to classify an area as hazardous should be based on the probability that a combustible dustcould be present. This action defines the NEC Class II condition Combustible Dust condition. Due to thecomplexity of the processes that create dust, the classification of these hazardous locations should bedetermined by specialists, unless the basis for the classification is simple and straightforward.

Note: Combustible Dust conditions may be identified within the National Electrical Code as HazardousClassified Class II or Zone 20, 21, or Zone 22 locations .

6.1.2

Once the NEC Class II Combustible dust condition has been defined, the next step should be todetermine the degree of hazard — that is, whether the area is Division 1, Division 2, Zone 20, Zone 21,Zone 22 or unclassified.

6.2* Conditions Necessary for Ignition of Combustible Dust.

6.2.1

In a Class II location Combustible Dust location , one of the sets of conditions in 6.2.1.1 through 6.2.1.3must be satisfied for ignition by the electrical installation.

6.2.1.1

In the first set of conditions, the following conditions exist:

(1) A combustible dust is present.

(2) The dust is suspended in the air in the proportions required to produce an ignitible mixture. Further,within the context of this recommended practice, a sufficient quantity of this suspension is present inthe vicinity of the electrical equipment.

(3) There is a source of thermal or electrical energy sufficient to ignite the suspended mixture. Within thecontext of this recommended practice, the energy source is understood to originate with the electricalsystem.

6.2.1.2*

In the second set of conditions, the following conditions exist:

(1) A combustible dust is present.

(2) The dust is layered thickly enough on the electrical equipment to interfere with the dissipation of heatand allow the layer to reach the ignition temperature of the dust.

(3) The external temperature of the electrical equipment is high enough to cause the dust to reach itsignition temperature directly or to dry out the dust and cause it to self-heat.

6.2.1.3

In the third set of conditions, the following conditions exist:

(1) A combustible metal dust ( Group E or Group IIIC) dust is present.

(2) The dust is layered or in suspension in hazardous quantities.

(3) Current through the dust is sufficient to cause ignition.

6.2.2

Once ignition has occurred, either in a cloud suspension or in a layer, an explosion is likely.

6.2.2.1

Often the initial explosion is followed by another much more violent explosion fueled from dustaccumulations on structural beams and equipment surfaces that are thrown into suspension by the initialblast.


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6.2.2.2

For that reason, good housekeeping is vitally important in all areas where dust is handled, and is assumedthroughout this recommended practice.

6.2.3

In classifying a particular location, the presence of a combustible dust is significant in determining thecorrect division.

6.2.3.1

The classification depends both on the presence of dust clouds and on the presence of hazardousaccumulations of dust in layer form.

6.2.3.2

As specified in 5.1.3.1, the presence of a combustible dust cloud under normal conditions of operation ordue to frequent repair or maintenance should be classified as Division 1 or Zone 20/Zone 21 .

6.2.3.3

Abnormal operation of machinery and equipment, which could simultaneously produce a dust cloud orsuspension and a source of ignition, also should be classified as Division 1 or Zone 20/Zone 21 .

6.2.3.4

In other words, if a dust cloud is present at any time, it is assumed to be ignitible, and all that is necessaryfor electrical ignition is failure of the electrical system.

6.2.3.5

If dust clouds or hazardous dust accumulations are present only as a result of infrequent malfunctioning ofhandling or processing equipment, and ignition can result only from abnormal operation or failure ofelectrical equipment, the location should be classified Division 2 or Zone 22 .

6.2.4

The presence of an ignitible dust cloud or an ignitible dust layer is important in determining the boundariesof the hazardous (classified) location.

6.2.5

The quantity of dust, its physical and chemical properties, its dispersion properties, and the location of wallsand cutoffs all must be considered.

6.3 Combustible Dust Class II, Division 1 or Zone 20/Zone 21 Classified Locations.

6.3.1

Where a combustible dust cloud is likely to be present under normal conditions, the location should beclassified as Division 1 or Zone 20/Zone 21 .

6.3.1.1

This practice does not support a design that permits a normal continued condition of more than the testedlayer thickness (see 4.2.3.3 ) of dust accumulation nor presence of greater than moderate isolated dustcloud, external to processing equipment.

6.3.2*

Where a dust layer greater than 3.0 mm ( 1⁄8 in.) thick is present under normal conditions, the locationshould be classified as Division 1 or Zone 20/Zone 21 .

6.3.3

The term normal does not necessarily mean the situation that prevails when everything is working properly.

6.3.3.1

For instance, if a bucket elevator requires frequent maintenance and repair, this repair should be viewed asnormal.

6.3.3.2

If quantities of ignitible dust are released as a result of the maintenance, the location is Division 1 or Zone20/Zone 21 .

6.3.3.3

However, if that elevator is replaced and now repairs are not usually required between turnarounds, theneed for repairs is considered abnormal.

6.3.3.4

The classification of the location, therefore, is related to equipment maintenance, both procedures andfrequencies.

6.3.3.5

Similarly, if the problem is the buildup of dust layers without the presence of visible dust suspensions, goodand frequent cleaning procedures or the lack thereof will influence the classification of the location.


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6.4 Combustible Dust Class II, Division 2 or Zone 22 Classified Locations.

