Technical Committee on Electrical Equipment in Chemical Atmospheres

Transcription

1 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 ( 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, If you have any questions or comments, please feel free to reach me at (617) or by at enette@nfpa.org. I look forward to our meeting to begin the revision cycle!

2 Technical Committee on Electrical Equipment in Chemical Atmospheres AGENDA NFPA 496/497/499 A2016 First Draft Meeting Sept. 30-Oct 1, 2015 Teleconference 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 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 A2016 Public Comments F. NFPA 497 A2016 Public Comments G. NFPA A2016 Public Comments

3 Attachment A: September 16-18, 2014 Meeting Minutes

4 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)

5 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, 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: 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 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 The Committee responded to 13 Public Inputs, and created 7 First Revisions to NFPA 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, 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, Respectfully submitted, Eric Nette, NFPA, Staff Liaison

6 Attachment B: A2016 Revision Cycle

7 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)

8 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 # (i.e. and click on the Next Edition tab. Process Stage Process Step Dates for TC Dates for TC 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/ /24/2014 Stage Final date for Receipt of TC First Draft ballot 2/20/ /14/2014 (First Draft) Final date for Receipt of TC First Draft ballot recirc 2/27/ /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 5/29/2015 5/29/2015 received no Comments) Appeal Closing Date for Consent Standards (Standards that received 6/12/2015 6/12/2015 no Comments) 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/ /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 4/15/2016 4/15/2016 Standards (& 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

9 Attachment C: EEC-AAA Committee Membership

10 Address List No Phone Electrical Equipment in Chemical Atmospheres 08/04/2015 Eric Nette EEC-AAA William T. Fiske Chair Intertek Testing Services 3933 US Route 11 South Cortland, NY Alternate: Ryan Parks RT 10/1/1994 EEC-AAA Donald W. Ankele Principal UL LLC 333 Pfingsten Road Northbrook, IL Alternate: John Chambers RT 1/14/2005 EEC-AAA Babanna Biradar Principal Bechtel Corporation 3000 Post Oak Boulevard Houston, TX Alternate: Antonino Nicotra SE 3/2/2010 EEC-AAA Ronald M. Brown Principal PPG Industries, Inc. 151 Colfax Street Springdale, PA U 03/07/2013 EEC-AAA Jonathan L. Cadd Principal Electrical Systems and Instrumentation, Inc Ward Street Midland, TX M 3/5/2012 EEC-AAA John H. Cawthon Principal State of Alaska Division of Fire & Life Safety 411 West 4th Street, Suite 2B Anchorage, AK E 8/9/2011 EEC-AAA Paul Chantler Principal Sherwin Williams 333 Republic 101 Prospect Avenue Cleveland, OH U 03/07/2013 EEC-AAA Chris Cirelli Principal Waters Corporation 177 Robert Treat Paine Drive Taunton, MA M 07/29/2013 EEC-AAA Frank C. DeFelice, Jr. Principal Allnex, Inc. 528 South Cherry Street Wallingford, CT U 8/5/2009 EEC-AAA Matt Egloff Principal Montana Tech, University of Montana General Engineering Department 1300 West Park Street Butte, MT SE 1/10/2008 EEC-AAA Felix J. Garfunkel Principal Parsons Corporation 100 High Street Boston, MA SE 07/29/2013 EEC-AAA William G. Lawrence, Jr. Principal FM Global 1151 Boston-Providence Turnpike PO Box 9102 Norwood, MA Alternate: Marlon B. Mitchell I 1/1/1990 EEC-AAA Robert Malanga Principal Fire and Risk Engineering 9 Flintlock Drive, Suite 100 Long Valley, NJ SE 4/17/1998 EEC-AAA Adam Morrison Principal Fike Corporation 704 SW 10th Street Blue Springs, MO M 03/03/2014 EEC-AAA 1

11 Address List No Phone Electrical Equipment in Chemical Atmospheres 08/04/2015 Eric Nette EEC-AAA Timothy J. Myers Principal Exponent, Inc. 9 Strathmore Road Natick, MA SE 7/26/2007 EEC-AAA Samuel A. Rodgers Principal Honeywell, Inc Woods Edge Road Colonial Heights, VA U 4/1/1996 EEC-AAA Joseph V. Saverino Principal Air Products and Chemicals, Inc Hamilton Boulevard Allentown, PA U 10/1/1994 EEC-AAA Rodolfo N. Sierra Principal US Coast Guard Design & Engineering Standards Systems Engineering Division (CG 5213) nd Street, SW Washington, DC E 3/4/2009 EEC-AAA James G. Stallcup Principal Grayboy, Inc Meadow Creek North Richland Hills, TX Alternate: James W. Stallcup, Jr. SE 1/1/1991 EEC-AAA Erdem A. Ural Principal Loss Prevention Science & Technologies, Inc. 2 Canton Street, Suite A2 Stoughton, MA SE 8/5/2009 EEC-AAA David B. Wechsler Principal Dalton Bluff Court Katy, TX American Chemistry Council U 1/1/1987 EEC-AAA Jack H. Zewe Principal Electrical Consultants Inc Illinois Avenue Kenner, LA SE 1/1/1992 EEC-AAA Jack E. Jamison, Jr. E 03/05/2012 Voting Alternate EEC-AAA Miller Engineering, Inc. 991 River Road Morgantown, WV International Association of Electrical Inspectors Voting Alt. to IAEI Rep. John Chambers Alternate UL LLC 333 Pfingsten Road Northbrook, IL Principal: Donald W. Ankele RT 04/08/2015 EEC-AAA Marlon B. Mitchell Alternate FM Global 743 Reynolds Road West Glocester, RI Principal: William G. Lawrence, Jr. I 10/18/2011 EEC-AAA Antonino Nicotra Alternate Bechtel Oil Gas & Chemicals 3000 Post Oak Boulevard Houston, TX Principal: Babanna Biradar SE 10/29/2012 EEC-AAA Ryan Parks Alternate Intertek Testing Services th Street, Suite 400 Plano, TX Principal: William T. Fiske RT 8/5/2009 EEC-AAA James W. Stallcup, Jr. Alternate Grayboy, Inc Meadow Creek North Richland Hills, TX Principal: James G. Stallcup SE 1/1/1994 EEC-AAA 2

12 Address List No Phone Electrical Equipment in Chemical Atmospheres 08/04/2015 Eric Nette EEC-AAA Eric Nette Staff Liaison National Fire Protection Association 1 Batterymarch Park Quincy, MA /16/2014 EEC-AAA 3

13 Attachment D: NFPA Process Quick Reference Guide

14 New Process (Second Draft Stage) Quick Reference Guide For additional information on the New Regulations visit: 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. Approval by meeting vote (simple majority) and final approval through ballot. 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.

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

16 Comparison to Previous Process: Accept PREVIOUS ACTIONS NEW PROCESS ACTIONS Sample Motion 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 Rejected 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) Committee rejects the comment 2) Committee provides response (CS) to PC 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. 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.

17 Term Comparison between Current and Old: CURRENT TERM Input Stage Public Input (PI) First Draft Meeting Committee Input Committee Statement (CS) First Revision (FR) First Draft Report First Draft Comment Stage Public Comment Second Draft Meeting Committee Comment Committee Action Second Revision Second Draft Report Second Draft OLD TERM ROP Stage Proposal ROP Meeting Committee Proposal that Fail Ballot Committee Statement Committee Proposal or Accepted Public Proposal ROP ROP Draft ROC Stage Public Comment ROC Meeting Committee Comment that Fail Ballot Committee Action Committee Comment or Accepted Public Comment ROC ROC Draft Note: The highlighted terms are the ones that will be most applicable at the Second Draft Meeting.

18 Attachment E: NFPA 496 A2016 Public Comments

19 National Fire Protection Association Report of 2 5/18/ :01 AM Public Comment No. 1-NFPA [ Section No ] 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 Article 505 of 506 of NFPA 70 (2) Electrical equipment containing sources of flammable vapors or gases and located in either classified or unclassified areas (3) Control rooms or buildings located in areas classified as hazardous by Article 500, Article 505, or Article of NFPA 70 (4) Analyzer rooms containing sources of flammable vapors or gases and located in areas classified as hazardous 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 NFPA for protection method pressurized. Note: This is new material that was not issued in the first draft. Related Item Public Input No. 1-NFPA [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

20 National Fire Protection Association Report of 2 5/18/ :01 AM Public Comment No. 2-NFPA [ Section No. 1.2 ] 1.2 Purpose. This standard provides information on the methods for purging and pressurizing enclosures to prevent ignition of a flammable atmosphere. Such an atmosphere may be introduced into the enclosure by a surrounding external atmosphere or by an internal source. By these means, electrical equipment that is not otherwise acceptable for a flammable atmosphere may be utilized in accordance with Article 500, Article 505, or Article of NFPA 70. Statement of Problem and Substantiation for Public Comment Article 506 of NFPA70 references NFPA for protection method pressurized. Note: This is new material that was not issued in the first draft. Related Item Public Input No. 1-NFPA [Chapter 7 [Title Only]] Submitter Information Verification Submitter Full Name: WILLIAM MILLER Organization: METTLER TOLEDO Street Address: City: State: Zip: Submittal Date: Wed Feb 18 19:31:49 EST 2015

21 Attachment F: NFPA 497 A2016 Public Comments

22 National Fire Protection Association Report of /18/ :12 AM Public Comment No. 1-NFPA [ 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 be considered part of the recommendations of this document. 2.2 NFPA Publications. National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 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 API Publications. American Petroleum Institute, 1220 L Street, NW, Washington, DC API RP 500, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as 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 Classified as Class I, Zone 0, Zone 1, and Zone 2, 2002, reaffirmed ASHRAE Publications. American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc., 1791 Tullie Circle NE, Atlanta, GA ASHRAE 15 ASHRAE STD 15 & 34, Safety Standard for Refrigeration Systems, (This is a combined standard) ASTM Publications. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA ASTM D323, Standard Method of Test for Vapor Pressure of Petroleum Products (Reid Method), 2008 (, reapproved 2014 ) CGA Publications. Compressed Gas Association, George Carter Way, Suite 103, Chantilly, VA CGA G2.1, Safety Requirements for the Storage and Handling of Anhydrous Ammonia, th edition, IEC Publications. International Electrotechnical Commission, 3, rue de Varembé, P.O. Box 131, CH-1211 Geneva 20, Switzerland. IEC , Explosive atmospheres Part 20-1: Material characteristics for gas and vapor classification Test methods and data, ISA Publications. The International Society of Automation, 67 T.W. Alexander Drive, P.O. Box 12277, Research Triangle Park, NC ISA-RP , Standard for Portable Electronic Products Suitable for Use in Class I and II, Division 2, Class I Zone 2 and Class III, DIivision 1 and 2 Hazardous (Classified) Locations, Other Publications. Merriam-Webster s Collegiate Dictionary, 11th edition, Merriam-Webster, Inc., Springfield, MA, 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), edition. NFPA 70, National Electrical Code, edition.

