M E M O R A N D U M - National Fire Protection Association B31.3, Process Piping, 2010. ASME B31.12,...

ROP TC Initial Ballot Cover Memo – September 24, 2010

National Fire Protection Association 1 Batterymarch Park, Quincy, MA 02169-7471 Phone: 617-770-3000 • Fax: 617-770-0700 • www.nfpa.org

M E M O R A N D U M

TO: Technical Committee on Gas Process Safety FROM: Kimberly Shea DATE: February 28, 2012 SUBJECT: NFPA 56PS ROP TC Letter Ballot (A2013)

____________________________________________________________ The ROP letter ballot for NFPA 56PS is attached. The ballot is for formally voting on whether or not you concur with the committee’s actions on the proposals. Reasons must accompany all negative and abstention ballots. Please do not vote negatively because of editorial errors. However, please bring such errors to my attention for action. Please complete and return your ballot as soon as possible but no later than Thursday, March 13, 2012. As noted on the ballot form, please return the ballot to NFPA either via e-mail to: [email protected] or via fax to (617) 984-7070. You may also mail your ballot to the attention of Kim Shea at NFPA, 1 Batterymarch Park, Quincy, MA 02169. The return of ballots is required by the Regulations Governing Committee Projects. Attachments: Proposals Letter Ballot

Report on Proposals – June 2013 NFPA 56PS_______________________________________________________________________________________________56PS-1 Log #CP1

_______________________________________________________________________________________________Technical Committee on Gas Process Safety,

Review entire document to: 1) Update any extracted material by preparing separate proposals todo so, and 2) review and update references to other organizations documents, by preparing proposal(s) as required.NFPA 2, Hydrogen Technologies Code, 2011 edition.NFPA 31, Standard for the Installation of Oil-Burning Equipment, 2011 edition.NFPA 51, Standard for the Design and Installation of Oxygen-Fuel Gas Systems for Welding, Cutting, and AlliedProcesses, 2007 edition.NFPA 51A, Standard for Acetylene Cylinder Charging Plants, 2012 edition.NFPA 51B, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work, 2009 edition.NFPA 52, Alternative Vehicular Fuel Systems, 2010 edition.NFPA 54, National Fuel Gas Code, 2012 edition.NFPA 55, Compressed Gases and Cryogenic Fluids Code, 2010 edition.NFPA 58, Liquefied Petroleum Gas Code, 2011 edition.NFPA 59, Utility LP-Gas Plant Code, 2012 edition.NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG), 2009 edition.NFPA 69, Standard on Explosion Prevention Systems, 2008 edition.NFPA 70®, National Electrical Code®, 2011 edition.2.3 Other Publications.2.3.1 ASME Publications. American Society of Mechanical Engineers, Three Park Avenue, New York, NY10016-5990.ANSI/ASME B31.1, Power Piping, 2010.ANSI/ASME B31.3, Process Piping, 2010.ASME B31.12, Hydrogen Piping and Pipelines, 2008.2.4 References for Extracts in Mandatory Sections.NFPA 54, National Fuel Gas Code, 2012 edition.NFPA 55, Compressed Gases and Cryogenic Fluids Code, 2010 edition.NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handlingof Combustible Particulate Solids, 2006 edition.D.1.1 NFPA Publications. National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.NFPA 1, Uniform Fire Code, 2012 edition.NFPA 2, Hydrogen Technologies Code, 2011 edition.NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages, 2012 edition.NFPA 37, Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines, 2010 edition.NFPA 51, Standard for the Design and Installation of Oxygen-Fuel Gas Systems for Welding, Cutting, and AlliedProcesses, 2007 edition.NFPA 51A, Standard for Acetylene Cylinder Charging Plants, 2012 edition.NFPA 52, Vehicular Gaseous Fuel Systems Code, 2010 edition.NFPA 54, National Fuel Gas Code, 2012 edition.NFPA 55, Compressed Gases and Cryogenic Fluids Code, 2010 edition.NFPA 58, Liquefied Petroleum Gas Code, 2011 edition.NFPA 59, Utility LP-Gas Plant Code, 2012 edition.NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG), 2009 edition.NFPA 69, Standard on Explosion Prevention Systems, 2008 edition.NFPA 70®, National Electrical Code®, 2011 edition.NFPA 77, Recommended Practice on Static Electricity, 2007 edition.NFPA 85, Boiler and Combustion Systems Hazards Code, 2011 edition.NFPA 86, Standard for Ovens and Furnaces, 2011 edition.NFPA 87, Recommended Practice for Fluid Heaters, 2011 edition.NFPA 400, Hazardous Materials Code, 2010 edition.D.1.2 Other Publications.D.1.2.1 AGA Publications. American Gas Association, 400 N. Capitol Street, N.W., Washington, DC 20001.AGA XK0101, Purging Principles and Practices, 2001.

1Printed on 2/28/2012

Report on Proposals – June 2013 NFPA 56PSD.1.2.2 AIChE Publications. American Institute of Chemical Engineers, Center for Chemical Process Safety, ThreePark Avenue, New York, NY 10016-5991.Crowl, D. A., Understanding Explosions, 2003.Guidelines for Hazard Evaluation Procedures, 2nd edition, 1992.D.1.2.3 ASME Publications. American Society of Mechanical Engineers, Three Park Avenue, New York, NY10016-5990.ANSI/ASME B31.1, Power Piping, 2010.ANSI/ASME B31.3, Process Piping, 2010.D.1.2.4 ASTM Publications. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA19428-2959.ASTM E 2079, Standard Test Methods for Limiting Oxygen (Oxidant) Concentration for Gases and Vapors, 2007.D.1.2.5 U.S. Government Publications. U.S. Government Printing Office, Washington, DC 20402.Kuchta, J. M., Investigation of Fire and Explosion Accidents in the Chemical, Mining, and Fuel-Related Industries — AManual, in U.S. Bureau of Mines Bulletin 680, U.S. Department of the Interior, 1985.U.S. Department of Labor, Occupational Safety and Health Administration (OSHA), Safety and Health Topics,“Competent Persons,” http://www.osha.gov/SLTC/competentperson/index.html.Title 49, Code of Federal Regulations, Parts 100-185, Hazardous Material RegulationsTitle 49, Code of Federal Regulations, Parts 190-199, Pipeline Safety Regulations

D.2 Informational References.D.2.1 ASSE Publications. American Society of Safety Engineers, 1800 E. Oakton Street, Des Plaines, IL 60018.ANSI/ASSE Z690.1, Vocabulary for Risk Management, 2011.ANSI/ASSE Z690.2, Risk Management — Principles and Guidelines, 2011.ANSI/ASSE Z690.3, Risk Assessment Techniques, 2011.D.3 References for Extracts in Informational Sections.NFPA 2, Hydrogen Technologies Code, 2011 edition.NFPA 54, National Fuel Gas Code, 2012 edition.NFPA 55, Compressed Gases and Cryogenic Fluids Code, 2010 edition.NFPA 58, Liquefied Petroleum Gas Code, 2011 edition.NFPA 59, Utility LP-Gas Plant Code, 2012 edition.NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG), 2009 edition.NFPA 69, Standard on Explosion Prevention Systems, 2008 edition.

To conform to the NFPA Regulations Governing Committee Projects. The committee encouragescomments from the public to identify any sections or paragraphs that may have been extracted from other NFPAdocuments and which have not been identified with extract tags.Subsection 2.3.2 is updated in 56PS-15 (Log #10).ANSI designations on ASME standards are struck in accordance with 502-26 (Log #21).The extract tag related to NFPA 654 was struck in 56PS-16 (Log #11).NFPA 51 and NFPA 51A are added in accordance with 56PS-5 (Log #7).NFPA 52 is added in accordance with 56PS-11 (Log #1).NFPA 55 is added in accordance with56PS-6 (Log #4).NFPA 51 is currently undergoing revision and is expected to be published prior to the Report on Comments meeting.The task group on reference documents will be notified when the document has been issued. If the revisions to NFPA51 do not impact its reference in NFPA 56, the edition will be automatically updated by NFPA staff prior to issuance ofNFPA 56.NFPA 51B is in the same revision cycle as NFPA 56. The task group on reference documents will be notified whenproposals and comments to NFPA 51B are available to review. If the revisions to NFPA 51B do not impact itsreference in NFPA 56, the edition will be automatically updated by NFPA staff prior to issuance of NFPA 56.NFPA 52 is currently undergoing revision. The task group on reference documents will be notified when the NFPA 52Report on Comments is complete. If the revisions to NFPA 52 do not impact its reference in NFPA 56, the edition willbe automatically updated by NFPA staff prior to issuance of NFPA 56.NFPA 55 is currently undergoing revision and is expected to be published prior to the Report on Comments meeting.The task group on reference documents will be notified when the document has been issued. If the revisions to NFPA55 do not impact its reference in NFPA 56, the edition will be automatically updated by NFPA staff prior to issuance ofNFPA 56.NFPA 58 is in the same revision cycle as NFPA 56. The task group on reference documents will be notified when


Report on Proposals – June 2013 NFPA 56PSproposals and comments to NFPA 58 are available to review. If the revisions to NFPA 58 do not impact its reference inNFPA 56, the edition will be automatically updated by NFPA staff prior to issuance of NFPA 56.NFPA 59A has completed its revision cycle and is expected to be published prior to the Report on Comments meeting.The task group on reference documents will be notified when the document has been issued. If the revisions to NFPA59A do not impact its reference in NFPA 56, the edition will be automatically updated by NFPA staff prior to issuance ofNFPA 56.NFPA 69 is currently undergoing revision. The task group on reference documents will be notified when the NFPA 69Report on Comments is complete. If the revisions to NFPA 69 do not impact its reference in NFPA 56, the edition willbe automatically updated by NFPA staff prior to issuance of NFPA 56.NFPA 70 is in the same revision cycle as NFPA 56. The task group on reference documents will be notified whenproposals and comments to NFPA 70 are available to review. If the revisions to NFPA 70 do not impact its reference inNFPA 56, the edition will be automatically updated by NFPA staff prior to issuance of NFPA 56.ASME B31.12 is added in accordance with 56PS-26 (Log #21).Annex D is updated to be consistent with changes made in chapter 2.NFPA 1 is added to Annex D in accordance with 56PS-20 (Log #20).NFPA 400 is added to Annex D in accordance with 56PS-20 (Log #20). NFPA 400 is currently undergoing revision andis expected to be published prior to the Report on Comments meeting. The task group on reference documents will benotified when the document has been issued. If the revisions to NFPA 400 do not impact its reference in NFPA 56, theedition will be automatically updated by NFPA staff prior to issuance of NFPA 56.NFPA 77 is in the same revision cycle as NFPA 56. The task group on reference documents will be notified whenproposals and comments to NFPA 77 are available to review. If the revisions to NFPA 77 do not impact its reference inNFPA 56, the edition will be automatically updated by NFPA staff prior to issuance of NFPA 56.Title 49 CFR Parts 100-199 are added to Annex D in accordance with 56PS-10 (Log #6) and 55PS-53 (Log #CP5).


Report on Proposals – June 2013 NFPA 56PS_______________________________________________________________________________________________56PS-2 Log #3

_______________________________________________________________________________________________Richard A. Craig, Compressed Gas Association

1. Revise the title of the document as follows:Standard for Fire and Explosion Purging of Prevention During Gas Blowing Cleaning and Flammable Gas Piping

Systems2. Revise the following sections using the term “gas blowing” to replace the term “cleaning” throughout the document.

This standard shall apply to fire and explosion prevention during gas blowing cleaning and purgingactivities for new and existing flammable gas piping found in electric generating plants and in industrial, institutional, andcommercial applications.

This standard provides minimum safety requirements for the gas blowing cleaning and purging offlammable gas piping systems, including gas blowing cleaning new or existing piping systems, purging piping systemsinto service, and purging piping systems out of service.

Personnel in the affected area(s), as determined by the gas blowing cleaning or purgingprocedure, shall be informed of the hazards associated with the activity prior to the initiation of any such activity.

Cleaning Written gas blowing cleaning and purging procedures shall bedeveloped and implemented by a competent person.

The written procedure for each gas blowing cleaning and purging activity shall address, as a minimum, thefollowing items:

(1) Scope of work and site-specific purge procedure development(a) Gas blowing Cleaning and purging method

If the conditions during the purging or gas blowing cleaning activity deviate from those indicated inthe written procedure, resulting in a safety hazard, the purging or gas blowing cleaning activity shall be discontinuedaccording to the stand-down instructions.

A written safety validation shall be performed for gas blowing cleaning and purging procedures.Prior to initiation of a gas blowing cleaning or purging activity, the safety validation shall be approved by a

designated individual who is competent and knowledgeable in the procedure and hazards and who is authorized toprovide such approval.

The management-of-change procedures shall ensure that the following issues are addressed prior to anychange:

(1) The technical basis for the proposed change(2) The safety and health implications(3) Whether the change is permanent or temporary(4) Modifications to gas blowing cleaning and purging procedures

The written gas blowing cleaning and purging procedure, as required by Section 4.3, shall be updated toincorporate the change.

Gas blowing Cleaning and purging procedures shall be documented and available at the job site.The safety validation and the Gas blowing Cleaning and purging procedures shall be retained for at least 2 years

following completion of the activity.Personnel in the affected area(s), as determined by the gas blowing cleaning or purging

procedure, shall be informed of the hazards associated with the activity prior to the initiation of any such activity.Personnel not involved in gas blowing cleaning or purging activities shall be

evacuated from the affected area(s) as determined by the procedure.gas blowing cleaning Piping system segments that can be isolated for gas blowing cleaning prior to

completion of the entire piping system shall be permitted to be gas blowing cleaning, tested, and secured in a gas blownclean condition in accordance with Section 6.7.

Hangers, supports, or other means capable of restricting the movement of piping shallbe installed prior to initiating gas blowing cleaning or purging activities in accordance with the procedure.

Fluid media for testing or gas blowing cleaning shall not introduce a flammableatmosphere into or create a fire hazard in the piping system being tested or gas blowing cleaning.

Where utilities such as steam, water, or compressed air are used in quantities or durationthat can disrupt distribution or operations internal or external to the facility, gas blowing cleaning or purging activitiesshall be coordinated with the managing authority of the utility.

Access to all parts of the piping system during gas blowing cleaning or purging activities shall


Report on Proposals – June 2013 NFPA 56PSbe restricted in accordance with the procedure.

Prior to gas blowing cleaning or purging, piping systems shall be inspectedand pressure tested to determine that the materials, design, fabrication, and installation practices comply with therequirements of this standard and the intended application.

Such training shall include hazards of flammable gas, hazards of any compressed gas used for gas blowingcleaning or purging, safe handling practices of flammable gas and compressed gas as applicable, emergency responseprocedures and equipment, and company policy.

Gas Blowing cleaningGas blowing cleaning

Flammable gas shall not be used for internal gas blowing cleaning of piping.An alarm shall precede the start of gas blowing cleaning in accordance with the written cleaning procedure.