6.4.1

The criterion for a Division 2 or Zone 22 location is whether the location is likely to have ignitible dustsuspensions or hazardous dust accumulations only under abnormal conditions. The term abnormal is usedhere in a limited sense and does not include a major catastrophe.

6.4.2

As an example, consider the replaced bucket elevator of 6.3.3.1, which releases ignitible dust only underabnormal conditions. In this case, there is no Division 1 or Zone 20/Zone 21 location because the elevatoris normally tight. To release dust, the elevator would have to leak, and that would not be normal.

6.4.3

Chemical process equipment does not fail often. Furthermore, the electrical installation requirement of theNEC for Division 2 or Zone 22 locations is such that an ignition-capable spark or hot surface will occur onlyin the event of abnormal operation or failure of electrical equipment. Otherwise, sparks and hot surfaces arenot present or are contained in enclosures. On a realistic basis, the possibility of process equipment andelectrical equipment failing simultaneously is remote.

6.4.4

The Division 2 or Zone 22 classification is applicable to conditions not involving equipment failure. Forexample, consider a location classified as Division 1 because of normal presence of ignitible dustsuspension. Obviously, one side of the Division 1 or Zone 20/Zone 21 boundary cannot be normallyhazardous and the opposite side never hazardous. Similarly, consider a location classified as Division 1 orZone 20/Zone 21 because of the normal presence of hazardous dust accumulations. One side of thedivision boundary cannot be normally hazardous, with thick layers of dust, and the other side unclassified,with no dust, unless there is an intervening wall.

6.4.5

Where there is no wall, a surrounding transition Division 2 location or Zone 22location separates a Division1 or Zone 20/Zone 21 location from an unclassified location. For Group E or Group IIIC combustible metaldusts which may be present in quantities sufficient to be hazardous , the surrounding transition is may beapplied as an additional Division 1 or Zone 20/Zone 21 location or as a Division 2 or Zone 22 either as anextra precaution or as conditions warrant .

6.4.6

Walls are much more important in separating Division 1 and Zone 20/Zone 21 locations from Division 2and Zone 22 and unclassified locations in Class II combustible dust locations than in Class I locations.

6.4.6.1

Only unpierced solid walls make satisfactory barriers in Class I locations, whereas closed doors, lightweightpartitions, or even partial partitions could make satisfactory walls between combustible dust Class II,Division 1 locations or Zone 20/Zone 21locations and unclassified locations.

6.4.6.2

Area classification does not extend beyond the wall, provided it is effective in preventing the passage ofdust in suspension or layer form.

6.5 Unclassified Locations.


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6.5.1

Experience has shown that the release of ignitible dust suspensions from some operations and apparatusis so infrequent that area classification is not necessary. For example, where combustible dusts areprocessed, stored, or handled, it is usually not necessary to classify the following locations:

(1) Where materials are stored in sealed containers (e.g., bags, drums, or fiber packs on pallets or racks)

(2) Where materials are transported in well-maintained closed piping systems

(3) Where palletized materials with minimal dust are handled or used

(4) Where closed tanks are used for storage and handling

(5) Where dust removal systems prevent the following:

(6) Visual dust clouds

(7) Layer accumulations that make surface colors indiscernible (see A.6.3.2 )

(8) Where excellent housekeeping prevents the following:

(9) Visual dust clouds

(10) Layer accumulations that make surface colors indiscernible (see A.6.3.2 )

6.5.2

Dust removal systems that are provided to allow an unclassified location should have adequate safeguardsand warnings against failure.

6.5.3

Open flames and hot surfaces associated with the operation of certain equipment, such as boilers and firedheaters, provide inherent thermal ignition sources.

6.5.3.1

Area classification is not appropriate in the immediate vicinity of inherent thermal ignition sources.

6.5.3.2

Dust-containing operations should be cut off by blank walls or located away from inherent thermal ignitionsources.

6.5.3.3

Where pulverized coal or ground-up solid waste is used to fire a boiler or incinerator, it is prudent to avoidinstalling electrical equipment that could become primary ignition sources for leaks in the fuel feed lines.

6.6 Procedure for Classifying Areas.

Subsections 6.6.1 through 6.6.4 detail the procedure that should be used for each room, section, or areabeing classified.

6.6.1 Step 1: Need for Classification.

The area should be classified if a combustible material is processed, handled, or stored there.

6.6.2 Step 2: Gathering Information.

6.6.2.1 Proposed Facility Information.

For a proposed facility that exists only in drawings, a preliminary area classification can be done so thatsuitable electrical equipment and instrumentation can be purchased. Plants are rarely built exactly as thedrawings portray, and the area classification should be modified later, based on the actual facility.


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6.6.2.2 Existing Facility History.

For an existing facility, the individual plant experience is extremely important in classifying areas within theplant. Both operation and maintenance personnel in the actual plant should be asked the followingquestions:

(1) Is a dust likely to be in suspension in air continuously, periodically, or intermittently under normalconditions in quantities sufficient to produce an ignitible mixture?

(2) Are there dust layers or accumulations on surfaces deeper than 3.0 mm ( 1⁄8 in.)?

(3) Are there dust layers or accumulations on surfaces that make the colors of the floor or equipmentsurfaces indiscernible?

