SUPPLEMENTARY

Report of the Committee on

Compressed Natural Gas Vehicular Fuel Systems

Douglas B. Home, CTudrman Atlanta Gas Light Co., GA

Pep. American Gas Association

Nancy C. Pehrson, Minnegasco, Inc., MN

Roy E. Adidns, Cryogenic Fuels, Inc., VA Ronald M. Baker, Process Engineering, Inc., NI-I Dennis Ft. Boone, Houston Metropolitan Transit Authority, "IX C. Everett Brett, The University of Alabama, AL c~j. Brtten, u s Dept. of Transportation, DC John C. Carter, Southern Cross Corp., GA David P. Oaan, Industrial Risk Insurers, CT Don-H. Coers, Chicago Bridge & Iron Co., IL Robert B. De Remer, AGA Laboratories, OH

Rep. American Gas Association John B. Dimmick, Pressed Steel Tank Co., Inc., WI C. H. Duke, City of Miami Fire Dept., FL

Rep. Fire Marshals Association of North America Douglas W. Dunford, Northwest Natural Gas Co., OR Lee W. Gibbs, Underwriters Laboratories, Inc., IL Michael D. Grant, Consumers' Gas Company Ltd., Canada

~,~ ~. Canadian Gas Assn. W. Gustafson, Cryogenic Services, GA

Richard A. Hoffmann, Hoffmann & Feige, Inc.; NY ThomasJ. Joyee, TJoyce Associates, Inc., VA W'dliam S. Kalaskle, Superior Valve Co., PA

Rep. Compressed Ga~ Association ManuelJ. PinTa, Southern California Gas Co., CA Robert E. Petsinger, CNG Services of Piusburgh, Inc., PA Ralph Rackham, Sulzer Canada, Inc., Canada Jean-Claude Rousseaux, IngersoU-Rand, NC Fred P. Snyder, Essec Cryogenics of MO, Inc., MO

H. Stannard, Stannard & Co., NJ thkuma~r, Cahex Petroleum Corp., "IX

Alternates

W'dlhun H. Baden, Compressed Gas Assn. Inc., VA (Air. to W. S. Kalaakie)

Dale C, eren, Essex Cryogenics of MO, Inc., MO (Alt. to F. P. Snyder)

Robert W. Nelson, Industrial Risk Insurers, CT (Alt. to D. P. Chart)

Richa~ D. Prather, The Peoples Gas Light & Coke Co., IL (Alt. to D. B. Home,Jr.)

Gary R. Woodford, Dept. of T r'ansportation, DC (Alt. to C.J. Britell)

StaffIJai~n: Theodore C. Lemoff

This list represents the membership at the time the Committee was balloted on the text of this edition. Since that time changes in the membership may have occurred.

The Supplementary Report of the Committee on Compressed Natural Gas Vehicular Fuel Systems is presented for adoption.

This Supplementary Report was prepared by the Technical . Committee on Compressed Natural Gas Vehicular Fuel S/stems and proposes for adoption,a Supplementary Report which documents its action on the public cornn~nts received on the proposed revision to NFPA 52-1988, Standard on Compressed Natural Ga~ Vehicular Fuel Systems, published in the Technical Committee Reports for the 1992 Annual Meeting. ~ ,

This Supplementary Report has been mbmitted to letter ballot of the Techmcal Committee on Compressed Natural Gas Vehicular Fuel Systems which consists of 27 voting members; of whom 23 voted affirmatively, 0 negatively, 1 abstained (Mr. Woodford), and 3 ballots were not returned (Messr~ Baker, Dimmick, and Duke).

31

N F P A 52 - - A92 T e D

(Log#52) 52-1 - (Various): No Action SUBMITITAt: Carmen E. RoMi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: N /A RECOMMENDATION: The fuel station task group endorses Committee Comment Log No,. 64, 66, 67, 68, 72, 21, 22, and 23; submitted by Robert DeRemer, American Gas A~odation Laborato- ries. The fuel station task group does not endorse Mr. DeRemer's

Comment Log #65. The task group agreed that the current definitions for ~3ontainer" and ~Pressure Vessel" and proposed definition for aO/linder" (proposal 52-10) are appropriate. SUBSTANTIATION: None. COMMITTEE ACTION: No Action. COMMITrEE STATEMENT: The comment does not meet the requirements of paragraph 11-8 of the NFPA Regulations Governing Committee Projects. The Committee thanks the commentor for his interest.

(Log # 25) 52- 2 - (1-1 Scope): Accept SUBMITIT..R: Aubrey P. Eddy, Soutl~em Cross Corp. COMMENT ON PROPOSAL NO.: 32-2 RECOMMENDATION: Revise as follows:

I-I Scope. This standard applies to the design and installation of compressed natural gas (CNG) engine fuel sDtems on vehide, of all types including aftermarket and OEMs and to their asaodated fueling (dispensing) systems. SUBSTANTIATION: All conversions should meet the same standards. COMMrlWEE ACTION: Accept.

/

(Log#el) 52-3- (1-1.1): Reject SUBMITTER: Graham Barker, Norwalk Company, Inc. COMMENT ON PROPOSAL NO.: 52-2 RECOMMENDATION: NFPA 52 should be separated into two (2) distinct codes: one for vehicles, the other for stations. SUBSTANTIATION: The CNG industry has grown to a point where organizations are specializing in either vehicles or stations and there is now widespread confusion by authorities as to which areas of Section 2 are applicable to fadlities and which to vehicles. Separate codes would eliminate these "interpretation" problems.

Countries such as Canada and New Zealand have already made this anM~i~'aACTlted their code sections more distinctly.

ON: Reje~ COMMrrrEE STATEMENT: The committee does not agree that the current form will result in widespread confusion.

(Log # 64) 52-4- (1-1.1 and 1-1.2 (New)): Reject SUBMrYrER: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 52-2 RECOMMENDATION: The proposed revision to split the coverage into two parts, one for vehide coverage and one for dispensing systems should be retained. Also, editorially, in the 5rd line of the exception, the words "these

standard" are not of the same sense. SUBSTANTIATION: This will make the document easier to understand for the inspection authorities. Also, editorially, in the 3rd line of the Exception, the words ~these standard" are not of.the s a m e s e n s e .

COMMITTEE ACTION: Reject. COMMITTEE STATEMENT: The "committee does not agree that the current form will result in confusion.

(Log # 4) 52- 5 - (1-5): Accept SUBMITITJ~ Nancy Pehrson, Minnegasco, a Division of Arlda, Inc. COMMENT ON PROPOSAL NO.: 52-9 RECOMMENDATION: Revise as follows:

"Container Valve. A valve ~4~....~d L 1 ~.~,d connected directly to a cothainer outlet." SUBSTANTIATION: ,_Based on substantiation given and committee acceptance the words -operated by hand" were meant to be deleted. COMMrFrEE ACTION: Accept.

(Log#5) 52- 6 - (1-5): Accept in Principle SUBMrI'IT.R: NancyPehrson, Minnega~o, a Division of Arkla, Inc. COMMENT O N PROPOSAL NO.: 52-22 RECOMMENDATION: Revise as follows:

Supply Line. The pipe, robing, or hose, including all related fittings v,~ .. ~L;. ".~ through which natural gas passes. SUBSTANTIATION: Supply line is also used to apply to stations under new 5-10.8 (see Proposal No. 96 from TCR). COMMITrEEACTION: Accept in Prindple.

1. Delete the definition of Supply Line. 2. Add a new definition of Fuel Line, using the current definition

of Supply Line. 3. In chapter 3, mlmtimte "fuel line" for "supply line*

COMMITI~E STATEMENT: The commentor is correct that the current definition does not agree with the TC1Z The committee believes that the definition should be changed to avoid any confusion between lines carrying gas on a vehicle andlines carrying gas in a fueling station. The term supply line is changed to fuel line in Chapter 5 for consistency with the new definition

(Log # 11) 52-7- (1-~): Reject ~ SUBMrIWER: Dean I. Ledbetter, Chem-Tec Equipment Company COMMENT ON PROPOSAL NO.: 52-9 RECOMMENDATION: Add the following new definitions:

Container Excess FlowValve. An automatic shutoffpressure differential flow sensor integrated into and as a part of a container valve mounted in the valve neck or which connects directly to a container valve. Otherwise it shall connect to a normally dosed remotely actuated shut-offvalve and may be either external or internal to the container.

Line Excess Flow Valve. An automatic shtit-offpres~mre differential flow sensor which connects directly to a fuel manifold or is incorpo- rated as a part of the manifold in the fuel line before the first stage regulator.

Furthermore the Excess Flow Valve ~hall: (a) Trigger immediately in the event of a line rupture or major

leak. (b) Structurally and operationally meet the Brooklyn road test data

shock and vibration levels. . • (c) Must be arranged so that the probable rupture flow is greater

than the trip settings. (d) Trigger in response to [changes in fuel] flow, without

depending on external (non-flow) senson. (e) Be protected from damage by road ha~rds and accidents to

maintain function, if located external to the container. SUBSTANTIATION: To prescribe performance, structural and operation requirements for this new major CNG fuel-system component and to allow probable new developments in EFV and container valve technology to fit the NFPA 52 specification while

oviM~T~tY and user acceptance of CNG vehicles. ACTION: Reject.

COMMITTEE STATEMENT: The proposed definitions are rejected as the device is not covered in the standard. See Committee Action on Comment 52-26 (Log #13).

(Log # 65) 52-S- (1-5): Reject SUBMITTE~ Robert B. DeRemer, P.E., American Gas Assodation Laboratories COMMENT ON PROPOSAL NO.: 52-6 RECOMMENDATION: Add the following new definition:

Container. A cylinder which complies with either DOT or CI'C regulations or a pressure vessel which complies with the ASME code. SUBSTANTIATION: Burst pressure. Existing definition is dem'er than the proposed one.

Container. The addition of this definition will help the user of the document to understand that the term acontalner" refers to both cylinders and pressure vessels. The proposed revisions use the term acontainer" to refer to both DOT/CTC cylinders and ASME pressure vessels as long as there is no reason to differentiate between t~ern. C O M M I T T ~ ACTION: Reject. COMM/TTEE STATEMENT: The committee believes that the current definition is appropriate.

3 2

N F P A 52 - - A 9 2 T C D

I

(Log # 66) 52-9- (1-5): Accept SUBMrrrER: Robert B. DeRemer, P.E., American Gas Assodation Laboratories COMMENT ON PROPOSAL NO.: 52-15 RECOMMENDATION: Change the word ~attention" to "attenua- tion". SUBSTANTIATION: The term "attenuation" is appropria~. COMM1TI"EE ACTION: Accept.

(Log # 26) 52-10 ~ (1-5): Accept SUBMITIT.R: Aubrey P. Eddy, Southern Cross Corp. COMMENT ON PROPOSAL NO.: 52-20 RECOMMENDATION: ,Add the word ~md" to definition of pressure relief device.