23 National Fire Protection Association Report of /18/ :12 AM Statement of Problem and Substantiation for Public Comment 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 Public Comment No. 2-NFPA [Section No [Excluding any Sub-Sections]] Public Comment No. 3-NFPA [Chapter C] Related Item First Revision No. 3-NFPA [Chapter 2] Relationship Submitter Information Verification Submitter Full Name: Aaron Adamczyk Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Fri Mar 06 20:18:48 EST 2015

24 National Fire Protection Association Report of /18/ :12 AM Public Comment No. 2-NFPA [ Section No [Excluding any Sub-Sections] ]

25 National Fire Protection Association Report of /18/ :12 AM An alphabetical listing of selected combustible materials, with their group classification and relevant physical properties, is provided in Table Table Selected Chemicals Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Vapor Density (Air = 1) Vapor Pressure b (mm Hg) Class I Zone Group c MIE (mj) MIC Ratio MESG (mm) Acetaldehyde C d I IIA Acetic Acid D d II IIA Acetic Acid- tert-butyl Ester D II Acetic Anhydride D II IIA 1.23 Acetone D d I IIA Acetone Cyanohydrin D IIIA Acetonitrile D I IIA 1.50 Acetylene A d GAS IIC Acrolein (Inhibited) B(C) d I IIB 0.13 Acrylic Acid D II IIB 0.86 Acrylonitrile D d I IIB Adiponitrile D IIIA Allyl Alcohol C d I IIB 0.84 Allyl Chloride D I IIA Allyl Glycidyl Ether B(C) e II Alpha-Methyl Styrene D II n-amyl Acetate D I IIA 1.02 sec-amyl Acetate D I IIA Ammonia D d,f GAS IIA Aniline D IIIA IIA Benzene D d I IIA Benzyl Chloride D IIIA Bromopropyne D I n-butane D d,g GAS IIA ,3-Butadiene B(D) d,e GAS IIB Butanol D d I IIA 0.91 Butyl alcohol (s) (butanol-2) D d I IIA Butylamine D GAS IIA 1.13 Butylene D I IIA 0.94 n-butyraldehyde C d I IIA 0.92 n-butyl Acetate D d I IIA sec-butyl Acetate D II tert-butyl Acetate D II n-butyl Acrylate (Inhibited) D II IIB 0.88 n-butyl Glycidyl Ether B(C) e II n-butyl Formal C IIIA 34.3 Butyl Mercaptan C I Butyl-2-Propenoate D II para tert-butyl Toluene D IIIA n-butyric Acid D d IIIA

26 National Fire Protection Association Report of /18/ :12 AM Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Vapor Density (Air = 1) Vapor Pressure b (mm Hg) Class I Zone Group c MIE (mj) MIC Ratio MESG (mm) Carbon Disulfide d,h I IIC Carbon Monoxide C d GAS IIB 0.54 Chloroacetaldehyde C IIIA Chlorobenzene D I Chloro-1- Nitropropane C IIIA Chloroprene D GAS Cresol D IIIA Crotonaldehyde C d I IIB 0.81 Cumene D I IIA 1.05 Cyclohexane D I IIA Cyclohexanol D IIIA IIA Cyclohexanone D II IIA 0.98 Cyclohexene D I IIA 0.97 Cyclopropane D d I IIA p-cymene D II IIA Decene D II n-decaldehyde C IIIA 0.09 n-decanol D IIIA Decyl Alcohol D IIIA Diacetone Alcohol D IIIA Di-Isobutylene D d I Di-Isobutyl Ketone D II o-dichlorobenzene D IIIA IIA 1,4-Dichloro-2,3 Epoxybutane D d I IIA ,1-Dichloroethane D I IIA ,2-Dichloroethylene D I IIA ,1-Dichloro-1- Nitroethane C IIIA ,3-Dichloropropene D I Dicyclopentadiene C I IIA 0.91 Diethylamine C d I IIA 1.15 Diethylaminoethanol C IIIA IIA Diethyl Benzene D II Diethyl Ether (Ethyl Ether) Diethylene Glycol Monobutyl Ether Diethylene Glycol Monomethyl Ether C d I IIB C IIIA C IIIA n-n-dimethyl Aniline C IIIA Dimethyl Formamide D II IIA 1.08 Dimethyl Sulfate D IIIA Dimethylamine C GAS IIA 2,2-Dimethylbutane D g I ,3-Dimethylbutane D g I 396 3,3-Dimethylheptane D g I

27 National Fire Protection Association Report of /18/ :12 AM Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Vapor Density (Air = 1) Vapor Pressure b (mm Hg) Class I Zone Group c MIE (mj) MIC Ratio MESG (mm) 2,3-Dimethylhexane D g I 438 2,3-Dimethylpentane D g I Di-N-Propylamine C I IIA ,4-Dioxane C d I IIB Dipentene D II IIA 1.18 Dipropylene Glycol Methyl Ether C IIIA Diisopropylamine C GAS IIA 1.02 Dodecene D IIIA Epichlorohydrin C d I Ethane D d GAS IIA Ethanol D d I IIA Ethylamine D d I Ethylene C d GAS IIB Ethylenediamine D d I Ethylenimine C d I Ethylene Chlorohydrin D IIIA Ethylene Dichloride D d I Ethylene Glycol Monoethyl Ether Acetate Ethylene Glycol Monobutyl Ether Acetate Ethylene Glycol Monobutyl Ether Ethylene Glycol Monoethyl Ether Ethylene Glycol Monomethyl Ether C II IIA C IIIA C IIIA C II D II Ethylene Oxide B(C) d,e I IIB Ethylhexaldehyde C II Ethylhexanol D IIIA Ethylhexyl Acrylate D IIIA Ethyl Acetate D d I IIA Ethyl Acrylate (Inhibited) D d I IIA 0.86 Ethyl Alcohol D d I IIA Ethyl Sec-Amyl Ketone D II 59 Ethyl Benzene D I Ethyl Butanol D II Ethyl Butyl Ketone D II Ethyl Chloride D GAS Ethyl Formate D GAS IIA 0.94 Ethyl Mercaptan C d I IIB n-ethyl Morpholine C I Ethyl-3-Propyl Acrolein C IIIA

28 National Fire Protection Association Report of /18/ :12 AM Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Ethyl Silicate D II 7.2 Vapor Density (Air = 1) Vapor Pressure b (mm Hg) Class I Zone Group c Formaldehyde (Gas) B GAS IIB 0.57 Formic Acid D II IIA 1.86 Fuel Oil D Fuel Oil 2 Fuel Oil 6 II or IIIA k k II or IIIA k k 257 IIIA or IIIB k k Furfural C IIIA Furfuryl Alcohol C IIIA Gasoline D d I n-heptane D d I IIA n-heptene D g I n-hexane D d,g I IIA Hexanol D IIIA IIA Hexanone D I Hexene D I sec-hexyl Acetate D II Hydrazine C II Hydrogen B d GAS IIC Hydrogen Cyanide C d GAS IIB 0.80 Hydrogen Selenide C I 7793 Hydrogen Sulfide C d GAS IIB Isoamyl Acetate D I Isoamyl Alcohol D II IIA 1.02 Isobutane D g GAS IIA 0.95 Isobutyl Acetate D d I Isobutyl Acrylate D I Isobutyl Alcohol D d I IIA Isobutyraldehyde C GAS IIA 0.92 Isodecaldehyde C IIIA Isohexane D g IIA 1.00 Isopentane D g Isooctyl Aldehyde C II Isophorone D Isoprene D d I Isopropyl Acetate D I Isopropyl Ether D d I IIA Isopropyl Glycidyl Ether C I Isopropylamine D GAS Kerosene D II IIA Liquefied Petroleum Gas D I 405 Mesityl Oxide D d I MIE (mj) MIC Ratio MESG (mm)

29 National Fire Protection Association Report of /18/ :12 AM Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Vapor Density (Air = 1) Vapor Pressure b (mm Hg) Class I Zone Group c MIE (mj) MIC Ratio MESG (mm) Methane D d GAS IIA Methanol D d I IIA Methyl Acetate D GAS IIA Methyl Acrylate D GAS IIB Methyl Alcohol D d I IIA 0.91 Methyl Amyl Alcohol D II IIA 1.01 Methyl Chloride D GAS IIA 1.00 Methyl Ether C d GAS IIB Methyl Ethyl Ketone D d I IIB Methyl Formal C d I Methyl Formate D GAS IIA Methylhexane D g I 280 Methyl Isobutyl Ketone D d I Methyl Isocyanate D GAS IIA 1.21 Methyl Mercaptan C GAS Methyl Methacrylate D I IIA 0.95 Methyl N-Amyl Ketone D II Methyl Tertiary Butyl Ether D I Methyloctane Methylpropane D g I Methyl-1-Propanol D d I IIA 0.98 Methyl-2-Propanol D d I Methyl-5-Ethyl Pyridine D Methylacetylene C d I Methylacetylene- Propadiene C I IIB 0.74 Methylal C I Methylamine D GAS IIA Methylbutane D g Methylcyclohexane D I Methylcyclohexanol D Methycyclohexanone D II Methylheptane D g Methylhexane D g Methylpentane D g Methylpropane D g I Methyl-1-Propanol D d I Methyl-2-Propanol D d I Methyloctane D g Methyloctane D g Methyloctane D g Monoethanolamine D IIA