(4) What is the dust accumulation after 24 hours?

(5) Is the equipment in good condition, in questionable condition, or in need of repair? Are equipmentenclosures in good repair, and do they prevent the entrance of dust?

(6) Do maintenance practices result in the formation of ignitible mixtures?

(7) What equipment is used for dust collection?

6.6.2.3 Material Density.

The specific particle density of the dust should be determined if it is at least 641 kg/m3 (40 lb/ft3).

6.6.2.4 Plot Plan.

A plot plan (or similar drawing) is needed that shows all vessels, tanks, building structures, partitions, andsimilar items that would affect dispersion or promote accumulation of the dust.

6.6.2.5 Fire Hazard Properties of Combustible Material.

The NEC group and the layer or cloud ignition temperature are shown in Table 5.2.2 for many materials.

6.6.2.5.1

A material could be listed in Table 5.2.2 under a chemical name different from the chemical name used atthe facility.

Table 5.2.3 is provided to cross-reference the CAS number of the material to the chemical name used inTable 5.2.2.

6.6.2.5.2

Where materials being used are not listed in Table 5.2.2 or in other reputable chemical references, theinformation needed to classify the area can be obtained by one of the following methods:

(1) Contacting the material supplier to determine if the material has been group classified and if theautoignition temperature has been determined

(2) Having the material evaluated for the group and tested for the autoignition temperature

6.6.3 Step 3: Selecting the Appropriate Classification Diagram.

The appropriate diagrams should be selected based on the following:

(1) Whether the process equipment is open or enclosed

(2) Whether the dust is Group E, F, or G, or Group IIIC, or IIIB.

(3) Whether the area is for storage

6.6.4 Step 4: Determining the Extent of the Hazardous (Classified) Location.

The extent of the hazardous (classified) location can be determined using sound engineering judgment toapply the methods discussed in Section 5.1 and the diagrams contained in this chapter.

6.6.4.1

The potential sources of leaks should be located on the plan drawing or at the actual location. Thesesources of leaks could include rotating or reciprocating shafts, doors and covers on process equipment,and so forth.


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6.6.4.2

For each leakage source, an equivalent example on the selected classification diagram should be locatedto determine the minimum extent of classification around the leakage source. The extent can be modifiedby considering the following:

(1) Whether an ignitible mixture is likely to occur frequently due to repair, maintenance, or leakage

(2) Where conditions of maintenance and supervision are such that leaks are likely to occur in processequipment, storage vessels, and piping systems containing combustible material

(3) Ventilation or prevailing wind in the specific area and the dispersion rates of the combustible materials

6.6.4.3

Once the minimum extent is determined, for practical reasons distinct landmarks (e.g., curbs, dikes, walls,structural supports, edges of roads) should be utilized for the actual boundaries of the area classification.Landmarks permit identification of the boundaries of the hazardous (classified) locations for electricians,instrument technicians, operators, and other personnel.

6.7* Housekeeping.

Housekeeping frequency (see Table A.6.7) and effectiveness are significant factors in the presence andcontrol of dust accumulations.

6.8 Extent of Hazardous (Classified) Locations.

6.8.1 General.

Careful consideration of the following factors is necessary in determining the extent of the locations:

(1) Combustible material involved

(2) Bulk density of the material

(3) Particle sizes of the material

(4) Particle density

(5) Process or storage pressure

(6) Size of the leak opening

(7) Quantity of the release

(8) Dust removal system

(9) Housekeeping

(10) Presence of any hybrid mixture

6.8.2

The dispersal of dusts and the influence of the factors in 6.8.1 on this dispersal are discussed generally in4.1.3. The importance of dust removal and housekeeping are discussed in other paragraphs of thischapter.

6.8.3

In addition, walls, partitions, enclosures, or other barriers and strong air currents will also affect the distancethat dust particles will travel and the extent of the Division 1 or Zone 20/Zone 21 and Division 2 or Zone 22locations.

6.8.4

Where there are walls that limit the travel of the dust particles, area classifications do not extend beyondthe walls. Providing walls and partitions is a primary means of limiting the extent of hazardous (classified)locations.

6.8.5

Where effective walls are not provided, the extent of the Division 1 or Zone 20/Zone 21 and Division 2 orZone 22 locations can be estimated as follows:

(1) By visual observation of the existing location using the guidelines in A.6.3.2

(2) By experience with similar dusts and similar operations and by taking into consideration differences inequipment, enclosures, dust-removal systems, and housekeeping rules and methods

(3) By using the classification diagrams in this chapter


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6.8.6

Tight equipment, ventilated hoods and pickup points, good maintenance, and good housekeeping practicesshould limit Division 1 locations to those inside process enclosures and equipment and those close toopenings necessary for transfer of material, as from conveyors to grinders to storage bins to bags. Similarly,the same factors will also limit the Division 2 and Zone 22 location surrounding the Division 1 or Zone20/Zone 21 location.

6.8.7

The size of a building and its walls will influence the classification of the enclosed volume. In the case of asmall room, it can be appropriate to classify the entire volume as Division 1 or Zone 20/Zone 21 or Division2 or Zone 22 .