Pressure Relief Device. A pressure ~ o r temperature activated device used to prevent the pressure from rising above a predeter- mined maximum and thereby prevent the rupture of a normally charged cylinder when subjected to a standard fire test as required by 49 CFR 173.34(d) or 73.34(d) of the TC Regulation& Pressure relief devices for COT/TC cylinders shall also include devices capable of protecting partially charged cylinders when subjected to these fire tests. . SUBSTANTIATION: The CG-5 type is a combination rupture disk/ fusible.plug which requires both pressure and temperature to function. COMMITIT.E ACTION: Accept.

iLog#51) 52-11 - (1-5): Accept SU'~[I'I'I 'I~[~ Carmen F_. Rossi, Fuel Station Task Group, Natural Gas Vehide Coalition COMMENT ON PROPOSAL NO.: 52-9 RECOMMENDATION: Delete the following from the definition of ~Container Valve:"

"container Valve. A valve vt,,.~,~,d L I .~.~.~, connected directly to a container outlet. ~ SUBSTANTIATION:f Refer to 9 /17/91 comment from Nancy " Pehrson (Committee Comment Los #4). COMMITIT.E ACTION: Accept. COMMITTEE STATEMENT: Refer to Committee Action ot~ Comment 52-5 (Log #4)

(Log# 1) 52-12 - (Chapter 2): Reject SUBMITIT..R: Paul Raymond, Cumberland, [ ] COMMENT O N PROPOSAL NO.: N / A RECOMMENDATION: Add the following new text.

"All underground steel facilities or piping will be installed in accordance with NFPA 54, Section 3 : SUBSTANTIATION: At this time it is evident that material spedfication and other requirements for underground s t ruc tures has not been determined. NFPA 54 will supply ample information instead of duplicatingit in NFPA 52. COMMITTEE ACTION: Reject. COMMrlTFEE STATEMENT: NFPA 54 does not cover piping over 150 psig. The coverage in NFPA 54 on protection of pipin[[ is generaI, and the material in paragraph 4-9.1 covers the subject.

COMMrlWEE STATEMENT: There means other than paints and coatings to prevent corrosion. Corrosion ~rotection of containers is covered in 4-5.2. "Corrosive environment is not defined in the comment and is subject to interpretation.

(Log # 5) 52-14 - (Chapter 2): Accept in Principle S U B ~ Paul Raymond, Cumberland, [ ] COMMENT ON PROPOSAL NO.: N / A RECOMMENDATION: Add the following ne~v text.

"Notify the local gas utility and munidpality for requirements and distribution system capadties." SUBSTANTIATION: The local gas utility can supply information as to its system capadty, possible stray currents from cathodic protec- tion systems and whether propane air plants are u.sed to peak shave during winter months. The Btu content of propane can cause possible problems with the carburetor of the CNG Vehide. COMMITFFAgACTION: Accept in Principle. Add a new 4-5.1: When served by a gas utility, the utility shall be notified of al lCNG

installationL COMMrlWEE STATEMENT: The comment is accepted, reworded for clarity and located in Otapter 4 which covers installation of compression equipment.

( L o g # 10) 52- 15 - (2-2.1): Accept in Principle SUBMITrF.~ Deepak Singh, National Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-26 RECOMMENDATION: Revise paragraph to read:

2-2.1 The specifications for the gas to be used in the vehicle should comply with SAEJ1297 National Gas Fuel Specification Recommen- dations for Natiomd Gas as a Vehicle Fuel. SUBSTANTIATION: SAEJ1297 has now been drafted and should be considered for adoption by the SAE on October 7, 1991. COMMI ACTION: Accept in Prindple. Add aNote to 2-2.1: Note: For additional information on gas quality see SAEJI297

National Gas Fuel Specification Recommendations for National Gas as a Vehide Fuel. ' COMMITTEE STATEMENT: The reference is added in a note as a non-manatory reference.

(Log # 54) 52- 16- (2-2.1): No Action SUBMITIT.~ Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-26 RECOMMENDATION: The fuel station task group endorses the 9 / 19/91 comments from Deepak Singh regarding TCR Proposal No. 52-26 (Committee Comment Log #I0). SUBSTANTIATION:' The fuel station task group endorses the above comment pending the SAE TC 7's approval of the draft revisions to SAEJI297. COMMITrEEACTION: No Action. COMMITTEE STATEMENT: The comment does not meet the requirements of paragraph 11-8 of the NFPA regulations~governing committee projects. The Committee thanks the commentor for his interest.

(Log # 2) 52-15 - (Chapter 2): Reject SUBMrIWF.~ Paul Raymond, Cumberland, [ ] COMMENT ON PROPOSAL NO.: N / A RECOMMENDATION: Add the following new text:

Atmospheric Corrosion. Any above ground steel piping, compres- sor equipment, containers etc. that are subject to a corrosive environment will require protection by means of paints or coatings. SUBSTANTIATION: Due to the various corrosive environments that these CNG fueling stations may be located, it isgood prudent engineering practices to protect all above ground steel structures from atmospheric corrosion. Various system components of dissimilar metals will accelerate the corrosion on possibly very high

UMITTEEre lines and containers. ACTION: Reject-

(Log # 58) 52-17 - (2-2.1 Exception): Accept in Principle SUBMITrER: Ed Peacock, Sahara Henderson Engineering Company, Inc. COMMENT ON PROPOSAL NO.: N / A RECOMMENDATION: Revise the exception. SUBSTANTIATION: We are concerned about the j~roposed CNG spedfication requiring a maximum pressure dewpomt only slightly below the lowest recorded ambient temperature.

Not only does this proposed specification fail to afford any more "margin of aafety" than the current ISA Instrument Air Specification, but it fails to take into consideration potential formation of liquid water, when high pressure stored CNG is rapidly expanded to significantly lower pressure NGV tank. The Joule-Thomsun temperature effect could well cool the CNG 100°F below the high pressure storage temperature, which is essentially ambient tempera- tUre .

30

NFPA 52 - - A92 TCD

To prevent anypossible flow blockage and minimize corrosion, we suggest that the Committee give serious consideration to ward a -

40°F pressure dewpoint. This should provide better and more safe CNG. COMMITrEEACTION: Accept in Principle. COMMITTEE STATEMENT: Refer to Committee Action on Comment 52-15 (Log #10).

(Log # 12) 52-18 - (2-3.1): Reject SUBMITI'ER: Den I. Ledbetter, CTE ChenvTec Equipment Company, .Inc. COMMENT ON PROPOSAL NO.: 52-27 RECOMMENDATION: Revise as follows:

Current text- ~'ystems a n d / o r system components, as follows, shall be approved: n Proposed text: ~System a n d / o r system components, as follows shall be listed or

approved: (i) Excess Flow Valves j . l . Container Excess FlowValves j.2. Line Excess Flow Valves"

SUBSTANTIATION: These new developments in CNG fuel system technology have received little or no recognition, Even though even the product's most ardent cridcs agree with its concept for improved safety of CNG vehicles.

This change creates a designated class of components so that s pe.cific requirements and codes can address performance and aesign. COMMITI'EE ACTION: Reject. / COMM1TFEE STATEMENT: Refer to Committee Action o n . Comment 52-26 (Log #13).

Allowing manufacturers to use hoses with identifiers permits a suitable hose to be used in the system, which may originally have been designed for a different application while retaining traceability by the authority having jurisdiction0 thereby not compromising safety. COMMITTEE ACTION: Accept in Principle. Accept the proposal with the following change: 2-10.4 Hose and metallic hose shall be disdnctiy marked by the

manufacturer, either by the manufacturer 's a permanently attached tag or by distinct markings, indicating the mafiufacturer's name or trademark, applicable service identifier, and design pressure. COMMFFFEE STATEMENT: To accept the comment with a change to insure that the marking is done by the manufacturer.

(Log # 6) 52-23- (3-3.11): Reject SUBMrlWER: Nancy Pehrson, Minnegasco, a Division of Arlda, Inc. COMMENT ON PROPOSAL NO.: 52-53 RECOMMENDATION: Delete the following:

~.,.,~: . . . . d ;.v:,. s .h:CLCvc; L, . . . . !

L ~ ! , " ""; ~,~ :~ ":'2:'L; ~" ~ ~ . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . . . . .

127 : . . ( 3 1 7 ~ . . . . . . ). • SUBSTANTIATION: The requirement given in 3-3.11 is design

specific, the current performance based standard in Section 3-3.2.1

~o Cifies the requirement on a general basis and is adequate. MMITI'EE ACTION: Reject.

COMMITI'EE STATEMENT: The current wording is needed to provide guidance to enforcers of the standard.

, (Log # 43) 52- 19 - (2-5.1.1): Accept SUBMITFER: Nancy Pehrson, Minnegasco, a Division of Arkla, Inc. COMMENT ON PROPOSAL NO.: 52-33

I RECOMMENDATION: Delete as follows: 2.5.1.3 TL~ ~ . . . . . . . . . i:~fd~.; . . . . . . f l ; ,d . . . . 11: L,. vc~,,~,~uc~,tl;

EUBSTANTiArCI~ON: Committee Action 2 was to accept the deletion of 2-5.13 and not 2-5.1.1 which the Committee revised. COMMITrEE ACTION: Accept.

(Log # 67) 52- 20 - (2-5J.2): Accept SUBMITFER: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 52-$4 RECOMMENDATION: Add the word "be n between "shall" and "in direct' . SUBSTANTIATION: Editorial. COMMYIq'EE ACTION: Accept.

(Log # 68) 52- 21 - (2-8.4 and 2-9.2): Accept SUBMITI'ER: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 52-40 and 52-54 RECOMMENDATION: Revise 2-8.4 and 2-9.2 as follows:

Change "case irons" to "cast irons". SUBSTANTIATION: 2-8.4, 2-9.2 - Editorial. COMMITTEE ACTION: Accept.

(Log # 60) 52- 22 - (2-10.4): Accept in Principle SUBMITTER: Graham Barker, Norwalk Company, Inc. COMMENT ON PROPOSAL NO.: 52-46 RECOMMENDATION: Accept original revision by NGV Coalition. SUBSTANTIATION: The NGV industry is growing and research is being carried out into high flow facilities, which may require large size or unique hoses. Manufacturers will not mark their hose for a specific application unless significant volume sales are available.

(Log # 69) 52- 24 - (3-4.1): Accept SUBMITFER: Robert,B. DeRemer, P.E., American Gas Assoc. Laboratories COMMENT ON PROPOSAL NO.: 52-54 RECOMMENDATION: Make a note that it is not permissible to terminate the vent outlet in the engine compartment. SUBSTANTIATION: New coverage which will require all types of relief devices located in the engine compartment to be vented outside of the engine compartment. Should pressure relief devices discharge inside of the engine compartment and the gas ignited, the occupants of the vehicle could be placed in danger. COMMITI'EE ACTION: Accept. Add a note to 3-4.1: Note: It is not permitted to terminate the vent outlet in the engine

compartment.

(Log # 27) 52-25 - (3-4.6 (New)): Accept in Principle SUBMrIq'ER: Aubrey P. Eddy, Southern Cross Corp. COMMENT ON PROPOSAL NO.: 52-57 RECOMMENDATION: Revise as follows:

3-4.6 The neck of the container and all CNG fittings within the compartment are enclosed in a gas tight enclosure made of linear low density polyethylene having a minimum thickness of 2 mils (.00~ in.) or an equally gas tight alternative enclosure which is vented directly outside of the vehicle. SUBSTANTIATION: Apparent typographical error. COMMITTEE ACTION: Accept in Principle.

Revise 3-6.4 by substituting 8 mils (200 micrometers) for "200 micrometers" COMM1TI'EE STATEMENT: To provide the requirement in English units.

