Technical Committee on Industrial and Medical Gases

Technical Committee on Industrial and Medical Gases Date: July 10, 2009 To: Technical Committee on Industrial and Medical Gases From: Denise Beach, Staff Liaison/Senior Engineer Re: Agenda Package July ROP Meeting Enclosed is the agenda package for the July 23, 2009 web/teleconference for the Report on Proposals (ROP) meeting. Please ensure that you have reviewed the proposals in advance of the meeting. The agenda and proposals will be posted on the committee webpage. Some items to have available for the meeting include: Agenda packet with proposals; your copy of ; copies of other IMG standards you may wish to reference. Optional items that are sometimes useful include previous ROP/ROCs if handy. If you have any questions or comments, please feel free to reach me at (617) 984-7501 or by e-mail at dbeach@nfpa.org. You can reach the IMG TC Chair, Mike St. Clair at (614) 292-1284 or by e-mail at St-clair.1@osu.edu. Live Meeting Web Access. TC Members should have received a separate email with instructions on connecting through the web. If you do not have the email, please follow these steps to connect to the meeting: 1. Copy this address and paste into your web browser: https://www.livemeeting.com/cc/nfpa/join 2. Copy and paste the required information: Meeting ID: 32Z7Q4 Entry Code: hw{.t=&9f Location: https://www.livemeeting.com/cc/nfpa 3. Dial the conferencing service directly, and enter the participant code shown below: Toll-free: +1-8883309941 Toll: +1-7134810090 Participant Code: 1036315

Technical Committee on Industrial and Medical Gases Web/Teleconference AGENDA July 23, 2009 12:00 4:00 PM 1. Chair s welcome, call to order, and opening remarks at 12:00 Noon. 2. Roll-call of Committee Members and Guests 3. Approval of Minutes from the April 2008 Report on Comments Meeting held in San Antonio, TX. 4. Staff Liaison Report A. Review of NFPA Policies and Committee Procedures B. Committee membership update The TC is within balance and size limits. M = 25%; IM = 25%; U = 25%; SE = 15%; I = 5%; RT = 5% C. Revision Cycle Review F2010 (last cycle F05) [IMG-AAA] Intent to enter cycle January 9, 2009 Proposal Closing May 29, 2009 Final Date for ROP Meeting August 28, 2009 ROP Published and Posted December 28, 2009 Comment Closing March 5, 2010 Final Date for ROC Meeting May 7, 2010 ROC Published and Posted August 27, 2010 Intent to make motion (ITMAM) closing October 22, 2010 Issuance of standard - NO controversy December 14, 2010 NFPA WSCE Meeting with NITMAM June 4-9, 2011 Issuance of Standard with controversy July 29, 2011 5. Old Business 6. New Business A. Review of public proposals (see enclosed Acrobat file) B. Creation of Committee proposals 7. Other Items? 8. Date/Location of Next Meeting. (ROC Meeting between March 5 and May 7, 2010) 9. Adjournment.

2010 FALL REVISION CYCLE PROCESS DATES STAGE PROCESS STEP FOR TC 1 PRELIMINARY 1.0 Notification of intent to enter cycle 1/9/09 2 3 4 REPORT ON PROPOSALS (ROP) REPORT ON COMMENTS (ROC) TECH SESSION PREPARATION & ISSUANCE OF CONSENT DOCUMENTS 2.1 Proposal closing date 5/29/09* 2.2 Final date for ROP meeting 8/28/09 2.3 Final date for mailing TC ballots 9/18/09 2.4 Receipt of (TC) ballots by staff liaison 10/23/09 2.5 Receipt of TC recirculation ballots 11/6/09 2.6 Final date for TCC meeting 2.7 Final date for mailing TCC ballots 2.8 Receipt of TCC ballots 2.9 Receipt of TCC recirculation ballots 2.10 Final copy (w/ ballot statements) to Secretary, Standards Council 11/13/09 2.11 Completion of Reports 11/20/09 2.12 ROP Published and Posted 12/28/09 3.1 Comment closing date 3/5/10 3.2 Final date for ROC meeting 5/7/10 3.3 Final date for mailing TC ballots 5/21/10 3.4 Receipt of (TC) ballots by staff liaison 6/4/10 3.5 Receipt of TC recirculation ballots 6/11/10 3.6 Final date for TCC meeting 3.7 Final date for mailing TCC ballots 3.8 Receipt of TCC ballots 3.9 Receipt of TCC recirculation ballots 3.10 Final copy (w/ ballot statements) to Secretary, Standards Council 6/25/10 3.11 Completion of Reports 7/16/10 3.12 ROC Published and Posted 8/27/10 4.1 Notice of Intent to Make a Motion (NITMAM) Closing Date 10/22/10 4.2 Posting of Filed NITMAM 11/19/10 4.3 Standards Council Issuance Date for Consent Documents 12/14/10 4.4 Appeal Closing Date for Consent Documents 12/29/10 5 6 TECHNICAL SESSION APPEALS & ISSUANCE OF DOCUMENTS W/ CAMS 5.0 Association Meeting for Documents with Certified Amending Motions 6/12-16/11 6.1 Appeal closing date for Documents with Certified Amending Motions 7/6/11 6.2 Council issuance for Documents with Certified Amending Motions 8/4/11 * Proposal Closing Dates may vary according to documents and schedules for Revision Cycles may change. Please check the NFPA website (www.nfpa.org) for the most up-to-date information on proposal closing dates and schedules.