Air, inert gas, steam, and water shall be acceptable gas blowing cleaning media.Where electric power is used to power the equipment necessary to implement the pipe gas blowing cleaning, it

shall be connected in accordance with .Where fuel gas is used to power the equipment necessary to implement the pipe gas blowing cleaning, it shall be

piped and connected in accordance with NFPA 54 or NFPA 58, as applicable.Where fuel oil is used to power the equipment necessary to implement the pipe gas blowing cleaning, it shall be

piped and connected in accordance with NFPA 31.Temporary piping systems, including hose assemblies, used to

connect the gas blowing cleaning media supply source to the piping system shall be in accordance with ANSI/ASMEB31.1, paragraph 122.10.

Pigs shall be permitted to be used to gas blow clean piping systems.A pig shall be permitted to be used to accomplish gas blowing cleaning and purging into service simultaneously

in accordance with 6.5.2.1 through 6.5.2.4.Pig gas blowing cleaning using flammable gas as the propellant shall utilize a closed piping system.Where a pig is used to accomplish gas blowing cleaning and purging simultaneously, the pig shall be sized to

minimize unintended commingling of flammable gas and air.A pig shall be permitted to be used to gas blow clean a piping system that is filled with flammable gas where

the flammable gas in the piping system is being consumed by end-use equipment or flares and the residual flammablegas in the launcher or receiver is discharged in accordance with 8.3.2.

Where a target is used to indicate debris during the gas blowing cleaning process, it shall be designedand secured to withstand the velocity and pressure of the exiting media and debris without breaking or failing.

Where piping systems are gas blown cleaned instages during fabrication or field assembly, the gas blown clean piping shall be isolated and protected against infiltrationof contaminants.

The recommendations can be resolved by changes made to the written gas blowing cleaning and purgingprocedures prior to the activity being conducted. If the person(s) responsible for developing or implementing theprocedures disagrees with the recommendations of the safety validation, the facility owner/operator or a designatedrepresentative (such as a facility manager or, for facilities under construction, a construction manager) should evaluatetechnical documentation to resolve the disagreement. The designated representative should be a competent person asdefined in 3.3.2 and should have the authority to modify or reject the procedure or the recommendation.

Where physical, operational, or personnel changes are made to a plant or facility, the gas blowing cleaning andpurging procedures should be re-evaluated. Such changes can include, but are not limited to, physical changes to pipingsystem design, change to the gas blowing cleaning or purging media, changes in responsibility for personnel, changesin local conditions such as encroachment by new equipment or nearby development, or changes in the chemicalcomposition of the gas being purged.

This is not intended to exclude specialized gas blowing cleaning chemicals used in solution with water inaccordance with the manufacturer’s instructions by competent personnel.

Pigging using flammable gas as the propellant can be considered where the system has been designed toaccommodate the activity and it is beneficial to accomplish gas blowing cleaning and purging simultaneously. The pig isdesigned to fit tightly inside the pipe and will effectively push the air out of the piping system as the volume behind thepig is filled with gas. When the pig reaches the receiver, the pig is isolated within the receiver and the discharge valve isclosed to ensure that a minimal amount of flammable gas is released. While there can be some small amount of fuel gasreleased due to seepage around the pig, the result is generally a smaller release than traditional purging into service.The purge procedure should identify safe disposal of the residual gas. The use of flammable gas as the propellant alsoeliminates the hazards associated with the intermediate purging step using inert gas in a traditional purge into service.


Report on Proposals – June 2013 NFPA 56PSSee Figure A.6.5.2 for an example of a pig launcher/receiver arrangement.

The use of a pig to accomplish gas blowing cleaning and purging into service simultaneously should becarefully reviewed by competent persons who are knowledgeable and experienced in the use of pigs in flammable gassystems. The pig should be sized to fit tightly in the piping system. Factors to be considered in pig selection include, butare not limited to, pipeline size, wall thickness, minimum bend radius, length of piping to be pigged, propelling media,flow rate/velocity, side connections, and valve type.

Pigging where the piping is already filled with flammable gas is often referred to as “on-line” or “in-service”pigging. In-service pigging is not limited to gas blowing cleaning processes, and 6.5.2.3 is not intended to prohibit orprevent other pigging processes. Other in-service pigging

The sample purge procedure in this annex is reprinted here with permission from National Grid and is intendedonly to provide an example showing the implementation of the gas blowing cleaning and purging procedures defined inSection 4.3. It should not be used as a procedure applicable to any specific site or facility.

3. Add a new definition to Section 3.3 as follows:. A process where gas is forced through the piping at a velocity required to remove debris.

As the term “cleaning” is read in this document, factories such as pharmaceutical and semiconductorfacilities will consider how to apply their standard method of cleaning to the requirements. Cleaning procedures utilizedin these industries have involved techniques like caustic washing or acid washing or solvent rinsing or hot Deionized(DI) water rinsing or hot gas drying (and/or combinations thereof), along with other specialized cleaning media that maybe utilized.

The cleaning techniques utilized by these companies is not in sync with section 6.2 Acceptable Fluid Media that states:Air, inert gas, steam, and water shall be acceptable cleaning media, nor with section 6.5 Pig Cleaning, that describeshow to propel and catch a pig used to clean the inside of the piping system. Both of these sections in the documentappear to indicate gas blowing as the cleaning technique to be used to remove foreign particles from within the pipingsystem..

By replacing the word cleaning with gas blowing, and/or the word clean with gas blown, throughout this document, themethod of pipe cleaning that is applied to the system piping is clarified as a gas blowing technique.

The committee rejected the proposal because gas blowing is industry jargon that refers to avery specific procedure. The scope of the standard should not be limited to gas blowing. The addition of the definitionof cleaning media in 56PS-19 (Log #19) addresses the submitter's concern that the cleaning media would be limited togases and water-based liquids.

_______________________________________________________________________________________________56PS-3 Log #CP3


Revise text to read as follows:1.1.1.1.1 For other than undiluted liquefied petroleum gas (LP-Gas) systems, the point of delivery shall be the outlet ofthe service meter assembly or the outlet of the service regulator or service shutoff valve where no meter is provided.[54, 1.1.1.1(A)] is the outlet of the customer meter or at the connection to a customer’s piping, whichever is fartherdownstream, or if there is no meter at the connection to customer piping.1.1.1.1.2 For undiluted LP-Gas, the point of delivery shall be considered to be is the outlet of the final pressureregulator, exclusive of line gas regulators where no meter is installed. Where a meter is installed, the point of deliveryshall be the outlet of the meter.[54, 1.1.1.1(A)], in the system.3.3.7* Line Gas Regulator. A pressure regulator placed in a gas line between the service regulator and the applianceregulator.A.3.3.7 Line Gas Regulator. The service regulator in an undiluted LP-Gas system can include any one of the following:(1) The second stage regulator or integral two-stage regulator(2) A2 psi (14 kPa) service regulator or integral 2 psi (14 kPa) service regulator

The committee extracted the text from NFPA 54, National Fuel Gas Code.



_______________________________________________________________________________________________Michael C. Polagye, FM Global

Revise text to read as follows:This standard shall not apply to the following items:

(1)*Piping systems covered by NFPA 2(2)*Piping systems covered by NFPA 54(3)*Piping systems covered by NFPA 58(4)*LP-Gas (including refrigerated storage) at utility gas plants NFPA 59(5)*LNG facilities covered by NFPA 59A(6) LP-Gas used with oxygen for cutting, welding, or other hot work(7)*Vehicle fuel dispensers

(8) Commissioning and maintenance of appliances or equipment(9) Vent lines from pressure relief valves(10) Systems regulated by U.S. Department of Transportation (DOT) 49 CFR 191 and 192

Fragmenting the purging and cleaning recommendations/requirements for natural gas and LPG pipingamongst different standards does not benefit the users of this standard nor the owners of natural gas and LPG pipingsystems. This fragmenting is due solely to the committee structure within NFPA that supports these various documents.An inter-committee task group should be established, with a TCC if necessary, to consolidate the purging and cleaningguidelines in NFPA 54, 58, and 59A into NFPA 56.

The committee disagrees that separating the purging and cleaning requirements among thesovereign documents is burdensome to the end user.




Add new subsections to1.1.2 and add new annex note A1.1.2(XX) in accordance with the following:This standard shall not apply to the following items:

(1)*Piping systems covered by NFPA 2(2)*Piping systems covered by NFPA 54(3)*Piping systems covered by NFPA 58(4)*LP-Gas (including refrigerated storage) at utility gas plants NFPA 59(5)*LNG facilities covered by NFPA 59A(6) LP-Gas used with oxygen for cutting, welding, or other hot work(7)*Vehicle fuel dispensers(8) Commissioning and maintenance of appliances or equipment(9) Vent lines from pressure relief valves(10) Systems regulated by U.S. Department of Transportation (DOT) 49 CFR 191 and 192(XX) *Piping systems covered by NFPA 51(YY) *Piping systems covered by NFPA 51A

The scope and application of NFPA 51 is included here for the convenience of the user:

This standard applies to the following:(1) Design and installation of oxygen–fuel gas welding and cutting systems and allied processes , except for

systems meeting the criteria in 1.1.5(2) Utilization of gaseous fuels generated from flammable liquids under pressure where such fuels are used with

oxygen(3) Storage on the site of a welding and cutting system installation of the following:(a) Gases to be used with such systems where more than one cylinder each of oxygen and fuel gas are stored in any

single storage area [includes storage of more than one cylinder each in any single storage area even though all suchstored cylinders may be intended for use in systems of the. [ :1.1]

Unless specifically indicated otherwise, the term shall be considered to includein this standard.[ :1.1.2]

Where only a portion of a fuel gas system is to be used for welding, cutting, or allied processes, only that portionof the system need comply with this standard. [ :1.1.3]

Where only a portion of an oxygen system is to be used with fuel gas for welding, cutting, or allied processes,only that portion of the system need comply with this standard. [ :1.1.4]

This standard shall not apply to the following:(1)*Systems consisting of a single cylinder not exceeding 3.4 m3 (120 ft3) of oxygen and a single cylinder not

exceeding 3.4 m3 (120 ft3) of fuel gas used for welding and cutting (2) Systems in which fuel gases are not to be usedwith oxygen, as described in NFPA 54, , and NFPA 58,

(3) The manufacture of gases and the filling of cylinders(4) Storage of empty cylinders(5) Compressed air–fuel gas systems[ :1.1.5]

The scope and application of NFPA 51A is included here for the convenience of the user:This standard shall apply to plants that are engaged in the generation and compression of acetylene and in

the charging of acetylene cylinders, either as their sole operation or in conjunction with facilities for charging othercompressed gas cylinders. [ :1.1]

This standard shall not apply to plants that only produce and compress acetylene for chemicaloperations or to plants that only produce and compress acetylene below a gauge pressure of 15 psi (103 kPa).

[ :1.3]NFPA 51

and NFPA 51A covers compressed gases andcryogenic fluids, including hydrogen and other flammable gases, from the bulk supply system to the source valve, apoint of demarcation between the supply system and the end user. Purging and cleaning of gas piping for compressedgases within the context of NFPA 51 and 51A is within the scope of the IMG TC. Gas blowing to remove debris after


Report on Proposals – June 2013 NFPA 56PSconstruction of a piping system, and the purging of small diameter piping systems used in the types of applicationencountered within systems regulated by NFPA 51 and 51A should not be considered to be analogous to the systemsthat are intended to be regulated by NFPA 56.

Revise text to read as follows:This standard shall not apply to the following items:

(1)*Piping systems covered by NFPA 2, Hydrogen Technologies Code(2) *Piping systems covered by NFPA 51, Standard for the Design and Installation of Oxygen-Fuel Gas Systems for

Welding, Cutting, and Allied Processes(3) *Piping systems covered by NFPA 51A, Standard for Acetylene Cylinder Charging Plants

(2)(4)*Piping systems covered by NFPA 54, National Fuel Gas Code(3)(5)*Piping systems covered by NFPA 58, Liquefied Petroleum Gas Code(4)(6)*LP-Gas (including refrigerated storage) at utility gas plants NFPA 59, Liquefied Petroleum Gas at Utility

Gas Plants(5)(7)*LNG facilities covered by NFPA 59A, Standard for the Production, Storage, and Handling of Liquefied Natural

Gas (LNG)(6) LP-Gas used with oxygen for cutting, welding, or other hot work(7)(8)*Vehicle fuel dispensers(8)(9) Commissioning and maintenance of appliances or equipment(9)(10) Vent lines from pressure relief valves(10)(11) Systems regulated by U.S. Department of Transportation (DOT) 49 CFR 191 and 192

(Accept annex material related to scopes of additional standards.)The committee struck (6) because oxygen-LP Gas systems are covered by NFPA 51. The

committee added titles to all standards listed in 1.1.2. The committee renumbered the additions to maintain numericalorder of NFPA standards.




Modify section 1.1.2 to add section (3) and annex note in accordance with the following:

This standard shall not apply to the following items:(1)*Piping systems covered by NFPA 2(2)*Piping systems covered by NFPA 54

(3) *Piping systems covered by NFPA 55(34)*Piping systems covered by NFPA 58(45)*LP-Gas (including refrigerated storage) at utility gas plants NFPA 59(56)*LNG facilities covered by NFPA 59A(67) LP-Gas used with oxygen for cutting, welding, or other hot work(78)*Vehicle fuel dispensers(89) Commissioning and maintenance of appliances or equipment(910) Vent lines from pressure relief valves(1011)* Systems regulated by U.S. Department of Transportation (DOT) 49 CFR 191 and 192

The scope of NFPA 55 is included here for the convenience of the user:

This code shall apply to the installation, storage, use, and handling of compressed gases andcryogenic fluids in portable and stationary containers, cylinders, equipment, and tanks in all occupancies.[ :1.1]

This code shall not apply to the following:Off-site transportation of materials covered by this code.

(2) Storage, use, and handling of radioactive gases in accordance with NFPA 801,.

Use and handling of medical compressed gases at health care facilities in accordance with NFPA 99,.

(4) Systems consisting of cylinders of oxygen and cylinders of fuel gas used for welding and cutting in accordancewith NFPA 51,

.(5)* Flammable gases used as a vehicle fuel when stored on a vehicle.(6)* Storage, use, and handling of liquefied and nonliquefied compressed gases in laboratory work areas inaccordance with NFPA 45, .(7) Storage, use, and handling of liquefied petroleum gases in accordance with NFPA 58,

.(8) Storage, use, and handling of compressed gases within closed-cycle refrigeration systems complying with themechanical code.(9) Liquefied natural gas (LNG) storage at utility plants under NFPA 59A,

.(10) Compressed natural gas (CNG), liquefied natural gas (LNG), utilized as a vehicle fuel in accordance with NFPA52, .(11)* Compressed hydrogen gas (GH2), or liquefied hydrogen gas (LH2) generated, installed, stored, piped, used orhandled in accordance with NFPA 2, Hydrogen Technologies Code when there are no specific or applicablerequirements in NFPA 55.(12) Nonflammable mixtures of ethylene oxide with other chemicals.(13) Ethylene oxide in chambers 10 scf (0.283 Nm3) or less in volume or for containers holding 7.05 oz (200 g) ofethylene oxide or less. [ :1.1.2]

A.1.1.2(1) For regulations on the transportation of gases, see 49 CFR 100–185 (Transportation) and Transportation ofDangerous Goods Regulations. [ :A.1.1.2(1)]

A.1.1.2(3) Bulk compressed gas and cryogenic fluid system installations are intended to be covered by therequirements of this code. Instrumentation and alarms that are attendant to the system and designed to interface with


Report on Proposals – June 2013 NFPA 56PSthe application in a health care facility are to be retained within the purview of NFPA 99, Standard for Health CareFacilities. [ :A.1.1.2(3)]

A.1.1.2(5) For information, see NFPA 52, Vehicular Gaseous Fuel Systems Code, or NFPA 58, Liquefied PetroleumGas Code. [ :A.1.1.2(5)]

A.1.1.2(6) The storage and use of compressed gases and cryogenic fluids outside the boundaries of laboratory workareas is covered by this code. [ :A.1.1.2(6)]

A.1.1.2(11) NFPA 55 is used as the source document for the fundamental requirements for compressed hydrogen gas(GH2), or liquefied hydrogen gas (LH2) system installations.