(Log # 13) 52-26- (3-6.1): Reject SUBMHWER: Dean I. Ledbetter, Chem-Tec Equipment Company, Inc. COMMENT ON PROPOSAL NO.: 52-59 RECOMMENDATION: Revise as follows:

Current text as amended by the Committee: Every container shall be equipped with a manual or normally

dosed remotely actuated shutoffvalve connected directly to the container. Remotely actuated valves shall be equipped with a provision to manually bleed the container.

34

N F P A 52 - - A92 T C D

Proposed text" Every container shall be equipped with a manual or normally

dosed remotely actuated shutoffvalve inaddition to a flow sensitive excess flow valve connected dikectiy to the container or situated within it for crash proof operation. Remotely actuated valves shall

~ e u ~ . l A ~ T i t h a provision to manually bleed the container. ON: To provide a means to stop catastrophic

releases of natu/al gas in the event of a fuel system failure down- stream of the container. Currently there is nothing in line to do this. COMMITTEE ACTION: Reject. COMMITTEE STATEMENT: The commentor does not provide technical support to justify the need for mandating this device. An excess flow valve is not the only way to provide protection against catastrophic release of gas in the case of failure, and the device will not operate under all possible failure conditions.

(Log # 28) 52- 27- (3-6.2.2): I~eject SUBM1TFER: Aubrey P. Eddy, Southern Cross Corp. COMMENT ON PROPOSAL NO.: N/A RECOMMENDATION: Revise as follows:

3.6.2.2 The valve location shall be marked with the words "MANUAL SHUTOFF VALVE. ~ The letters shall be a minimum of 3/4 in. high. Decals or stencils are acceptable. SUBSTANTIATION: No minimum size if given. This insures visibility for the valve location in case of emergency. COMMITI"EE ACTION: Reject. • COMMITI"EE STATEMENT: The commentor provided no substantiation that 3/4 in size will meet the stated need and fit in all installations.

(Log # 29) 52-28-(3-10.1.1): Reject SUBMITI'ER: Aubrey P. Eddy, Southern Cross Corp. COMMENT ON PROPOSAL NO.: 52-64 RECOMMENDATION: Revise as follows: . • 3.10.1.1 A label readily visible and located in the engine compart- ment shall include the following:

(a) CNG fueled vehicle. (b) System working pressure ' (c) Installer's name or company (d) Container retest date (s) (e) Total water volume in gallons (liters)

SUBSTANTIATION: No information currently available to justify including an expiration date. U..a draft standard...(is) being developed by agas industry task group." COMMITFEE ACTION: Reject. COMMITTEE STATEMENT: The committee believes that an expiration date is needed a needed labeling option.

(Log # 7O) 52- 30- (3.11.2): Accept in Principle r SUBMrYrER: Robert B. DeRemer, P.E., American Gas Assoc. Laboratories COMMENT ON PROPOSAL NO.: N/A RECOMMENDATION: Reword as follows:

UAf(er installation the entire system shall be pressurized to its working pressure, and every connection shall be leak checked with a non-ammonia soap solution or a leak detector instrument." SUBSTANTIATION: New wording more dearly states the require- ment. COMMITrEE ACTION: Accept in Principle.

Revise 3-11.2 to read: 3-11.2 After installation Before use, every connection shall be

checked with a non-ammonia soap solution or a leak detector instrument after the equipment is connected and pressurized to its working pressure. COMM1TI'EE STATEMENT: To accomplish the commentors intent with an editorial change.

(Log # 45) 52- 31 - (4-3.4): Accept - SUBMI'IWER: Nancy Pehrson, Minneg'asco, a Division of Ar~a, Inc. COMMENT ON PROPOSAL NO.: 52-72 RECOMMENDATION: Revise text to read:

4-3.4 Compression equipment shall be redesigned for use with CNG and for the pressures and temperatures to which it may be subjected under normal operating conditions. It shall have pressure, relief devices which shall limit each stage pressure to the maximum allowable working pressure for the compression cylinder and piping associated with that stage of compression. SUBSTANTIATION: Misprint. Redesigned not shown as revised text. If this is the Committee's intent, qualification of the redesign by "with the approval of the original, equipment manufacturer" should be noted.

Redesign without qualification could result in compressors unsuital~ly modified outside original engineering limitations. COMMITFEE ACTION: Accept. ' Substitute "deslgned" for "redesigned in 4-3.4.

(Log # 53) 52- $2 - (4-3.4): Accept SUBMITTER: Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-72 RECOMMENDATION: In the first sentence of proposed 4-3.4, the word "redesigned" should read "designed." SUBSTANTIATION: This appears to be a typographical error. COMMITTEE ACTION: Accept.

Refer to/Committee Action on 52-31 (Log #45).

(Log # 24) 52-29- (3-10.2): Reject S U B ~ Paul F. Swenson, Consolidated Natural Gas Company COMMENT ON PROPOSAL NO.: 52-65 RECOMMENDATION: Revise the following text-

"...The marking shall consist of a border and the letters WNG/ C " . . . n

S'UBSTANTIATION: 1. VNG/C denotes °vehlcular natural'gas/ compressed." This recommendation is consistent with a proposal submitted to the SAE TC7 committee in regard to fuel composition.

2. "CNG" is the registered service mark of Consolidated Natural Gas Company. NGV operators frequently mistake these stickers for corporate identification. In order to prevent this misinterpretation from occurring in the future, W N G / & is the recommended designation. COMMITI'EEACTION: Re jec t . . COMMITTEE STATEMENT: The committee believes ~ a t the term CNG is widely used and recognized and sees no advantage in changing.

(Log # 63) 52- 33 - (4-3.4): Accept . SUBMITFER: Graham Barker, Norwalk Company, Inc. COMMENT ON PROPOSAL NO.: 52-72 RECOMMENDATION: Change the word Uredesigned" back to "designed. ~ SUBSTANTIATION: The change appears to have been made without comment by the Committee. Using Uredesigned" withou/~ substantiation such as "by the original manufacturer" will allow " unqualified people to modify unsuitable equipment and could lead to some extremely unsafe facilities. This section should be made more rigid as opposed to being

relaxes, by adding words to ensure that the original engineering limitations are not compromised. COMMITFEE ACTION: Accept.

Refer to Committee Action on 52-$1 (Log #45).

(Log # 72) 52- 34 - (4-3.5): Accept SUBMrI'IT.R: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 62-72 RECOMMENDATION: Delete the first word %Vhen" SUBSTANTIATION: Editorial. COMM1TI'EE ACTION: Accept.

8 5

N F P A 5 2 - - A 9 2 T C D

(Log # 42) 52- 35 - (4-3.8 (New)): Accept SUBM1TIT~ Nancy Pehrson, Minnegasco, a Division of Arkla, Inc. COMMENT ON PROPOSAL NO.: 52--72 RFf~MMENDATION: Add new 4-3.8:

4-3.8 Engine driven compressor installations sb~!l conform, where applicable, to NFPA 37, Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines. SUBSTANTIATION: Electric motor driven compression equipment must comply with electrical r equ l remen~ No mention is m.-~le of minimal safety requirements for engine driven equipment. Reference to NFPA 37 will insure meeting recognized and accepted methods of installation. COMMITTEE ACTION: Accept.

(Log # 73) 52- 36 - (4-4.3.4.1): Accept SUBMITrER: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 52-74 RECOMMENDATION: Reword as follows:

~Ventilation shall be by a continuous mechanical ventilation system or by a mechanical ventilation system activated by a continuous monitoring natural gas detection system when a gas concentration of not more than one fifth of the lower limit of flammability is i.~resent. In either case, the system shall shut down.the fueling system m the event of failure of the ventilation system." SUBSTANTIATION: Rewording requires that a means be provided to prove ventilation air flow both when a continuous ventilation system is used and when a gas detection-activated ventilation system is used. The current proposed revisions require refueling system shut down only in the case of failure n f a continuous ventilation ~ O s t e m .

MMITrEE AcTION: Accept.

, (Log# 7) 52-40 - (4-17): Accept in Principle SUBMrlWER: Nancy Pehrson, Minnegasco, a Division of Arkla, Inc. COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: Revise as follows:

4-17 Vehicle Fueling Appliances in commercial applications. 4-17.1 Vehicle fueling appliances (VFA) shall not exceed a gas flow

of I0 scfm. VFA's tha i [be listed. 4-17.2 The installation OfVFA's sha!! be exempt from the

rec~uiremen~of Sectio n 4-2, ~.S, 4-4, 4~ an d 4-8 t ~ u g h 4-16. ~ . ~

4-17.3 f ~ A VFA installed with storage contain- ers shaH comply with the provisions of Chapters ~ and 4. - ~ I 7.4 The installation Of VFA's shall comply with the requirements of Chapter 5, other than t, as flow. SUBSTANTIATION: 4-17- Addition of "in commercial applica- tions" will clarify section in document.

4-17.2 - VFA's in residential applications per 5.2 must comply with approximate sections in Chapter 2:2-5 through 2-10 cover such components as pressure reliefs, gau~es, regulators, piping, valves and hose& This exemption as written is m conflict With 4-]7.4. Listed VFA's whether in residential or commercial applications should have components comply with applicable sections of Chapter 2.

4-17.5 and 4 - Pan of the committee proposal was lost in the

ACTION: Acceptin Principle. Accept the proposed changes to 4-17. 4-17.1, 4-17.3 and 4-17.4. Revise 4-I 7.]I to read: 4-17.2 The installation ofVFA's ~ d l be exempt from the

requirements of Section 4-2, 4-3, 4-4, 4-6 and 4-8 through 4-16. The VFA shall be exempt from Section 2-5 through 2-9 10. C O M M r r r E E STATEMENT: The comment is accepted except for the exception from sections 2-5 thru 2-9 which the committee as the appliance is listed and the listing is equivalent to the sections exempted.

(Log # 74) 52- 37 - (4-4.32;): Accept SUBMITIT.J~ Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: N / A RECOMMENDATION: Editorially change 20 percent to one fifth. SUBSTANTIATION: Rewording will be consistent with 4-4.3.4.1. COMMITTEE ACTION: Accept.

1

(Log # 50) 52-38-(4-9.1): Accept in Principle • SUBMITIT, R: Carmen E. Ro~i, Fuel Station Task Group, Natural Gas Vehicle coalition COMMENT ON PROPOSAL NO.: 52-90 RECOMMENDATION: Revise the next to the last sentence (3rd sentence) of 4-9.1 (4-9, Installation of Piping and Hoses.) as underlined:

"Underground and aboveground piping shall be protected from corrosion in compliance with present recognized practices." SUBSTANTIATION: Refer to 9 /1 /91 comment from Mr. Paul Raymond (Committee Comment Log #2). COMMrITEEACTION: Accept in Principle.

Revise the last sentence of 4-9.1 to read: ~Undergroundpiping shall b e . . . "

COMMI'ITEE STATEMENT: To comply with the submitters intent.

(Log # 32) 52- 39 - (4-14.9): Accept S U B M I T I T ~ Aubrey P. Eddy, Southem (koss Corp. COMMENT ON PROPOSAL NO.: 52-77 RECOMMENDATION: Revise as follows:

~ d ~ s with the words "STOP MOTOR', "NO SMOKING", GAS shall be posted at dispensing station and

compressor areas. The location of signs shall be determined by local conditions but the lettering shall be large enough to be visible and legible from each point of transfer.* SUBSTANTIATION: Visible does not mean legible. COMMITTEE ACTION: Accept.