30 National Fire Protection Association Report of /18/ :12 AM Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Vapor Density (Air = 1) Monoisopropanolamine D Monomethyl Aniline C Monomethyl Hydrazine C I Vapor Pressure b (mm Hg) Class I Zone Group c Morpholine C d II IIA 0.95 Naphtha (Coal Tar) D II IIA Naphtha (Petroleum) D d,i I IIA Neopentane D g Nitrobenzene D IIA 0.94 Nitroethane C I IIB 0.87 Nitromethane C I IIA Nitropropane C I IIB Nitropropane C d I n-nonane D g I IIA Nonene D I Nonyl Alcohol D IIA n-octane D d,g I IIA 0.94 Octene D I n-octyl Alcohol D IIA 1.05 n-pentane D d,g I IIA Pentanol D d I IIA Pentanone D I IIA Pentene D I Pentene D I Pentyl Acetate D I Phenylhydrazine D Process Gas > 30% H 2 B j GAS Propane D d GAS IIA Propanol D d I IIA Propanol D d I IIA Propiolactone D Propionaldehyde C I IIB 0.86 Propionic Acid D II IIA 1.10 Propionic Anhydride D n-propyl Acetate D I IIA 1.05 n-propyl Ether C d I Propyl Nitrate B d I Propylene D d GAS IIA Propylene Dichloride D I IIA 1.32 Propylene Oxide B(C) d,e I IIB Pyridine D d I IIA Styrene D d I IIA 1.21 Tetrahydrofuran C d I IIB Tetrahydronaphthalene D IIIA MIE (mj) MIC Ratio MESG (mm)

31 National Fire Protection Association Report 0 of 18 5/18/ :12 AM Chemical CAS No. Class I Division Group Type a Flash Point ( C) AIT ( C) %LFL %UFL Tetramethyl Lead C II Vapor Density (Air = 1) Vapor Pressure b (mm Hg) Class I Zone Group c Toluene D d I IIA 0.24 n-tridecene D IIIA Triethylamine C d I IIA Triethylbenzene D ,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 ,3,3-Trimethylpentane D g 425 Tripropylamine D II IIA 1.13 Turpentine D I n-undecene D IIIA Unsymmetrical Dimethyl Hydrazine MIE (mj) MIC Ratio C d I IIB 0.85 Valeraldehyde C I Vinyl Acetate D d I IIA Vinyl Chloride D d GAS IIA 0.96 Vinyl Toluene D Vinylidene Chloride D I IIA 3.91 Xylene D d I IIA Xylidine C IIIA a Type is used to designate if the material is a gas, flammable liquid, or combustible liquid. (See and ) MESG (mm) b Vapor pressure reflected in units of mm Hg at 77 F (25 C) unless stated otherwise. c Class I, Zone Groups are based on 1996 IEC TR , Explosive atmospheres Part 20-1:Material characteristics for gas and vapor classification Test methods and data, which contains additional data on MESG and group classifications. d Material has been classified by test. e Where 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. f For 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. g Commercial grades of aliphatic hydrocarbon solvents are mixtures of several isomers of the same chemical formula (or molecular weight). The autoignition temperatures (AIT) of the individual isomers are significantly different. The electrical equipment should be suitable for the AIT of the solvent mixture. (See A ) h Certain chemicals have characteristics that require safeguards beyond those required for any of the above groups. Carbon disulfide is one of these chemicals because of its low autoignition temperature and the small joint clearance necessary to arrest its flame propagation. i Petroleum naphtha is a saturated hydrocarbon mixture whose boiling range is 68 F to 275 F (20 C to 135 C). It is also known as benzine, ligroin, petroleum ether, and naphtha. j Fuel and process gas mixtures found by test not to present hazards similar to those of hydrogen may be grouped based on the test results. k Liquid type and flash point vary due to regional blending differences. Statement of Problem and Substantiation for Public Comment

32 National Fire Protection Association Report 1 of 18 5/18/ :12 AM Updated Table note c by updating reference to IEC Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Chapter 2] Public Comment No. 3-NFPA [Chapter C] Related Item First Revision No. 4-NFPA [Section No ] Relationship Referenced current standard names and years Submitter Information Verification Submitter Full Name: Aaron Adamczyk Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Fri Mar 06 20:39:09 EST 2015

33 National Fire Protection Association Report 2 of 18 5/18/ :12 AM Public Comment No. 7-NFPA [ 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 Statement of Problem and Substantiation for Public Comment As discussed there was a need to address gas cylinder storage classification Related Item First Revision No. 11-NFPA [Section No. 5.9 [Excluding any Sub-Sections]] Submitter Information Verification Submitter Full Name: DAVID WECHSLER Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu May 14 14:45:45 EDT 2015

34 National Fire Protection Association Report 3 of 18 5/18/ :12 AM Public Comment No. 5-NFPA [ Section No ] Storage of Liquid or Gaseous Hydrogen. Replace drawings with attached figures [See Figure (a) and Figure (b).] Figure (a) Liquid Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. This diagram applies to liquid hydrogen only. Figure (b) Gaseous Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. This diagram applies to gaseous hydrogen only. Additional Proposed Changes File Name Description Approved 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 Statement of Problem and Substantiation for Public Comment Updates drawings to match material in 2016 edition of NFPA 55 Related Item Committee Input No. 1-NFPA [Section No ] Submitter Information Verification 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

35 Figure (a) liquid hydrogen storage tank and vaporizer (part of system containing liquid hydrogen) 1

36 Figure (b) liquid hydrogen tank fill connection 2

37 Figure (c) liquid hydrogen vent stack 3

38 Figure (d) gas hydrogen storage receivers 4

39 Figure (e) gas hydrogen storage cylinders 5

40 Figure (f) gas hydrogen vent stack 6

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47 National Fire Protection Association Report 4 of 18 5/18/ :12 AM Public Comment No. 8-NFPA [ Section No ] Storage of Liquid or Gaseous Hydrogen. Update figures with attachments - alternate updates [See Figure (a) and Figure (b).] Figure (a) Liquid Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. This diagram applies to liquid hydrogen only. Figure (b) Gaseous Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. This diagram applies to gaseous hydrogen only. Additional Proposed Changes File Name Description Approved section_5.10.8_figures_-_divisions_-_alternate.pdf figures for divisions - alternate Statement of Problem and Substantiation for Public Comment Updating to match NFPA 55 classified area requirements Related Item Committee Input No. 1-NFPA [Section No ] Submitter Information Verification Submitter Full Name: ROB EARLY Organization: PRAXAIR Affilliation: NFPA Industrial and Medical Gases Committee Street Address: City: State: Zip: Submittal Date: Thu May 14 15:07:02 EDT 2015

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54 National Fire Protection Association Report 5 of 18 5/18/ :12 AM Public Comment No. 6-NFPA [ Section No ] Storage of Liquid or Gaseous Hydrogen. Replace drawings with attached figures. [See Figure (a) and Figure (b).] Figure (a) Liquid Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. This diagram applies to liquid hydrogen only. Figure (b) Gaseous Hydrogen Storage Located Outdoors, or Indoors in an Adequately Ventilated Building. This diagram applies to gaseous hydrogen only. Additional Proposed Changes File Name Description Approved 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 Statement of Problem and Substantiation for Public Comment Harmonizes figures with updates in NFPA 55, 2016 edition Related Item Committee Input No. 2-NFPA [Section No ] Submitter Information Verification Submitter Full Name: ROB EARLY Organization: PRAXAIR Affilliation: NFPA Industrial and Medical Gases committee Street Address: City: State: Zip: Submittal Date: Mon May 11 16:30:44 EDT 2015

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61 Figure (a) liquid hydrogen storage tank and vaporizer (part of system containing liquid hydrogen) 1

62 Figure (b) liquid hydrogen tank fill connection 2

63 Figure (c) liquid hydrogen vent stack 3

64 Figure (d) gas hydrogen storage receivers 4

65 Figure (e) gas hydrogen storage cylinders 5

66 Figure (f) gas hydrogen vent stack 6

67 National Fire Protection Association Report 6 of 18 5/18/ :12 AM Public Comment No. 9-NFPA [ Section No ] Storage of Liquid or Gaseous Hydrogen. Update with attached drawings - alternate [See Figure (a) and Figure (b).] Figure (a) Liquid Hydrogen Storage Located Outdoors or Indoors in an Adequately Ventilated Building. This diagram applies to liquid hydrogen only. Figure (b) Gaseous Hydrogen Storage Located Outdoors, or Indoors in an Adequately Ventilated Building. This diagram applies to gaseous hydrogen only. Additional Proposed Changes File Name Description Approved section_5.11.8_figures_-_zones_-_alternate.pdf updated figures - alternate Statement of Problem and Substantiation for Public Comment updates figures to match NFPA 55 Related Item Committee Input No. 2-NFPA [Section No ] Submitter Information Verification Submitter Full Name: ROB EARLY Organization: PRAXAIR Affilliation: NFPA Industrial and Medical Gases Committee Street Address: City: State: Zip: Submittal Date: Thu May 14 15:09:17 EDT 2015