TECHNICAL COMMITTEE ON INDUSTRIAL AND MEDICAL GASES TO: FROM: TECHNICAL COMMITTEE ON INDUSTRIAL AND MEDICAL GASES G. R. Colonna, Staff Liaison DATE: April 30, 2008 SUBJ: Minutes of April 16-17, 2008 Meeting; April 29 Conference Call I. Attendance: Members and Alternates: Michael St. Clair, Chair, NFPA Industrial Fire Protection Section, OH John Anicello, Airgas Inc., CA William Barlen, Barlen and Associates, Inc., NJ Rob Cameron, Airgas-Nor Pac, Inc., WA Ronald Czischke, Underwriters Laboratories Inc., IL David De Fina, Sterigenics International, Inc., IL Rob Early, Praxair, NY Keith Ferrari, Praxair, NC Larry Fluer, Fluer, Inc., Compressed Gas Association, CA Rick Ginn, Wright Brothers, Inc., National Welding Supply Association, OH Martin Gresho, Sandia National Laboratories, CA Gerald Hayes, Air Liquide America, Compressed Gas Association, AZ Charles Henrici, IL Glenn Mahnken, FM Global, RI Brian Musch, Sterigenics US, LLC, IL David Namyst, Intel Corporation, CA Eugene Ngai, Air Products and Chemicals, Inc., Compressed Gas Association, PA Roger Smith, Compressed Gas Association, Inc., VA Peter Steiner, Air Products & Chemicals, Inc., Compressed Gas Association, PA Randolph Viscomi, ARC Specialty Products Corporation, NJ (by telephone 4/16 only) Guy R. Colonna, NFPA, Staff Liaison

IMG-AAA Minutes April 16, 2008/Page 2 (plus April 29, 2008) Guests: Julie Cordero, Sandia National Laboratories, NM Jeff LaChance, Sandia National Laboratories, II. Minutes of Meeting: 1. The meeting was called to order at 8:45 a.m., Wednesday, April 16, 2008, at the Drury Plaza Hotel, San Antonio. 2. All members and guests were self-introduced. The Chair noted that the agenda for this meeting primarily involved completing the Committee's action on the ROC for NFPA 55. The chair noted that Jeff LaChance, Sandia National Laboratories, would make a presentation supporting the discussion on their work at Sandia on risk-informed separation distances for hydrogen. 3. The minutes of the previous meeting (June 26-28, 2007 and August 10, 2007) were approved as submitted. 4. The Staff reviewed the schedule for processing the ROC for NFPA 55. The deadline for NITMAM for the Fall 2008 cycle is October 17, 2008. If no NITMAM is filed, NFPA 55 will proceed to the Standards Council for issuance as a consent document and not be required to be considered during the Technical Committee Report session at the NFPA Annual Meeting next June in Chicago. 5. The Chair asked David DeFina and Randy Viscomi (joining the meeting by conference call) to update the Committee on the actions taken during this revision cycle to bring NFPA 560 requirements into NFPA 55, with the future objective of withdrawing NFPA 560. These discussions were directed to the new Chapter 14 in the ROP. A Committee Comment (Log #CC1) introduced the definition for pressure relief device based upon NFPA 560. 6. The Committee invited Jeff LaChance, Sandia National Laboratories to report on the research conducted by Sandia that produced the report, "Risk Informed Separation Distances for Hydrogen Gas Storage Facilities." This report will be posted to the Committee web page. 7. The Committee completed action on Public Comments and created 19 additional Committee Comments. The Committee identified a few items for which further review was requested - a conference call meeting was scheduled for April 29th to address these outstanding items. 8. Staff agreed to prepare a staff draft of NFPA 55 based upon the ROC actions. 9. The Committee discussed revision cycles for both NFPA 55 and (the next document scheduled for revision). Depending upon the revision cycle for NFPA 55 following this revision, the consensus was to have in the same cycle.