(Log # SS) 52-41 - (4-17): Reject SUBMrrlT.R: Ralph Rackham, Sulzer Canada Inc. COMMENT O N PROPOSAL NO.: 52-78 RECOMMENDATION: We agree with Log #31 except:

Change WFA ~ to ~ wherever the term appears. SUBSTANTIATION: The term WFA" was proposed by the undersigned as a replacement for the term ~RFF ~ in Section 5. As the Committee rejected this change in Section 5 it would not be used in Section 4. C O M M r r r E E ACTION: Reject. COMMYrrEE STATEMENT: The committee believes that the term "VFA" is appropriate as used.in 4-17.

(Log # 34) 52- 42 - (4-17): Accept in Principle S U B M r r I v . ~ Ralph Rackham, Sulzer Canada Inc. COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: Change 4-17.3 to read:

"Storage for use with a RFF shall comply with the requirements of

4-17.4 RFF's shall comply with Chap. 5. SUBSTANTIATION: The above change would correct Log #31 to the text originally proposed by the undersigned. COMMrlWEEACTION: Accept in Principle. COMMrlWEE STATEMENT: Refer to Committee Action on Comment 52-40 (Log #7).

3 8

N F P A 52 m A92 T C D

(Log # 49) 52- 43 - (4.17): Accept in Principle SUBMITIT.R: Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: Revise Committee proposed 4.17 as follows:

4-17 Residential Fueling Facilities (RFF) in Commercial Applica- tions.

4.17.1 An RFF for commercial installation shall comply with Chapter 5, with the followingexceptions: Exception No. I: An RFF shall not exceed a gas flow of 10 sdm. Exception No. 2: An RFF shall be listed or approved for commer-

cial installation. Exception No. 3: An RFF installed with storage containers shall

comply with the provisions of Chapters 2 and 4. 4.17.2 Where more than one RFFis located in a common.area,

spacing between the RFF's shall not be less than 3 feet, unless spedfied otherwise in the RFF's installation instructions.

4.17.3 Multiple RFF's shall not be manifolded toge,ther on the discharge side, unless specified otherwise in the RFF s installation instructions.

4.17.4 RFF's shall not be installed within I0 feet of any storage. SUBSTANTIATION: Committee proposed 4-17 has been further revised by the fuel station task group for darification. The proposed phrase Wehide Fue!in~AJ3pliance (VFA)" is replaced, by "Residen-' tial Fueling Facility (RFF) to be consistent with "RFF terminology in Claapter 5. Additional provisions have been added to address • multiple RFF installations, as well as manifolding multiple RFF's, in commercial applications. COMMITrEEACTION: Accept in Principle. . COMMITrEE STATEMENT: Refer to Committee Action on Comment 52-40 (Log #7).

(Log # 71) 52-44- (4-17 (New)): Accept in Princi{31e SUBM1TFER: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: VFA's should not be exempt from Section 4-12 for Installation of Electrical Equipment. Also, the TCR left out the last part of 4.17.3 and the first part of

4-17.4 SUBSTANTIATION: VFA's will be installed in the same types of public and commercial locations as other types of CNG fueling equipment, therefore the same installation requirements should tP MlY •

MITrEEACTION: Accept in Principle. COMMITrEE STATEMENT: Refer to Committee Action on Comment 52-40 (Log #7).

(Log # 4o) 52-45 - (4.17.1): Reject SUBMITrER: Nancy Pehrson, Minnegasco, a Division ofArlda, Inc. COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: Revise as follows:

4.17.1 Vehicle fueling appliances (VFA) shall not exceed/l gas flow of 10 scfm. VFA's shal[be listed or approved for the type of installation. SUBSTANTIATION: No listing requirements currently exist for appliances used for fueling indoors or with storage or installed in tandem. COMMITrEE ACTION: Reject. COMMITrEE STATEMENT: The committee believes that listing is requiredfor these appliances

COMMITYEEAGTION: Accept in Principle. Accept theproposal with the following changes: I. Change "RFF" to WFA"" 2. Add a new exception to 4-17.7 as follows: Exception: Storage in the vehicle fuel supply container.

COMMITrEE STATEMENT: The change to VFA is made for consistency with the rest of 4.17. The exception is added to prevent confusion and to be consistent with Chapter 5.

(LOg # 75) 52-47- (Chapter 5): Accept SUBMrlWER: Robert B. DeRemer, P.E., American Gas Association Laboratories COMMENT ON PROPOSAL NO.: 52-107 RECOMMENDATION: Use "an RFF" instead of "a RFF". SUBSTANTIATION: Per " fhe Gregg Reference manual", 1895, the word "an" shall be used before all vowel sounds. The term RFF cbe~Mins with a vowel sound.

MITrEE ACTION: Accept.

• (Log # 48) 52- 48 - (5-1.1, 5-3.5, 5-3.6, 5-3.7): Accept in Principle in Part SUBMITTE~ Carmen E. Rossi, Fuel S~itinn Task Group, Natural Gas Vehide Coalition COMMENT ON PROPOSAL NO.: 52-106 RECOMILdF/~IDATION: Add the following provisions to Chapter 5, Residential Fueling Fadlity:

5-2.2 RFF's which are listed are exempt from the requirements of 4-2, 4-$, 4-4, 4.6, 4-8 through 4-16, and 2-5 through 2-10.

5-3.5 Unless specifically ~ermitted in the installation instructions of a listed RFF, multiple RFF s shall not be manifolded together on the discharge side.

5-3.6 Where more than one RFF is irtstalled in a common area, spacing between the RFF's shall not be less than 3 ft unless the installation instructions of a listed RFF permit spacing less than 3 ft. 5-3.7 RFF's used in commercial applications shall comply with 4-17.

SUBSTANTIATION: The added coverage addresses listed RFF's and multiple RFF installations, as well as manifolding multiple RFF's. A provision is added referencing proposed 4-17 regarding RFF's in commercial applications (see task group comment on Committee Propo~sal No. 52-78). COMMYITEEACTION: Accept in Principle in Pal l COMMITrEE STATEMENT: Refer to Committee Actions on Comments 52-49, (Log #36) 52-51, (Log #37) and 52-52, (Log #38).

(Log # 36) 52- 49 - (5-2.2): Accept in Principle SUBMITIT.R: Ralph Rackham, Sulzer Canada Inc. COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: Add:

5-2.2 RFF's which are listed are exempt for the requirements for 4-2, 4-3, 4-4, 4-6 and 4-8 through 4-16 and 2-5 through 2-10. SUBSTANTIATION: The above clarifies the intent of Log #31 that all RFF's that are listed are exempt from some of the requirements of Sections 2 and 4. COMMITrEEACTION: Accept in Principle. Add a new 5-2.3: 5-2.3 VFA'.s shall be exempt for the requirements for 4-2, 4.$, 4-4,

4-6 and 4-8 through 4-16 and 2-5 through 2-9. COMMrlTEE STATEMENT: To accept the comment and make changes consistent with Committee Action on Comment 52-40 (Log #7).

(Log # 35) 52- 46 - (4-17.5, 4-17.6 and 4-17.7 (New)): Accept in Prindple SUBMTrrER: Ralph Rackham, Suizer Canadalnc. COMMENT ON PROPOSAL NO.: 52-78 RECOMMENDATION: Add the following new subsections:

4-17.5 Where more than one RFF are located in a common area, spacing between the RFF's shall not be less than 3 feet unless' permitted in the installation instructions. "4.17.6 Unless specifically permitted in the installation instructions, multiple RFF's shall not be manifolded together on the discharge side.

4.17.7 RFF's shall not be installed within 10 ft of any storage. SUBSTANTIATION: The above addresses concerns that several RFF's might be installed in one location and circumvent the intent of Section 4.

(Log # 41 ) 52- 50 - (5-2.2, 5-4.1.3): Reject SUBM1TFER: Nancy Pehrson, Minnegasco, a Division of Arkla, Inc. COMMENT ON PROPOSAL NO.: 52-79 RECOMMENDATION: Revise as follows:

5-2.2 Fueling appliances shall be listed or approved for the type of installation. 5-4.3.1 All RFF equipment shall be installed in accordance with the

equipment manufacturer's instructions. 5-4.3. 2 Listed residential fueling appliances shall be installed in

accordance with their listing and the manufacturer's instructions. SUBSTANTIATION: The code allows for indoor fueling of vehicles using fueling appliances under certain conditions (see Section

3 7

NFPA 52 - - A92 TCD

5-4.2). Currently there are no listing requirements for Indoor fueling application& Addition of the work "-approved" in text would continue to allow indoor installations until listing requirements become available. COMMIT]'EE ACTION: Reject. C O M M r r r E E STATEMENT: This change is not needed in light of other changes made in the TCD.

(Log # 37) 52- 51 - (5-33, 5-3.6 (New)): Accept SUBMITrER: Ralph Rackham, Sulzer Canada Inc. COMMENT ON PROPOSAL NO.: N / A RECOMMENDATION: Add the following new text:

5-3.5 Unless specifically permitted in the installation instructions of a listed RFF, multiple RFF's shall not be manifolded together on the discharge side.

5-3.6 Where more than one RFF are installed in a common area, spacing between the RFF's shall not be less than 3 feet unless the installation instructions of a listed RFF permit spacing less than $ ft. SUBSTANTIATION: The above addresses concerns that several RFF's might be installed in one location and circumvent the intent of Section 4. COMMITTEE ACTION: Accept, and substitute WFA" for ~R.FF'.

(Log # sg) 52- 52 - (5-3.7): Reject SUBMITIT.R: Ralph Rackham, Sulzer Canada Inc. COMMENT ON PROPOSAL NO.: 52-72 RECOMMENDATION: Add:

5-3.7 RFF's used in commercial applications shall comply with 4-17. SUBSTANTIATION: This clarifies the me of RFF's in commercial ~p(~M licati°ns.

MrrFEE ACTION: Reject. COMMrIWEE STATEMENT: Reference to commercial applications are inappropriate in Chapter 5.

( ~ # s9) 52- 53 - (5-4.3.2, 5-4.3.2~I, 5-4.3.2.2): No Action SUBMIT] 'F~ Ralph Rackham, Suher Canada Inc. COMMENT ON PROPOSAL NO.: 52-83 RECOMMENDATION: Log# I W to Log # IUUU indusive refer to the wrong section e.g. 5-4.5.2 actually refers to 4-4.3.2. SUBSTANTIATION: Editorial change. COMMrr] 'EE ACTION: No Action. COMMrIWEE STATEMENT: The comment is editorial and expresses the intent of the committee. It will be forwarded to the editor.

(Log # 8) 52-54- (5-4.3.2.1 and 5-4.3.2.2): Accept SUBM1TTER: Nancy Pehrson, Minnegasco, a Division ofArkla, l n c COMMENT ON PROPOSAL NO.: 52-83 RE C()MMENI)ATION: De~.le~ " the followin~ . . . . . • ~ " ; ~ ' _ " ~, , "~ " ' , ~'~." ~ t ~ " ~ ' ' 8 ~ . . . . . . . . 7 . . . . . •

":~ 7 t ' ' ' ' . . . . . . ' ? " ' W ' " : " " ~ ; " . , ' v v ' ~ ' ~ 7 "~ ~ ",,'?~,...': : .~ : ' ~ . ' ~ .

S U B S T A N T I A T I O N : The standards referenced do not clearly def ine condi t ions unde r which compressed natural gas is u ~ l afld should not yet be referenced. Garages where no work is done is covered under NFPA 88.4. The statements "where applicable" could be considered confusing.