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74 National Fire Protection Association Report 7 of 18 5/18/ :12 AM Public Comment No. 3-NFPA [ 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 recommended practice 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 NFPA 70, National Electrical Code, NFPA Fire Protection Guide to Hazardous Materials, C.1.2 Other Publications. C ASTM Publications. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA ASTM E659, Standard Test Method for Autoignition Temperature of Liquid Chemicals, C IEC Publications. International Electrotechnical Commission, 3, rue de Varembé, P.O. Box 131, CH-1211 Geneva 20, Switzerland. IEC , Electrical apparatus for explosive gas atmospheres, Part 1-1: Flameproof enclosures d Method of test for ascertainment of maximum experimental safe gap, 2002 (Superseded by IEC ). IEC , Explosive atmospheres Part 11: Equipment protection by intrinsic safety I, IEC , - 1, Explosive atmospheres Part 20-1: Material characteristics of gas and vapor classification Test methods and data, C NAS Publications. National Materials Advisory Board of the National Academy of Sciences, 500 Fifth Street, NW, Washington, DC NMAB 353-1, Matrix of Combustion-Relevant Properties and Classification of Gases, Vapors and Selected Solids, C UL Publications. Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL Technical Report No. 58 (TR 58), An Investigation of Flammable Gases or Vapors with Respect to Explosion-Proof Electrical Equipment, (Withdrawn) C Other Publications. Brandes, E. and Redeker, T. Maximum Experimental Safe Gap of Binary and Ternary Mixtures. Journal de Physique IV France, Vol. 12, No. 7, Lunn, G. A., Maximum Experimental Safe Gap: The Effects of Oxygen Enrichment and the Influence of Reaction Kinetics, Journal of Hazardous Materials, , Phillips, H. Differences Between Determinations of Maximum Experimental Safe Gaps in Europe and U.S.A. Journal of Hazardous Materials, Thomas, G., Pipeline Explosions I: An Evaluation of MESG as a Relative Measure of Potential Explosion Severity and the Genesis of a Mimic Gas Concept for Explosion Hazard Testing, 5th Int. Seminar on Fire and Explosion Hazards, Edinburgh, Scotland, C.2 Informational References. The following documents or portions thereof are listed here as informational resources only. They are not a part of the recommendations of this document. C.2.1 ASHRAE Publications. American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc., 1791 Tullie Circle, NE, Atlanta, GA ASHRAE STD 15 & 34, Designation and Safety Classification of Refrigerants Saftey Standard for Refrigeration Systems, 2013, Errata, (This is now a combined standard.) C.2.2 ASTM Publications. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA ASTM D56, Standard Method of Test for Flash Point by the Tag Closed Tester, 2005, reapproved ASTM D93, Standard Test Method for Flash Point by Pensky-Martens Closed Cup Tester, ASTM D3278, Standard Method of Tests for Flash Point of Liquids by Small Scale Closed-Cup Apparatus, 1996, reapproved ASTM E681, Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases), 2009.

75 National Fire Protection Association Report 8 of 18 5/18/ :12 AM C.2.3 Bureau of Mines Publications. U.S. Government Printing Office, Washington, DC 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 Classification Code for Installations Handling Flammable Fluids, Hilado, C. J., and S. W. Clark. Autoignition Temperatures of Organic Chemicals. Chemical Engineering, September 4, Rodgers, S. A., Fuel Ratio Method for Estimating the MESG of Nitrogen-Diluted and Oxygen-Enriched Fuels, Including the Brandes-Redeker Method to Estimate the MESG of Mixed Fuels, AIChE 6th Global Congress on Process Safety, 44th Annual Loss Prevention Symposium, San Antonio, TX March 22 24, C.3 References for Extracts in Informational Sections. (Reserved) Statement of Problem and Substantiation for Public Comment IEC superseded by IEC UL TR 58 has been withdrawn. Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Chapter 2] Public Comment No. 2-NFPA [Section No [Excluding any Sub-Sections]] Related Item First Revision No. 12-NFPA [Chapter C] Relationship Referenced current standard names, and years. Referenced current standard name in note c. Submitter Information Verification Submitter Full Name: Aaron Adamczyk Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Fri Mar 06 20:47:19 EST 2015

76 Attachment G: NFPA 499 A2016 Public Comments

77 National Fire Protection Association Report of /18/ :33 AM Public Comment No. 1-NFPA [ Section No. 1.2 ] 1.2 Purpose The purpose of this recommended practice is to provide the user with a basic understanding of the parameters that determine the degree and the extent of the hazardous (classified) location. This recommended practice also provides the user with examples of the applications of these parameters This recommended practice is intended as a guide and should be applied with sound engineering judgment. Where all factors are properly evaluated, a consistent area classification scheme can be developed This recommended practice is based on the criteria established by Articles 500 and 502 of NFPA The application of this recommended practice does not address all potential hazards associated with solid particulate materials, including, but not limited to, the possible need for explosion venting or explosion suppression addressed in other NFPA standards This recommended practice does not address the criteria for classifying locations in accordance with Article 506 of NFPA 70. Statement of Problem and Substantiation for Public Comment Note: for Clarification - This comment only applies to the deletion of 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 , 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. Related Public Comments for This Document Related Comment Public Comment No. 2-NFPA [New Section after 4.3] Public Comment No. 3-NFPA [New Section after 5.1.4] Public Comment No. 4-NFPA [New Section after 5.2.1] Public Comment No. 5-NFPA [Section No ] Public Comment No. 6-NFPA [Section No. 6.10] Public Comment No. 9-NFPA [Section No. 6.7] Public Comment No. 10-NFPA [Section No. A.6.3.2] Public Comment No. 11-NFPA [Section No. A.6.7] Public Comment No. 12-NFPA [Section No. 6.3] Public Comment No. 13-NFPA [Section No. 6.4] Public Comment No. 14-NFPA [Section No ] Public Comment No. 15-NFPA [Chapter 6] Relationship

78 National Fire Protection Association Report of /18/ :33 AM Related Item Public Input No. 28-NFPA [New Section after 4.3] Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu Mar 05 10:20:07 EST 2015

79 National Fire Protection Association Report Public Comment No. 2-NFPA [ 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 Combustible Dust Groups. Combustible dusts are addressed in the National Electrical Code, in Articles 500, 502, and In Class II- Divisions, hazardous (classified) location the combustible dust are divided into Groups E, F, and G 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 (retain appendix material *) 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 (retain appendix material *) Group G. Atmospheres containing combustible dusts not included in Group E or Group F, including flour, grain, wood, plastic, and chemicals In Class II- Zones, hazardous (classified) location the combustible dust are divided into Zone Groups IIIC and IIIB 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 present similar hazards in the use of electrical equipment Zone Group IIIB. Atmospheres containing 1) 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 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 * 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 Table 4.x.x (former Table 5.2.3) provides a cross-reference of selected chemicals sorted by their Chemical Abstract Service (CAS) numbers References that deal with the testing of various characteristics of combustible materials are listed in B.2.1, B.2.2, and B.2.4. Statement of Problem and Substantiation for Public Comment Added material is needed to support the inclusion of the Zone methodolgy for combustible dusts as shown in the of 51 5/18/ :33 AM

80 National Fire Protection Association Report of /18/ :33 AM earlier Public Input 28. Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 3-NFPA [New Section after 5.1.4] Public Comment No. 4-NFPA [New Section after 5.2.1] Public Comment No. 5-NFPA [Section No ] Public Comment No. 6-NFPA [Section No. 6.10] Public Comment No. 9-NFPA [Section No. 6.7] Related Item Public Input No. 28-NFPA [New Section after 4.3] Submitter Information Verification Relationship Supports the addition of Zone methodology which was not permitted by clause Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu Mar 05 10:40:57 EST 2015

81 National Fire Protection Association Report Public Comment No. 3-NFPA [ New Section after ] TITLE OF NEW CONTENT Type your content here... Add new section as shown below: 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 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 Zone 21. A Zone 21 location is a location (a) In which ignitible concentrations of combustible dust are 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 Zone 22. A Zone 22 location is a location (a) In which ignitible concentrations of combustible dust are not likely to occur in normal operation and, if they do occur, will only persist for a short period; or (b) In which 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. Statement of Problem and Substantiation for Public Comment With the inclusion of Combustible Dust Zones, the relavent document texts required revision based upon NEC Article 506 addressing Zone 20, 21, and 22, combustible Dust locations based upon the NEC Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 2-NFPA [New Section after 4.3] Public Comment No. 4-NFPA [New Section after 5.2.1] Public Comment No. 5-NFPA [Section No ] Public Comment No. 6-NFPA [Section No. 6.10] Related Item Public Input No. 30-NFPA [New Section after 5.1.4] Relationship Action supports inclusion of Zone methodology Action supports inclusion of Zone methodology of 51 5/18/ :33 AM

82 National Fire Protection Association Report of /18/ :33 AM Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu Mar 05 10:54:40 EST 2015

83 National Fire Protection Association Report of /18/ :33 AM Public Comment No. 7-NFPA [ Section No ] 5.1.9* Where Group E dusts are present in hazardous quantities, there are only Division 1 locations. Statement of Problem and Substantiation for Public Comment This material is more correctly addressed in (3) which follows the NEC. Related Public Comments for This Document Related Comment Public Comment No. 8-NFPA [Section No. A.5.1.9] Related Item First Revision No. 5-NFPA [Section No ] Relationship Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Tue Mar 10 08:58:29 EDT 2015

84 National Fire Protection Association Report Public Comment No. 4-NFPA [ New Section after ] TITLE OF NEW CONTENT Type your content here... Add new section and renumber accordingly: New 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 Group IIIC. 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 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. Statement of Problem and Substantiation for Public Comment Texts support the inclusion of these material groups for Combustible Zone dust groups Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 2-NFPA [New Section after 4.3] Public Comment No. 3-NFPA [New Section after 5.1.4] Public Comment No. 5-NFPA [Section No ] Public Comment No. 6-NFPA [Section No. 6.10] Public Comment No. 9-NFPA [Section No. 6.7] Related Item Public Input No. 24-NFPA [New Section after 5.2.1] Relationship Deals with Zone methodology Deals with Zone methodology Deals with Zone methodology Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu Mar 05 10:58:33 EST 2015 of 51 5/18/ :33 AM

85 National Fire Protection Association Report of /18/ :33 AM Public Comment No. 5-NFPA [ Section No ]

86 National Fire Protection Association Report 0 of 51 5/18/ :33 AM 5.2.2*

87 National Fire Protection Association Report 1 of 51 5/18/ :33 AM A listing of selected combustible dusts with their group classification and relevant physical properties is provided in Table The chemicals are listed alphabetically. Table Selected Combustible Dusts Chemical Name CAS No. NEC Group Code Layer or Cloud Ignition Temperature ( C) Acetal, linear G NL 440 Acetoacet-p-phenetidide G NL 560 Acetoacetanilide G M 440 Acetylamino-t-nitrothiazole G 450 Acrylamide polymer G 240 Acrylonitrile polymer G 460 Acrylonitrile-vinyl chloride-vinylidenechloride copolymer ( ) G 210 Acrylonitrile-vinyl pyridine copolymer G 240 Adipic acid 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 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 G 460 Anthranilic acid G M 580 Apricot pit G 230 Aryl-nitrosomethylamide G NL 490 Asphalt F 510 Aspirin [acetol (2)] G M 660 Azelaic acid G M 610 Azo-bis-butyronitrile G 350 Benzethonium chloride G CL 380 Benzoic acid G M 620 Benzotriazole G M 440 Beta-naphthalene-axodimethylaniline G 175 Bis(2-hydroxy- 5-chlorophenyl) methane G NL 570 Bisphenol-A G M 570 Boron, commercial amorphous (85% B) E 400 Calcium silicide E 540