IMG-AAA Minutes April 16, 2008/Page 3 (plus April 29, 2008) 10. The Committee conducted a conference call meeting as a follow-up to the ROP meeting earlier in the month. The agenda for the conference call was limited to 6 items - Log#4, Log#20, Committee Comment development related to ROP items on metal hydride, Committee Comment to develop annex material, Log#6 and Committee Comment, and Log#10. Attendance on the conference call included: St. Clair, Anicello, Barlen, Czischke, De Fina, Early, Fluer, Gresho, Nii, Smith, Younis, Hayes, Musch, Ngai, and Henrici. 11. With the completion of the actions on the Public and Committee Comments, the Chair accepted a motion to prepare the ROC letter ballot for NFPA 55; the motion carried. The letter ballot for NFPA 55 will be prepared and sent to the Committee separately from these minutes. This concluded the Committee's agenda items pertaining to document revisions. 12. None of the Committee documents are currently in cycle so no date for a future meeting has been established at this time. 13. There being no further business, the meeting was adjourned at 5:30 p.m. on April 17 and 5:50 pm on April 29, 2008 (for the conference call). Respectfully submitted, G. R. Colonna, Staff Liaison

51A- Log #CP1 Technical Committee on Industrial and Medical Gases, Review entire document to: 1) Update any extracted material by preparing separate proposals to do so, and 2) review and update references to other organizations documents, by preparing proposal(s) as required. To conform to the NFPA Regulations Governing Committee Projects. 51A- Log #18 Keith Le Febvre, Sigma Engineered Systems Inspection of generator needs to be performed yearly to check for stress cracks. Generator (Rexarc style) tends to be stressed at nopper tubes and support feed tube. Cracks can occur over time. Note: Supporting material is available for review at NFPA Headquarters. 51A- Log #19 Keith Le Febvre, Sigma Engineered Systems Clarification of plumbing is required. We provide solutions to customers. one of those solutions was the installation of sight glasses on Ammonia Scrubbers built by Rexarc. This upgrade is rated at 300 psi and also has needle valves to reduce flow to these glasses. This provides a very reliable read of what a scrubber is doing and at each hourly inspection can be observed and determined if operating properly. With original equipment No visual indicator, the only way an operator is alerted of a problem is on alarm. This also makes setup of the equipment and check out infinitely easier. Sight glasses are being used in the Oxweld NA7 generator as a level indicator as well as water flow indicators and have predated the Rexarc design. Sight glasses we installed are 300 psi rated on a maximum 15 psi acetylene system. The scrubber and its gaskets will fail before the sight glass does, particularly with needle valves reducing flow to just what is required and nothing more. It was suggested that these sight glasses violate 51A. Note: Supporting material is available for review at NFPA Headquarters. 51A- Log #20 Keith Le Febvre, Sigma Engineered Systems Static eliminators are required on Rexarc compressor lube systems. Static charge can build up on lube oil canister resulting in 500K volt discharges. Note: Supporting material is available for review at NFPA Headquarters. 1

51A- Log #21 Keith Le Febvre, Sigma Engineered Systems Acetylene generator system emergency shutdown needs to be fitted with nitrogen purge and auto deluge activation. Safety improvement. Note: Supporting material is available for review at NFPA Headquarters. 51A- Log #22 Keith Le Febvre, Sigma Engineered Systems High pressure relief valves need to be located higher. Valve too low, subject to fouling. Note: Supporting material is available for review at NFPA Headquarters. 51A- Log #23 Keith Le Febvre, Sigma Engineered Systems A whole new section needs to be applied for scale detection. Cylinders require active bottom inspection for leaks. Note: Supporting material is available for review at NFPA Headquarters. 51A- Log #13 Update all referenced publications to the most current edition of the included documents. In addition: Update the extract text in the following sections: NFPA 1:2009 in Sections 3.3.5, 3.3.5.1, 3.3.5.2 and 3.3.5.3 NFPA 51:2007 in Sections 3.3.1.3 and 3.3.7 NFPA 5000:2009 in Sections 3.3.4, 3.3.6.2, 3.3.8, 3.3.10, 3.3.11 and 3.3.12. The extract text should be updated to reflect the current text in the source documents referenced. 2