Correlation between NFPA 55 and NFPA 2 is the responsibility of the two technical committees involved. Theinstallation requirements for bulk GH2 or LH2 are viewed as fundamental provisions. Use specific requirements fordesignated applications such as vehicular fueling are not resident in NFPA 55 and are under the purview of the NFPA 2Technical Committee.

Where there are specific provisions or controls included in NFPA 55 the specific controls of NFPA 55 will governexcept that modifications made to provisions that have been extracted can be followed when the modifications havebeen made within NFPA’s extract procedure as indicated in the Manual of Style. [ :A.1.1.2(11)]

Not excluding NFPA 55, from NFPA 56 results inthe inclusion of a broad number of flammable as well as gases that are toxic, highly toxic, unstable reactive, pyrophoricor corrosive within the scope of this new document. The gases are now included in the scope of the document includethose that have health hazard properties as well as the physical hazard of flammability. For example, gases used insemiconductor manufacturing such as arsine, phosphine, diborane and mixtures of these gases in either a flammable ornon-flammable background providing that the end mixture is flammable. Neither flammable nor pyrophoric gases aredefined in NFPA 56 raising a question as to whether it was intended to regulate pyrophoric gases within the context ofthis new standard.

The majority of flammable gases regulated by NFPA 55 are not used as fuel gases within the accepted andconventional use of the term per se and the construction of piping systems for these gases is not typical of those usedfor gases used in power transmission and similar applications. For bulk gas systems that are within the scope of NFPA55 the standard covers both compressed gases and cryogenic fluids, including hydrogen and other flammable gases,from the bulk supply system to the , a defined point of demarcation between the supply system and thepoint at which the gas enters the end user’s piping system. Purging and cleaning of gas piping for compressed gasesother than those regulated by NFPA 54, 58 and 59A is within the scope of the IMG TC. Use specific requirements areregulated by use or occupancy specific standards, for example, NFPA 99 for Health Care, NFPA 853 for installation ofStationary Fuel Cell Power Systems, NFPA 318 for Semiconductor Manufacturing Facilities or NFPA 45 for Laboratoryuse, etc.

NFPA 55 is the source document for the fundamental provisions addressing the use of hydrogen and they have beenextracted into NFPA 2 which has been specifically exempted from NFPA 56 and included in the committee scopestatement. While NFPA 2 is properly exempted NFPA 55 is not. The scope of the Industrial and Medical GasesTechnical Committee is as follows (underlining for emphasis):

As currently drafted NFPA 55 applies to all occupancies, and NFPA 56 applies to operations within the scope of theNFPA 55 document including compressed gas filling plants where cylinder gases are filled or packaged. NFPA 56 hasbeen extended to include piping systems used for mixtures of flammable gases with those having other propertiesincluding those with other physical or health hazards. In addition, it could be applied to the loading and unloading offlammable gases in transportation to include the transfer piping systems that are used to serve mobile equipment. Theloading and unloading of bulk supplies of flammable gases is regulated by the US Department of Transportation andeven the requirements contained in NFPA 55 are minimal and focused primarily on location or siting of transportvehicles engaged in the transfer process.

NFPA 55 has recently integrated two use specific standards into the document including NFPA 560 specific to the useof ethylene oxide when used for gas sterilization, and NFPA 51A for the use in acetylene charging plants anddischarging stations when mobile systems are used as the source of bulk acetylene in cylinder charging operations.

The scope of NFPA 56 is as follows:


Report on Proposals – June 2013 NFPA 56PS

One could possibly interpret that the bulk gas supply systems regulated by NFPA 55 are located upstream of the “pointof delivery” (being the point of transfer between the bulk gas supplier and the user system), but unresolved is what is thepoint of delivery for small diameter piping system such as those commonly found in use for individual cylinders orgroups of cylinders when they are being filled in filling plants, or when these containers are used as a source with thegas piped to a piece of equipment or process in typical industrial applications.

Excepting piping systems regulated by NFPA 55 including those associated both bulk and non-bulk supplies will serveto return the attention of NFPA 56 to systems which it is believed were the focus of the US Chemical Safety Boardrather than to impose a new set of requirements on the use of flammable gases across a spectrum of industries inapplications that likely were never intended to be regulated under this new document. It also serves to eliminatepotential conflicts in application of the committee scope statements by excluding gases that are toxic, highly toxic,corrosive, and pyrophoric or those with other health or physical hazards, such as instability thereby solving potentialproblems in the document related to the discharge of gases.

Add text to read as follows:(3) *Piping systems covered by NFPA 55Also add recommended related annex material (A.1.1.2(3).

The committee accepted the new (3) and related annex material. The committee did notaccept the modification to delete "or equipment" in (8).

_______________________________________________________________________________________________56PS-7 Log #5


Modify section 1.1.2(6) with the following:This standard shall not apply to the following items:

(1)*Piping systems covered by NFPA 2(2)*Piping systems covered by NFPA 54(3)*Piping systems covered by NFPA 58(4)*LP -Gas (including refrigerated storage) at utility gas plants NFPA 59(5)*LNG facilities covered by NFPA 59A(6) LP Fuel -Gas used with oxygen for cutting, welding, or other hot work(7)*Vehicle fuel dispensers(8) Commissioning and maintenance of appliances or equipment(9) Vent lines from pressure relief valves(10) Systems regulated by U.S. Department of Transportation (DOT) 49 CFR 191 and 192

There are other fuel gases besides LP that are used in cutting and welding and hot work operations.The document as written requires all non LP fuel gases, such as acetylene, to follow this procedure. It has not beendemonstrated that these other fuel gases have been problematic in the typical cutting, welding, and hot work operations.The alternative may be to exempt gases covered by NFPA 51B.

The committee deleted (6) in 56PS-5 (Log #7).



_______________________________________________________________________________________________Dennis M. Kovach, American Electric Power/Edison Electric Institute

Add text to read as follows:(8) Commissioning and maintenance of appliances or equipment and related accessories covered by NFPA 54.

While the intent of this section as originally written may be understood by the reader, there has beensome concern expressed that equipment is not defined in this standard. The current definition of equipment in NFPA 54("Devices other than appliances") is subject to a very wide range of interpretations. This may result in a device beingdesignated "equipment- to avoid addressing the provisions set forth in NFPA 56 when, in fact, such provisions arenecessary to safely commission and maintain said device. Specifically, prebuilt "equipment skids" containing devicessuch as fuel gas heaters, fuel gas separators/scrubbers, regulating valve stations, as well as interconnecting piping areroutinely purchased during the construction of a natural gas-fired power plant. It should be clear such "equipment" fallswithin the scope of NFPA 56 if that is indeed the committee's intent.

Revise text to read as follows:A.1.1.1.1 The piping system includes segments located between pieces of equipment, such as gas conditioning orcompressing equipment. This document does not cover the commissioning or maintaining of that equipment. but doesHowever, the standard can cover be applied to the commissioning or maintaining of those piping segments andequipment as a system when and if the complete system is purged into or out of service as a unit. The equipmentmanufacturer's written instructions should be included as part of the written purge procedure. as it relates to the flow ordisplacement of flammable gas.

The committee addressed the submitter's concern through modification to the annex materialregarding consideration of equipment installed in the flammable gas flow path that does not consume or utilize gas, butmay contain large volumes of gas that must be safely purged out.

_______________________________________________________________________________________________56PS-9 Log #44


Add text to read as follows:(9) Vent lines from pressure relief valves except when such vent lines are also used for cleaning or purging of

flammable gas piping systems.At our existing power plants, we have found cases where vent stacks serve relief valves as well as

vents designed for cleaning or purging activities. In other cases, consideration is being given to tying into existing reliefvalve vent stacks with new piping being added to facilitate the rules for purging found in NFPA 56. Because these linesare being used for routine purging activities, they should not be wholly excluded from the provisions of this standard.

Revise text to read as follows:(9) Vent lines from pressure relief valves or devices unless such vent lines are also used for purging of flammable gas

piping systems.The committee removed the reference to cleaning because use of the relief valve or device

during cleaning could lead to debris impeding the action of the valve or device.




Modify section 1.1.2(10) and add annex note A.1.1.2(10) in accordance with the following:

This standard shall not applyto the following items:

(1)*Piping systems covered by NFPA 2(2)*Piping systems covered by NFPA 54(3)*Piping systems covered by NFPA 58(4)*LP-Gas (including refrigerated storage) at utility gas plants NFPA 59(5)*LNG facilities covered by NFPA 59A(6) LP-Gas used with oxygen for cutting, welding, or other hot work(7)*Vehicle fuel dispensers(8) Commissioning and maintenance of appliances or equipment(9) Vent lines from pressure relief valves(10)* Systems regulated by U.S. Department of Transportation (DOT) in 49 CFR Parts 100 through 199 191 and 192

DOT regulations in 49 CFR Parts 100 through 199 govern the transport of gases in pipelines as well asgases delivered by mobile vehicles or rail systems when the materials are in the public transportationsystem. The offsite transportation of compressed gases or cryogenic fluids including pipeline transmissionsystems and loading and unloading functions as regulated by 49 CFR is not within the scope of NFPA 56.

In addition to transmission piping systems included in Parts 191 and 192, other processes are coveredunderDOT jurisdiction when hazardous materials are offered for transportation. The prime example includes the loading andunloading of a cargo tank commercial motor vehicle where piping systems are utilized to allow the loading/unloadingfunctions to occur.

The addition of an annex note will serve to minimize the misapplication of the Standard by providing statements ofintent to not include gases that are regulated by 49 CFR from falling under the scope of NFPA 56.

Revise text to read as follows:(10)* Systems regulated by U.S. Department of Transportation (DOT) 49 CFR Parts 100 through 199 191 and 192

DOT regulations in 49 CFR Parts 100 through 199 govern the transport of gases in commerce bypipelines, motor vehicles or rail systems. The transportation of compressed gases or cryogenic fluids, including offsitepipeline transmission systems and loading and unloading functions as regulated by 49 CFR, is not within the scope ofNFPA 56.

The committee made editorial changes.



_______________________________________________________________________________________________James Ranfone, American Gas Association

Add new text to read as follows:(11) CNG fuel-dispensing facilities covered by NFPA 52.

Current section 1.1.2(7) states "Vehicle fuel dispensers" which could be interpreted as only applying toonly the hoses and equipment used in the last stage of fuel dispensing into vehicles. The Annex A note to this sectionalso states fuel dispensers coved by various NFPA standards which does not clarify what is meant by "fuel dispensers."The new (11) would clearly state that for CNG facilities, the entire system including compression , storage, dispensing,and associated piping, are not subject to NFPA 56.

Add text to read as follows:(11) Fuel-dispensing facilities covered by NFPA 52.

The committee made the exclusion more generic because NFPA 52, Vehicular Gaseous FuelSystems Code, covers more than just CNG.

_______________________________________________________________________________________________56PS-12 Log #42

_______________________________________________________________________________________________Kenny Wheat, Gas Processors Association

Revise text to read as follows:1.1.2 Nonapplication of Standard. This standard shall not apply to the following items:(11) Midstream Facilities and Equipment covered by API 521 (ISO 23251).

GPA and its member companies would like to request that gas processing facilities and other facilitieswhose purpose is to but not limited to treat, separate, dehydrate, and recover natural gas liquids, be included in 1.1.2Nonapplication of Standard section of this proposed standard. Gas processing facilities and the like are currentlycovered under API Standard 521 - Pressure-relieving and Depressuring Systems, which is the identical nationaladoption of ISO 23251, Petroleum and natural gas industries - Pressure-relieving and depresssuring systems. API 521specifies requirements and gives guidelines for examining the principal causes of overpressure; determining individualrelieving rates; and selecting and designing disposal systems, including such component parts as piping, vessels, flares,and vent stacks. API 521 covers the same topics and requirements which are identified by the proposed standardNFPA 56. However, API 521 identifies these topics in a much more specific manner as they apply to refining facilities,processing facilities, petrochemical facilities, gas plants, liquefied natural gas (LNG) facilities and oil & gas productionfacilities. In fact, before going to publication, it may in NFPA's interest to reference API 521 in its referenced documentssection of the proposed standard.

The committee rejects the proposal because API 521 addresses depressuring and pressurerelieving systems, which are already excluded in (9). In addition, API 521 is a guide, and may not be written inmandatory, enforceable language.




Modify section 1.2 in accordance with the following:This standard provides minimum safety requirements for gas blowing the cleaning and the purging of

flammable gas piping systems, including the gas blowing of cleaning new or existing piping systems, and thesubsequent purging of piping systems into or out of service from the point of delivery to the equipment isolation valve.,and purging piping systems out of service.

NFPA 56 describes actions intended to remove foreign material from newly installed piping systems,or after repair of existing installations. The standard covers the piping system from the point of delivery as defined forthe various systems to the equipment isolation valve thereby exempting the appliance or equipment involved in the enduse of the gas.

The term “cleaning” is not a defined term, and is subject to interpretation by those installing various gas deliverysystems. In medical and semiconductor manufacturing applications the act of “cleaning” can involve different and moredetailed procedures that are designed to remove trace quantities of contaminants including particulate matter with adiameter greater than 1/10th of a micron (0.000004 inches).

On the other hand “gas blowing” is conventionally used as a means to blow debris from construction out of a typicalfuel transmission system where high velocity air, or gas is discharged through the piping system at velocities andvolumes sufficient to entrain the debris into the gas stream and to transport it out of the piping system. The terminologyused within the context of this standard is important in order that users can quickly understand its intent and thatapplication of the document is within the use intended. Companion definitions have been submitted along withproposals to address and further clarify the use of the term “cleaning” throughout the document.

This extreme level of cleaning is not within the document scope or direction. The revised text helps to identify theobjective, but leaves it to the user to develop the applicable procedure for their piping system.

Revise text to read as follows:This standard provides minimum safety requirements for the cleaning and purging of flammable gas

piping systems, including cleaning new or existing piping systems, and purging piping systems into or out of servicefrom the point of delivery to the equipment isolation valve., and purging piping systems out of service.

The committee did not accept changing "cleaning" to "gas blowing" in 56PS-2 (Log #3). Thecommittee made further editorial changes for clarity.