6.8.8

When classifying large buildings, careful evaluation of prior experience with the same or similarinstallations should be made. Where experience indicates that a particular design concept is sound, thatdesign should continue to be followed. Sound engineering judgment and good housekeeping should beused to minimize the extent of hazardous (classified) locations.

6.8.8.1

Wherever possible with large buildings, walls should be used to cut off dusty operations to minimize thehazardous (classified) location. Where walls are not possible, the concentric volume approach of a Division1 or Zone 20/Zone 21 location surrounded by a larger Division 2 or Zone 22 location, should be used asshown in the diagrams in Section 6.10. See Figure 6.10(a) .

6.8.8.2

Where it is necessary to have a number of dusty operations located in a building, there could be amultiplicity of Division 1 or Zone 20/Zone 21 locations, with intervening Division 2 or Zone 22 andunclassified locations.

6.8.9

The quantity of dust released and its distance of travel are of extreme importance in determining the extentof a hazardous (classified) location. This determination requires sound engineering judgment. However,one cannot lose sight of the purpose of this judgment; the location is classified solely for the installation ofelectrical equipment.

6.9 Discussion of Diagrams and Recommendations.

6.9.1

The series of diagrams in Section 6.10 illustrate how typical dusty areas should be classified and therecommended extent of classification.

6.9.2

The diagrams should be used as aids in developing electrical classification maps of operating units, storageareas, and process buildings. Most of the maps will be plan views. However, elevations could be necessaryto provide the three-dimensional picture of an actual operation.

6.9.3

An operating unit could have many interconnected sources of combustible material, such as storage tanks,bins and silos, piping and ductwork, hammer mills, ball mills, grinders, pulverizers, milling machines,conveyors, bucket elevators, and bagging or other packaging machines. These in turn present sources ofleaks, such as flanged and screwed connections, fittings, openings, valves, and metering and weighingdevices. Thus, actual diagrams of the equipment could be required so that the necessary engineeringjudgment to establish the boundaries of Division 1 or Zone 20/Zone 21 and Division 2 or Zone 22 locationscan be applied.

6.9.4

These diagrams apply to operating equipment processing dusts when the specific particle density is greater

than 641 kg/m3 (40 lb/ft3). When dusts with a specific particle density less than 641 kg/m3 (40 lb/ft3) arebeing handled, there is a pronounced tendency for the fine dust to drift on air currents normally present inindustrial plants for distances considerably farther than those shown on these diagrams. In those cases, itwill be necessary to extend the hazardous (classified) location using sound engineering judgment andexperience.

6.9.5

Good engineering practices, good housekeeping practices, and effective dust removal systems arenecessary to limit the extent of the classified areas and to minimize the chances of primary explosions andsecondary explosions, which are often more violent.


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6.10 Classification Diagrams.


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The classification diagrams shown in Figure 6.10(a) through Figure 6.10(i) assume that the specific

particle density is greater than 641 kg/m3 (40 lb/ft3).

Figure 6.10(a) Group F or Group G Dust — Indoor, Unrestricted Area; Open or Semi-EnclosedOperating Equipment.

Figure 6.10(b) Group E Dust — Indoor, Unrestricted Area; Open or Semi-Enclosed OperatingEquipment.


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Figure 6.10(c) Group F or Group G Dust — Indoor, Unrestricted Area; Operating EquipmentEnclosed; Area Classified as a Class II, Division 2 Location.

Figure 6.10(d) Group F or Group G Dust — Indoor, Unrestricted Area; Operating EquipmentEnclosed; Area is an Unclassified Location.


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Figure 6.10(e) Groups E, F, or G Dusts — Storage Area Bags, Drums, or Closed Hoppers.

Figure 6.10(f) Group E Dust — Indoor, Walled-Off Area; Operating Equipment Enclosed.


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Figure 6.10(g) Group F or Group G Dust — Indoor, Walled-Off Area; Operating Equipment Open orSemi-Enclosed.

Figure 6.10(h) Group F or Group G Dust — Indoor, Walled-Off Area; Multiple Pieces of OperatingEquipment.

Figure 6.10(i) Group F or Group G Dust — Indoor, Unrestricted Area; Ventilated Bagging Head.


Revisions reflect the application of current combustible dust Class- Division methodology with the combustible dust Zone methodology.



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2] Zone methodology


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Related Item

Public Input No. 5-NFPA 499-2013 [Chapter 4]




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6.3 Class II, Division 1 or Zone 20/21 Classified Locations.

6.3.1

Where a combustible dust cloud is likely to be present under normal conditions, the location should beclassified as Division 1 or using the zone methodolgy Zone 20 or Zone 21 .

6.3.1.1

This practice does not support a design that permits a normal continued condition of more than the testedlayer thickness (see 4.2.3.3 ) of dust accumulation nor presence of greater than moderate isolated dustcloud, external to processing equipment.

6.3.2*

Where a dust layer greater than 3.0 mm ( 1⁄8 in.) thick is present under normal conditions, the locationshould be classified as Division 1 1 or using the zone methodology, Zone 20 or Zone 21 .

6.3.3

The term normal does not necessarily mean the situation that prevails when everything is working properly.