51A- Log #14 Construction-related controls specified for buildings, and portions thereof, where high hazard contents are stored, used, or handled in quantities g reater than the maximum allowable quantity per control area as specified in NFPA 5000. The requirements for construction vary with the type of hazardous materials employed. A tier of building safety that exceeds the construction requirements for control areas to accommodate quantities of hazardous materials in excess of those permitted using the control area concept.[ 2009] NFPA uses the concept of protection levels in a manner that is analogous to Group H occupancies in other model codes. Although NFPA 1 and NFPA 5000 do not have unique occupancy classifications for occupancies containing hazardous materials, Protection Levels 1 to 5 in NFPA codes and standards reflect increased building safety requirements that are applicable to occupancies containing hazardous materials, which generally correlate to the Group H, Division 1 to 5 occupancy classifications in other codes. [ 2009] Delete the existing definition of Protection Levels and replace it with extract text from NFPA 5000 2009. The definition is also correlated with NFPA 55:2009. 3

51A- Log #3 4.4 Ventilation. Rooms housing acetylene operations, excluding calcium carbide storage rooms (see 5.2.7), shall be provided with mechanical exhaust or fixed natural ventilation ventilated in accordance with NFPA 55, Standard for the Storage, Use, and Handling of Compressed Gases and Cryogenic Fluids in Portable and Stationary Containers, Cylinders, and Tanks.that ventilates the space at a rate of not less than 1 ft3/min/ft2 (0.03 m3/min/0.09m2) of floor area over the area of storage or use. 4.4.1 Rooms or areas where gases other than acetylene are stored or used shall be ventilated in accordance with NFPA 55. 4.4.2 Calcium carbide storage rooms shall be in accordance with 5.2.7. 4.4.3 Continuous Operation. When mechanical exhaust systems are provided the systems shall operate continuously unless an alternate design is approved by the authority having jurisdiction. 4.4.1 4.4.3.1 Reduction in Ventilation. Mechanical exhaust ventilation shall be permitted to be reduced below 1 ft3/min/ft2 (0.03 m3/min/0.09 m2), provided that full ventilation is automatically restored when the acetylene concentration exceeds 25 percent of the lower flammable limit (LFL) when measured by a gas detection system in accordance with Section 4.5. 4.4.4 Shutoff Controls. Where powered exhaust ventilation is provided, a manual shutoff switch shall be provided outside of the room in a position adjacent to the principal access door to the room or in an approved location. 4.4.4.1 The switch shall be of the break-glass or equivalent type and shall be labeled as follows: WARNING: VENTILATION SYSTEM EMERGENCY SHUTOFF 4.4.5 Inlets to the Exhaust System. Inlets to exhaust systems serving rooms used for acetylene operations shall be located within 12 in. (304.8 mm) of the highest point in the room. 4.4.6 Recirculation of Exhaust. Exhaust ventilation shall not be recirculated within the room or building. 4.4.7 Ventilation Discharge. The point of termination for the exhaust ventilation system discharge shall be a minimum of 15 m (50 ft) from air intakes to building ventilation systems, air-conditioning equipment, and air compressors. Fixed natural ventilation. The movement of air into and out of a space through permanent openings that are arranged in such a way that the required ventilation cannot be reduced by operating windows, doors, louvers or similar devices. The use of ventilation systems varies with the location of the manufacturing facility. Facilities located in warmer climates traditionally use natural ventilation as a means to ventilate the space and in warmer climates it is not unusual for a facility to have one exterior wall and a roof, or simply a roof for protection from the elements. On the other hand, facilities in colder climates are more likely to be enclosed and mechanical systems are used as a means to provide ventilation. The reference to NFPA 55 requires the code user to interpret application, e.g., are the gases heavier or lighter than air, etc. The revised provisions are intended to interpret the requirements of NFPA 55 as they may be applicable to acetylene manufacturing operations. Minor modifications were made to the fundamental provisions found in NFPA 55 for clarification. For example, the terms mechanical exhaust ventilation or exhaust ventilation were used to differentiate between mechanical and natural means. Ventilation for calcium carbide storage rooms was left under the direction of the building code as each building requires fundamental ventilation to prevent deterioration of the building and requirements vary based on occupancy. Additional reasons as to specific changes by section are as follows: Section 4.4: Requirements for ventilation have been revised to establish the criteria applicable to acetylene operations under the specific criteria listed in the sections that follow. Provisions have been added to recognize that natural ventilation may be used in lieu of mechanical exhaust as specified in NFPA 55. A term fixed natural ventilation has been added to avoid a reduction in required ventilation from the area under consideration. Section 4.4.1: This section is in effect an exception to 4.4 which defers to NFPA 55 for requirements when rooms or areas are used for gases other than acetylene. Section 4.4.2: The provisions for calcium carbide storage rooms including construction features and ventilation are 4