Modify sections 1.3 in accordance with the following:The provisions of this standard reflect a consensus of what is necessary to provide an acceptable

degree of protection from the hazards addressed in this standard at the time the standard was issued.Unless otherwise specified, the provisions of this standard shall not apply to facilities, equipment, structures, or

installations that existed or were approved for construction or installation prior to the effective date of the standard.Where specified, the provisions of this standard shall be retroactive.

In those cases where the authority having jurisdiction determines that the existing situation presents anunacceptable degree of risk, the authority having jurisdiction shall be permitted to apply retroactively any portions of thiscode deemed appropriate.

The retroactive requirements of this standard shall be permitted to be modified if their application clearly wouldbe impractical in the judgment of the authority having jurisdiction and only where it is clearly evident that a reasonabledegree of safety is provided.

The broadening of scope of this document to include all flammable gases has a far reaching effect onusers of all flammable gases in all occupancies with uses ranging from those involving the use of fuel gas from thepublic supply to laboratory, industrial, medical and other uses potentially not anticipated when the document wasdrafted. The controls required transcend those that may be applicable to the commissioning and installation of fuel gassystems which are designed primarily to address the use of natural gas and fuel gases for power generation into theworld of general industrial application. Gases that are highly toxic or which have other health hazard properties inaddition to being flammable are required to be discharged to a “safe” (unenforceable term) outdoor location with the solecontrol being that of providing LFL detectors or monitorsand disregarding the health hazard properties of the gas involved.

The standard as now configured excepts fuel gas systems regulated by NFPA 2, 54, 58 and 59, but now includessystems regulated by NFPA 55 which includes the universe of flammable gases, and in doing so it imposesrequirements which are questionable for small diameter piping systems to gases which have properties other than justthat of flammability including those which are toxic, highly toxic, pyrophoric, corrosive and those that are of an unstablereactive nature. The standard is designed to be applied to all systems retroactively without consideration to the type ofsystem or the occupancy in which it is found. If retroactivity in the use of such a standard is deemed to be necessary forthe protection of the public and the employees in industry and commercial applications, then those portions of thestandard that are designed to address the transmission offuel gas in power plants and similar applications could be written in a way for retroactive application.

The scope of the standard is questionable to the degree that it superimposes itself into the regulatory scheme underthe purview of NFPA 55, . Retroactivity within the context of NFPA55 follows the language suggested by NFPA’s as published in A.1.6.1.5 of that publication. Theproposal submitted correlates the requirements of Section 1.3 with that used by the thereby eliminatinga potential conflict between NFPA 55 and 56. The Standard imposes itself on industrial gas filling and manufacturingfacilities including those engaged in specialty gas manufacturing and mixing where manifolds are routinely filled andemptied as containers are handled in filling and discharging processes. The exemption of the NFPA 2 HydrogenTechnologies Code from NFPA 56 applies to hydrogen when found in a concentration of 95% or more, but hydrogen inconcentrations less than 95% are included within the context of the standard. Systems containing hydrogen in lesser butflammable concentrations currently regulated by NFPA 55 are now included within the context of NFPA 56.

The retroactive application of this standard to applications which range across the spectrum of any and all diameters ofpiping systems to gases, that have a flammability regardless of subsidiary hazards including those of toxicity, corrosivity,instability, and other physical and/or health hazard properties is inappropriate given the historical use of these materialsby general industry. Prescribing retroactivity requirements of the standard in concert with those adopted by NFPA 55,NFPA 2 and other documents based on the recommendations of the Manual of Style will address new construction andinstallations. The addition of proposed Section 1.3.2 gives the AHJ the authority to impose retroactive requirements ifdeemed to be appropriate based on a judgment of risk.

The provisions proposed are those created by NFPA and recommended for use by committees in the codes andstandards development process. Accepting this proposal represents an acceptable approach that allows code users toimplement the use of the standard as new systems are installed or where the AHJ determines that the risk to thecommunity is best served by retroactive application.



The committee rejected the proposal because the requirement for developing andimplementing written cleaning and purging procedures should be retroactive for existing installations. The committeerecognizes that it is not practical to apply the construction requirement in 4.1 retroactively, and developed 56PS-28 (Log#CP2) to remove any implication of retroactivity of the construction standards.

_______________________________________________________________________________________________56PS-15 Log #10


Modify section 2.3.2 in accordance with the following:U.S. Government Printing Office,Washington, DC 20402.

Title 29, Code of Federal Regulations, Part 1926, “Safety and Health Regulations for Construction,” Definitions.Title 49, Code of Federal Regulations, Part 191, “Transportation of Natural and Other Gas by Pipeline: Annual Reports,

Incident Reports, and Safety-Related Condition Reports,” and Part 192, “Transportation of Natural and Other Gas byPipeline: Minimum Federal Safety Standards.”

49 CFR 191 and 192 requirements have been exempted from scope of NFPA 56 [refer to 1.1.2(10)]and so are not part of the document. The implication is that 49 CFR requirements are enforceable through the use ofNFPA 56.

Listing these references brings PHMSA requirements into a code that will be enforced by a local code official.Compliance with PHMSA requirements requires a consistent approach based on the interpretation and application ofthese regulations. Compliance with interpretations issued by a local code official is expected to introduceinconsistencies in the application of regulations that are not anticipated by either the code user or the Federal regulatorybody.

Deleting the reference to 49 CFR from Section 2.3.2 will remove the conflict from the document.

Revise text to read as follows:U.S. Government Printing Office,Washington, DC 20402.

Title 29, Code of Federal Regulations, Part 1926, “Safety and Health Regulations for Construction,” Definitions.Title 49, Code of Federal Regulations, Parts 100-185, Hazardous Material Regulations

Title 49, Code of Federal Regulations, Parts 190-199, Pipeline Safety RegulationsPart 191, “Transportation of Naturaland Other Gas by Pipeline: Annual Reports, Incident Reports, and Safety-Related Condition Reports,” and Part 192,“Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards.”

The committee updated the references based on changes made in 56PS-10 (Log #6).

_______________________________________________________________________________________________56PS-16 Log #11


Modify section 2.4 in accordance with the following:

NFPA 54, 2012 edition.NFPA 55, 2010 edition.NFPA 654,

2006 edition.NFPA 654 is a standard for the prevention of fire and dust explosions from the manufacturing

process for the handling of combustible particulate solids. Management of change for gas blowing and purgingoperations should be under the purview of the GPS Committee and not tied to the use of NFPA 654 as a sourcedocument. The use of the extract text has served its purpose for the initial development of the requirements.

A separate proposal has been issued to eliminate the NFPA 654 extract tag in section 4.5.




Add new section definition as follows:3.3.XX . Any device that utilizes a fuel to produce light, heat, power, refrigeration, or air conditioning.

[ :2012]The term “appliance” is used within the body of the standard. A definition is needed to provide

guidance in terms of what to include or exclude. For example, in section 1.1.2 (8), appliances are to be excluded.Lacking a definition, just what is to be excluded is not known. The definition of appliance as found in NFPA 54 has beenused as source of the term throughout the model codes. The use of the NFPA 54 definition will bring consistency to itsuse in this application.

Revise text to read as follows:(8) Commissioning and maintenance of appliances or equipment

The committee could not resolve the definition of appliance from NFPA 54 with the context ofNFPA 56. Therefore, the committee instead deleted the word appliances from the exclusion statement. The committeeaddressed the use of appliance in extracted text in 56PS-3 (Log #CP3).

_______________________________________________________________________________________________56PS-18 Log #16


Add new definition as follows:3.3.XX* To make a piping system free from foreign matter or other unwanted contamination by the act of

gas blowing.

As the term is read in this document, operations such as pharmaceutical manufacturers andsemiconductor facilities will consider how the requirements of NFPA 56 will apply to their standard method of cleaning.Cleaning procedures utilized in these industries as well as those of the chemical manufacturers have developedcleaning techniques including but not limited to caustic washing, acid washing, solvent rinsing, hot Deionized (DI) waterrinsing or hot gas drying (and/or combinations thereof), along with other specialized cleaning media including flammableliquids or other solvents that may be utilized.

The cleaning techniques utilized by these companies is not in sync with section 6.2 Acceptable Fluid Media that states:nor with section 6.5 Pig Cleaning, that describes

how to propel and catch a pig used to clean the inside of the piping system. The cleaning procedures described in thisdocument are focused on gas blowing as the cleaning technique to remove foreign particles from within the pipingsystem. The procedure of “gas blowing” was identified by the CSB that caused the event at Kleen Energy, and it is thistechnique that NFPA properly desires to control.

Adding a definition for “cleaning” will serve to properly identify the process that is to be controlled and it will eliminatethe confusion caused by mixing the use of the term throughout industry that has established practices for cleaningpurposes other than gas blowing which is the term used by most in the power transmission industry. In addition, itserves to differentiate the focus of the document from process operations where non-flammable gases are used andwhereby piping systems are cleaned and dried before being put into service. The health care providers, gasmanufacturers, beverage producers and many other industries routinely clean piping systems where “gas blowing” is nota consideration.

The committee disagrees that a definition for "cleaning" is needed in the standard. Thecommittee refers to the Merriam Webster dictionary definition, "to rid of dirt, impurities, or extraneous matter," todescribe the context of cleaning in the standard.




Add new section definition and Annex note as followsL=:3.3.XX Liquids or gases used to clean piping systems.A.3.3.XX Cleaning media that incorporate chemical washing techniques include the use of chemical substances

(usually liquid) capable of dissolving or dispersing a foreign substance or contaminants and can include steaming,vacuum or combinations of the above.

The term “cleaning media” is used in section 6.2. In industrial systems, cleaning systems can involvethe use of solvents (water, etc.) or other chemical media to wash out the piping system which may be used to removecutting oils and fine particulates that may be occluded on the internal surface of the system. Various media in the form ofliquids or gases are listed to allow the broad spectrum of cleaning techniques used.

The addition of a definition for cleaning media may not be needed if the committee accepts a separate proposal whichhas been submitted to revise the term “cleaning” as it appears throughout the document to “gas blowing”.

Revise text to read as follows:3.3.XX* Materials used to clean piping systems.A.3.3.XX Cleaning media can include liquids, gases, and solids. Cleaning media that incorporate chemical washingtechniques include the use of chemical substances (usually liquid) capable of dissolving or dispersing a foreignsubstance or contaminants and can include steaming, vacuum or combinations of the above.

The committee revised the proposed definition to use the more generic term "materials" inplace of liquids and gases. The committee added a sentence to the annex text to describe what materials could beused.




Add new definition and annex note as follows:3.3.XX A material that is a gas at 68°F (20°C) or less at an absolute pressure of 14.7 psi (101.3 kPa),

that is ignitable at an absolute pressure of 14.7 psi (101.3 kPa) when in a mixture of 13 percent or less by volume withair, or that has a flammable range at an absolute pressure of 14.7 psi (101.3 kPa) with air of at least 12 percent,regardless of the lower limit. [ :2010]

A.3.3.XX . Pyrophoric gases such as silane or silicon tetrahydride are classified as such under thedefinition for pyrophoric materials found in NFPA 1, ; NFPA 400, ; or NFPA 55,

. The control strategy used for the regulation of pyrophoric materials issomewhat different than that of materials that do not autoignite on release to the atmosphere. Pyrophoric gases are notconsidered to be flammable gases per se.

The term “flammable gas” is used within the body of the standard. A definition is needed to provideguidance in terms of what to include or exclude. For example, in section 6.1.1.1 flammable gases are not to be used forinternal cleaning of piping, but the semiconductor industry may use flammable solvents for internal cleaning of piping.Lacking a definition, just what is to be included or excluded is not known. The definition of flammable gas as found inNFPA 55 has been used as source of the term throughout the model codes. The use of the NFPA 55 definition will bringconsistency to its use in this application.

An annex note has been provided to inform the user that pyrophoric gases should not be considered to be flammablegases per se. The control strategy for pyrophoric gases is quite different from that of the typical flammable gas. Silane,is a pyrophoric gas that is found in wide use throughout the high tech industries. It is regulated by NFPA 55 in the NFPAregulatory scheme. NFPA 55 refers the user to ANSI/CGA G-13, for specificrequirements. This same approach is used by the International Fire Code in addressing the requirements for thisparticular gas.

Providing an annex note will allow the users to recognize that pyrophoric gases are no regulated by NFPA 56 as theyare not defined as flammable gases, rather they are classified as pyrophoric materials under the definitions integral tothe documents which prescribe the required regulatory controls.




Add new definition as follows:. A process where gas is forced through the piping at a velocity required to remove debris.

In industries such as pharmaceutical, semiconductor and packaged gas industries, the removal ofdebris from internal piping systems can be accomplished by solvent washing, acid cleaning, caustic cleaning, gasblowing and other techniques.

In the document, section 6.2 Acceptable Fluid Media states:This section when combined with section 6.5 Pig Cleaning, describes how to propel and catch a pig

used to clean the inside of the piping system with a fluid. These sections in the document describe what has commonlybeen called gas blowing as the cleaning technique to be used to remove foreign particles from within the piping system.

Gas blowing was the source of the incident reported by Chemical Safety Board (CSB) as stated in the Origin andDevelopment of NFPA 56(PS), in this document. By limiting use of “gas blowing” to the removal of debris, the conflictwith conventional cleaning is removed from the publication and additional requirements that would specify acceptablecleaning agents will not be required.

The committee rejected the use of "gas blowing" in 56PS-2 (Log #3). There are other uses ofthe term gas blowing, such as de-pressurization. The committee does not agree that the term should be limited asstated in the proposed definition. In addition, gas blowing is jargon specific to the natural gas industry and should not beincluded in the standard.




Add a new definition and related annex note as follows:3.3.XX* . The point where gas is transferred from the supply system to the user system.A.3.3.XX . For packaging operations, the source valve serving the bulk supply is the point of delivery.

As written, the publication appears to lean towards overland pipeline delivery systems and does notadequately address gas delivery from bulk supply systems which may be either fixed or mobile. The term “Point ofDelivery” is used but not defined per se. In the typical industrial operations regulated by NFPA 55 where the source ofthe gas is a bulk supply, the term “source valve” is used to define a point where the bulk supply system terminates andthe gas is transferred to the user’s system.

Adding a definition for “point of delivery” will assist code users in understanding why there are differences applied inSection 1.1.1. The annex note has been drafted to alert users to the fact that in gas filling (also called packaging) plantsthe source valve located at the bulk supply is the point of delivery thereby exempting the piping system integral to bulktanks and manifold systems which are all a portion of the bulk supply separate and distinct from the user’s pipingsystem.

Revise text to read as follows:1.1.1.1* Coverage of fuel gas piping systems shall extend from the point of delivery to the gas-consuming equipmentisolation valve.(1.1.1.1.1 - 1.1.1.1.3 unchanged)1.1.1.2* Coverage of flammable gas piping systems other than fuel gas piping systems shall extend from the sourcevalve serving the gas supply system to the gas-consuming equipment isolation valve.A.1.1.1.2 Flammable gas container, cylinder, or tank filling operations are not included in the scope of NFPA 56 becausethere is no gas-consuming equipment.Global change - where point of delivery is used throughout, add "or source valve".