6.3.3.1

For instance, if a bucket elevator requires frequent maintenance and repair, this repair should be viewed asnormal.

6.3.3.2

If quantities of ignitible dust are released as a result of the maintenance, the location is Division 1, orusing the zone methodology, Zone 20 or Zone 21 .

6.3.3.3

However, if that elevator is replaced and now repairs are not usually required between turnarounds, theneed for repairs is considered abnormal.

6.3.3.4

The classification of the location, therefore, is related to equipment maintenance, both procedures andfrequencies.

6.3.3.5

Similarly, if the problem is the buildup of dust layers without the presence of visible dust suspensions, goodand frequent cleaning procedures or the lack thereof will influence the classification of the location.


To agree with the insertion of the Zone documentation



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2] Zone material

Public Comment No. 5-NFPA 499-2015 [Section No. 5.2.2] Zone material

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Submittal Date: Mon Mar 16 11:18:54 EDT 2015


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6.4 Class II, Division 2 or Zone 22 Classified Locations.

6.4.1

The criterion for a Class II, Division 2 or a Zone 22 location is whether the location is likely to have ignitibledust suspensions or hazardous dust accumulations only under abnormal conditions. The term abnormal isused here in a limited sense and does not include a major catastrophe.

6.4.2

As an example, consider the replaced bucket elevator of 6.3.3.1, which releases ignitible dust only underabnormal conditions. In this case, there is no Division 1 location because the elevator is normally tight. Torelease dust, the elevator would have to leak, and that would not be normal.

6.4.3

Chemical process equipment does not fail often. Furthermore, the electrical installation requirement of theNEC for Class II, Division 2 or Zone 22 locations is such that an ignition-capable spark or hot surface willoccur only in the event of abnormal operation or failure of electrical equipment. Otherwise, sparks and hotsurfaces are not present or are contained in enclosures. On a realistic basis, the possibility of processequipment and electrical equipment failing simultaneously is remote.

6.4.4

The Class II, Division 2 and the Zone 22 classification is applicable to conditions not involving equipmentfailure. For example, consider a location classified as Division 1 because of normal presence of ignitibledust suspension. Obviously, one side of the Division 1 boundary cannot be normally hazardous and theopposite side never hazardous. Similarly, consider a location classified as Division 1 because of the normalpresence of hazardous dust accumulations. One side of the division boundary cannot be normallyhazardous, with thick layers of dust, and the other side unclassified, with no dust, unless there is anintervening wall.

6.4.5

Where there is no wall, a surrounding transition Class II, Division 2 or Zone 22 location separates a ClassII, Division 1 or Zone 20/21 location from an unclassified location. For Group E, the surrounding transitionis an additional Division 1 location (See A.6.3. for Group IIIC materials) .

6.4.6

Walls are much more important in separating Class II, Division 1 or Zone 20/21 locations from Class II,Division 2 or Zone 22 and unclassified locations in Class II locations than in Class I locations.

6.4.6.1

Only unpierced solid walls make satisfactory barriers in Class I locations, whereas closed doors, lightweightpartitions, or even partial partitions could make satisfactory walls between Class II, Division 1 or Zone20/21 locations and unclassified locations.

6.4.6.2

Area classification does not extend beyond the wall, provided it is effective in preventing the passage ofdust in suspension or layer form.


Revisions needed to correlate with Zone information.




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33 of 51 5/18/2015 11:33 AM



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6.6.3 Step 3: Selecting the Appropriate Classification Diagram.

The appropriate diagrams should be selected based on the following:

(1) Whether the process equipment is open or enclosed

(2) Whether the dust is Class II, Group E, F, or G, or for Zones, Group IIIC or IIIB.

(3) Whether the area is for storage


To correlate with Zone material



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2] Zone information

Related Item





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City:

State:

Zip:



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6.7* Housekeeping.

Housekeeping frequency (see Tables A.6.7 a and Table A.6.7 b ) and effectiveness are significant factorsin the presence and control of dust accumulations.


Revision needed to support inclusion of Combustible Dust Zones.




Public Comment No. 2-NFPA 499-2015 [New Section after 4.3]






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6.10 Classification Diagrams.


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Revise sentence

The classification diagrams shown in Figure 6.10(a) through Figure 6.10(i) and Figure 6.11(a) through

Figure 6.11(I) assume that the specific particle density is greater than 641 kg/

m 3

m3 (40 lb/

ft 3

ft3 ).

Figure 6.10(a) Group F or Group G Dust — Indoor, Unrestricted Area; Open or Semi-EnclosedOperating Equipment.

Figure 6.10(b) Group E Dust — Indoor, Unrestricted Area; Open or Semi-Enclosed OperatingEquipment.


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Figure 6.10(c) Group F or Group G Dust — Indoor, Unrestricted Area; Operating EquipmentEnclosed; Area Classified as a Class II, Division 2 Location.

Figure 6.10(d) Group F or Group G Dust — Indoor, Unrestricted Area; Operating EquipmentEnclosed; Area is an Unclassified Location.


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Figure 6.10(e) Groups E, F, or G Dusts — Storage Area Bags, Drums, or Closed Hoppers.

Figure 6.10(f) Group E Dust — Indoor, Walled-Off Area; Operating Equipment Enclosed.