found in NFPA 5000. Section 4.4.3 and 4.4.4: Requirements based on NFPA 55. The requirements in 4.4.3.1 have been relocated from existing section 4.4.1 with minor edits in units of measure. Section 4.4.5 Acetylene with a molecular weight of 26 is lighter than air. The provisions for lighter than air gases have been drawn from NFPA 55 with a minor clarification to indicate that the highest point in the room or area is a bounding factor. Section 4.4.6: The exhaust air is treated as one pass air and recirculation is prohibited. Section 4.4.7: The point of termination for the ventilation discharge is coordinated with the requirements of NFPA 55. Editorial revisions have been made to the SI conversions equivalent to 1cfm/sf for clarity. A new definition has been added to Chapter 3 to define fixed natural ventilation. Ventilation systems that can be shut down by closing a door, window or similar devices should not be relied upon to be functional in all circumstances. In some cases the walls of the room may be open with the area located under a roof. In other cases ventilation may be achieved through the use of natural draft or similar means. When natural ventilation is used as a means of control it is intended that the openings used for the introduction or removal of air from the space be maintained in an open condition. 5

51A- Log #4 4.5* Gas Detection System. Rooms in which acetylene operations are conducted shall be provided with an a listed or approved flammable gas detection system. A.4.5 A listing standard for gas detection and sensing systems is published by Underwriter s Laboratories as UL 2075. 4.5.1 Gas detection systems shall not be required for structures equipped with fixed natural ventilation and constructed as weather protection in accordance with the requirements of NFPA 55,. 4.5.2 4.5.1 System Design. 4.5.2.1 4.5.1.1 Listed System Required. The flammable gas detection system shall be listed or approved for use with acetylene and any other flammable gases used in the room. Add the following informational reference to Annex B under a new section for Underwriter s Laboratories (UL): UL 2075, UL Standard for Safety Gas and Vapor Detectors and Sensors, 2004. Add the following referenced publication to Section 2.2: NFPA 55,, 2009. Gas detection systems specified in Section 4.5 are required to be approved, while the gas detection systems required in existing Section 4.5.1.1 are required to be listed. is a Standard and gas detection systems should be able to be either listed or approved. UL 2075 provides a listing standard for application in the event a listing is sought. By providing for the use of either a listed or approved gas detection system safety is maintained while allowing for the development of new technology. A new Section 4.5.1 has been provided to exempt areas equipped with natural ventilation from the requirements for gas detection systems. Gas detection in spaces that are constructed with natural ventilation do not provide an adequate means to collect meaningful samples of the atmosphere of the surrounding space thereby calling into question the efficacy of any installed gas detection system. For areas constructed as weather protection (See NFPA 55:2009:6.5.2 the space is considered to be an outdoor area. Areas equipped with mechanical exhaust ventilation systems where operation of the mechanical system is designed to meet the minimum requirements for ventilation are required to be protected by a gas detection system as such spaces are allowed to reduce the required ventilation based on the presence of the gas detection system. 6

51A- Log #17 4.6.1.1* Listed electric heaters shall be allowed to be used in operating areas regulated by 4.7.2 when installed and used in accordance with the manufacturer s instructions and the listing. A.4.6.1.1 The autoignition temperature for acetylene as listed in NFPA 497 is 305 C (581 F). Acetylene is the only material listed as being in Group A at the present time. Electrical equipment is required to comply with the requirements of NFPA 70, based on Class and Group designations determined by conditions as well as the material present. 4.6.2 Boilers, water heaters and other heating equipment containing one or more of the following potential hazards employing flames, or capable of creating sparks shall be located in a separate building or room not directly communicating with areas devoted to acetylene operations. (1) Open flames. (2) Release of sparks or spark generation during operation. (3) Exposed surface temperatures exceeding the lowest autoignition temperature of any of the materials present. The Electrical Code (NFPA 70) establishes the requirements for the use of electrical equipment and references NFPA 497 for specific materials where the autoignition temperature of acetylene is published. :1.5 would allow the use of this equipment today, when approved by the AHJ. Section 4.7 establishes the requirements for electrical equipment, and all electrical equipment must comply with the electrical code. A change in Section 4.6 to allow the use of listed electrical heating systems is in accord with the electrical code, and listed equipment is available that can be installed in electrically classified areas. Although the use of listed equipment in itself imposes requirements regarding the ignitability of vapors information regarding the autoignition temperature of acetylene is included in the code change. Section 4.6.1.1 is in effect an exception to 4.6.1 to allow the use of listed equipment. A reference to 4.7.2 is included to alert the user to the base classification for areas of this nature. Listed products can be accessed on the Underwriter s Laboratories (UL) website at www.ul.com. There are products available that can be used in both Class I and II locations and are suitable for use with various Groups classifications including those in Group A, B, C, etc. The proposed revision to Section 4.6.2 is to alert users to the fact that surface temperatures are of concern as well as active sources of ignition such as open flame and sparks. The revision to the term create sparks has been made to direct the user to either a release of sparks or spark generation rather than opening the potential for spark creation to include things like the materials of construction for equipment contained in the area or other extrinsic elements of the installation such as floor construction, etc.. 51A- Log #15 5.1.1 Calcium carbide shall be stored in packages meeting U.S. Department of Transportation or Transport Canada regulations or in containers approved by the authority having jurisdiction. Calcium carbide may be stored or handled in containers other than original shipping containers. For example, hoppers that are used for transfer of the material or silos used to store the material may be used. Containers used in-house are not designed for release into the transportation system; therefore having a broad requirement to meet the requirements of the transportation system is not practical. 7