5-4.3.2.1 - Refers you to a document which under Section I-1.2 states "this code shall not apply to those service stations or portions of service stations where liquefied petroleum gases, l iquefiednatural gases or compressed gases are dispensed... '. An example of where reference to the code may be confusing could be the electrical requirements: Note Figure 6.1 and Table 6 in NFPA 50A and compare to the proposed Table 5-12.1 and Figure A-I-12.I. Would it be easily u n d e r s ~ which table would be determining?"

5-4.3.2.2 - Refers to a code designed for heavier than air fuels. Refer to Chapters 4 in NFPA 88A and 3 in NFPA 88B on hazards. I-lay~rds would not be the same for the two "types of fuel.

Specific example~ NFPA 88A Section 4-4.2 Would heating equipment of an approved type with all "flames associated being located 18 in. above the floor" be considered safe for a fuel that is lighter than air, particularly if it was ceiling mounted? NFPA 88B Section 5-2.2.2 is similar but specifically calls out no dispensing of fuels (flammable liquids) and heaters 18 in. above floor level.

The Committee should recommend to the 88A/B Committees to review the hazard sections of the codes with respect to lighter than air fuels and modify as appropriate. Either 52 or 30A Committee should define conditions under which liquid and gaseous fuels should be dispensed concurrently. COMMITTEE ACTION: Accept.

(Log # 55) 52- 55 - (5-4.S.2.1 and 5-4.3.2.2): No Action SUBMrlWER: Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-83 RECOMMENDATION: The fuel station task group endorses the 9 /17/91 comments from Nancy Pehrson regarding TCR Proposal No. 52*85 (Committee Comment Log #8). SUBSTANTIATION: The fuel station task group endorses the substantiations under Committee Comment Log #8. COMMrlWEE ACTION: No Action. C O M ~ STATEMENT: The comment does not meet the requirements of paragraph 11-8 of the NFPA regulations governing committee projects. The Committee thanks the commentor for his interest.

(Log # 57) 52-56- (5-5.1.1): Accept SUBMrlWER: Steve Frank, Fuel Cylinder Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-33 RECOMMENDATION: Revise the 2nd paragraph under 2-5.1.1 as underlined: "

"Cylinders produced under DOT and TC exemptions or special permits which require fire tests for design qualification shall be equipped with pressure relief devices in accordance with CGA S-I.I, and of the type, temperature rating, pressure rating, number and l-'o~tion used in the fire tests." SUBSTANTIATION: The above revision clarifies that the pressure relief devices referenced in the second paragraph are listed to C~A S-I.1 as spedfled under the 1st paragraph of 2-5.1.1. COMMITTEE Ac' r ION: Accept.

(Log # 9) 52-57- (5-6.3): Reject SUBMrIWER: Nancy Pehrson, Minnegasco, a Division ofArkla, I nc COMMENT ON PROPOSAL NO.: 52-89 RECOMMENDATION: Revise as follows:

5-6.3 A ~,~o,.;~ ~,.';,.~'device shall be provided in the u'ansfer system to prevent overpressurization in the vehicle. This device shall be tested annually.

4-14.2 CNG dispensing systems shall be equipped to automatically stop fuel flow when a fuel supply container reaches the temperature- corrected fill Upon failure, this device shall shut down in a safe manner. SUBSTANTIATION: Apressure refiefdevice operating in conjunction with the 4-14.2 required temperature compensated fill control may not necessarily protect the vehide tank from overpressurization. Take the following examples: Dome load valve with leaking 0-ring increasing set pressure above the ambient required pressure or electronically temperature compensated device where thermocouple fails resulting in high scale reading, either could result in overpressure condition. Systems shouldbe main- mined and tested regularly to assure proper operation. COMMITrEE ACTION: Reject. COMMrrFEE STATEMENT: The committee believes that the term f"poressure relief" device is necessary. Annual testing is not practical

r all pressure relief devices. The committee is not aware that a device as suggested in 4-14.2 exist&

38

N F P A 5 2 - - A 9 2 T C D

(Log # 56) 52-58- (5-6.3): NoAction SUBM]']WER: Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-89 RECOMMENDATION: The fuel station task group endorses the 9 /17/91 comments from Nancy Pehrson rega~dinl~ T ~ Proposal No. 52-83 (Committee Comment Log #9). The tas~ gJroup's endorsement applies to Mr. Pehrson~s suggested reviiion to 5-6.5. SUBSTANTIATION: The task group concurred with Ms. Pehrson's suggested revisions to 5-6.3 since other NFPA 52 provisions address overpressure protection without the venting of gas. There is also a driv~ to reduce methane gas emissions into the atmosphere. COMMITrEEACTION: No Action. COMMITTEE STATEMENT: The comment does not meet the requirements of paragraph 11-8 of the NFPA regulations governing committee projects. The Committee thanks' the commentor for his interest.

(Log # SO) 52-59-(5-10.7): Reject - SUBMITYER: Aubrey P. Eddy, Southern Cross Corp. COMMENT ON PROPOSAL NO.: 52-95 RECOMMENDATION: Revise as follow~

5-10.7 An emergency manual shutdown device shall be provided at the dispensing area and also at a location remote from the dispens- ing area, Either, when activated, shall disable the compressor and also shutoff the gas supply to it. SUBSTANTIATION: All compressors are not driven by an electric motor, therefore shut ring off the Power would have no effect on these. COMMITTEE ACTION: Reject. COMMITIVA:. STATEMENT: The present wording is dearer.

52- 60- (5-10.8): Rejea ' (Log # 31) SUBMrlWER: Aubrey P. Eddy. Southern Cross Corp. COMMENT ON PROPOSAL NO.: 52-96 RECOMMENDATION: Revise as follows:

5-10.8 Each underground supply line between a gas storage facility and a dispenser at a fast fill station shall have an excess flow valve located at the storage facility that will blose when the flow rate through h exceeds the normal filling rate. SUBSTANTIATION: An excess flow valve would provide adequate protection in case of a line I~reak. The fast dosing quarter turn valve in 5-10.9 can be used to stop the flow of gas in an emergency. Not all fill stations have electricity to Power the serf dosing valve. COMMITTEE ACTION: Reiect. COMMITTEE STATEMENT: An excess flow valve does not provide positive shutoff under all conditions of emergency shutdown.

(Log#46) 52- 61 - (5-10.8): Accept SUBMITrER: Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehide Coalition COMMENT ON PROPOSAL NO.: 52-96 RECOMMENDATION: Delete the following from' Committee proposed 5-10.8 (now renumbered hack to 4-10.8), as follow~

~5-10.8 Each . . . .~ .~ , . . . , .~ o~r,t,I/line between a gas storage facility and a dispenser at a fast-fill station shall have a ~.'~" ~I,,~:~.g valve that will dose when;

the power supply to the dispenser is cot off, or a. b. any emergency shutdown device at the refueling station is

activated." SUBSTANTIATION: 1. Delete the term "undergrgund:"

In some cases, a remove fast-fill dispenser will not have a supply line installed underground between it and the gas storage facility. -The 5-10.8 provision references ~fast-fill dispensers and-does not distingvish between remote and close-mounted dispensers.

2. l~ le te the term "suppl)-. ~ Refer to 9 /17/91 comment from Nancy Pehrson (Committee

Comment Log #5) The Fuel Station Task Group agrees that Ms. Pehrson's comment

to delete the term "supply ~ f ~ m the definition of "supply line" is more appropriately addressed in the task group's abo~e comment. The cuffent-definition references the term- "vehicle" which conflicts with the phrase "supply line ~ under Committee proposed 5-10.8.

5. Delete the term ~self-closihg:" The term describing a "self<losing" type valve is unclear and

should be deleted or defined under 1-5. COMMYrTEE ACTION: Accept.

(Log # 44) 52- 62 - (5-12.1 Note): Accept SUBMrrrER: Nancy Pehrson, Minnegasco, a Division of Arlda, Inc. COMMENT ON PROPOSAL NO.: 52-100 RECOMMENDATION: Revise as follows:

NOTE: The electrical ~la~ification under Table 5-12.1 may be permitted to be reduced, or b ~ r d o u s areas limited or eliminated, by adequate positive pressure ventilation from a source of clean air or inert gas in conjunction with effective safe,guards against ventilator failure by purging methods recogmzed in NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment. Such changes should be mbject to approval by the authority havingjurisdiction. SUBSTANTIATION: The revision references recognized, and accepted methods of purging. COMMITrEEACTION: Accept, and change ~ a y ~ to "shall*.

(Log # 47) 52- 63 - (5-12.1 Table): Accept in Principle SUBMrrrER: Carmen E. Rossi, Fuel Station Task Group, Natural Gas Vehicle Coalition COMMENT ON PROPOSAL NO.: 52-100 RECOMMENDATION: Revise Committee proposed Table 5-12.1 (to be renumbered 4-12.1) as follows:

Under the location heading "Area containing compression and andllary equipment;"

I. Delete the table line indicating "outdoors, Division ], Up to 5 ft (1.5 m) from equipment." 2. Revise the table line of "Outdoors, Division 2," under the

"column heading of ~r_.xtent of Classified Area" to read ~tJp to 10 ft (3.0 m) from equipment* 5. Delete the table line indicating "Indoors; Division 1, Up to 5 R

(1.5 m) from equipment." 4. Revise the table line of "Indoors, Division 2, ~ under the column

heading of W.xtent of Oa~if ied Area ~ to read ~Up to 10 ft (3.0 m) from equipment (Ceiling areas shall be Class 1, Division 1)" SUBSTANTIATION: The revisions and deletions correct errors in the Committee's proposed revisions and correlates current industry practice and with NFPA/AGA documents referenced in the Committee Statement. The revisions further address the safe installation of engine-driven compressorL The parenthetical statement under proposal #4 was added since an "enclosure" has at least one side predomlnantely open and a roof designed to prevent accumulation of escaped gas. COMMITTEE ACTION: Accept in Principle.

1. Add an Exception to 4-12.1: \ Exception: Electrical eq~)pment o n in*ternal combustion engines installed in accordance vnth NFPA 37.

2. Add a 2 new lines to the table under Dispensing Equipment: Indoors 1 Inside dispenser enclosure

• Indoors 2 Entire room, with adequate ventilation (see 4-4.5). COMMITTEE STATEMENT: To accomplish the intent of the comn~ntor to exempt internal combustion engines from the electrical table, and to accomplish the submitters intent on indoor locations.

(Log # 62) 52- 64 - (5-12.1 Table): Accept SUBMrrrER: Graham Barker, Norwalk Company, Inc. COMMENT ON PROPOSAL NO.: 52-100 RECOMMENDATION: Change area classification containing compressor and auxiliary equipment to Division 2. SUBSTANTIATION:This would allow engine drive compressors to be used and not contravene the code. Also, based on the definition in NFPA 70, the compressor and andllary equipment meets the description for a Div~ion 2 area; particularly when the compressor has been designed for hazardous gases.. COMMrlWEE ACTION: Accept.