88 National Fire Protection Association Report 2 of 51 5/18/ :33 AM Chemical Name CAS No. NEC Group Code Layer or Cloud Ignition Temperature ( C) Carbon black (more than 8% total entrapped volatiles) F Carboxymethyl cellulose 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) F 180 Charcoal (more than 8% total entrapped volatiles) F Cherry pit G 220 Chlorinated phenol G NL 570 Chlorinated polyether alcohol G 460 Chloroacetoacetanilide G M 640 Chromium (97%) electrolytic, milled 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 G CL 310 Cube root, South America G 230 Di-alphacumyl peroxide, on CA G 180 Diallyl phthalate G M 480 Dicyclopentadiene dioxide G NL 420 Dieldrin (20%) G NL 550 Dihydroacetic acid G NL 430 Dimethyl isophthalate G M 580 Dimethyl terephthalate G M 570 Dinitro-o-toluamide G NL 500

89 National Fire Protection Association Report 3 of 51 5/18/ :33 AM Chemical Name CAS No. NEC Group Code Layer or Cloud Ignition Temperature ( C) Dinitrobenzoic acid G NL 460 Diphenyl G M 630 Ditertiary-butyl-paracresol G NL 420 Dithane m 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 G 150 Ferromanganese, medium carbon E 290 Ferrosilicon (88% Si, 9% Fe) E 800 Ferrotitanium (19% Ti, 74.1% Fe, 0.06% C) E CL 380 Flax shive G 230 Fumaric acid G M 520 Garlic, dehydrated G NL 360 Gilsonite 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 G 260 Hemp hurd G 220 Hexamethylene tetramine G S 410 Hydroxyethyl cellulose G NL 410 Iron, 98% H reduced 2 E 290 Iron, 99% carbonyl 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 E 240 Magnesium, grade B, milled E 430 Manganese vancide G 120 Mannitol G M 460 Methacrylic acid polymer G 290 Methionine (l-methionine) G 360 Methyl cellulose G 340 Methyl methacrylate polymer G NL 440

90 National Fire Protection Association Report 4 of 51 5/18/ :33 AM Chemical Name CAS No. NEC Group Code Layer or Cloud Ignition Temperature ( C) Methyl methacrylate-ethyl acrylate G NL 440 Methyl methacrylate-styrenebutadiene G NL 480 Milk, skimmed G 200 N,N-dimethylthioformamide G 230 Nitropyridone G M 430 Nitrosamine G NL 270 Nylon polymer G 430 Para-oxy-benzaldehyde G CL 380 Paraphenylene diamine G M 620 Paratertiary butyl benzoic acid G M 560 Pea flour G 260 Peach pit shell G 210 Peanut hull G 210 Peat, sphagnum G 240 Pecan nut shell G 210 Pectin G 200 Pentaerythritol G M 400 Petrin acrylate monomer G NL 220 Petroleum coke (more than 8% total entrapped volatiles) F Petroleum resin G 500 Phenol formaldehyde G NL 580 Phenol formaldehyde, polyalkylene-p G 290 Phenol furfural G 310 Phenylbetanaphthylamine G NL 680 Phthalic anydride G M 650 Phthalimide G M 630 Pitch, coal tar F NL 710 Pitch, petroleum F NL 630 Polycarbonate G NL 710 Polyethylene, high pressure process G 380 Polyethylene, low pressure process G NL 420 Polyethylene terephthalate G NL 500 Polyethylene wax G NL 400 Polypropylene (no antioxidant) G NL 420 Polystyrene latex G 500 Polystyrene molding compound G NL 560 Polyurethane foam, fire retardant G 390 Polyurethane foam, no fire retardant G 440 Polyvinyl acetate G NL 550 Polyvinyl acetate/alcohol G 440 Polyvinyl butyral G 390

91 National Fire Protection Association Report 5 of 51 5/18/ :33 AM Chemical Name CAS No. NEC Group Code Layer or Cloud Ignition Temperature ( C) Polyvinyl chloride-dioctyl phthalate G NL 320 Potato starch, dextrinated G NL 440 Pyrethrum G 210 Rayon (viscose) flock G 250 Red dye intermediate G 175 Rice G 220 Rice bran G NL 490 Rice hull G 220 Rosin, DK G NL 390 Rubber, crude, hard G NL 350 Rubber, synthetic, hard (33% S) G NL 320 Safflower meal G 210 Salicylanilide G M 610 Sevin G 140 Shale, oil F Shellac G NL 400 Sodium resinate G 220 Sorbic acid (copper sorbate or potash) G 460 Soy flour G 190 Soy protein G 260 Stearic acid, aluminum salt G 300 Stearic acid, zinc salt G M 510 Styrene modified polyester-glass fiber G 360 Styrene-acrylonitrile (70-30) G NL 500 Styrene-butadiene latex (>75% styrene) G NL 440 Styrene-maleic anhydride copolymer G CL 470 Sucrose G CL 350 Sugar, powdered G CL 370 Sulfur G 220 Tantalum E 300 Terephthalic acid G NL 680 Thorium (contains 1.2% O) E CL 270 Tin, 96%, atomized (2% Pb) E 430 Titanium, 99% Ti E CL 330 Titanium hydride (95% Ti, 3.8% H) E CL 480 Trithiobisdimethylthioformamide G 230 Tung, kernels, oil-free G 240 Urea formaldehyde molding compound G NL 460 Urea formaldehyde-phenol formaldehyde G 240 Vanadium, 86.4% E 490 Vinyl chloride-acrylonitrile copolymer G 470 Vinyl toluene-acrylonitrile butadiene G NL 530 Violet 200 dye G 175

92 National Fire Protection Association Report 6 of 51 5/18/ :33 AM Chemical Name CAS No. NEC Group Code Layer or Cloud Ignition Temperature ( C) Vitamin B1, mononitrate G NL 360 Vitamin C G 280 Walnut shell, black G 220 Wheat G 220 Wheat flour G 360 Wheat gluten, gum G NL 520 Wheat starch G NL 380 Wheat straw G 220 Wood flour G 260 Woodbark, ground G 250 Yeast, torula G 260 Zirconium hydride E 270 Zirconium (contains 0.3% O) E 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 might 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 can 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. Additional Proposed Changes File Name Description Approved 499_table_4.5.2_revised.rtf Replace existing table with this revised table reflecting Combustible Zone Dust Groups. Statement of Problem and Substantiation for Public Comment Table needs to be revised to reflect the Combustible Zone dusts, added with Section Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 2-NFPA [New Section after 4.3] Public Comment No. 3-NFPA [New Section after 5.1.4] Public Comment No. 4-NFPA [New Section after 5.2.1] Public Comment No. 6-NFPA [Section No. 6.10] Public Comment No. 9-NFPA [Section No. 6.7] Public Comment No. 12-NFPA [Section No. 6.3] Related Item Relationship Supports Zone methodology Supports Zone methodology Supports Zone methodology Supports Zone methodology

93 National Fire Protection Association Report 7 of 51 5/18/ :33 AM Public Input No. 25-NFPA [Section No ] Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu Mar 05 11:15:47 EST 2015

94 Table 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 G//IIIB NL 560 Acetoacetanilide 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 G//IIIB 210 ( ) Acrylonitrile-Vinyl Pyridine Copolymer G//IIIB 240 Adipic Acid 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 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 G/IIIB 460 Anthranilic Acid G/IIIB M 580 Apricot Pit G/IIIB 230 Aryl-nitrosomethylamide G/IIIB NL 490 Asphalt F/IIIB 510 Aspirin [acetol (2)] G/IIIB M 660 Azelaic Acid G/IIIB M 610 Azo-bis-butyronitrile G/IIIB 350 Benzethonium Chloride G/IIIB CL 380 Benzoic Acid G/IIIB M 440 Benzotriazole G/IIIB M 440 Beta-naphthalene-axo-dimethylaniline G/IIIB 175 Bis(2-hydroxy-5-chlorophenyl) Methane G/IIIB NL 570 Bisphenol-A G/IIIB M 570 Boron, Commercial Amorphous (85% B) E/IIIC 400 Calcium Silicide E/IIIC 540 Carbon Black (More Than 8% Total Entrapped Volatiles) F/IIIB Carboxymethyl Cellulose 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) F/IIIB 180 Charcoal (More Than 8% Total Entrapped Volatiles) F/IIIB Cherry Pit G/IIIB 220 Chlorinated Phenol G/IIIB NL 570

95 Chlorinated Polyether Alcohol G/IIIB 460 Chloroacetoacetanilide G/IIIB M 640 Chromium (97%) Electrolytic, Milled 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 G/IIIB CL 310 Cube Root, South America G/IIIB 230 Di-alphacumyl Peroxide, on CA G/IIIB 180 Diallyl Phthalate G/IIIB M 480 Dicyclopentadiene Dioxide G/IIIB NL 420 Dieldrin (20%) G/IIIB NL 550 Dihydroacetic Acid G/IIIB NL 430 Dimethyl Isophthalate G/IIIB M 580 Dimethyl Terephthalate G/IIIB M 570 Dinitro-o-toluamide G/IIIB NL 500 Dinitrobenzoic Acid G/IIIB NL 460 Diphenyl G/IIIB M 630 Ditertiary-butyl-paracresol G/IIIB NL 420 Dithane m 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 G/IIIB 150 Ferromanganese, Medium Carbon E/IIIC 290 Ferrosilicon (88% Si, 9% Fe) E/IIIC 800 Ferrotitanium (19% Ti, 74.1% Fe, 0.06% C) E/IIIC CL 380 Flax Shive G/IIIB 230 Fumaric Acid G/IIIB M 520 Garlic, Dehydrated G/IIIB NL 360 Gilsonite 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 G/IIIB 260 Hemp Hurd G/IIIB 220