The committee did not accept the proposed definition for "point of delivery" because "point ofdelivery" is defined by the US Code of Federal Regulations. The committee instead clarified the extent of coverage offlammable gas piping systems in a new paragraph 1.1.1.2 using terminology consistent with NFPA 55, CompressedGases and Cryogenic Fluids Code. The committee added annex material to clarify that NFPA 56 does not apply tooperations where flammable gas is not consumed by burning or further processing.

_______________________________________________________________________________________________56PS-23 Log #18


Add a new definition as follows:3.3.XX An independent, systematic analysis of a procedure to ensure that foreseeable hazards,

errors and malfunctions have been addressed.

The term safety validation is used in the body of the document and annex A without definition. TheAnnex note A.4.4 contains a statement that is in effect the definition. Excerpting this statement to the definition sectionimproves the use of document as most users will refer to the definition rather than an annex note that may be obscure.

As used within the context of the document, a safety validation is only required to be performed on written procedures.Acceptance of this proposal will provide the needed definition resulting in a consistent applicationof the term.

The committee rejected the proposal because the safety validation is described adequately inthe mandatory text, Section 4.4.




Add new definition as follows:3.3.XX A shutoff valve on the piping system serving a bulk gas supply system where the gas supply, at

service pressure, first enters the supply line. [ , 2010]

Term “source valve” is used but not defined per se. In the typical industrial operations regulated byNFPA 55 where the source of the gas is a bulk supply, the term “source valve” is used to define a point where the bulksupply system terminates and the gas is transferred to the user’s system.

In gas filling (also called packaging) plants the source valve located at the bulk supply is the point of delivery therebyexempting the piping system integral to bulk tanks and manifold systems which are all a portion of the bulk supplyseparate and distinct from the user’s piping system.

Revise definition to read as follows:3.3.XX A shutoff valve on the piping system serving a gas supply system where the gas supply, atservice pressure, first enters the supply line.

The committee removed the word "bulk" from the definition because it is not uniformly defined.




Add new text A.3.3.9 and modify section 3.3.9.1 and 3.3.9.2 in accordance with the following:To free a gas conduit of air or gas, or a mixture of gas and air. [ 2012]

The purging procedure can vary by the system configuration, volume of space to purge, current gasconduit contents and intended gas service.

To replace the existing contents air or inert gas in of a closed system with by a flammablegas.

To replace the existing normal flammable gas content of a closed system by inert gas,air, or water. in a system with non-flammable contents.

Industry uses various purging techniques depending on several conditions of the piping system (i.e.piping system design, piping system volume, gases used, etc). Some purging procedures are very simple and quicklyaccomplished such as purging out a regulator connection in a flammable gas piping system; while long distance (orcapacity) piping systems will require a more extensive procedure. The wording to be added to the annex providesallowances for different purging techniques to be documented in the procedure in order to purge a piping system.

Section 3.3.9.1. The current definition limits the contents of a system to be purged into service to air or an inert gas.The contents of a system could consist of a gaseous atmosphere that is neither inert nor flammable depending on theprocess to which it is connected or a liquid system which could include fluids other than water. The assumption made byNFPA 56 is that all flammable gases are used as fuels while at the same time broadening the scope of the standard toall flammable gases regardless of their use. Similar restrictions and/or limitations are placed on the contents of a systemthat is being purged out of service.

Both definitions are specific in their content resulting in the defacto establishment of requirements, i.e., either theatmosphere in the case of being purged into service must be air or an inert gas, and when purged out of service theflammable gas must be replaced by wither air, inert gas or water. Having a requirements inside of a definition is inconflict with the implied or otherwise included in a definition is not allowed by the Manual of Style. In addition the existingdefinitions limit purging to closed systems only. Purging may be accomplished by continuous fluid flow to a dischargepoint in an open system.

If prescriptive requirements related to the atmosphere of a piping system are to be created the requirements are betterdescribed elsewhere in the standard. The proposed changes describe the function of the purging activity withoutprescribing required atmospheres. Acceptance of the proposal will result in resolving a conflict with the Manual of Styleand will serve to recognize that the content of piping systems may be other than anticipated when only fuel gases wereconsidered.

The committee rejected the proposal because the proposed revisions add complexity. Theexisting definitions describe the terms purge into service and purge out of service as used in the context of the standard.In addition, the proposed modification to 3.3.9.2 is too broad a description of materials. The committee encouragespublic comments that are more specific.




Modify section 4.1 in accordance with the following:Flammable gas piping systems shall be designed, constructed, inspected and tested

in accordance with ANSI/ASME B31.1 Power Piping, ANSI/ASME B31.3 Process Piping, ASME B31.12 HydrogenPiping and Pipelines, NFPA 55 Compressed Gases and Cryogenic Fluids Code, or NFPA 54 National Fuel Gas Code,or other approved codes or standards, as applicable.

As drafted the standard limits the standards that can be used to B31.1 and 31.3 and other codes andstandards may be applicable. For example, the appropriate code to be used for hydrogen piping systems is B31.12.

NFPA 56 has exempted hydrogen regulated by NFPA 2 from the document, however, NFPA 2 only regulates hydrogenwhen in a concentration of 95% or greater. The B31.12 code could be used for hydrogen piping with a hydrogenconcentration less than 95% and other standards could be approved for use as well. For example, the use of CGAG-5.7, Carbon Monoxide and Syngas Pipeline Systems or CGA G-5.6 Hydrogen Pipeline Systems could be approvedfor use in specific applications.

As an editorial note ASME, the publisher of B31, ASME Code for Pressure Piping uses a title of ASME rather thanANSI/ASME to preface their individual codes. Some NFPA publications have revised the terminology to ASME B31.x toaddress the approach taken by the publisher of the code. Adding the title of the ASME documents to follow the ASMEpublication number is in keeping with Section 3.6.2.2 of the NFPA Manual of Style.

Including “other approved codes or standards” is in keeping with the model code approach and offers the designer anoption not otherwise allowed. There is no reason to limit construction to only B31.1 and B31.3 for any and all flammablegas applications.

_______________________________________________________________________________________________56PS-27 Log #45


Add text to read as follows:Flammable gas piping systems shall be constructed in accordance with ANSI / ASME B31 .1, ANSI / ASME B31.3.

ANSI / ASME B31 .8, or NFPA 54. as applicable.Recent reviews at a number of our power plants have revealed both equipment skids and entire

sections of piping that were originally designed in accordance with B31 .8. Concern has been expressed that thissection of NFPA 56 wilt force a re-design and/or replacement of this piping. While the general intent of NFPA 56 is toavoid regulating activities by the gas supplier, recognition needs to be given that some end-user equipment that shouldbe covered under this standard may have been installed under the B31.8 standard.

The committee addressed the submitter's intent to recognize other ASME standards in56PS-31 (Log #21).

_______________________________________________________________________________________________56PS-28 Log #CP2


Add text to read as follows:4.1.1 The requirement of 4.1 shall not be required to be applied retroactively.

The committee recognizes that it may be impractical or impossible to apply construction requirementsretroactively. The committee exempts section 4.1 from retroactivity as stipulated in 1.3.




Add text to read as follows:New flammable gas piping systems shall be designed and installed to facilitate the requirements found in Chapters 6, 7

and 8.While the focus of this standard is on commissioning and maintenance activities, the requirements

found in Chapters 6-8 may require design modifications at existing facilities. Requiring new facilities to consider theserules in the design process should facilitate safer conduct of cleaning and purging activities at those locations. Theproposed new language is necessary to make these provisions enforceable when specifying/constructing new systems.

Add text to read as follows:1.3 Coordination. Coordination of the flammable gas piping system design and construction, including any temporarypiping, and the minimum safety requirements for cleaning and purging specified in chapters 6, 7, and 8 shall berequired.[Renumber subsequent]

The committee agrees with the submitter's intent, but not the approach. The committee addeda new paragraph to chapter 1 to require coordination between the design and construction requirements and theimplementation of purging and cleaning procedures.

_______________________________________________________________________________________________56PS-30 Log #65

_______________________________________________________________________________________________Dale P. Evely, Southern Company Services, Inc.

Add the following as a new section in the Standard and renumber existing sections that follow thenew section:

4.2 When liquid nitrogen or other liquid gases are utilized as an inert gas supply source, the design temperatureratings of the entire piping system that the inert gas will contact shall be understood and complied with under alloperating conditions.

The standard identifies nitrogen as one of the possible sources of inert gas to be used to meet therequirements of this standard. To provide the amount of nitrogen that might be needed for this purpose the user of thestandard may decide to use liquid nitrogen as the gas source. This additional text is needed to prevent embrittlementand potential failure of the nitrogen related piping system components. Liquid gases other than nitrogen could present asimilar risk.

Add text to read as follows:4.2* The delivered temperature and pressure of cleaning or purging media shall be compatible with the flammable gaspiping system.[Renumber subsequent]A.4.2 The person or agency performing cleaning or purging operations should coordinate with the system designer orfacility operator to ensure that the media is being supplied at a temperature and pressure that is compatible with theflammable gas piping system materials and construction.

The committee agrees with the intent of the submitter, but broadened the language to refer toany cleaning or purging media.




Modify text 4.3.1 in accordance with the following:4.3.1* The written procedure for each cleaning and purging activity shall address, as a minimum applicable, the

following items:(1) *Scope of work and site-specific purge procedure development

(a) Cleaning and purging method(b) Piping and instrument diagrams (PIDs)(c) Chemical and physical properties of flammable gas, purge media, and discharge gas(d) Determination of purge end point introducing flammable gas, inert gas, or air(e) Assessment and control of purge inlet and discharge locations(f) Temporary piping system design(g) Personal protective equipment (PPE)(h) Training and qualifications(i) Management review and approval(j) Restoration of service(k) Target design, launcher/receiver venting review for pigging operations(l) Regulatory permits(m) Evaluation of engineering controls to limit potential unintended ignition of gases (controlled oxidation, “flaring”)(n) Written stand-down instructions to stop activity in a controlled manner(o) Hazards

(2)*Environmental conditions and work locations(a) Establishment and clear identification of exclusion zones where flammable gas-air mixtures are likely to exist(b) Limited access for personnel not directly involved with purge operations(c) Assessment of potential for gas migration (building openings, adjacent structures)(d) Prohibition of hot work within exclusion zones(e) Lockout/tagout

(f) Impact of environmental conditions (wind speed and direction, temperature, barometric pressure) on purgeoperations

(g) Vehicular and air traffic, if applicable(h) Topography(i) Noise control/monitoring

(3) *Communication plans(a) Pre-job briefings(b) Work permits(c) Roles and responsibilities(d) Emergency response plan(e) Facility alarm, alert and warning systems(f) General facility notification prior to start of purge operations(g) General facility notification at the conclusion of purge operations(h) Notification of regulatory authorities as required (local emergency responders, utility operators, community

officials, environmental authorities, etc.)(4)*Control of ignition sources(a) Bonding and grounding considerations(b) No smoking or spark-producing work within exclusion zones(c) Elimination of hot work within exclusion zone(d) Static electricity ignition sources at discharge point

(5) Pre-purge piping system assessment(a) Assessment of piping system for trapped liquids, pyrophoric solids, and other flammable or combustible deposits

within the piping system(b) Ensuring that the piping system is properly isolated(c) Limiting site conditions that impact the safety of the activity

(5)*Purge monitoring and instrumentation


Report on Proposals – June 2013 NFPA 56PS(a) Ensuring that monitoring instruments are appropriate for gas being purged(b) Training(c) Calibration(d) Monitoring frequency and reporting(e) Appropriate selection of sample point(s)(f) General atmosphere checks in vicinity of purge gas Release

Revise A.4.3.1 and add new A.4.3.1(1) through (6)in accordance with the following:

A.4.3.1 It is recognized that purging as part of routine maintenance of small piping segments can be accomplishedsafely, provided that the written procedure (standard practice) is incorporated into a plant or facility operations andmaintenance (O&M) manual that addresses the potential hazards occurring at the time of the purging operations.Purging should be conducted by competent personnel trained in purging operations, including recognition of potentialhazards associated with purging. It is not intended that a new written procedure and/or safety validation be requiredeach time the activity occurs within a facility.

A.4.3.1(1): Scope of work and site-specific purge procedures typically include following, but not limited to:(a) Cleaning and purging method(b) Piping and instrument diagrams (PIDs)(c) Chemical and physical properties of flammable gas, purge media, and discharge gas(d) Determination of purge end point introducing flammable gas, inert gas, or air(e) Assessment and control of purge inlet and discharge locations(f) Temporary piping system design(g) Personal protective equipment (PPE)(h) Training and qualifications(i) Management review and approval(j) Restoration of service(k) Target design, launcher/receiver venting review for pigging operations(l) Regulatory permits(m) Evaluation of engineering controls to limit potential unintended ignition of gases (controlled oxidation, “flaring”)(n) Written stand-down instructions to stop activity in a controlled manner(o) Hazards

A.4.3.1(2) There are many factors that should be used to identify an exclusion zone. During a purging into or out ofservice, the procedure should address gas migration and dispersion based on wind direction, wind speed, and physicalcharacteristics of the gas. Typical factors to be considered are as follows but not limited to:

(a) Establishment and clear identification of exclusion zones where flammable gas-air mixtures are likely to exist(b) Limited access for personnel not directly involved with purge operations(c) Assessment of potential for gas migration (building openings, adjacent structures)(d) Prohibition of hot work within exclusion zones(e) Lockout/tagout(f) Impact of environmental conditions (wind speed and direction, temperature, barometric pressure) on purge

operations(g) Vehicular and air traffic, if applicable(h) Topography(i) Noise control/monitoring

A.4.3.1(3) Communication plans typically include following but not limited to:(a) Pre-job briefings(b) Work permits(c) Roles and responsibilities(d) Emergency response plan(e) Facility alarm, alert and warning systems(f) General facility notification prior to start of purge operations(g) General facility notification at the conclusion of purge operations(h) Notification of regulatory authorities as required (local emergency responders, utility operators, community

officials, environmental authorities, etc.)



A.4.3.1(4) Bonding requirements can be found in NFPA 70 and NFPA 77. Users should consider grounding of thepiping system to dissipate any electrical charge on the piping. Other factors to consider but not limited to:

(a) Bonding and grounding considerations(b) No smoking or spark-producing work within exclusion zones(c) Elimination of hot work within exclusion zone(d) Static electricity ignition sources at discharge point

A.4.3.1(5): Pre-purge piping system assessment typically include following but not limited to:(a) Assessment of piping system for trapped liquids, pyrophoric solids, and other flammable or combustible deposits

within the piping system(b) Ensuring that the piping system is properly isolated(c) Limiting site conditions that impact the safety of the activity

A.4.3.1(6) The procedure for monitoring the discharge gases and nearby areas should recognize that the responsetime of the sampling system could result in a time delay between a hazardous situation developing and being detectedby detection equipment. Where sampling systems are used, the response time should be short relative to the expectedperiod of time in which a hazard could develop.

Detection equipment selection should consider possible sample contamination by other commingled gases, moisture,or debris. The sampling system and/or detection equipment selection should consider appropriate mitigation measuressuch as filtration.