51A- Log #5 6.3.2.6 The use of multiple pressure relief devices serving the same section of a gas generator shall be allowed., provided that the aggregate cross-sectional venting area of the individual pressure relief devices is not less than the cross-sectional area of the common vent line to which they are connected. 6.3.2.6.1* When multiple pressure relief devices are connected to a common vent line or manifold the cross-sectional area of the common vent line or manifold shall not be less than the aggregate cross-sectional venting area of the individual pressure relief devices connected. A.6.3.2.6.1. The aggregate cross sectional area of the connected pressure relief devices is the sum of the cross sectional areas for each of the individual relief devices connected to the manifold. Existing Section 6.3.2.6 is in error. The cross sectional area of the common vent line serving a system must be not less than or larger than the cross sectional areas of the pressure relief devices served. As currently written one could connect a series of pressure relief devices to a common vent line thereby exceeding the carrying capacity of the common vent line creating a back pressure on the system in the event multiple relief devices were to operate. The paragraph has been divided into a charging statement and a subparagraph in keeping with the Manual of Style. A clarifying note has been added to further explain the use of the term aggregate within the context of the requirements. 51A- Log #9 6.5.1.2 When discharging to sumps, pits, or other receptacles, the point of discharge shall be located outdoors not less than 15 ft (4.5 m) 25 ft (7.6 m) from sources of ignition and the line of adjoining property that is able to be built upon. 6.5.1.2.1 The minimum required distances shall not apply when fire barriers without openings or penetrations having a minimum fire resistive rating of 2 hours interrupt the line of sight between the storage and the exposure. The configuration of the fire barriers shall be designed to allow natural ventilation to prevent the accumulation of hazardous gas concentrations. The separation distance of 25 feet has been correlated with changes proposed to Section 8.1.1.1.1. The 25 foot distance correlates the requirements for separation from ignition sources as found in 55:7.6.3.2 which prohibits the use of open flame, smoking and ignition sources within 25 feet of the area used for the storage or use of flammable gases. It could be noted that there is an apparent inconsistency between the requirements of 55:Table 7.6.2 for separation from property lines as the table uses variable distances based on quantity. On the other hand the discharge to sumps, pits, etc. represent a circumstance where it must be assumed that the gas is always present. As a result the required distances are conservatively based. Encroachment on sources of ignition or property lines is allowed by proposed Section 6.5.1.2.1 in a manner consistent with that used in 55:Table 7.6.2. 8

51A- Log #6 Revise the title to Chapter 7 as follows: Chapter 7 Acetylene Gasholders, Purifiers, and Low and Medium Pressure Driers and Purifiers Revise the title to Section 7.3 as follows: 7.3* Low and Medium Pressure Purifiers and Driers. Purifiers and driers shall have inlet and outlet shutoff valves located and arranged so that they are able to be closed in an emergency. By definition LOW pressure acetylene does not exceed 1 psig. MEDIUM pressure acetylene includes pressures in the range >1 psig <15 psig, and HIGH pressure acetylene includes pressures >/= 15 psig to </=400 psig. The typical equipment (driers and purifiers) used are MEDIUM pressure systems. The revisions to the the titles to Chapter 7 and Section 7.3 recognize that the requirements apply to both low and MEDIUM pressure systems. 9