96 Hexamethylene Tetramine G/IIIB S 410 Hydroxyethyl Cellulose G/IIIB NL 410 Iron, 98% H 2 Reduced E/IIIC 290 Iron, 99% Carbonyl 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 E/IIIC 240 Magnesium, Grade B, Milled E/IIIC 430 Manganese Vancide G/IIIB 120 Mannitol G/IIIB M 460 Methacrylic Acid Polymer G/IIIB 290 Methionine (l-methionine) G/IIIB 360 Methyl Cellulose G/IIIB 340 Methyl Methacrylate Polymer 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 G/IIIB M 430 Nitrosamine G/IIIB NL 270 Nylon Polymer G/IIIB 430 Para-oxy-benzaldehyde G/IIIB CL 380 Paraphenylene Diamine G/IIIB M 620 Paratertiary Butyl Benzoic Acid G/IIIB M 560 Pea Flour G/IIIB 260 Peach Pit Shell G/IIIB 210 Peanut Hull G/IIIB 210 Peat, Sphagnum G/IIIB 240 Pecan Nut Shell G/IIIB 210 Pectin G/IIIB 200 Pentaerythritol G/IIIB M 400 Petrin Acrylate Monomer G/IIIB NL 220 Petroleum Coke (More Than 8% Total Entrapped Volatiles) F/IIIB Petroleum Resin G/IIIB 500 Phenol Formaldehyde G/IIIB NL 580 Phenol Formaldehyde, Polyalkylene-p G/IIIB 290 Phenol Furfural G/IIIB 310 Phenylbetanaphthylamine G/IIIB NL 680 Phthalic Anydride G/IIIB M 650 Phthalimide G/IIIB M 630 Pitch, Coal Tar F/IIIB NL 710 Pitch, Petroleum F/IIIB NL 630 Polycarbonate G/IIIB NL 710 Polyethylene, High Pressure Process G/IIIB 380 Polyethylene, Low Pressure Process G/IIIB NL 420 Polyethylene Terephthalate G/IIIB NL 500 Polyethylene Wax G/IIIB NL 400 Polypropylene (no antioxidant) G/IIIB NL 420 Polystyrene Latex G/IIIB 500 Polystyrene Molding Compound G/IIIB NL 560 Polyurethane Foam, Fire Retardant G/IIIB 390

97 Polyurethane Foam, No Fire Retardant G/IIIB 440 Polyvinyl Acetate G/IIIB NL 550 Polyvinyl Acetate/Alcohol G/IIIB 440 Polyvinyl Butyral G/IIIB 390 Polyvinyl Chloride-dioctyl Phthalate G/IIIB NL 320 Potato Starch, Dextrinated G/IIIB NL 440 Pyrethrum G/IIIB 210 Rayon (Viscose) Flock 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 G/IIIB NL 390 Rubber, Crude, Hard G/IIIB NL 350 Rubber, Synthetic, Hard (33% S) G/IIIB NL 320 Safflower Meal G/IIIB 210 Salicylanilide G/IIIB M 610 Sevin G/IIIB 140 Shale, Oil F/IIIB Shellac G/IIIB NL 400 Sodium Resinate G/IIIB 220 Sorbic Acid (Copper Sorbate or Potash) G/IIIB 460 Soy Flour G/IIIB 190 Soy Protein G/IIIB 260 Stearic Acid, Aluminum Salt G/IIIB 300 Stearic Acid, Zinc Salt G/IIIB M 510 Styrene Modified Polyester-Glass Fiber G/IIIB 360 Styrene-acrylonitrile (70-30) G/IIIB NL 500 Styrene-butadiene Latex (>75% styrene) G/IIIB NL 440 Styrene-maleic Anhydride Copolymer G/IIIB CL 470 Sucrose G/IIIB CL 350 Sugar, Powdered G/IIIB CL 370 Sulfur G/IIIB 220 Tantalum E/IIIC 300 Terephthalic Acid G/IIIB NL 680 Thorium (contains 1.2% O) E/IIIC CL 270 Tin, 96%, Atomized (2% Pb) E/IIIC 430 Titanium, 99% Ti E/IIIC CL 330 Titanium Hydride (95% Ti, 3.8% H) E/IIIC CL 480 Trithiobisdimethylthio-formamide G/IIIB 230 Tung, Kernels, Oil-free G/IIIB 240 Urea Formaldehyde Molding Compound G/IIIB NL 460 Urea Formaldehyde-phenol Formaldehyde G/IIIB 240 Vanadium, 86.4% E/IIIC 490 Vinyl Chloride-acrylonitrile Copolymer G/IIIB 470 Vinyl Toluene-acrylonitrile Butadiene G/IIIB NL 530 Violet 200 Dye G/IIIB 175 Vitamin B1, Mononitrate G/IIIB NL 360 Vitamin C G/IIIB 280 Walnut Shell, Black G/IIIB 220 Wheat G/IIIB 220 Wheat Flour G/IIIB 360 Wheat Gluten, Gum G/IIIB NL 520 Wheat Starch G/IIIB NL 380 Wheat Straw G/IIIB 220 Wood Flour G/IIIB 260

98 Woodbark, Ground G/IIIB 250 Yeast, Torula G/IIIB 260 Zirconium Hydride E/IIIC 270 Zirconium (contains 0.3% O) 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.

99 National Fire Protection Association Report Public Comment No. 15-NFPA [ Chapter 6 ] Chapter 6 Classification of Combustible Dust Class II (Combustible Dust) or Zone 20, Zone 21, and Zone 22 Locations 6.1 General The decision to classify an area as hazardous should be based on the probability that a combustible dust could be present. This action defines the NEC Class II condition Combustible Dust condition. Due to the complexity of the processes that create dust, the classification of these hazardous locations should be determined 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 Hazardous Classified Class II or Zone 20, 21, or Zone 22 locations Once the NEC Class II Combustible dust condition has been defined, the next step should be to determine 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 In a Class II location Combustible Dust location, one of the sets of conditions in through must be satisfied for ignition by the electrical installation 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 in the vicinity of the electrical equipment. (3) There is a source of thermal or electrical energy sufficient to ignite the suspended mixture. Within the context of this recommended practice, the energy source is understood to originate with the electrical system * 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 heat and 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 its ignition temperature directly or to dry out the dust and cause it to self-heat 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 Once ignition has occurred, either in a cloud suspension or in a layer, an explosion is likely Often the initial explosion is followed by another much more violent explosion fueled from dust accumulations on structural beams and equipment surfaces that are thrown into suspension by the initial blast. 8 of 51 5/18/ :33 AM

100 National Fire Protection Association Report 9 of 51 5/18/ :33 AM For that reason, good housekeeping is vitally important in all areas where dust is handled, and is assumed throughout this recommended practice In classifying a particular location, the presence of a combustible dust is significant in determining the correct division The classification depends both on the presence of dust clouds and on the presence of hazardous accumulations of dust in layer form As specified in , the presence of a combustible dust cloud under normal conditions of operation or due to frequent repair or maintenance should be classified as Division 1 or Zone 20/Zone Abnormal operation of machinery and equipment, which could simultaneously produce a dust cloud or suspension and a source of ignition, also should be classified as Division 1 or Zone 20/Zone In other words, if a dust cloud is present at any time, it is assumed to be ignitible, and all that is necessary for electrical ignition is failure of the electrical system If dust clouds or hazardous dust accumulations are present only as a result of infrequent malfunctioning of handling or processing equipment, and ignition can result only from abnormal operation or failure of electrical equipment, the location should be classified Division 2 or Zone The presence of an ignitible dust cloud or an ignitible dust layer is important in determining the boundaries of the hazardous (classified) location The quantity of dust, its physical and chemical properties, its dispersion properties, and the location of walls and cutoffs all must be considered. 6.3 Combustible Dust Class II, Division 1 or Zone 20/Zone 21 Classified Locations Where a combustible dust cloud is likely to be present under normal conditions, the location should be classified as Division 1 or Zone 20/Zone This practice does not support a design that permits a normal continued condition of more than the tested layer thickness (see ) of dust accumulation nor presence of greater than moderate isolated dust cloud, external to processing equipment * Where a dust layer greater than 3.0 mm ( 1 8 in.) thick is present under normal conditions, the location should be classified as Division 1 or Zone 20/Zone The term normal does not necessarily mean the situation that prevails when everything is working properly For instance, if a bucket elevator requires frequent maintenance and repair, this repair should be viewed as normal If quantities of ignitible dust are released as a result of the maintenance, the location is Division 1 or Zone 20/Zone However, if that elevator is replaced and now repairs are not usually required between turnarounds, the need for repairs is considered abnormal The classification of the location, therefore, is related to equipment maintenance, both procedures and frequencies Similarly, if the problem is the buildup of dust layers without the presence of visible dust suspensions, good and frequent cleaning procedures or the lack thereof will influence the classification of the location.

101 National Fire Protection Association Report Combustible Dust Class II, Division 2 or Zone 22 Classified Locations The criterion for a Division 2 or Zone 22 location is whether the location is likely to have ignitible dust suspensions or hazardous dust accumulations only under abnormal conditions. The term abnormal is used here in a limited sense and does not include a major catastrophe As an example, consider the replaced bucket elevator of , which releases ignitible dust only under abnormal conditions. In this case, there is no Division 1 or Zone 20/Zone 21 location because the elevator is normally tight. To release dust, the elevator would have to leak, and that would not be normal Chemical process equipment does not fail often. Furthermore, the electrical installation requirement of the NEC for Division 2 or Zone 22 locations is such that an ignition-capable spark or hot surface will occur only in the event of abnormal operation or failure of electrical equipment. Otherwise, sparks and hot surfaces are not present or are contained in enclosures. On a realistic basis, the possibility of process equipment and electrical equipment failing simultaneously is remote The Division 2 or Zone 22 classification is applicable to conditions not involving equipment failure. For example, consider a location classified as Division 1 because of normal presence of ignitible dust suspension. Obviously, one side of the Division 1 or Zone 20/Zone 21 boundary cannot be normally hazardous and the opposite side never hazardous. Similarly, consider a location classified as Division 1 or Zone 20/Zone 21 because of the normal presence of hazardous dust accumulations. One side of the division boundary cannot be normally hazardous, with thick layers of dust, and the other side unclassified, with no dust, unless there is an intervening wall Where there is no wall, a surrounding transition Division 2 location or Zone 22location separates a Division 1 or Zone 20/Zone 21 location from an unclassified location. For Group E or Group IIIC combustible metal dusts which may be present in quantities sufficient to be hazardous, the surrounding transition is may be applied as an additional Division 1 or Zone 20/Zone 21 location or as a Division 2 or Zone 22 either as an extra precaution or as conditions warrant Walls are much more important in separating Division 1 and Zone 20/Zone 21 locations from Division 2 and Zone 22 and unclassified locations in Class II combustible dust locations than in Class I locations Only unpierced solid walls make satisfactory barriers in Class I locations, whereas closed doors, lightweight partitions, or even partial partitions could make satisfactory walls between combustible dust Class II, Division 1 locations or Zone 20/Zone 21locations and unclassified locations Area classification does not extend beyond the wall, provided it is effective in preventing the passage of dust in suspension or layer form. 6.5 Unclassified Locations. 0 of 51 5/18/ :33 AM