In some cases, gas release processes require the sampling of end points. In such cases, breathing air could berequired for working in and around inert materials that have been released or hat can create an exposure hazard. It isalso important that personnel working in and around releases of gas understand the hazards of inert materials such asnitrogen. All workers should be rained in the use and handling of the gases involved, proper

PPE, and all the risks. Further information on risks of inert gas asphyxiation is available from the U.S. Chemical SafetyBoard, www.csb.gov. Other factors to consider but not limited to:

(a) Ensuring that monitoring instruments are appropriate for gas being purged(b) Training(c) Calibration(d) Monitoring frequency and reporting(e) Appropriate selection of sample point(s)(f) General atmosphere checks in vicinity of purge gas Release

The approximately forty-eight procedure topics listed in 4.3.1, are currently identified as the minimumtopics that would be required in each cleaning and purging procedure written. For many industrial facilities that conductsimple purging on small process flammable gas piping systems, not all topics are necessary to be included to have asafe procedure. The detail of the procedure should be related to the actual pipe system (size/volume, etc) beingcleaned and purged, the recommended topics in 4.3.1 should be specified as being where or as as opposedto being established as mandatory.

In addition, each topic as listed provides little to no detailed explanation of what must be written to satisfy the topiclisted. The topics should be moved to the Annex as an offer of explanation of the type of detail to consider when writingand cleaning and purging procedure, but not necessarily a requirement each and every time. The subsequent Safetyvalidation will verify the suitability of the procedure after it is written, to match the application.

The committee rejected the proposal because the extensive lists of items to be addressed inthe written procedures is valuable for casual or less experienced users. The committee developed 56PS-32 (Log #CP4)to further clarify that the committee recognizes that some items will not be applicable to all procedures or installations.However, the committee sees the value in ensuring that these items are addressed and noted as not applicable, ratherthan moving them to the non-mandatory annex.


Report on Proposals – June 2013 NFPA 56PS_______________________________________________________________________________________________56PS-32 Log #CP4


Revise text to read as follows:4.3.1(1)(o)* Hazards Precautions for gases that have toxic, highly toxic, unstable reactive, corrosive, or other deleteriousproperties beyond flammabilityA.4.3.1(1)(o) Gases with properties in addition to flammability may require capture, scrubbing, or other engineereddisposal methods. These gases may not be suitable for release to the atmosphere outdoors.

The proposal addresses specific hazards related to a broader category of flammable gases than hadpreviously been considered. The committee replaced the generic term "hazards" to provide a more specific requirementto be addressed in the written cleaning and purging procedures.

_______________________________________________________________________________________________56PS-33 Log #25


Modify section 4.4 in accordance with the following:A written safety validation shall be performed for cleaning and purging procedures. For designs

where generic safety validation exists, a job specific safety validation shall not be required. If there is a genericprocedure, it only needs to be validated when originally published or when the procedure is changed.

Many facilities have similar operations or piping system designs within the same factory. Proceduresand safety validations that address these piping systems may already be in existence and well understood byemployees and supervisors. The allowance of the use of generic procedures helps to keep employees consistent in theirunderstanding of the process and the procedures.

Many industrial compressed gas filling facilities alternate the use of various gases which may be contained in thepiping system, on a frequent basis. The same piping system may be used for flammable or non-flammable gases as theprocess needs dictate. For existing piping systems that have completed a safety validation, it should not be necessary torepeat the validation process each time the gas species is changed in the piping system. If the piping system design orthe procedures are changed, a new safety validation is required.

The addition of a concept that recognizes generic procedures facilitates the use of standard operating procedureswhich are available for many piping system that are found in use throughout industry.

Add text to read as follows:4.4.3* Prior to initiation of a cleaning or purging activity, the safety validation shall be approved by a designatedindividual who is competent and knowledgeable in the procedure and hazards and who is authorized to provide suchapproval.A.4.4.3 It is recognized that purging as part of routine operation or maintenance of small piping segments can beaccomplished safely, provided that the written procedure (standard practice) is incorporated into a plant or facilityoperations and maintenance (O&M) manual that addresses the potential hazards occurring at the time of the purgingoperations. Purging should be conducted by competent personnel trained in purging operations, including recognition ofpotential hazards associated with purging. It is not intended that a new written procedure and/or safety validation berequired each time the activity occurs within a facility.

The committee recognizes the submitter's concern, but addressed it by repeating the existingannex note to 4.3.1. Where routine operations or maintenance procedures exist, the committee did not intend to requirea new procedure or safety validation to be performed every time the activity is undertaken.




Modify sections 4.4.1 and annex note A.4.4.1 in accordance with the following:The safety validation shall be conducted independently after the procedure has been written and shall evaluate

hazards, errors, and malfunctions related to each step in the procedure to validate the measures prescribed in theprocedure or make recommendations for additional hazard mitigation measures if necessary.

The safety validation should not be performed solely by the same person or group responsible for developingthe procedures. It can be performed or reviewed by an independent person a second qualified individual or groupwithin the company or department or by a third-party consultant.

For many small industrial companies with small piping systems and minimal personnel resources, thesafety validation is verified by department employee(s) with sufficient training and knowledge in the safety concerns.The term independent, implies that persons outside of the department or the factory, should be used for the safetyvalidation. Personnel resources may be limited.

Being an independent person does not necessarily indicate an understanding of the process safety concerns,especially, if the procedure or safety concerns are highly technical. In the modified supporting Annex, A.4.4.1, thereference to a second qualified individual is preferred to independent person as it states a measure of understanding bythe person conducting the safety validation.

The term “qualified individual” is a defined term. The modification is in keeping with the intent of the document, butprovides information as to how such a validation may be performed.

Revise text to read as follows:The safety validation should not be performed solely by the same person or group persons responsible for

developing the procedures. It can be performed or reviewed by an independent person or group within the company ordepartment or by a third-party consultant.

The committee did not accept the revision to the mandatory text in 4.4.1 because"independently" is qualified further by the annex material. The committee modified the word "group" to "persons" toclarify that the person or persons involved can be in the same company or department. The requirement does notprohibit independent validation by people in the same department or group within a company.

_______________________________________________________________________________________________56PS-35 Log #27


Modify section 4.5 in accordance with the following:Written procedures to manage change to process materials, technology, equipment,

procedures, and facilities shall be established and implemented.[ 4.3]

NFPA 654 is a. These requirements may not be appropriate in the future

for flammable gas systems. Management of change for these types of cleaning systems should be under the purview ofthis NFPA 654 Committee. The use of the extract text served its purpose for the initial development of the requirements.

Deleting the extract tag does not change the requirement, but it signifies the intent of the GPS committee to exerciseownership over the fundamental requirement as it will be used within the context of NFPA 56 over time.




Modify section 4.1 in accordance with the following:Prior to cleaning or purging, piping systems shall be inspected and pressure

tested to determine that the materials, design, fabrication, and installation practices comply with the requirements of thisstandard and the intended application.

It should not be necessary to restate the requirements because the piping system requirement iscovered by the code of construction documents, stated in 4.1. Section 4.1 establishes the requirements for constructionof the piping system, and the referenced codes and standards specify the requirements for design, fabrication,installation, inspection and testing.

NFPA 56 does not establish design for the piping system. Suitability of the system is determined by the codes andstandards governing the system design.

Revise text to read as follows:Prior to cleaning or purging, piping systems shall be inspected and pressure

tested to determine that the materials, design, fabrication, and installation practices comply with the requirements of thisstandard and the intended application.4.14.1.1 Pressure testing and inspection procedures shall be documented.4.14.1.2 Where piping is designed and installed in accordance with NFPA 54, pressure testing and inspection shall be inaccordance with NFPA 54, Chapter 8.4.14.1.3 Where piping is designed and installed in accordance with ANSI/ASME B31.1, pressure testing and inspectionshall be in accordance with Chapter VI of ANSI/ASME B31.1.4.14.1.4* Where piping is designed and constructed in accordance with ANSI/ASME B31.3, leak testing and inspectionshall be in accordance with Chapter VI of ANSI/ASME B31.3.4.14.1.5* Where pneumatic testing is conducted in accordance with ANSI/ASME B31.1, paragraph 137.5.2, or withANSI/ASME B31.3, paragraph 345.5.3, the test mediumshall be air, carbon dioxide, or an inert gas. Oxygen shall never be used.[Renumber annex sections accordingly]

The committee accepted the proposed change to 4.14 and relocated the entire section to 4.1.1to be consistent with changes to 4.1 in 56PS-26 (Log #21). The committee removed the specific reference to carbondioxide as a test gas because the specific reference implied that carbon dioxide is a preferred test media. It is notprohibited, but it is not preferred over any inert gases.




Modify section 4.15.1 in accordance with the following:The use of Hhot work permit process shall not be permitted unless the safety validation prohibits it. within the

affected area determined by the procedure until the piping system or segment has been purged out of serviceThe use of hot work permitting systems is a common industry practice that allows this type of safe

work. Such hot work may be required at various stages of process work. The hot work permit process provides ways tovalidate that the area is suitable for hot work such as: monitoring with flammable gas detectors, work zone demarcation,permit validation, reducing the pressure in the system, and checking for leaks.

It is not unusual for hot work to be conducted in areas where there are piping systems present containing or chargedwith flammable gases. The hot work permit system established by OSHA recognizes the need to have qualifiedindividuals inspect the area prior to conducting hot work. The current requirement does not define “the affected area”which could be interpreted to mean the entire plant site. CGA supports the use of a hot work permit process torecognize that the application of this new standard affects the use of any and all flammable gases in any application.

Revise text to read as follows:4.15.1 Hot work shall not be permitted during purging operations within the affected area exclusion zone whereflammable gas-air mixtures are likely to exist as determined by the procedure until the piping system or segment hasbeen purged out of service.

The committee modified the existing language to be consistent with 4.3.1(2)(d). The committeebetter defined the period of applicability for the requirement, rather than specifically refer to the hot work permit process,which is already required by NFPA 51B, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work.

_______________________________________________________________________________________________56PS-38 Log #28


Modify section 5.1.1 in accordance with the following:Such training shall include hazards of flammable gas, hazards of any compressed gas used for cleaning or

purging, safe handling practices of flammable gas and compressed gas as applicable, and company emergencyresponse action plans and procedures and equipment, and company policy.

Not all facilities will have an emergency response plan, but all facilities are required to have anemergencyaction plan. An emergency response plan is not required under OSHA 29 CFR 1910.38. An emergency response planmay be required for some facilities under the requirements of 1910.119 ProcessSafety Management, and when required it should be referenced by the emergency action plan.

NFPA 1, Fire Code; NFPA 30, Flammable and Combustible Liquids Code; and NFPA 400 Hazardous Materials Codealso require an emergency action plan. Section 60.1.5.1 (Hazardous Materials) of NFPA 1contains the following requirement:

An emergency action plan, consistent with the available equipment and personnel,shall be established to respond to fire and other emergencies in accordance with requirements set forth in this Code.[ 1.10.1]

A company site specific emergency action plan is required for each location. All employees are trained in thesecompany emergency action plans. Company emergency action plans are more specific and demanding than overallcompany policies.

The proposed revisions to this section will correlate the requirements with those of OSHA 1910.38 and is pertinent toall facilities where emergency action plans are required.




Modify section 6.1.1.1 add section 61.1.2.1 in accordance with the following:

Flammable gas shall not be used for internal cleaning of piping except as permitted by section 6.5.6.1.1.2 When required, notification, as specified in section 4.3.1, An alarm shall precede the start of cleaning in

accordance with the written cleaning procedure.Section 6.1.1.1 as written does not allow the use of a flammable gas for cleaning. However, in 6.5.2.1,

the use of a flammable gas is allowed under certain conditions. Providing a pointer to Section 6.5 informs the userthat there are conditions where the use of flammable gases for gas blowing of a system may be appropriate.

Alarms are used to alert users to abnormal or upset conditions. The alarm specified by Section 6.1.1.2 is betterdesignated as a “notification” as personnel are to be notified that the operation will be conducted. Notifications can takevarious forms while alarms are generally of the type specified by NFPA 72, National Fire Alarm and Signaling Code. Thetype of notification to be used and the method for the notification shall be stated in the cleaning and purging procedureas deemed necessary by the safety validation.

The method of notification is to be specified in the written procedures. Notification does not preclude the use of alarmsystems that may in fact be specified or regulated by NFPA 72, while allowing the use of other methods. Either systemmust inform all personnel in the area that a gas blowing operation will be conducted.

Revise text to read as follows:6.1.1.2 Notification An alarm shall precede the start of cleaning in accordance with the written cleaning procedure.

The committee did not accept the proposed revision to 6.1.1.1 because the flammable gas isnot the cleaning medium in 6.5; it is the pig propellant. The pig is the cleaner. The committee agrees that notification ismore appropriate than alarm, and made editorial changes to the proposed revision to 6.1.1.2.




Modify section 6.2 and add new section 6.2.1 and A.6.2.1 annex note in accordance with thefollowing:

Air, inert gas, steam, and water shall be acceptable cleaning media.Other cleaning media shall be permitted to be used as prescribed by the cleaning procedure.

A.6.2.1 Chemical washing can include the use of chemical substances (usually liquid) capable of dissolving ordispersing a foreign substance or contaminants and can include steaming, vacuum, or combinations of the above.

The word included in the section title implies that the only fluids that are acceptable arethose specified. Titles are editorial in nature and should not be used as a regulatory tool. If it is intended that mediaother than air, inert gas steam or water be prohibited the better choice would be to make that a positive statement thanto imply the circumstance through the use of a title. That said, limiting “cleaning” to only those media across thespectrum of all flammable gases regardless of usage needs to be revised to allow the use of other media based on arecognition that cleaning within the context of industry is other than “gas blowing” which is the subject of NFPA 56.

Cleaning in in the context of an “overland pipeline” typically means blowing dirt or debris out of the pipe or the runningof a pig through the line to remove foreign material. Historically, the gas used for blowing out the pipe or driving the pighas been the gas that is transported in the line (e.g. natural gas), which is now the subject of NFPA 56. Within a facilitythere can be many varieties of piping systems that may need cleaning where steam liquid solvents or chemical washingis utilized. Some of these cleaning fluids may be either flammable or combustible depending on the purpose and thetype of material sought to be removed from the piping system. The addition of 6.2.1 will allow the use of other cleaningmedia as addressed by the cleaning procedures. The annex note in A.6.2.1 is used to illustrate the use of othermaterials when appropriate.

A companion proposal has been introduced to revise the term “cleaning” to “gas blowing” to better describe the activitythat is the subject of NFPA 56. If the term gas blowing is accepted it will resolve the problem of trying to describe thefact that there are many types of cleaning methods and explaining why piping systems are cleaned to removeparticulate matter, as well as oils from cutting and fitting operations. The preferred solution is to use gas blowing in lieuof the term cleaning throughout the document.

Adding a new section that recognizes that there are other types of cleaning media that can be used will assist the userin understanding that cleaning per se is a general term and not one that should be restricted to the use of the mediaspecified.