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Figure 6.10(g) Group F or Group G Dust — Indoor, Walled-Off Area; Operating Equipment Open orSemi-Enclosed.

Figure 6.10(h) Group F or Group G Dust — Indoor, Walled-Off Area; Multiple Pieces of OperatingEquipment.

Figure 6.10(i) Group F or Group G Dust — Indoor, Unrestricted Area; Ventilated Bagging Head.



499_work_figs_dbw03102015.pdf replacement figures


With the inclusion of Combustible Zone Dusts, these new classification examples, provide correlation with the Division figures which exist in this document.


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Figure 6.10 (f) contains an elevation which does not correctly agree with the figure plan view. Rather than correcting the elevation, which serves little additional purpose and other figures do not have elevations, the elevation should be deleted.



Public Comment No. 1-NFPA 499-2015 [Section No. 1.2] Supporting Zone Methodology

Public Comment No. 2-NFPA 499-2015 [New Section after 4.3] Supporting Zone Methodology

Public Comment No. 3-NFPA 499-2015 [New Section after 5.1.4] Supporting Zone Methodology

Public Comment No. 4-NFPA 499-2015 [New Section after 5.2.1] Supporting Zone Methodology

Public Comment No. 5-NFPA 499-2015 [Section No. 5.2.2] Supporting Zone Methodology


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Public Input No. 26-NFPA 499-2014 [Section No. 6.10]




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Revise as shown in red For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows:

Change from ‘6.1 m (20 ft)’ to ‘20 ft (6.1 m)’

from ‘3.05 m (10 ft)’ to ‘10 ft (3.05 m)’

No changes proposed

Div. 1 – 3 ft (915 mm) Div. 2 – See Note

Open door or frequently opened door

Self-closing door kept closed

Revise as shown in red – Remove elevation view

X

Source

Wall or partition With all openings kept closed.

(new) Note: Group E combustible dusts which may be present in quantities sufficient to be hazardous are considered Class II, Division 1 locations per NEC 500.5 (C) (1) . A Class II, Division 2 location may be applied either as an extra precaution or as conditions warrant.

Action: For consistency with NFPA 497 figures 5.xx, use convention of ft (m)


Div. 1 – 3 ft (915 mm) Div. 2 – 10 ft (3.05 m)



Div. 2 10 ft (3.05 m)


Revise as shown in red/blue For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows:


from ‘3.05 m (10 ft)’ to ‘10 ft (3.05 m)’

Figure 6.11 (a) Zone Group IIIB Dust – Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment

Zone 21 Zone 22

Zone 22 Zone 21

For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows:


from ‘3.05 m (10 ft)’ to ‘10 ft (3.05 m)’

Revise as new figure

20 ft (6.1 m)

Zone 20/Zone 21 Zone 22

Figure 6.11 (b) Zone Group IIIC Dust – Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment

Zone 20/Zone 21 Zone 21/Zone 22

Zone 21

Zone 21 10 ft (3.05 m) 10 ft (3.05 m)

For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows: Revise as new figure

Figure 6.11 (c) Zone Group IIIB Dust – Indoor, Unrestricted Area; Operating Equipment Enclosed; Area Classified as a Class II, Zone 22 Location

Zone 21

Zone 21

Zone 22

Zone 22

10 ft (3.05 m)

For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows:



Zone 21 Zone 22

Figure 6.11 (d) Zone Group IIIB Dust – Indoor, Unrestricted Area; Operating Equipment Enclosed; Area is an Unclassified Location


Figure 6.11 (e) Zone Group IIIC or IIIB Dust – Storage Area; Bags, Drums or Closed Hoppers.

Zone 21 Zone 22


Zone 20/21 – 3 ft (915 mm) Zone 22 – See Note



X

Source

Wall or partition With all openings kept closed.

Note: Combustible metal dusts which may be present in quantities sufficient to be hazardous are considered Class II, Division 1 locations per NEC 500.5 (C) (1) and the NEC defines Group IIIC combustible dusts as combustible metal dusts. These are Zone 20/21 locations. A Zone 22 location may be applied to Group IIIC combustible metal dust either as an extra precaution or as conditions warrant.

For consistency with NFPA 497 figures 5.xx, use convention of ft (m)


Zone 20/ Zone 21

Figure 6.11 (f) Zone Group IIIC Dust – Indoor, Walled-Off Area; Operating Equipment Enclosed;

Zone 22

Minimize Zone 20/21 cutoff volume and area


Zone 21 - 3 ft (915 mm) Zone 22 – 10 ft (3/05 m)

Figure 6.11 (g) Zone Group IIIB Dust – Indoor, Walled-Off Area; Operating Equipment Open or Semi- Enclosed

Zone 21 Zone 22

Zone 21 Zone 22



Zone 22 10 ft (3.05 m)


Figure 6.11 (h) Zone Group IIIB Dust – Indoor, Walled-Off Area; Multiple Pieces of Operating Equipment

Zone 21 Zone 22

Zone 22 Zone 21

20 ft (6.1 m)


Figure 6.11 (i) Zone Group IIIB Dust – Indoor, Unrestricted Area; Ventilated Bagging Head

Zone 21 Zone 22

Zone 22 Zone 21

10 ft (3.05 m) 10 ft (.053 m)

10 ft (3 .05 m ) 10 ft (3.05m)


Public Comment No. 8-NFPA 499-2015 [ Section No. A.5.1.9 ]

A.5.1.9

Areas that would otherwise be classified as Division 2 due to dust accumulation or release potential areclassified as Division 1 where Group E dusts are present in quantities sufficient to be hazardous. In Figure6.10(a) through Figure 6.10(i) , these areas are denoted as additional Division 1 locations.