51A- Log #8 Revise Section 8.1.1.1.1 as follows: 8.1.1.1.1 Drain lines from high pressure [pressure above 15 psi (103 kpa)] acetylene systems, oil separators, condensate traps, and driers shall be piped outdoors to a location away from any not less than: (1) 25 feet (7.6 m) from building openings. (2) 25 feet (7.6 m) from sources of ignition. and (3) 10 feet (3 m) from combustible material. (4) 50 feet (15.2 m) from air intakes. 8.1.1.1.1.1* The minimum required distances shall not apply when fire barriers without openings or penetrations having a minimum fire resistive rating of 2 hours interrupt the line of sight between the drain line discharge and the exposure. The configuration of the fire barriers shall be designed to allow natural ventilation to prevent the accumulation of hazardous gas concentrations. A.8.1.1.1.1 Drains lines are designed to drain condensate or other fluids, they are not vent lines which are used to vent or exhaust gases from the system. Drain lines should be piped to the outside of the building to avoid potential evolution of vapors that have been entrained into a liquid discharge. The location and collection of liquid drainage will be controlled by environmental considerations depending on the nature of the discharge. Additional safeguards may be required when high pressure acetylene is vented. Protection against the potential ignition of vented gases due to a static electric discharge should be considered. For further information see NFPA 77 The use of rapid opening valves in drain lines should be avoided in order that unintended ignition does not occur. Add NFPA 77 to Annex I.1.1 as follows: NFPA 77 2007. Piping of any drain line should be to the exterior of the building, and not just those lines serving oil separators, condensate traps and driers. As currently written the term away from is unenforceable as it fails to provide the designer with guidance as to specific location. Distances have been chosen to correlate with the approach used in NFPA 55. Refer to Section 7.6.2.5 for distance from building openings; Section 7.1.6.3 for separation from combustibles, Section 7.6.3.2 for sources of ignition and Section 7.6.2.4 for the distance from air intakes. Drain lines are not vent lines per se, rather they are designed to drain fluid, however, it is possible to have gases entrained into the liquid and venting to the outside is appropriate. In older facilities the drain lines were taken to a drain pit or lime pond, in newer facilities the drain lines may be taken to tanks where the atmosphere in the tank is vented through a vent line. Additional requirements for discharge from systems that may contain residual calcium carbide or waste products from the process may be found in Section 6.5. Section 8.1.1.1.1.1 has been added to provide flexibility to the user through the use of fire barriers. The concept has been taken from footnote a to Table 7.6.2 in NFPA 55. The reduction in distance from air intakes is allowed with the recognition that discharge from a drain line is controlled. The discharge from system leakage or component failure such as those anticipated by 55:Table 10.3.2.2.1 is not applicable as the discharge is controlled through the process. Informational annex notes have been provided to inform the reader as to the purpose of the drain lines and to avoid confusion between requirements for system vents which are regulated under separate requirements. Additional precautionary information is provided regarding concerns for static electricity and the use of rapid opening valves (ball valves, etc.) in discharge lines that could lead to unintended ignition in the drain line system. 10

51A- Log #7 Delete Section 8.1.1.2 and relocate it to become a new Section 7.4 with modifications to include low pressure systems as follows (underlining and strikeouts show the modifications from 8.1.1.2): 7.4 Drain Lines from Low and Medium Pressure Acetylene Systems. Drain lines from low and medium gauge pressure [15 psi (103 kpa) and lower] acetylene systems shall be permitted to be piped to an indoor drain where the effluent water drained from the system is visible to the operator from the drain valve location. Chapter 8 is specific to acetylene compressors and high pressure driers. Section 8.1.1.2 was drafted to address requirements for low and medium pressure systems. Relocating the provision to Chapter 7 puts the requirement in the proper chapter. 51A- Log #2 8.1.1.3 Pressure Relief Device Vent Lines Pipes. Vent lines pipes serving equipment provided with pressure relief devices shall be in accordance with 6.3.2. 8.1.2.2 Pressure Relief Device Vent Lines Pipes. Vent lines pipes serving pressure relief valves shall be in accordance with 6.3.2. The title to Sections 8.1.1.3 and 8.1.2.2 and the terminology used in the accompanying text has been revised to be consistent with Section 6.3.2. Section 6.3.2 consistently refers to these lines as pipes. Although the term line is used for other services, e.g., discharge lines (Section 8.1.2.3.2), inlet lines (8.1.2.3.1), etc., the term pipe is used when vents are mentioned. The change is intended to be editorial and consistency is warranted throughout the document. 51A- Log #11 10.1.1 Cylinder charging manifolds shall be provided with a shutoff valve and a blow-down valve vented to the outdoors or to the low pressure system. 10.1.1.1* The blow-down valve shall either be arranged to vent the manifold to the outdoors in accordance with 6.3.2.4.2 or the discharge shall be returned to a low or medium pressure acetylene system with the pressure rating and capacity to contain both the maximum pressure and volume released from the manifold. A.10.1.1.1 Additional safeguards may be required when high pressure acetylene is vented. Protection against the potential ignition of vented gases due to a static electric discharge should be considered. For further information see NFPA 77 The use of rapid opening valves in vent lines should be avoided in order that unintended ignition does not occur. By definition a low pressure system is 1 psig or less. It is not uncommon for a facility to have a medium pressure system that would be available to vent the filling manifold back into. Venting of overpressure into low or medium pressure systems is able to be done safely providing the system receiving the gas has both the capacity and the pressure rating sufficient to handle the gas returned. A new subsection (10.1.1.1) and accompanying annex note has been created to address the requirements of the Manual of Style. 11