102 National Fire Protection Association Report 1 of 51 5/18/ :33 AM Experience has shown that the release of ignitible dust suspensions from some operations and apparatus is so infrequent that area classification is not necessary. For example, where combustible dusts are processed, 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 ) (8) Where excellent housekeeping prevents the following: (9) Visual dust clouds (10) Layer accumulations that make surface colors indiscernible (see A ) Dust removal systems that are provided to allow an unclassified location should have adequate safeguards and warnings against failure Open flames and hot surfaces associated with the operation of certain equipment, such as boilers and fired heaters, provide inherent thermal ignition sources Area classification is not appropriate in the immediate vicinity of inherent thermal ignition sources Dust-containing operations should be cut off by blank walls or located away from inherent thermal ignition sources Where pulverized coal or ground-up solid waste is used to fire a boiler or incinerator, it is prudent to avoid installing electrical equipment that could become primary ignition sources for leaks in the fuel feed lines. 6.6 Procedure for Classifying Areas. Subsections through detail the procedure that should be used for each room, section, or area being classified Step 1: Need for Classification. The area should be classified if a combustible material is processed, handled, or stored there Step 2: Gathering Information Proposed Facility Information. For a proposed facility that exists only in drawings, a preliminary area classification can be done so that suitable electrical equipment and instrumentation can be purchased. Plants are rarely built exactly as the drawings portray, and the area classification should be modified later, based on the actual facility.

103 National Fire Protection Association Report 2 of 51 5/18/ :33 AM Existing Facility History. For an existing facility, the individual plant experience is extremely important in classifying areas within the plant. Both operation and maintenance personnel in the actual plant should be asked the following questions: (1) Is a dust likely to be in suspension in air continuously, periodically, or intermittently under normal conditions 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 equipment surfaces 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 equipment enclosures 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? Material Density. The specific particle density of the dust should be determined if it is at least 641 kg/m 3 (40 lb/ft 3 ) Plot Plan. A plot plan (or similar drawing) is needed that shows all vessels, tanks, building structures, partitions, and similar items that would affect dispersion or promote accumulation of the dust Fire Hazard Properties of Combustible Material. The NEC group and the layer or cloud ignition temperature are shown in Table for many materials A material could be listed in Table under a chemical name different from the chemical name used at the facility. Table is provided to cross-reference the CAS number of the material to the chemical name used in Table Where materials being used are not listed in Table or in other reputable chemical references, the information 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 the autoignition temperature has been determined (2) Having the material evaluated for the group and tested for the autoignition temperature 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 Step 4: Determining the Extent of the Hazardous (Classified) Location. The extent of the hazardous (classified) location can be determined using sound engineering judgment to apply the methods discussed in Section 5.1 and the diagrams contained in this chapter The potential sources of leaks should be located on the plan drawing or at the actual location. These sources of leaks could include rotating or reciprocating shafts, doors and covers on process equipment, and so forth.

104 National Fire Protection Association Report 3 of 51 5/18/ :33 AM For each leakage source, an equivalent example on the selected classification diagram should be located to determine the minimum extent of classification around the leakage source. The extent can be modified by 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 process equipment, 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 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 and control of dust accumulations. 6.8 Extent of Hazardous (Classified) Locations 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 The dispersal of dusts and the influence of the factors in on this dispersal are discussed generally in The importance of dust removal and housekeeping are discussed in other paragraphs of this chapter In addition, walls, partitions, enclosures, or other barriers and strong air currents will also affect the distance that dust particles will travel and the extent of the Division 1 or Zone 20/Zone 21 and Division 2 or Zone 22 locations Where there are walls that limit the travel of the dust particles, area classifications do not extend beyond the walls. Providing walls and partitions is a primary means of limiting the extent of hazardous (classified) locations Where effective walls are not provided, the extent of the Division 1 or Zone 20/Zone 21 and Division 2 or Zone 22 locations can be estimated as follows: (1) By visual observation of the existing location using the guidelines in A (2) By experience with similar dusts and similar operations and by taking into consideration differences in equipment, enclosures, dust-removal systems, and housekeeping rules and methods (3) By using the classification diagrams in this chapter

105 National Fire Protection Association Report 4 of 51 5/18/ :33 AM Tight equipment, ventilated hoods and pickup points, good maintenance, and good housekeeping practices should limit Division 1 locations to those inside process enclosures and equipment and those close to openings 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 Zone 20/Zone 21 location The size of a building and its walls will influence the classification of the enclosed volume. In the case of a small room, it can be appropriate to classify the entire volume as Division 1 or Zone 20/Zone 21 or Division 2 or Zone When classifying large buildings, careful evaluation of prior experience with the same or similar installations should be made. Where experience indicates that a particular design concept is sound, that design should continue to be followed. Sound engineering judgment and good housekeeping should be used to minimize the extent of hazardous (classified) locations Wherever possible with large buildings, walls should be used to cut off dusty operations to minimize the hazardous (classified) location. Where walls are not possible, the concentric volume approach of a Division 1 or Zone 20/Zone 21 location surrounded by a larger Division 2 or Zone 22 location, should be used as shown in the diagrams in Section See Figure 6.10(a) Where it is necessary to have a number of dusty operations located in a building, there could be a multiplicity of Division 1 or Zone 20/Zone 21 locations, with intervening Division 2 or Zone 22 and unclassified locations The quantity of dust released and its distance of travel are of extreme importance in determining the extent of 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 of electrical equipment. 6.9 Discussion of Diagrams and Recommendations The series of diagrams in Section 6.10 illustrate how typical dusty areas should be classified and the recommended extent of classification The diagrams should be used as aids in developing electrical classification maps of operating units, storage areas, and process buildings. Most of the maps will be plan views. However, elevations could be necessary to provide the three-dimensional picture of an actual operation 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 of leaks, such as flanged and screwed connections, fittings, openings, valves, and metering and weighing devices. Thus, actual diagrams of the equipment could be required so that the necessary engineering judgment to establish the boundaries of Division 1 or Zone 20/Zone 21 and Division 2 or Zone 22 locations can be applied These diagrams apply to operating equipment processing dusts when the specific particle density is greater than 641 kg/m 3 (40 lb/ft 3 ). When dusts with a specific particle density less than 641 kg/m 3 (40 lb/ft 3 ) are being handled, there is a pronounced tendency for the fine dust to drift on air currents normally present in industrial plants for distances considerably farther than those shown on these diagrams. In those cases, it will be necessary to extend the hazardous (classified) location using sound engineering judgment and experience Good engineering practices, good housekeeping practices, and effective dust removal systems are necessary to limit the extent of the classified areas and to minimize the chances of primary explosions and secondary explosions, which are often more violent.

106 National Fire Protection Association Report 5 of 51 5/18/ :33 AM 6.10 Classification Diagrams.

107 National Fire Protection Association Report 6 of 51 5/18/ :33 AM 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/m 3 (40 lb/ft 3 ). Figure 6.10(a) Group F or Group G Dust Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment. Figure 6.10(b) Group E Dust Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment.

108 National Fire Protection Association Report 7 of 51 5/18/ :33 AM Figure 6.10(c) Group F or Group G Dust Indoor, Unrestricted Area; Operating Equipment Enclosed; Area Classified as a Class II, Division 2 Location. Figure 6.10(d) Group F or Group G Dust Indoor, Unrestricted Area; Operating Equipment Enclosed; Area is an Unclassified Location.

109 National Fire Protection Association Report 8 of 51 5/18/ :33 AM 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.

110 National Fire Protection Association Report 9 of 51 5/18/ :33 AM Figure 6.10(g) Group F or Group G Dust Indoor, Walled-Off Area; Operating Equipment Open or Semi-Enclosed. Figure 6.10(h) Group F or Group G Dust Indoor, Walled-Off Area; Multiple Pieces of Operating Equipment. Figure 6.10(i) Group F or Group G Dust Indoor, Unrestricted Area; Ventilated Bagging Head. Statement of Problem and Substantiation for Public Comment Revisions reflect the application of current combustible dust Class- Division methodology with the combustible dust Zone methodology. Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Relationship Zone methodology

111 National Fire Protection Association Report 0 of 51 5/18/ :33 AM Related Item Public Input No. 5-NFPA [Chapter 4] Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Tue Mar 17 10:08:44 EDT 2015

112 National Fire Protection Association Report Public Comment No. 12-NFPA [ Section No. 6.3 ] 6.3 Class II, Division 1 or Zone 20/21 Classified Locations Where a combustible dust cloud is likely to be present under normal conditions, the location should be classified as Division 1 or using the zone methodolgy Zone 20 or Zone This practice does not support a design that permits a normal continued condition of more than the tested layer thickness (see ) of dust accumulation nor presence of greater than moderate isolated dust cloud, external to processing equipment * Where a dust layer greater than 3.0 mm ( 1 8 in.) thick is present under normal conditions, the location should be classified as Division 1 1 or using the zone methodology, Zone 20 or Zone The term normal does not necessarily mean the situation that prevails when everything is working properly For instance, if a bucket elevator requires frequent maintenance and repair, this repair should be viewed as normal If quantities of ignitible dust are released as a result of the maintenance, the location is Division 1, or using the zone methodology, Zone 20 or Zone However, if that elevator is replaced and now repairs are not usually required between turnarounds, the need for repairs is considered abnormal The classification of the location, therefore, is related to equipment maintenance, both procedures and frequencies Similarly, if the problem is the buildup of dust layers without the presence of visible dust suspensions, good and frequent cleaning procedures or the lack thereof will influence the classification of the location. Statement of Problem and Substantiation for Public Comment To agree with the insertion of the Zone documentation Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 5-NFPA [Section No ] Related Item Public Input No. 5-NFPA [Chapter 4] Relationship Zone material Zone material Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: 1 of 51 5/18/ :33 AM