Action under comment was to delete original statement to agree with 5.1.3.1 (3) and the NEC.




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Public Comment No. 10-NFPA 499-2015 [ Section No. A.6.3.2 ]


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A.6.3.2


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Generally speaking, the NEC indicates that an area is a Division 1 location if either of the followingconditions exists:

(1) There are explosive dust clouds under normal operating conditions.

(2) Explosive dust clouds can be produced at the same time that a source of ignition is produced.

The dust described in condition (2) can be provided directly by some malfunction of machinery orequipment or by accumulations of dust that are thrown into the air. Presumably, if all the dust on all thesurfaces in a room is sufficient to produce a dust concentration above the minimum explosibleconcentration, then that quantity of dust should define a Division 1 location.

From a practical point of view, a room with a concentration of dust that is above the minimum explosibleconcentration [condition (1)] would result in an atmosphere so dense that visibility beyond 0.9 m to 1.5 m (3ft to 5 ft) would be impossible. Such a condition is unacceptable under today's standards for chemical plantworkplaces. If such a situation were to exist, accumulations on horizontal surfaces would build up veryrapidly.

On the other hand, working back from dust layers on horizontal surfaces in a room to a minimum explosibleconcentration in the room, based on laboratory dust explosion tests, would show a very thin layer of dust,on the order of 3.0 mm ( 1⁄8 in.), to be hazardous. This is an equally impractical answer, because one of themost difficult experimental problems in dust explosion test work is to obtain a reasonably uniform cloud forignition. As a result, the test apparatus is designed specifically to obtain uniform dust distribution. For dustlying on horizontal surfaces in a room or factory to attain such an efficient uniform distribution during anupset condition obviously is impossible.

A typical calculation considers cornstarch with a powder bulk density of approximately 400 kg/m3 (25

lb/ft3). The minimum explosible concentration is 40 g/m3 (0.04 oz/ft3). In a room 3.05 m high × 3.05 m wide× 3.05 m long (10 ft high × 10 ft wide × 10 ft long), the depth of dust that would accumulate on the floor ifthe room were completely filled with a cornstarch cloud at the minimum explosible concentration can becalculated as follows:

For SI units:

[A.6.3.2a]

For inch-pound units:

[A.6.3.2b]

Evenly distributed over 9.3 m2 (100 ft2), the depth of dust would be as follows:

For SI units:

[A.6.34.2c]

For inch-pound units:

[A.6.3.2d]

Theoretically, throwing this amount of dust from the floor and ledges into the room volume would create ahazardous condition. Accomplishing such a feat, even experimentally, would be virtually impossible.

The optimum concentration is that in which the maximum rate of pressure rise is obtained under testconditions. Because the optimum concentration is far higher than the minimum explosible concentration,the layer thicknesses necessary to produce an optimum concentration range from 1.9 mm to 12.7 mm(0.075 in. to 0.5 in.). There is then much more dust available to be thrown into uniform suspension withoutpostulating a 100 percent efficiency of dispersal and distribution. In addition, a number of factors such asparticle size and shape, moisture content, uniformity of distribution, and so on negatively affect thesusceptibility of a dust to ignition. Thus, dusts encountered in industrial plants tend to be less susceptible to


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ignition than those used in the laboratory to obtain explosion concentration data. The classifications ofareas in accordance with Table A.6.3.2(a) and Table A.6.3.2 (b) are recommended, based on a buildup ofthe dust level in a 24-hour period on the major portions of the horizontal surfaces.

Table A.6.3.2(a) Division Class II - Division Determination Guidelines Based on Dust Layer Thickness

Thickness of Dust Layer Classification

>3.0 mm ( 1⁄8 in.) Division 1

<3.0 mm ( 1⁄8 in.), but surface color not discernible Division 2

Surface color discernible under the dust layer Unclassified

Based on these thicknesses of dust, good housekeeping can determine the difference between aclassification of Division 1 and a classification of Division 2 and between a classification of Division 2 andunclassified. It should be emphasized, however, that housekeeping is a supplement to dust sourceelimination and ventilation. It is not a primary method of dust control.

Table A.6.3.2 (b) shows Zone Determination Guidelines Based on Dust Layer Thickness

(see table added as graphic)

{renumber Table A.6.3.2 (b) to A.6.3.2 (c)}

Table A.6.3.2 (c) shows the theoretical thickness of dust on the floor of a 3.05 m × 3.05 m × 3.05 m (10 ft× 10 ft × 10 ft) room necessary to satisfy the concentration requirements for a uniform dust cloud ofminimum explosible concentration and for a uniform dust cloud of optimum concentration for four dusts.