(Log # 59) 52- 65 - (5-12.2 (New)): Accept in Prindple SUBMrrI 'ER: Graham Barker, Norwalk Company, Inc. COMMENT ON PROPOSAL NO.: N / A RECOMMENDATION: Add the following~

~ / h e n a compressor is driven by a natural 8 TM engine, the engine ahall be design~! and installed in accordance with the appropriate sections of NFPA 37 (Stationary engines and gas mrbinesL" SUBSTANTIATION: Many facilities have already been installed with natural gas driven andapproved by the ~authority having

9 •

' N F P A 52 - - A 9 2 T C D

jurisdiction," even though this contravenes the current NFPA 52 code, as the engines cannot meet Division 1 electrical requirement~ A number of engines have not been installed in accordance with

ANY code; therefore, by referencing NFPA 37, a minimum safety standard can be implemented. The electrical classification for the compressor should also be changed to Division 2. COMM1TrEEACTION: Accept in Principle. COMMITTEE STATEMENT: Refer to Committee Action on Comment 52-65 (Log #47).

TCR l~ditorial Oranges

1. In proposal 52-79 change "Fueling Appliances" to "Vehicle Fueling Appliances"

2. In proposal 52-53, change the second Committee Action to: Accept the deletion of 2-5.1.3

The following draft of NFPA 52-1992 incorporates the Committee Actions on the Public Comments which make up the Technical committee Documentation and which appear on the preceding pages. The draft is presented only a san aid to the reviewer.

NFPA52

Standard for Compressed Natural Gas (CNG)

Vehicular Fuel Systems

1 9 9 ~ Edition

NOTIC~ Information on referenced publications can be found in Chapter 6 and Appendix B.

Chapter I Introduction

I-I Scope. This standard applies to the design and installation of compressed natural gas (ClqO) engine fuel systems on vehicles of all types including aftermarket and OF.Ms and to their associated fueling (dispensing) systems.

Exception: Vehicles complyin~ with Federal Motor Vehicle Safe~ Standards covering the installation of CNG fuel systems on vehicles and certified by the manufacturer as meeting these smndards~ shall not be required to comply with ~-8.4 and C~apter $. Engine Fuel Systems (except 5-10. Labeling)

1-2 Alternate Provisions. It is recognized that advancement in technology and improvements in system design and equipment may result in equipment fabrication methods, component desigia requirements and installation and operating practices which differ from those specifically called for in this standard. Such deviations or improvements may provide desirable safety and compatible operation meeting the intent of this standard. Such deviations may be accepted when the authority having jurisdiction has seen evidence that a special investigation o f all factors has been made and, based on sound experience and engineering judgment, concludes that the proposed deviations meet the intent of this standard.

I-3 Re~roactivity. The provisions of this document are considered necessary to provide a reasonable level of protection from loss of life and property from fire and explosion. They reflect situations and the state-of-the-ar~ at the time the standard was issued.

Unless otherwise noted, it b not intended that the provisions of this document be applied to facilities, equipment, structures, or installations that were existing or approved for construction or installation prior to the effective date of the document, except in those cases where it is determined by the authority havingjuriadic- tion that the existing situation involves a distinct hazard to life or adjacent property.

1-4 Metric Practice. Metric units in this s t ~ d a r d are based upon ASTM-380, Standard for Metric Practice. " ~ - - ~ ~ , ' ~ . ~ " • ~ . . . . . . . . . . ~ ~, ~ . . . . . . . .

1-5 DefmitionL

ANSI. American National Standards Institute.

Approved. Acceptable to the "authority having jurisdiction."

NOTE: The National FLre Protection Association does not rove, inspect or c e r ~ any installations, procedures, pment, or materials nor does it approve or evainate testing ratories. In determining the acceptability of installations or

procedures, equipment or materials, the authority having jurisdiction may base acceptance on compliance with NFPA or other appropriate standard~ In the absence of such standards, said audiority may require evidence of proper installation, procedure or use. The authority having jurisdiction may also /efer to the listings or labeling practices of an organization concerned with product evaluations which is in a position to determine compliance with appropriate standards for the current production of listed items.

ASME Code. The American Society of Mechanical Engineers' Boiler and PremjLre Vessel Coc~; ~.%~=... :, .%.~.... : ' ; , ~ : ' . v . VIII (D;.~:v.. "-~, --.d . % . = - . : ~

Authority HavingJurisdiction. The -authority, having jurisdiction" is the organization, office or individual responstble for ~"approving" equipment, an installation or a procedure.

NOTE: The l~hrase "authority havingjurisdiction" is used in NFPA documents in a broad manner since jurisdictions and "approval" agencies vary as do their responsibilities. Where pu-t/iic safety-is primary, the "authority having jurisdiction ~ may be a federal, state, local or other regional department or individual such as a fire chief, fire r/mrshal, chief of a fire

revention bureau, labor department, health department, cling official, electrical inspector, or 'others having statutory

authority. For insurance purposes, an insurance inspection department, rating bureau, or other insurance company representative may be the "authority having jurisdiction." In many circumstances the property owner or his designated agent assumes the role of the ~uthori ty havingjurisdictlon*; at government installations, the commanding officer or depart- mental official may be the "authority having jurisdiction. ~"

Bulk Storage. Storage in pressure veasel-q other than cylinders.

Capacity. The ~.~. .~t . . -"- ; /water volume of a container in standard cuf t (cO. wallons (liters).

Cascade Storage System. Storage in multiple pressure vessels, cylinders or containers.

S_CF. Cu ft of gas determined at 14.7 psia a n d ~ 6 0 ° F (I01 kPaand ~: . : 15.5°C).

Code. For new construction, "C.~de" shall mean the applicable edition of the ASME Code referenced in this edition of NFPA 52. For secondhand pressure vessels and existing installations, the term ' ~ l e " shall inclfide those editions of the ASME Code which were current at the time that a pressure vessel was built.

• / C o m ~ t e Container. A container fabricated of two or more

matenals that interact together to facilitate the container design criteria.

Compressed Natural Gas (CNG). Mixtures of hydrocarbon gases and vapors, consisting principally, of methane in gaseous form which has been compressed for use as a vehicular fuel.

Container. A pressure vessel or cylinder used to store ~ C , .

Conudner Appurtenances. Devices connected to container openings for safety, control or operating purposes.

Container Valve. A valve .q~. . . . :~ ~ ,~.~..,I', connected directly to a container outlet.

Container Valve. A valve ~g~...~.: ~I : ~ . d , connected directly to a container outlet.

40

N F P A 52 - - A 9 2 T C D

Cylinder. A container constructed, inspected, and maintained

T , ~ . = , . T • ~ . ~ . . . . . . . . . . . . . 1 - t

Dew Point. Temmerature. The Temnerature. referred to a _mecific ~ • nressure, at whicl~ water vanor be~ns-m condense.

]~ew Point. (at Container Pressure~ The dew Point value of the g~ ~ e maximum anficinated container nresmzre of the CNG -

Vehicular Fuel System ?usually measured in the container nrior m nressure reductionL When nresenfin~ or referencin~ De~ Point. ~he value shall be ~ e n in tei'ms of he-container ores~ure: e.~.. -4"F Dew Point at S600-PSIG.

Dispensing Station. A natural gas installation other than a bulk plant that dispenses CNG from storage containers or a distribution pipeline by means of a compressor or pressure booster into fuel supply containers :.,:-'.'.~d ~,~. a vehicle or into portable cylinders.

Ellclosure. A structure whose nuroose is the nrotection of Cq~liprnent from the environment dr to orovid-e noise attenuation.

/

Flexible Metal and Wire Braid Hose. A metal hose made from continuous robing which is corrugated for fiexibiUty and which, for pressurized applications, shall have an external wire braid.

~'~'t'/':~ ' :".~. The pipe, robing or hose, including all related fittings, on a vehicle through whiEh natural gas passes.

Fuel Supply Container. A container mounted upon a vehicle to store C'NG as the fuel supply to the internal comfiustion engine of this vehicle.

. . . . . . . L - - - L ~ - . . . . . .

T7"__ '~ 7~ . . . . . . . . . ~7 : I~ 7_~':0;_L ~' "~'~.; . . . . . . . . ~ . . . . . .

Inam!!ation. A system that includes natural ga s containers, p ress~e bo~te r , compre~ors, and all attached valves, piping, and appur to nances. When filling containers or transferring natiL, al gas_ directly from distribution lines by means of a compressor, an installation includes the compressor and all piping and piping components

' beyond the shutoffvalve between the distribution system, and the " compressor.

Labeled. Equipment or materials to which has been attached a label, symbol or other identifying mark of an organization accept- able to the "authority havingju_,Tsdiction" and concerned with product evaluation, that maintains periodic inspection of produc- tion of labeled equipment or materials and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

Limited-Combustible Material. A material (as defined in NFPA 920, Standard, on Types of Building. Construction) not complying with the definition of noncombusuble material which, in the form in which it is used, has a pgtential heat value not exceeding 8500 Btu per lb (8141kJ/kg), and complies with one of the foLlowmg paragraphs (a) or (b). Matenah subject to increase in combustibility or flame spread rating beyond the limits herein established through the effects of age, momure, or other atmospheric condition shal lbe considered combustible. (see NFPA 959, Standard Test Method for Potential Heat of Building Materials.) " ,

(a) Materials having a structural base of noncombustible material, with a surfacing not exceeding a thickness of 1/8 in. (3.2 ram) which has a flame spread rating not greater than 50.

(b) Materials, in the form and thickness used, other than as described in (a), having neither a flame spread rating greater than 25 nor evidence of continued progressive combustion and of such composition that surfaces that would be exposed by cutting through the material on any plane would have neither a flame spread rating greater than 25 nor evidence of continued progressive combustion.

Listed. Equipment or materiah included in a list published by an organization acceptable to the "authority having[jurisdiction" and concerned with product evaluation, that maintains periodic

inspection of production of listed equipment or materials and whose lisung states e l ther /ha t the equipment or rnatenaJ meets ap.propri- ate standards or has been tested and found suitable for use m a specified manner.

NOTE: The means for identify~g listed equipment may vary for each organization concerned with product evaluation, some of which do not recognize equipment as listed unless it is also labeled. The "authority l~vingjurisdiction" should utilize the system employed by the lisdng organization to identify a liotea product.

Metallic Hose. A hose in which the strength of the hose depends • primarily upon the strength of metallic pans; ' i t may have metallic

liners a n d / o r covers. . "

Natural Cas. Mixtures of hydrocarbon gases and vapors consisting principally of methane in g~eous form.

Noncombustible Material. A material (as defined in ]~"PA 220, Standard on Types of Building Construction) which, in the form in which it is used and under the conditions anticipated, will not ignite, bum, support combustion, or release flammable vapors when

- subjected to fire or heat. Materials reported as noncombustible, when tested in accordance with AS'I'M E-156, Standard Method of Test for Behavior of Materials in a Vertical Tube Furnace'at 750"C, shall be considered noncombustible materials.

Point of Transfer. The point where the fueling connection is made.

Pressure Relief Device. A nressure a n d / o r temnerature activated device used to t)revent the ~ressure from risin~ above a t)redeter~ mined maximt/m and thereby nrevent the ruffture of a fiormallv char~ed cylinder when subiected to a standard fire test as reoufi'ed by 4§CFR 173.~I(d) or 73.~(d~ of the TC Re~,ulafions. Preisure relief devices for DOT/TC cylinders shall also include devices fgl)ithle of nrotectin~ Dartial]v char~ed cylinders when sub_leered to these fire t~sts. . . . .

Pressure Relief Device Channels. The passage or passages beyond the operating parts of the pressure rel ief device through which fluid must pass to reach the atmosphere.

Pressure Vessel. A container or other component designed in accordance with the ASME Code.