113 National Fire Protection Association Report 2 of 51 5/18/ :33 AM Submittal Date: Mon Mar 16 11:18:54 EDT 2015

114 National Fire Protection Association Report Public Comment No. 13-NFPA [ Section No. 6.4 ] 6.4 Class II, Division 2 or Zone 22 Classified Locations The criterion for a Class II, Division 2 or a Zone 22 location is whether the location is likely to have ignitible dust suspensions or hazardous dust accumulations only under abnormal conditions. The term abnormal is used here in a limited sense and does not include a major catastrophe As an example, consider the replaced bucket elevator of , which releases ignitible dust only under abnormal conditions. In this case, there is no Division 1 location because the elevator is normally tight. To release dust, the elevator would have to leak, and that would not be normal Chemical process equipment does not fail often. Furthermore, the electrical installation requirement of the NEC for Class II, Division 2 or Zone 22 locations is such that an ignition-capable spark or hot surface will occur only in the event of abnormal operation or failure of electrical equipment. Otherwise, sparks and hot surfaces are not present or are contained in enclosures. On a realistic basis, the possibility of process equipment and electrical equipment failing simultaneously is remote The Class II, Division 2 and the Zone 22 classification is applicable to conditions not involving equipment failure. For example, consider a location classified as Division 1 because of normal presence of ignitible dust suspension. Obviously, one side of the Division 1 boundary cannot be normally hazardous and the opposite side never hazardous. Similarly, consider a location classified as Division 1 because of the normal presence of hazardous dust accumulations. One side of the division boundary cannot be normally hazardous, with thick layers of dust, and the other side unclassified, with no dust, unless there is an intervening wall Where there is no wall, a surrounding transition Class II, Division 2 or Zone 22 location separates a Class II, Division 1 or Zone 20/21 location from an unclassified location. For Group E, the surrounding transition is an additional Division 1 location (See A.6.3. for Group IIIC materials) 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 Only unpierced solid walls make satisfactory barriers in Class I locations, whereas closed doors, lightweight partitions, or even partial partitions could make satisfactory walls between Class II, Division 1 or Zone 20/21 locations and unclassified locations Area classification does not extend beyond the wall, provided it is effective in preventing the passage of dust in suspension or layer form. Statement of Problem and Substantiation for Public Comment Revisions needed to correlate with Zone information. Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Related Item Public Input No. 5-NFPA [Chapter 4] Relationship Submitter Information Verification 3 of 51 5/18/ :33 AM

115 National Fire Protection Association Report 4 of 51 5/18/ :33 AM Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Mon Mar 16 11:30:30 EDT 2015

116 National Fire Protection Association Report 5 of 51 5/18/ :33 AM Public Comment No. 14-NFPA [ Section No ] 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 Statement of Problem and Substantiation for Public Comment To correlate with Zone material Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Related Item Public Input No. 5-NFPA [Chapter 4] Relationship Zone information Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Mon Mar 16 11:40:30 EDT 2015

117 National Fire Protection Association Report 6 of 51 5/18/ :33 AM Public Comment No. 9-NFPA [ Section No. 6.7 ] 6.7* Housekeeping. Housekeeping frequency (see Tables A.6.7 a and Table A.6.7 b ) and effectiveness are significant factors in the presence and control of dust accumulations. Statement of Problem and Substantiation for Public Comment Revision needed to support inclusion of Combustible Dust Zones. Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 2-NFPA [New Section after 4.3] Public Comment No. 4-NFPA [New Section after 5.2.1] Public Comment No. 5-NFPA [Section No ] Public Comment No. 6-NFPA [Section No. 6.10] Public Comment No. 10-NFPA [Section No. A.6.3.2] Public Comment No. 11-NFPA [Section No. A.6.7] Related Item Public Input No. 30-NFPA [New Section after 5.1.4] Relationship Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Mon Mar 16 10:31:29 EDT 2015

118 National Fire Protection Association Report 7 of 51 5/18/ :33 AM Public Comment No. 6-NFPA [ Section No ]

119 National Fire Protection Association Report 8 of 51 5/18/ :33 AM 6.10 Classification Diagrams.

120 National Fire Protection Association Report 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-Enclosed Operating Equipment. Figure 6.10(b) Group E Dust Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment. 9 of 51 5/18/ :33 AM

121 National Fire Protection Association Report 0 of 51 5/18/ :33 AM Figure 6.10(c) Group F or Group G Dust Indoor, Unrestricted Area; Operating Equipment Enclosed; Area Classified as a Class II, Division 2 Location. Figure 6.10(d) Group F or Group G Dust Indoor, Unrestricted Area; Operating Equipment Enclosed; Area is an Unclassified Location.

122 National Fire Protection Association Report 1 of 51 5/18/ :33 AM 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.

123 National Fire Protection Association Report 2 of 51 5/18/ :33 AM Figure 6.10(g) Group F or Group G Dust Indoor, Walled-Off Area; Operating Equipment Open or Semi-Enclosed. Figure 6.10(h) Group F or Group G Dust Indoor, Walled-Off Area; Multiple Pieces of Operating Equipment. Figure 6.10(i) Group F or Group G Dust Indoor, Unrestricted Area; Ventilated Bagging Head. Additional Proposed Changes File Name Description Approved 499_work_figs_dbw pdf replacement figures Statement of Problem and Substantiation for Public Comment With the inclusion of Combustible Zone Dusts, these new classification examples, provide correlation with the Division figures which exist in this document.

124 National Fire Protection Association Report 3 of 51 5/18/ :33 AM 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. Related Public Comments for This Document Related Comment Public Comment No. 1-NFPA [Section No. 1.2] Public Comment No. 2-NFPA [New Section after 4.3] Public Comment No. 3-NFPA [New Section after 5.1.4] Public Comment No. 4-NFPA [New Section after 5.2.1] Public Comment No. 5-NFPA [Section No ] Public Comment No. 9-NFPA [Section No. 6.7] Related Item Public Input No. 26-NFPA [Section No. 6.10] Relationship Supporting Zone Methodology Supporting Zone Methodology Supporting Zone Methodology Supporting Zone Methodology Supporting Zone Methodology Submitter Information Verification Submitter Full Name: David Wechsler Organization: [ Not Specified ] Street Address: City: State: Zip: Submittal Date: Thu Mar 05 11:30:34 EST 2015

125 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)

126 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)

127 Revise as shown in red For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows: Change from 3.05 m (10 ft) to 10 ft (3.05 m)

128 No changes proposed

129 No changes proposed

130 Revise as shown in red Remove elevation view Wall or partition With all openings kept closed. Self-closing door kept closed Open door or frequently opened door Source Div. 1 3 ft (915 mm) Div. 2 See Note X (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 (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)

131 Revise as shown in red For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows: Open door or frequently opened door Div. 1 3 ft (915 mm) Div ft (3.05 m)

132 Revise as shown in red/blue 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) Open door or frequently opened door Self-closing door kept closed Div ft (3.05 m)

133 Revise as shown in red For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows: Change from 3.05 m (10 ft) to 10 ft (3.05 m)

134 Revise as new figure 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) Zone 21 Zone 22 Zone 21 Zone 22 Figure 6.11 (a) Zone Group IIIB Dust Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment

135 Revise as new figure For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows: Zone ft (6.1 m) 10 ft (3.05 m) Zone ft (3.05 m) Zone 20/Zone 21 Zone 22 Zone 20/Zone 21 Zone 21/Zone 22 Figure 6.11 (b) Zone Group IIIC Dust Indoor, Unrestricted Area; Open or Semi-Enclosed Operating Equipment

136 Revise as new figure For consistency with NFPA 497 figures 5.xx, use convention of ft (m) as follows: Change from 3.05 m (10 ft) to 10 ft (3.05 m) 10 ft (3.05 m) Zone 21 Zone 22 Zone 21 Zone 22 Figure 6.11 (c) Zone Group IIIB Dust Indoor, Unrestricted Area; Operating Equipment Enclosed; Area Classified as a Class II, Zone 22 Location

137 Revise as new figure Zone 21 Zone 22 Figure 6.11 (d) Zone Group IIIB Dust Indoor, Unrestricted Area; Operating Equipment Enclosed; Area is an Unclassified Location

138 Revise as new figure Zone 21 Zone 22 Figure 6.11 (e) Zone Group IIIC or IIIB Dust Storage Area; Bags, Drums or Closed Hoppers.

139 Revise as new figure Wall or partition With all openings kept closed. Self-closing door kept closed Open door or frequently opened door Source Zone 20/21 3 ft (915 mm) Zone 22 See Note X Note: Combustible metal dusts which may be present in quantities sufficient to be hazardous are considered Class II, Division 1 locations per NEC (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 Zone 22 Minimize Zone 20/21 cutoff volume and area Figure 6.11 (f) Zone Group IIIC Dust Indoor, Walled-Off Area; Operating Equipment Enclosed;

140 Revise as new figure Open door or frequently opened door Zone 21-3 ft (915 mm) Zone ft (3/05 m) Zone 21 Zone 22 Zone 21 Zone 22 Figure 6.11 (g) Zone Group IIIB Dust Indoor, Walled-Off Area; Operating Equipment Open or Semi- Enclosed

141 Revise as new figure 20 ft (6.1 m) Open door or frequently opened door Self-closing door kept closed Zone ft (3.05 m) Zone 21 Zone 22 Zone 21 Zone 22 Figure 6.11 (h) Zone Group IIIB Dust Indoor, Walled-Off Area; Multiple Pieces of Operating Equipment

142 Revise as new figure 10 ft (3.05 m) 10 ft (.053 m) 10 ft (3.05m) 10 ft (3.05 m ) Zone 21 Zone 22 Zone 21 Zone 22 Figure 6.11 (i) Zone Group IIIB Dust Indoor, Unrestricted Area; Ventilated Bagging Head