Table A.6.3.2 (b c ) Dust Thickness

MinimumConcentration

Depth ofDust

OptimumConcentration

Depth ofDust

BulkDensity

Material g/m3 oz/ft3 cm in. g/m3 oz/ft3 cm in. kg/m3 lb/ft3

Cornstarch 1.13 0.04 0.03 0.012 14.2 0.5 0.38 0.15 11–23 25–50

Cork 0.99 0.035 0.05 0.022 5.7 0.2 0.32 0.125 5–7 12–15

Sugar 1.28 0.045 0.02 0.0068 14.2 0.5 0.19 0.075 23–25 50–55

Wood flour 0.99 0.035 0.04 0.016 28.4 1.0 1.19 0.47 7.3–16 16–36

Polyethylene(low density)

0.57 0.020 0.02 0.0072 14.2 0.5 0.46 0.18 9.5–15.9 21–35



Table_A.6.3.2_b_zones_new.docx new Table A.6.3.2 (b) for Combustible dust Zones


To provide proper correlation with the inclusion of Combustible Dust Zones following design/evaluation based currently applied to Class II- Division methodology.






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Table A.6.3.2 (b) for Zones1

Thickness of Dust Layer Classification

>3.0 mm (1/8 in.) Zone 20 or Zone 21

<3.0 mm (1/8 in. ) Zone 21 or Zone 22

Surface color discernible under the dust layer or

combustible metal dust is not in a hazardous quantity

Zone 22 or Unclassified.

1 Combustible metal dusts which may be present in quantities sufficient to be hazardous are considered Class II, Division 1 locations per NEC 500.5 (C) (1). The NEC defines Group IIIC combustible dusts as combustible metal dusts. These are Zone 20/21 locations. A Zone 22 location may be applied to Group IIIC combustible metal dusts either as an extra precaution or as conditions warrant.

Public Comment No. 11-NFPA 499-2015 [ Section No. A.6.7 ]

A.6.7

Table A.6.7a and Table A.6. 7 b lists the recommended frequency of housekeeping for combustible dusts.

Table A.6.7 a and Table A.6.7 b criteria should be applied as follows: Given the condition in (1), whichshould then be correctly paired with the defined hazardous area classification shown in (2), this would yielda suggested release frequency and housekeeping activity as addressed in (3) and (4).

Table A.6.7 Recommended 7 a Class II- Division Recommended Frequency of Housekeeping

Depth of DustAccumulation on

Equipment

(1)

Area

Classification

(2)

Release

Frequency

(3)

Housekeeping

Activity

(4)

Negligible, up to <1 mm ( 1⁄32

in.)Unclassified Infrequent Clean as appropriate

Up to 3 mm ( 1⁄8 in.) Class II, Division 2 InfrequentClean as necessary to maintain less than3 mm ( 1⁄8 in.)

Up to 3 mm ( 1⁄8 in.) oroccasional cloud formation

Class II, Division 1or Division 2

OccasionalClean at frequency appropriate tominimize additional dust accumulations orformation of a cloud

>3 mm ( 1⁄8 in.) to layer testvalue, or presence of dustcloud

Class II, Division 1Continuous/

frequently

Clean at frequency appropriate tominimize additional dust accumulations

Exceeds layer test value, orpresence of extensive dustcloud

Class II, Division 1 InfrequentImmediately shut down and cleanequipment

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Table A.6.7 b

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NFPA_499_Table_A6.7_for_zones_submitt.docx Table to support Zones under A6.7 b


Table added to support Zones, applying existing 499 Class II- Division design/critieria





Public Comment No. 10-NFPA 499-2015 [Section No. A.6.3.2] Zone material

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Table A.6.7a Recommended Frequency of Housekeeping (Class- Divisions)

Housekeeping. Housekeeping frequency (see Table A.6.7a and A.6.7 b) and effectiveness are

significant factors in the presence and control of dust accumulations.

A.6.7 Table A.6.7 a and A.6.7 b lists the recommended frequency of housekeeping

for combustible dusts.

Table A.6.7 criteria should be applied as follows: Given the condition in (1), which should then

be correctly paired with the defined hazardous area classification shown in (2), this would yield a

suggested release frequency and housekeeping activity as addressed in (3) and (4).

Table A.6.7b Recommended Frequency of Housekeeping (Zones)

Depth of Dust Accumulation

on Equipment

(1)

Area Classification

(2)

Release Frequency

(3)

Housekeeping Activity

(4)

Negligible, up to <1 mm (1⁄32 in.)

Unclassified

Infrequent Clean as appropriate

Up to 3 mm (1⁄8 in.) Zone 22 Infrequent Clean as necessary to

maintain less than 3 mm (1/8 in.)

Up to 3 mm (1⁄8 in.) or

occasional cloud

formation

Zone 21 or Zone 22 Occasional Clean at frequency

appropriate to

minimize

additional dust

accumulations or

formation of a

cloud

3 mm (1⁄8 in.) to layer test

value, or presence of dust

cloud

Zone 20 or Zone 21 Continuous/

frequently

Clean at frequency

appropriate to

minimize

additional dust

accumulations

Exceeds layer test value, or

presence of extensive dust

cloud

Zone 20 Infrequent Immediately shut

down and clean

equipment

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