Service Pressure. The settled uressure at a uniform ras temoera- L ~ ¢ of 7O°F and full o'as content. It is the nressure for which-the eqttipment has been Eonstructed. under nbrmal conditions.

Service Valve. A valve operated by hand connected directly to the outlet of a container other than" a O/linder not larger than 5/4-in. pipe size and having an inlet diameter not exceeding the internal diameter of l/2-in~, Schedule 80 pipe.

Settled Pressure. The pressure in a container at 70W (21.1°C) which cannot exceed the marked service or design pressure on the container.

Shall. Indicates a mandatory requirement.

Should. Indicates a recommendation or that which is advised but not required.

. ,

41

NFPA 52 - - A92 TCD

Sources of Ignition. Devices or equipment which, because of their modes of use or operation, are capable of providing sufficient thermal energy to ignite flammable compressed natural gas-ah- mixtures when intr6cluced into such a n~xmre or when such a mixture comes into contact with them, and which will permit propagation of flame away from them.

Chapter 2 Genera] C~G and F~uipmem Qualifications

2-1 General.

2-1.1 The provislons,of this chapter apply only to pressurized system components handling ~ O .

2-2 c ~ Qua~ty.

2-2.1 Gas quality in the container shall comply with the following:

H2S and soluble sulfides partial pressure...0.05psi max water vapor .................................................... 7.0 Ib/MMCF, max CO 2 partial pressure ........................................ 7 psi max 0 2 .................................................................. 0.5 volume %, max

Exception: When the dew point of the gas entering the cylinder is below the lowest anticipated container temperature at the maximum anticipated container pressure, the above shall not apply.

Note: For additional information on ~ oualitv see SAE 11297 National Gas Fuel Snecification Recofi~m~ndations for National Gas

Natural gas introduced into any system covered by this standard shall have a distinctive odor potent enough for its presence to be detected down to a concentration in air of not over 1/5 of the lower limit of flkmmability.

~-s Approve.

2-$.1 Systems and/or system components, as follows, shall be listed or approved:

(a) Containers

(b) Pressure relief devices, inciuding pressure relief valves

(c) Pressure gauges

(d) Pressure regulators

(e) Valves

(f) Hose and hose connections

(g) Vehicle fueling connections

(h) Engine fuel systems

(i) Electrical equipment related to CNG systems.

2-$.2 Devices not otherwise specifically provided for shall be constructed to provide safety equivalent to that required for other parts of a system.

2-4 Design and Construction of Containers.

2.4.1 Containers shall comply with 2.4.2 through 2-4.6 or shall be designed, fabricated, tested and marked using criteria which incorporate an investigation to determine that it is safe and suitable for the proposed service, is recommended for that service by the manufacturer, and is acceptable to the authority h a v i n g j ~ c t i o n .

2-4.1.1 Containers shall be fabricated of steel, aluminum or composite materials.

The container shall be designed to be suitable for CNG service and permanently marked CNG by the manufacturer.

Containers manufactured prior to the effective date of this standard may be used in CNG service if recommended for CNG service by the container many ,c ra te r or acceptable to the authority having jurisdiction.

2-4.2 O/HHnders shall be manufactured, inspected, marked, tested, retested" equipped, and used in accordance with US Department of Transportation (DOT) or Canadian Transport Commission (Cq'C) regul~tions, exemptions or special permits, or ANSI/AGA NGV2. ]~a~sic Reo~rements o f T w e BNG Fuel Containers. specificaliy for ~ G servlce and shall ha~e a rated service pressure of not less than 2400 psig at 70°F (16.5 MPa at 21.I°C).

Note I: Current DOT and TC snecification, exemotions and snecific oermits do not address the use ~f cylinders as vehlc:le fuel contain- Crs. The intent of the reference in this standard is to permit only those cylinders which are aonroved for the n-ansnortaiJon of natural was to be used in CNG mrv~c-e.

NOTE 2: Four relevant cylind~ inspection standards which are useful ar~ Compressed Gas A~ociauon, Inc. Pamphlets:

C,.6, Standards for Visua~ Inspection of Compressed Gas Cylinders.

C,-5.1, Standards for Visual Inspection of High Pressure Aluminum Compressed Gas Cylinders.

C-5.2, Guidelines for Visual Inspection and Req~_m!!fication of Fiber Reinforced High Pressure Cylinders.

C-10, Recommendations for Changes of Service for Compressed Gas Cylinders Including Procedures for Inspection and ContAminant Removal.

2-4.5 Pressure vessels shall be manufactured, inspected, marked, and tested in accordance with the Rules for the Construction of Unfired Pressure Vessels, Section VIII (Division I) or Section X. ASME Boiler and Pressure Vessel Code.

2-4.5.1 Adherence to applicable ASME Code Case Interpretations and Addenda shall be considered as compliance with the ASME Code,

2-4.4 The "+" (plus) and "*" (star) markings on DOT and CTC cylinders shall not apply in accordance with DOT and CTC regu.lations for cylinders for flammable compressed gases. The star marking shall be removed/obliterated. The removal of the marking shall be done by peening and otherwise in accordance with DOT or CTC regulations. Grinding is prohibited.

2.4.5 In'addition to the marking required by documents cited in 2.4.2 and 2-4.S, such containers and any used under the provisions of 2-4.1 shall be labeled with the words "CNG ONLY' in letters at least 1 in. (25 ram) high in contrasting color and in a location which will be visible after installation. Decals or stencils are acceptable. (see 3-10.1.)

2-4.6 Welding or brazing for the repair or alteration of an ASME pressure vesse~ shall comply with the documents under which the pressure vessel was fabricated. Other welding or brazing is permit- ted only on saddle plates, lugs or brackets attached to the pressure vessel by the pressure vessel manufacturer.

The exchange or interchange of pressure vessel appurtenances (see definition) intended for the same purpose is not considered a repair or alteration.

2-5 Pressure Relief Devices.

2-5.1 Each fuel supply emmdrter ~ complyin{g with 2-4.2 shall be fitted with s one or more pressure relief de~ice~ m accordance with 2-5.1.1 through 2-5.1.S.

2-5.1.1 Pressure refief devices for cylinders shall be in accordance with Compressed Gas Association (CGA) Pamphlet S-I.1, Cy_fin_' ders

42

N F P A 52 ~ A92 T C D

v

x

Cylinders produced under DOT and CTC exemptions or special permits which require fire tests for design qualification shall be eq~pped with pressure relief devices in accordance with COA S-1.1 a ~ of the type, temperature rating, pressure rating, number and location used in the fire tests.

2.5.1.2 The pressure relief device shall be in direct communication ~ , ,~ , , , , ,~ ,~ . with the fuel and be vented to the atmosphere by a method that will withstand the maximum pressure which will result.

The discharge flow rate of the pressure relief device shall not be reduced below that required for the capacity of the container upon .

• which the device is insfalled.

Pressure relief device shall be located so that the temoerature to which they are subiected shall be reoresentative of the-temveramre to which the cylinder is sub ieetcfL -

2-5.2 Pressure vesseis complying with 2-4.3 shall be provided with one or more springioaded pressure reUefvalves set to open in accordance wi~h the ASME Code.

2-5.2.1 The minimum rate of discharge of pressure relief devices on c, on,.~)'ne~ ~a l l t~, in accordance w i t h C,GA P a m p , ~ e = S-1.1

v~- , -~ , or the ASME Code - - wliichever is appUcable.

2-5.2.2 Pressure relief valves for CNG service shall not be fitted with lifting devices. The adjustment, if external, shah be ~rovided with means for sealing the adjustment to prevent tampenng by unautho- rized persons. I f at any ume it is nece .ss.ss.ss.ss.ss.ss~. to break such seal, the valve shall be removed from service un;il ~t has been reset and sealed. Any adjustments necessary shall be made by the manufac- turer or other companies having competent personnel and adequate facilities for the repair, adjustment, and testifig of such valves. The organization making such adjusunent shall attach a permanent tag with the setting, capaclty, and date.

. . . . e . . . . V _ e . , , - - r . u . . , ~ ' ! ! t t t ~ • • t . , L a ~ v a t • b , ~a~ t ~ ,

• ~=, ? ' .=? =,~ r L ~ , ~ ? ` _ e v , = , ~ ~ . 0~ ~,. ~ - , , . . . . . . . . . . . . . .

~ / "•'-" '- '" ~ • ' - ' ~ '-~P~-'~7 "~ '~'~ *~- 1 ~ • •=~,~,h. ~ - s .

2-5.3 Containers and pressure vessels complying otherwise With 2-4.1 shall be provided with pressure relief devices approved by the authority having jurisdiction.

2-6 Pressure Gauges.

2-6.1 Pressure gauges shall comply with 2-6.2 through 2-6.4 and are subject to further qualification depending upon their application as noted in Chapters 3 and 4. , ,

orovided, shall be capable of reading ag least 1.2 times the system /tesima nressure.

-~.~' ,'~, . . . . . . . . . s , . . ~ ~ . ,'-'. . . . . . . . . . .= . . . . . . . . . . v . . . . .

2-6.4 ~ A gauge shall have an opening not to exceed 0.055 in. (1.4 ram) (No. 54 drill size) at the inlet connecti6n.

2-7 Pressure Regulators.

2-7.1 A pressure regnlamr inlet and each chamber shall be designed for its maximum w o r k i ~ - ~ s m ¢ service nressure with a pressure safety factor of at least 4. - . -.

2-7.2 Low pressure chambers shall provide for overpremn'e relief or be able to withstand the op,.,,;.h, s v,~,~,=,,, serviff nressure of the upstream pressure chamber. -

2-8 Piping.

2-8.1 Pipe, tubing, fittings, gaskets, and packing material shall be compatible with the fuel under the service conditions.

2-8.2 Pipe, mblng, fittings and otherpiping components between a container and the first shutoffvalve shall be capable of withstanding a hydrostatic test of at least four times the rate~l ~,,,,k;,~s t,,~--,,, ~ semce nressure without structural failure.

2-8.3 Natural gas piping shall be fabricated and tested in accordance with ANSI/ASMEB$1.5-1980, American National Standard Code for Chemical Plant and Petroleum Refinery Pip.ing.

2-8.4 The following components sfiall not be used:

(a) Fittings, street ells and other piping components of cast iror~ other than those complying with ~ T M Specific•dons

A.536 (Grade 60-40-18), A-595 and A-47 (Grade 35018),

(b) Plastic pipe, tubing and fittings for high pressure service,

(c) Galvanized pipe and fittings,

(d) Aluminum pipe, tubing and fittings.

Exception No. 1: Refueling[ connection may be made of nonsparking wrought aluminum ahoy suitable for the pressure employed. -

Exception No. 2: Aluminum pipe, tubing and fittings may be used downstream of the first stage pressure regulator in an engine fuel system.

(e), Pipe nipples for the initial connection to a container, and

(f) Copper alloy with copper content exceeding 70 percent.

2-8.5 Piping components such as strainers, snubbers and expansion joints shall be j~ermanentiy marked by the manufacturer to mdicate the service raungs. .

2-9 Valves.

2-9.1 Valves, valve packing and gaskets shall be suitable for the fuel over the full range of pressures and temperatures to which they may be subjected under normal operating conditions.