Add text to read as follows:Air, inert gas, steam, and water shall be acceptable cleaning media.

Other cleaning media, except flammable gas, shall be permitted to be used in accordance with the writtencleaning procedure.A.6.2.1 Chemical washing can include the use of chemical substances (usually liquid) capable of dissolving or

dispersing a foreign substance or contaminants and can include steaming, vacuum, or combinations of the above.

The committee revised 6.2.1 to reiterate the prohibition on the use of flammable gas.




Modify section 6.3 in accordance with the following:

Not all power/fuel supply used during cleaning will be by temporary power/fuel systems. Power/fuelsupply necessary for pipe cleaning may be supplied from permanent sources. The modification allows either supplysource.

Add text to read as follows:Temporary

This section is applicable only to temporary power and fuel supplies necessary to implement the cleaningprocedures. Local building codes and electrical codes should be used to provide permanent power and fuel supplies tothe facility.

To address situations where temporary equipment is connected to the permanently installedpower and fuel supplies available on site.




Modify section 6.4 and new A.6.4 in accordance with the following:Temporary piping systems, including hose assemblies, used to

connect the cleaning media supply source to the piping system shall be in accordance with ANSI/ASME B31.1 PowerPiping, paragraph 122.10, ASME B31.3 Process Piping, ASME b31.12 Hydrogen Piping and Pipelines, or otherapproved codes and standards.

A.6.4 ASME B31.1, paragraph 122.10 contains more detailed requirements for temporary piping than does ASMEB31.3 or ASME B31.12.

As drafted the standard limits the standards that can be used to B31.1 and 31.3 and other codes andstandards may be applicable. For example, the appropriate code to be used for hydrogen piping systems is B31.12.

NFPA 56 has exempted hydrogen regulated by NFPA 2 from the document, however, NFPA 2 only regulates hydrogenwhen in a concentration of 95% or greater. The B31.12 code could be used for hydrogen piping with a hydrogenconcentration less than 95% and other standards could be approved for use as well. For example, the use of CGAG-5.7, Carbon Monoxide and Syngas Pipeline Systems or CGA G-5.6 Hydrogen Pipeline Systems could be approvedfor use in specific applications.

As an editorial note ASME, the publisher of B31, ASME Code for Pressure Piping uses a title of ASME rather thanANSI/ASME to preface their individual codes. Some NFPA publications have revised the terminology to ASME B31.x toaddress the approach taken by the publisher of the code. Adding the title of the ASME documents to follow the ASMEpublication number is in keeping with Section 3.6.2.2 of the NFPA Manual of Style.

Including “other approved codes or standards” is in keeping with the model code approach and offers the designer anoption not otherwise allowed. There is no reason to limit construction to only B31.1 and B31.3 for any and all flammablegas applications.

Revise text to read as follows:Temporary piping systems, including hose assemblies, used to

connect the cleaning media supply source to the piping system shall be in accordance with ANSI/ASME B31.1 PowerPiping, paragraph 122.10, or the same code or standard used for the permanent piping system.

The committee modified the proposal to remove the specific list of standards, but retained theoption to design and construct the temporary piping system to the same code as the permanent piping system. Thecommittee did not accept the addition of the annex text because the reference to the specific paragraph in ASME B 31.1was retained in the mandatory text.




1. Revise Section 7.1 as follows:The purging of piping systems into service shall be in

accordance with NFPA 54, where the piping being purged contains one or more sections ofpiping meeting the size and length criteria of Table 7.1

***Insert Table 7.1 here\***

2. Add a new Section 8.1 as follows:

8.1 The purging of piping systems out of service shall be in accordance with NFPA 54, National Fuel Gas Code, wherethe piping being purged contains one or more sections of piping meeting the size and length criteria of Table 7.1.

As drafted, NFPA 56 applies to piping and tubing of any size or volume. The historical use of NFPA54 is to establish a volume and size relationship where purging is required. The use of this proposed table will exemptsmall volume systems from the purging process as these small systems can be placed into service or removed fromservice without specialized purging procedures.

Small systems are typically used in operations involving the filling of containers including, but not limited to the filling ofportable containers, mobile vehicles including cargo tanks, tube trailers, etc. The majority of industrial installations fornon-fuel gas systems contain piping and tubing systems constructed with piping of less than 4” nominal diameter.

Adopting Table 8.3.1 from NFPA 54 into NFPA 56 will address the need for purging based on a pipe volume asdetermined by the table which has been established and tested over an extended period of time.

The committee rejected the proposal because the reference to the NFPA 54 table may not beappropriate for the gases or pressures covered under this standard. The table in the context of NFPA 54, National FuelGas Code, covers fuel gas at pressures up to 125 psig, providing an inherent volume calculation. Without an upper limiton pressure, there is no way to determine how much gas could be released in a purge process in NFPA 56. Thecommittee is open to the concept of offering alternative criteria for cleaning and purging of piping systems based onvolume of gas, but would like to see additional research.




Modify section 7.1.2, 7.1.2.1 and 7.1.2.2 in accordance with the following:If the facility plant is owned or operated by the serving flammable natural gas supplier, flammable natural gas

piping between the point of delivery and the plant equipment isolation valve shall be permitted to be purged into servicein accordance with the serving flammable natural gas supplier’s written procedures.

The flammable natural gas supplier’s written procedures shall include a safety validation in accordance withSection 4.4.

The flammable natural gas supplier’s written procedures and process shall be coordinated with the facility plantoperational personnel.

Current wording limits the requirements to natural gas usage only. There may be other applicationsthat involve other flammable gases besides natural gas, like carbon monoxide or propylene. Modifying the text expandsthe scope to all flammable gases and not only natural gas applications.

Current wording uses the word “plant”. To the users of this document this may imply “Power Plant”, however, thescope of this document is broad enough the word “facility” better describes the possible locations affected by thisdocument.

The proposal was rejected because the requirement was specifically written for natural gassuppliers who are regulated by federal law to have written purging requirements and procedures. The committee is notaware of any similar regulation governing other flammable gas suppliers.




Modify section 7.2.1 in accordance with the following:The vent discharge from a piping system being purged into service shall discharge

directly to a safe outdoor location as determined by the written purge procedure. to a specified location determined bythe written procedures that will prevent impingement exposure on other portions of the piping system and minimize theeffects of high temperature thermal radiation or the effects of contact with the gas from the escaping plume on thepiping system , personnel, adjacent structures, and unspecified ignition sources.

Flares are an acceptable method for disposing of flammable gases in the chemical and refining industry.“The term “safe” is a vague and unenforceable term, and as suggested by the Manual of Style the use

of the term is to be avoided. What is deemed to be safe to one individual is not necessarily deemed to be safe byanother. If it is intended that NFPA 56 be used as a regulatory tool, the use of vague language should be eliminated.

NFPA 55 Section 6.1.4 addresses the termination point for gases to be vented from a system. The concepts includedin this text have been used as the starting point to describe what should be considered in designating a “safe” point ofdischarge.

The intent of this proposal is to set up a condition to allow a variety of discharge points including atmosphericdischarge and discharge to abatement systems designed specifically for the gas to be handled. Flares and afterburnersand scrubbers are designed to limit the amount of toxic released.

Revise text to read as follows:The vent discharge from a piping system being purged into service shall discharge

directly to a safe outdoor location as determined by the written purge procedure. to a specified unconfined outdoorlocation determined by the written procedure, or shall be captured or further processed before release.4.3.1(1)(f)* Mitigation or capture strategiesA.4.3.1(1)(f) Gases that have hazards other than flammability could be subject to mitigation strategies such asscrubbing, flaring, afterburning, thermal oxidizing, or capture.

The committee agrees with the intent of the submitter to recognize other mitigation strategiesfor gases having hazards other than flammability. The committee requests further input from the public to developannex and/or definitions for unobstructed, unconfined, and capture.




Modify sections 7.2.2.2, 7.2.2.3, 7.2.2.4 and 7.2.2.5 in accordance with the following:During purging discharge, the discharge gases from the permanent piping system shall be monitored on a

continual basis with appropriate detection equipment that complies with Section 7.3.Purging operations introducing inert gas shall be continuous continue until the oxygen concentration detected

at the discharge end point of the permanent piping system or in the vent line is less than 60 percent of the limitingoxidant concentration as determined in accordance with 7.2.3 of NFPA 69 or the flammable gas concentration is lessthan 10% of the lower flammability limit..

Except as permitted in paragraph 7.2.2.5, pPurging operations that introduce flammable gas shall continue becontinuous until at least 90 percent flammable gas by volume or the minimum concentration established by the purgingprocedure is detected at the discharge end of the permanent piping system or in the vent line.

Where a piping system containing inert gas is purged into service, it shall be permitted to isolate the pipingsystem discharge the gas downstream in lieu of venting in accordance with the following:

(1) The piping system design can accommodate the activity.(2) The end-point concentration of inert gas does not prevent complete combustion or consumption of the flammable

gas in the end-use equipment or process.(3) The inert gas–flammable gas mixture is released in a controlled manner to end-use equipment, or process

equipment, or flares.The requirements of Section 7.2.2.2 suggest, but do not require the use of online analyzers.

Depending on the type of system being purged non-continuous monitoring can be adequate for purging operations.Some purging operations like pressure pulsing are not continuous and thus monitoring is not continuous. Purgingoperations for maintenance purposes often use temporary vent locations. The monitoring point must be where the gasmixture is discharged in order to measure the conditions inside the pipe being purged. The revisions to Section 7.2.2.4contain a number of editorial changes:

• Adding a reference to Section 7.2.2.5, which is in effect an exception to 7.2.2.4, and the addition of the note to7.2.2.4 directs the user to 7.2.2.5 for this special case.

• The term “permanent“ was stricken as the discharge should be monitored regardless of whether the piping ispermanent or temporary.

• The revisions to describe the “discharge” delete the use of the term “discharge end” as it serves no purpose if thedischarge is monitored. Whether the discharge is from the vent or any other portion of the system makes little differenceit is the discharge that must be monitored.

This proposal and the and a companion proposal for Section 8.3.3.2 through 8.3.3.4 improves the consistency of thesetwo groups of similar requirements.

The modification to Section 7.2.2.5 to delete the “or flares” text does not change the intent of the section. Flares areviewed as process equipment or abatement equipment attendant to a process, and the added text does not appear tobe necessary. Additionally there are other types of process equipment such as scrubbers or after burners that could beused to dispose of the inert-flammable gas mixture.

Acceptance of this proposal will serve to clarify the requirements and to recognize that there may be monitoringmethods other than those that imply the use of electronic means. For example, with toxic gas or corrosive gas systemsDraeger tubes or other chemical means may be used as a means of monitoring content of flammable gas in thedischarge.

Revise text to read as follows:During purging discharge, the discharge gases from the permanent piping system shall be monitored on a

continual basis with appropriate detection equipment that complies with Section 7.3.Purging operations introducing inert gas shall be continuous continue in accordance with the written

procedure until the oxygen concentration detected at the discharge end point of the permanent piping system or in thevent line is less than 60 percent of the limiting oxidant concentration as determined in accordance with 7.2.3 of NFPA69.

Except as permitted in paragraph 7.2.2.5, pPurging operations that introduce flammable gas shall continue in


Report on Proposals – June 2013 NFPA 56PSaccordance with the written procedure be continuous until at least 90 percent flammable gas by volume or the minimumconcentration established by the purging procedure is detected at the discharge end of the permanent piping system orin the vent line.

Where a piping system containing inert gas is purged into service, it shall be permitted to isolate the pipingsystem discharge the gas downstream in lieu of venting in accordance with the following:

(1) The piping system design can accommodate the activity.(2) The end-point concentration of inert gas does not prevent complete combustion or consumption of the flammable

gas in the end-use equipment or process.(3) The inert gas–flammable gas mixture is released in a controlled manner to end-use equipment, or process

equipment, or flares.The committee does not accept the addition of "10 percent of the lower flammability limit of the

flammable gas" to 7.2.2.3 because the paragraph addresses operations where air in a piping system is being replacedwith inert gas. Therefore, a flammable gas concentration measurement is inappropriate. The committee added "inaccordance with the written procedure" to every occurrence of "continue" to allow for the various purging methodsappropriate for the gases being purged.

_______________________________________________________________________________________________56PS-47 Log #47


Add text to read as follows:Gas detection equipment used for monitoring the discharge gases shall be readily accessible or remotely monitored

such that readinqs may be taken from a location outside the exclusion zone.While the standard contains a number of requirements for monitoring gases being discharged, as

currently written there are no restrictions from placing personnel in harm's way to obtain these readings.

The proposal is rejected because the standard currently permits the procedure and safetyvalidation to determine exclusion zones and accessibility to personnel. The proposal would impact all purgingoperations, including where inert gas is being introduced. The proposal would restrict users to remotely operatedequipment, which may not be necessary or desirable for all applications.




Modify sections 7.3.2, 7.3.3, 7.3.5, A.7.3.2, A.7.3.3, and. delete section 7.3.4 and A7.3.4 inaccordance with the following:

Detection equipment shall be designed and listed or approved for the gas being monitored and the environmentwhere it is used and operated calibrated in accordance with the manufacturer’s instructions.

Flammable Combustible gas detectors indicators shall be capable of measuring numerically display the gasconcentration in accordance with 7.2.2.4. by volume scale from 0 to 100 percent in measurement incrementsdetermined by the procedure.

* Lower flammability limit (LFL) monitors shall numerically display the gas concentration as a percentage of theLFL from 0 to 100 percent in measurement increments determined by the procedure.

Oxygen detectors monitors shall be capable of measuring shall numerically display the oxygen concentration inaccordance with 7.2.2.3. by volume from 0 to 25 percent or higher in measurement increments determined by theprocedure.

Any detection equipment should be listed or approved not only for the specific gas or gases being sensed inthe process but also for the type of environment they might be subjected to or used in. Detectors for use in hazardouslocations as defined in NFPA 70 should be listed for such use. This is particularly important for detection equipmentused to monitor areas where flammable gas is being discharged. Detection equipment specifications such as responsetime, limits of measurement range, operating temperature, and gas pressure limitation should be known, and theprocedure should developed such that these factors will not negatively impact the safety of the activity.

Combustible gGas detectors indicators for flammable fuel gases typically should display increments of 1percent or smaller. The procedure and the safety validation should indicate the maximum increment based on gas beingdetected and the response time. Selection and use of the combustible gas indicator should be appropriate to ensure thata hazard is detected in a timely manner.

LFL gas monitors for fuel gases should display increments of 1 percent or smaller. The procedure and thesafety validation should indicate the maximum increment based on gas being detected and the response time. Selectionand use of the LFL gas monitor should be appropriate to ensure that a hazard is detected in a timely manner.

Much of the language in this section implies the use of electronic devices for the purpose of detectingflammable gases and the presence of oxygen. This type of instrument is available for common flammable gases suchas natural gas. However, they may not be available for the less common gases. The only available detector may be aDraeger tube or some other equivalent means of chemically detecting the gas of interest. This type of device can not becalibrated before use. Therefore the language has been adjusted to accommodate a broader spectrum of detectors.The type of detector, its accuracy, the required precision and calibration methodology must be specified in theprocedure.