51A- Log #10 10.1.1 Cylinder charging manifolds shall be provided with a shutoff valve and a blow-down valve vented to the outdoors or to the low pressure system. 10.1.1.1* The blow-down valve shall either be arranged to vent the manifold to the outdoors in accordance with 6.3.2.4.2 or the discharge shall be returned to a low or medium pressure acetylene system with the pressure rating and capacity to contain both the maximum pressure and volume released from the manifold. By definition a low pressure system is 1 psig or less. It is not uncommon for a facility to have a medium pressure system that would be available to vent the filling manifold back into. Venting of overpressure into low or medium pressure systems is able to be done safely providing the system receiving the gas has both the capacity and the pressure rating sufficient to handle the gas returned. A new subsection (10.1.1.1) and accompanying annex note has been created to address the requirements of the Manual of Style. 51A- Log #1 10.1.2 A check valve shall be installed in the pipeline at each cylinder charging manifold and in each cylinder charging lead. 10.1.2.1 Check valves shall not be required on charging leads used to charge individual cylinders on mobile acetylene trailer systems equipped with manifold systems serving multiple containers. Mobile acetylene trailers contain cylinders that are manifolded in place. Cylinders are filled through the same manifold that is connected to the user system when the trailer is used as a mobile source. A check valve is a one-way valve that allows flow in one direction and blocks the flow in the reverse direction. When individual cylinders are placed into use the gas is controlled by the user through individual pressure control and discharge systems furnished by the user. By contrast the gas supply cylinders on mobile acetylene trailers are filled and consumed through a fixed manifold piping system integral to the trailer where the user provides controls on the discharge from the manifold system. Gas must be able to flow both into and out of the fixed cylinder manifold system, and the inclusion of check valves on individual cylinder leads would preclude either the filling or the use of gas through a singular piping system. Removal of the requirement for check valves allows the manifold system to function in a bidirectional manner when cylinders are filled or when the system is in use. Placement of a check valve on the cylinder manifold at the user location may be done, however, the check valve is not part of the mobile acetylene trailer system. 12

51A- Log #16 Revise Section 10.6 to address safeguards to include fire protection requirements for Mobile Acetylene Trailer Systems (MATS) for MATS charging facilities attendant to acetylene charging plants. Mobile Acetylene Trailer Systems (MATS) are the subject of Section 10.6. At the current time reference is made to CGA G-1.6 Recommended Practices for Mobile Acetylene Trailer Systems, through the use of an annex note. There have been two recent (2007) fires involving MATS at user sites during unloading operations which have come to the attention of the National Transportation Safety Board (NTSB). Specific recommendations have been made by the NTSB regarding the G-1.6 document and CGA s Acetylene Committee is currently in the process of revising the publication with revision expected to be completed at the end of 2009. Copies of the NTSB report on the fires at the unloading facilities have been added to the IMG TCs e-committee pages and the document is on file at NFPA offices. The proposed code change has been entered to allow CGA s Acetylene Committee complete the task of review in order that the industry can reach consensus on the issue of fire protection for MATS at both loading as well as unloading facilities. Fire protection is the subject of Chapter 11 and perhaps a new Section 11.2.2 is the appropriate place to establish a requirement for MATS. The proposal has been crafted to allow further consideration or clarification of the control strategy applicable to MATS within the context of the document. The IMG TC task group on is reviewing the NTSB report and potential revisions that may affect NFPA 51 are also being discussed. 51A- Log #12 1. Delete the title for B.2 Informational References and combine the remaining publications with B.1.2.1. B.2 Informational References 2. Revise the CGA references located in B.1.2.1 (and B.2) to the current publication and reorder as follows. CGA Pamphlet G-1, 2001 2003. CGA Pamphlet G-1.6, 2001 2008. CGA Pamphlet G-1.7, 1995 2005. CGA G-1.8, 1999 2008. CGA Safety Bulletin SB-4, 1997 2005. Item No. 1: Strike the title for B.2 and incorporate the references to CGA G-1 and G-1.8 into B.1.2.1. All of the references to CGA Publications are informational references having a subdivision of Informational References under a list of Informational References is not needed. All of the CGA references are informational. Item No. 2: Update the list of CGA references to the current publication as indicated. 13