The original language in this section covered detection equipment both purging into service but was also referenced bySection 8, Purging out of service. Because these two processes are different this could lead to confusion for the user.The text of section 7.3.4 has been moved to the companion proposal to add section 8.4 since it applies purging out ofservice. .

The change to Section 7.3.2 includes the addition of “or approved” detection systems. While there may be flammableor combustible gas detection systems available for natural gas that are listed systems there are not readily available“listed” systems for all gases that are now being regulated by this standard including those that are toxic, highly toxic,corrosive, unstable reactive, etc. Adding “or approved” will enable the use of other systems. On the other hand, therequirements for listing as suggested by the annex note to A.7.3.2 is appropriate if limited to compliance with NFPA 70.

Acceptance of this proposal will serve to clarify the requirements and to recognize that there may be monitoringmethods other than those that imply the use of electronic means. For example, with toxic gas or corrosive gas systemsDraeger tubes or other chemical means may be used as a means of monitoring content of flammable gas in thedischarge.

The committee rejected the proposal because the term "flammable gas detector" is inconsistentwith recognized industry practice. Combustible gas indicator has been used across many industries for severaldecades. The committee recognizes the additional hazards related to some flammable gases, however, the documentscope is limited to fire and explosion prevention. The committee requests further input from the public regarding the use


Report on Proposals – June 2013 NFPA 56PSof alternative equipment for or approaches to detecting flammable gas while piping is purged into service, with specialconsideration to accuracy, reliability, and possible approval criteria or guidance.

_______________________________________________________________________________________________56PS-49 Log #38


Modify sections 8.3.2 in accordance with the following:The discharge from a piping system being depressurized or purged out of service shall discharge to a specified

location determined by the written procedures that will prevent impingement exposure on other portions of the pipingsystem and minimize the effects of high temperature thermal radiation or the effects of contact with the gas from theescaping plume on the piping system, personnel, adjacent structures, and unspecified ignition sources. The ventdischarge from a piping system being depressurized or purged out of service shall discharge directly to a safe outdoorlocation as determined by the written purge procedure.

The term “safe” is a vague and unenforceable term, and as suggested by the Manual of Style the useof the term is to be avoided. What is deemed to be safe to one individual is not necessarily deemed to be safe byanother. If it is intended that NFPA 56 be used as a regulatory tool, the use of vague language should be eliminated.

NFPA 55 Section 6.1.4 addresses the termination point for gases to be vented from a system. The concepts includedin this text have been used as the starting point to describe what should be considered in designating a “safe” point ofdischarge.

The intent of this proposal is to allow a variety of discharge points including atmospheric discharge and discharge toabatement systems designed specifically for gas to be handled. Flares, afterburners and scrubbers are designed to limitthe amount of flammable or toxic gas released.Having the discharge point specified by the written procedures ensures that the proper validation is conducted to identifythat the “safe location” is confirmed.

See Committee Action on proposal 56PS-45 (Log #35).Revise text to read as follows:

The vent discharge from a piping system being purged into service shall dischargedirectly to a safe outdoor location as determined by the written purge procedure. to a specified unconfined outdoorlocation determined by the written procedure, or shall be captured or further processed before release.

The committee agrees with the intent of the submitter to recognize other mitigation strategiesfor gases having hazards other than flammability. The committee requests further input from the public to developannex and/or definitions for unobstructed, unconfined, and capture.




Modify sections 8.3.3.2, 8.3.3.3 and 8.3.3.4 in accordance with the following:During purging discharge, the discharge gases the discharge from the permanent piping system shall be

monitored on a continual basis with detection equipment that complies with Section 8.4 7.3.Purging operations that introduce inert gas shall continue be continuous until the flammable gas concentration

detected at the discharge end of the permanent piping system or in the vent line is such that the inert gas–flammablegas mixture is not ignitable when released in air.

Purging operations that introduce air to displace inert gas shall continue be continuous until at least 19.5percent oxygen by volume is detected at the discharge end of the permanent piping system.

The changes in Section 8.3.3.2 focus the requirement on the discharge from the piping system and thelanguage proposed is a simplification. A companion proposal has been submitted to provide requirements for detectionequipment in a new Section 8.4 rather than to refer the user to Section 7.3. Doing so will avoid confusion as toapplication which is somewhat different between purging into and out of service.

This proposal and the and a companion proposal for Section 7.2.2.2 through 7.2.2.5 improves the consistency of thesetwo groups of similar requirements.

Depending on the type of system being purged non-continuous monitoring can be adequate for purging operations.Some purging operations like pressure pulsing are not continuous and thus monitoring is not continuous. Purgingoperations for maintenance purposes often use temporary vent locations. The monitoring point must be where the gasmixture is discharged in order to measure the conditions inside the pipe being purged.

The revisions in 8.3.3.2 and 8.3.3.3 are to require the application of monitoring equipment regardless of whether theinstallation is permanent or temporary as a hazard can exist under either set of conditions. Refer to the proposal to adda new Section 8.4 when these changes are considered.Acceptance of this proposal will assist the user in the application of controls being required by the standard.

Revise text to read as follows:During purging discharge, the discharge gases the discharge from the permanent piping system shall be

monitored in accordance with the written procedure on a continual basis with detection equipment that complies withSection 8.4 7.3.

Purging operations that introduce inert gas shall continue in accordance with the written procedure becontinuous until the flammable gas concentration detected at the discharge end of the permanent piping system or inthe vent line is such that the inert gas–flammable gas mixture is not ignitable when released in air.

Purging operations that introduce air to displace inert gas shall continue in accordance with the writtenprocedure be continuous until at least 19.5 percent oxygen by volume is detected at the discharge end of the permanentpiping system.

The committee added references to the written procedure to every use of "continue" to allow forthe various purging methods appropriate for the gases being purged.




Add text to read as follows:Gas detection eguipment used for monitoring the discharge gases shall be readily accessible or remotely monitored

such that readings may be taken from a location outside the exclusion zone.While the standard contains a number of requirements for monitoring gases being discharged, as

currently written there are no restrictions from placing personnel in harm's way to obtain these readings.

The proposal is rejected because the standard currently permits the procedure and safetyvalidation to determine exclusion zones and accessibility to personnel. The proposal would impact all purgingoperations, including where inert gas is being introduced. The proposal would restrict users to remotely operatedequipment, which may not be necessary or desirable for all applications.




Add new 8.4, 8.4.1, 8.4.2, 8.4.3, 8.4.4 and supporting Annexes A.8.4.1, A.8.4.2 and A.8.4.3accordance with the following:

8.4.1* Sense of smell shall not be used to detect the presence of flammable gas.A.8.4.1 Odor fade, odor masking, olfactory fatigue, an individual’s inability to smell the flammable gas, or the fact that a

flammable gas is not odorized can reduce safety and lead to an inadequate warning of a flammable gas–air mixture.Calibrated detection equipment should be used by trained workers whenever the presence of flammable gas is beingmonitored.

8.4.2* Detection equipment shall be designed and listed or approved for the gas being monitored and the environmentwhere it is used and operated in accordance with the manufacturer’s instructions.

A.8.4.2 Any detection equipment should be listed or approved not only for the specific gas or gases being sensed inthe process but also for the type of environment they might be subjected to or used in. Detectors for use in hazardouslocations as defined in NFPA 70 should be listed for such use. This is particularly important for detection equipmentused to monitor areas where flammable gas is being discharged. Detection equipment specifications such as responsetime, limits of measurement range, operating temperature, and gas pressure limitation should be known, and theprocedure should developed such that these factors will not negatively impact the safety of the activity.

8.4.3* Lower flammability limit (LFL) detectors shall be capable of measuring the gas concentration in accordance with8.3.3.3.

A.8.4.3 LFL gas detectors for flammable gases typically display increments of 1 percent or smaller. The procedure andthe safety validation should indicate the maximum increment based on gas being detected and the response time.Selection and use of the LFL gas detector should be appropriate to ensure that a hazard is detected in a timely manner.

8.4.4 Oxygen detector shall be capable of measuring the oxygen concentration in accordance with 8.3.3.4.A new Section 8.4 has been added to establish a set of requirements specific for use during purging a

system out of service. There are some differences between the monitoring required from that established in Section 7.3.For example, when flammable gas is introduced into a system, it is important to ensure that the oxygen concentrationhas been reduced to a level below that which will support combustion. On the other hand in activity when the pipe ispurged out of service the oxygen concentration must be raised to a level of 19.5% or greater to avoid having the purgegas act as an asphyxiant.

The Annex notes provided have been based on those found in Section 7.3 with minor modifications. The termdetection is used in lieu of monitoring, etc.

The change to Section 8.4.2 includes the addition of “listed or approved” detection systems. While there may beflammable or combustible gas detection systems available for natural gas that are listed systems there are not readilyavailable “listed” systems for all gases that are now being regulated by this standard including those that are toxic,highly toxic, corrosive, unstable reactive, etc. Adding “or approved” will enable the use of other systems. On the otherhand, the requirements for listing as suggested by the annex note to A.8.4.2 is appropriate if limited to compliance withNFPA 70.

A companion proposal has been submitted to Sections 8.3.3.3 and 8.3.3.4.

Revise text to read as follows:

8.4.1* Sense of smell shall not be used to detect the presence of flammable gas.A.8.4.1 Odor fade, odor masking, olfactory fatigue, an individual’s inability to smell the flammable gas, or the fact that a

flammable gas is not odorized can reduce safety and lead to an inadequate warning of a flammable gas–air mixture.Calibrated detection equipment should be used by trained workers whenever the presence of flammable gas is beingmonitored.

8.4.2* Detection equipment shall be designed and listed for the gas being monitored and the environment where it isused and operated in accordance with the manufacturer’s instructions.8.4.2.1 Where listed gas detection equipment is not available for the specific gas being detected, the gas detectionequipment shall be recommended for the application by the manufacturer and approved.

A.8.4.2 Any detection equipment should be listed or approved not only for the specific gas or gases being sensed in


Report on Proposals – June 2013 NFPA 56PSthe process but also for the type of environment they might be subjected to or used in. Detectors for use in hazardouslocations as defined in NFPA 70 should be listed for such use. This is particularly important for detection equipmentused to monitor areas where flammable gas is being discharged. Detection equipment specifications such as responsetime, limits of measurement range, operating temperature, and gas pressure limitation should be known, and theprocedure should developed such that these factors will not negatively impact the safety of the activity.

8.4.3* Lower flammability limit (LFL) detectors shall be capable of measuring the gas concentration in accordance with8.3.3.3.

A.8.4.3 LFL gas detectors for flammable gases typically display increments of 1 percent or smaller. The procedure andthe safety validation should indicate the maximum increment based on gas being detected and the response time.Selection and use of the LFL gas detector should be appropriate to ensure that a hazard is detected in a timely manner.

8.4.4 Oxygen detectors shall be capable of measuring the oxygen concentration in accordance with 8.3.3.4.The committee moved the option for approved equipment to a new paragraph because the

committee wants to reinforce the preference for using listed equipment whenever it is available.

_______________________________________________________________________________________________56PS-53 Log #CP5


Revise text to read as follows:A.7.1.2 There are instances where a plant is located on a much larger piece of land where the point of delivery may beon or beyond the perimeter of the property and travel a significant distance before reaching any piece of equipmentassociated with the plant or process and where the serving natural gas supplier operates the pipeline between the pointof delivery and the plant. The serving natural gas supplier generally has specialized procedures for purging andoperating transmission and distribution lines as required by state regulations and/or federal regulation under the USDepartment of Transportation 49 CFR Part 192.629.

The revisions to the annex note were added to clarify the basis for special provisions for natural gassupplier-owned plants.




1. Revise Section A.7.2.2.3 as follows:

When purging with an inert gas, it is generally acceptable to use an oxygen detector to measure the absenceof oxygen. When flammable gas is being introduced, an appropriate gas detection device that can operate in theabsence of oxygen should be used. Catalytic combustion–type indicators should not be used for purging into service inan oxygen-free environment.

Subsection 7.2.3 of NFPA 69 is extracted here for the convenience of the user [Table C.1(a) and Table C.1(b) of NFPA69 are is reprinted here as Table A.7.2.2.3(a) and Table A.7.2.2.3(b), respectively]:

2. Delete table A7.2.2.3(b) in its entirety.

***Insert Table A.7.2.2.3(b) here***

The document scope is for cleaning and purging flammable gas piping systems. The table iscomprised of solid materials only. Listing non-gas items can cause confusion as to the scope of the document and thework required.

Deleting the extract table from NFPA 69 will clarify and simplify the document for the average user.

Revise text to read as follows:A.7.2.2.3 When purging with an inert gas, it is generally acceptable to use an oxygen detector to measure the absenceof oxygen. When flammable gas is being introduced, an appropriate gas detection device that can operate in theabsence of oxygen should be used. Catalytic combustion–type indicators should not be used for purging into service inan oxygen-free environment.

Subsection 7.2.3 of NFPA 69 is extracted here for the convenience of the user [Table C.1(a) and Table C.1(b) of NFPA69 are is reprinted here as Table A.7.2.2.3(a) and Table A.7.2.2.3(b), respectively]:2. Delete table A.7.2.2.3(b) in its entirety.

The committee accepted the proposal, but editorially removed the underlining from paragraph 1because it is existing text.




Add text to read as follows:Separate combustible gas indicators, lower flammability limit (LFL) monitors, and oxygen monitors may all be required

to conduct purging activities. The procedure and safety validation should indicate the type of monitors required at eachlocation where monitoring will be conducted.

There has been a misperception within our company that there is a ~one-size -fits-all " gas monitoravailable to conduct purging operations. In several instances purging activities were either delayed or improperlyconducted because either the right equipment was unavailable or the wrong equipment was used. To date, we have notbeen able to identify a gas monitoring device capable of meeting all three parameters set forth in sections 7.3.3, 7.3.4,and 7.3.5.

Revise text to read as follows:A.4.3.1(6) The procedure for monitoring the discharge gases and nearby areas should recognize that the response timeof the sampling system could result in a time delay between a hazardous situation developing and being detected bydetection equipment. Where sampling systems are used, the response time should be short relative to the expectedperiod of time in which a hazard could develop.Separate combustible gas indicators, lower flammability limit (LFL) monitors, and oxygen monitors could be necessaryto conduct purging activities. The procedure and safety validation should indicate the type of monitors required at eachlocation where monitoring will be conducted. Detection equipment selection should consider possible samplecontamination by other commingled gases, moisture, or debris. The sampling system and/or detection equipmentselection should consider appropriate mitigation measures such as filtration.In some cases, gas release processes require the sampling of end points. In such cases, breathing air could be requiredfor working in and around inert materials that have been released or that can create an exposure hazard. It is alsoimportant that personnelworking in and around releases of gas understand the hazards of inert materials such as nitrogen. All workers should betrained in the use and handling of the gases involved, properPPE, and all the risks. Further information on risks of inert gasasphyxiation is available from the U.S. Chemical Safety Board,www.csb.gov.

The committee modified the language to be consistent with the NFPA Manual of Style andrelocated the proposal to A.4.3.1(6) because it is relevant to the existing text.


Date post:	19-May-2018
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