2-9.1.1 Shutoffvalves shall have a rated ~ pervice not less than the rated ,,oi~,,m p;,---,,,~ service ore•sure of

the entire system and be capable of wi~standing a hydroitatlc test of at least fob/times the ratedworking pressure service pressure without rupture oF g, . . . . ,a,~,,~ d,.,%~,-,~:.',,,. Leakagd shall not occur at less than 1~1/2 times the rated -oikL,/s t , ,~., , ;~ service pressure using dry air as the test medium.

2-9.2 Valves of cast iron or seml-steel other than those complying with ASTM Specifications A-536 (Grade 60-40-18), A-395 and A-47 (,Grade 35018) shall not be used as primary stop valves. ,

2-9.3 The following valves shall not be used:

(a) Valves of a design that will allow the valve stem to be removed without removal of the complete valve bonnet or disassembly of the, valve body, and

~ / • ~ z v ~ . o W t t 4 S V C t t V ~ o ~ , . , s x z ~ . s ~ , ~ s ~ [ ~ Z a ~ S I . L O W S , ~ S . & X S.C~ZSSSV~

2-9.4 The manufacturer shall stamp or otherwise permanently mark the valve body to indicate the service ratings.

43

N F P A 52 - - A 9 2 T C D

Exception: Container valves incorporating integral pressure relief devices marked in accordance with 2-5.1.$ need no additional marking.

2-10 Hoses and Hose Connections.

2-10.1 Hose and metallic hose shall be of or lined with materials that are resistant to corrosion and the actions of natural gas.

2.10.9 Hose, metallic hose, flexible metal hose, tubing, and their connections shall be suitable for the most severe pressure and temperature conditions expected'under normal operating condi- tions with a burst pre .ssure of at least four times the ~a~:..~,,,, -~-'--'-~'~8- ~,~.~,~, L tel 'vice _DreMure.

2-I0.$ Hose assemblies shall be tested by the manufacturer or its designated representative prior to use to at least twice the service pressure.

2-10.4 Hose and metallic hose shall be distinctly marked manufacturer, either by the manufacturer's permanently attached tag or by distinct markings, indicating the manufacturer's name or t~demark, . ~ - ' . is-- applicable service identifier, and desitm ~,,,, kl.i~ pressure.

2-11 ~A~ Vehicle Fueling Connection.

~-I~ 11.1 A vehicle fueling connection shall provide for the reliable and secure connection of the fuel system containers to a source of high pressure natural gas.

2-12 11.9 The fueling connection shall be suitable for the pressure expected under normal conditions and corrosive conditions which nmght be encountered.

~_i~ 11.~ The fueling connection shall prevent escape of gas when the connector is not properly engaged or becomes separated.

2-I -~ 11.4 The refueling receptacle on an engine fuel system shall be firmly supported, and shall:

(a) Receive. the fueling connector and accommodate the ~,-~,~Id,;~ ~ ; ~ . ~ ~ serwce ~ressure of the vehicle fuel system, and

(b) Incorporate a means to prevent the entry of dust, water and other foreign material. If the means used is capable of sealing system pressure it shall be capable of being depressurized before removal, and

(c) 121ave a different fueling connection for each pressure base vehicle fuel system.

9.11.5 A vehicle fuelin~ connection comnlvln~ with ANSI/A.G.A. NGV l. Reouiremenm for Natural Gas Ve~hicle~ (NGV3 Refuelin~ Connectior~ Devices. Requirement l-~O. shall ][~e provi~fd.

Chapter ~ Engine Fuel Systems

3.1 Application.

3-1.1 This chapter applies to the design, installation, inspection, and testing of CNG fuel supply systems for vehicular internal combustion engines.

3.1.2 I ~ ; : , , . , ,,,%~,2. component~ 6. ~ ~,e oIo;,..i shall be installed ~ in ~or.danc.e wi[th_ _~e ~ man .ufactt~Ler0 instructions v . . V l l . t l . w , a l l c m , t . ~ ~ U I ~ W a t L ~ A ~ L t ~ o t t ; a 1 . , . t v ~ a o ~ J i ~ s v t t a ~ . l . t ~ ) , t a a v . ~ , t a A a t . -

t.t~tg ~ . t , .

3-2 System Component Qualifications.

3.2.1 System components shali comply with the appropriate provisions in Chapter 2 and with 3-2.2 through 3-2,4,

3-2.2 Components in the engine compartment shall be suitable for service over a range of temperatures fi;om -40°F to 250°F (-40 to 121°C). All other components shall be suitable for service over a range of-40"F to 180"F (-40 to 82.2°C).

3-2.3 AI-mlnum or copper pipe, tubing or fittings shall not be used between the fuel container and the first stage pressure regulator.

3-2.4 Fuel carrying components shall be labeled or stamped with the following:

(a) The manufacturer's name or symbol,

(b) The model designation,

(c) The design ~,,~,kh,~ ~ ,~ , ,a~ service pressure.

(d) Direction of fuel flow when necessary for correct installation, and

(e) Capacity or electrical rating as applicable.

Exception: Not applicable to container valves, tubing and fittings.

3.8 Installation of Fuel Supply Containers.

3-3.1 Fuel supplycontainers on vehicles may be located within, below or abo~e the driver or passenger compartment provided all connections to the container(s) are external to, or sealed and vented from, these compartments.

3-3.2 Each fuel supply container shall be mounted in a location to minimize damage from collision. No part of a container or its appurtenances shall protrude beyond the sides or top of the vehicle at the point where i t h installed.

3-3.2.1 The fuel system shall be installed with as much road clearance as practical but not less than the minimum road clearance of the vehicle when loaded to its gross vehicle weight rating. Tins minimum clearance shall be me .a .sured from the lowest part of the fuel system.

3-3.2.2 No portion of a fuel supply container or container appurte- nance shallbe located ahead of the front axle or behind the rear bumper mounting face of a vehicle. Container valves shall b e . protected from physical damage using the vehicle structure, valve protectors or a suitab!e metal shield. , ,

3-3.$ Each container rack shall be secured to the vehicle body, bed or frame to prevent damage from road hazards, slippage, loosening or rotation using a method capable of withstanding a static force hi the six princlpaIdirections (see Fi~mre 3-$.3) of eight times the weight of a fidly pressurized container(s).

Left <

Up

Backward ~

Down

Figure 3-3.3 The Six Principal Directions.

Forward

5 Right

3-3.3.1 Each fuel supply container in the rack shall be secured to its cradle in such a manner that it is capable of withstanding a static force applied in the six principal directions (see Figure 3.3'.$) of eight times the weight of the fully pressurized container with a m~admum displacement of 1/9 in (12.7 ram).

3-3.4 The container weight shall not be supported by outlet valves, manifolds or other fuel connections.

"3-3.5 Fuel supply containers located less that!. 8 in..(203 ram) from the exhaust system shall be shielded against direct neat.

44

J

N F P A 52 - - A92 T C D

$-3.6 The mounting system shall minimize fretting corrosion between the contalder and the mounting system.

3-S.7 Fuel supply containers shall not be installed so as to adversely affect the d r i ~ g characteristics of the vehicle.

~-S.8 Metal clamnin~ bands and their sunDorts shall not be in direct contact with a cofitaiher. A resilient non-.~ter retalnin~ ~asket shall

, be installed between the clamnin~ bands and their sunu~o~ts and a container. - -

9-~.9 A container, when located in a vehicle comvartment canable of accumulatin~r natural wa~, shall be installed such that:

(a~ The vressure relief device for the vrotection of the container is installed in the same vehicle comnarmfent as the container:.

(b~ The discharge from a pressure relief device referred to in (a~ above is:

(fl Vented m the outside thorough a smooth walled metallic tube no smaller than the outlet diamete-r of the relief device, secured at 12 inches (300 mm~ intervals when the robe exceeds 24 inches (600 n)m~ in length, and

lib Located so that the vent nnenin~ Win not be blocked bv debris thrown un from the road. such ~ sno~', ice. mud. etc.. or otherwise pffected ~v the elements.

~-3.I0 Where p container is installed ab~y¢ ~he operator or oassen~er comvarunent of a vehicle:

(a) The container, its nivin'~, f iu ln~ and valve shall be vrotected ~Tom damage by. - - - -

(D A ~,uard rail or similar device which is designed to absorb the imuact b f a collision with a stationary ohiect when the vehicle is m6vin~ either forward or backward at 5 ~niles her hour (8 km uer hour)_and the ~ rail or similar device shall be free of nrofec- lions that could-damage a qontai'ner, its yglves and fittin~s.-ana

/ (ii) A shield desi~,ned to absorb imuacts that may occur durin~

loadinm unloadind or use of the'veMcle and the shield shall be ~ree of nro~-ections thaEcould damage a container, its valve and fitting.

Ib~ The ton of the container and anv CNG hiDing, fi~tin~, valve. h o u s i n m ~ a _ r d r m l o r s h i e l d s h a l l n o i b e m o ~ e - t h a n 1S.5-feet

• (4.15.n~ ~bove the road surface.

(c~ The cvlinder shall be orotected bv metallic or nonmetallic covers from accidental con-tact with overhead electrical wirln~.

9-5.11 The minimum clearance from the road to a container, its housin~ and fittings, whichever is lowest when the container is installed below th~ frame and between the axles of a CNG vehicle. ~hall not. with ~he vehicle loaded to its ~nss weight r~ling, be less

• than:

(a) 7 inches (175 mm~ for a vehicle havin~ a wheel base less than 9r equal ~o 127 inches (B175 mm~: or -

(b~ 9 inches (225 mm~ for a vehicle havin~ a wheel base ~reater than 127 inches (51752020mm~.

3-~.12 Containers that are installed behind a rear axle o fa CNG ¥¢hicle shall ~ installed transversely.

Excention: Containers shall be nermitted to be installed in other 0rier~tations when the cont~ine1" valve and fittings are located at the end of the container most ¢rotected from a source of imvact.

9-4 Installation of Venting Systems.

9-4.1 All pressure relief devices and connections between pressure ~sca~. ~ng components installed within a closed compartment (see

shall be vented to the outside of the vehicle m a suitable location.

Note: It is not permitted to terminate the vent outlet in the engine compartment.

9-4~2 The venting s~stem for the discharge of pressure relief devices (pressure relief devices channels) shall be constructed of metallic tubing with threaded, compression or flare fittings and shall be secured at the outer end.

5.4.3 The vent or vents for the venting system shall not exit into a wheel well.

5-4.4 Anent shall not restrict the operation of a container pressure relief device or pressure relief device channel.

9-4.5 Vent outlets shall be nrotected bv cans. covers, or other means to keen water, dirt imd insects from collecfin~ in the lines. Protec- five d~-vices shall not restrict the flow of was. -

9-4.6 The neck of the container and all CNG fittings within the comnarunent are enclosed in a was tight enclosur~made of linear low density nolvethvlene havin~h miAimum thickness of 8 mils 1200 micrgmete~l Or an eouallv ~as-ti~ht alternative enclosure which is vented direcdv outsid~ of ihE vehicle.

3-5 Installation of Piping.

S-5.1 Manifolds connecting fuel containers shall be fabricated m minimize vibration and shall be installed in a protected location or shielded to prevent damage from unsecured objects. '

9-5.2 A pipe threadjoinfing material impervious to the action of the natural gas used in the system shall be applied to all male pipe threads prior to assembly. •

9-5.S Piping and fittings shall be clear and free from cutting or threating burrs and scales, and the ends of all piping shall be reamed.

9-5.4 Where necessary-to prevent abrasion, supply lin& passin$ ~rough apanel shall be p ~ c t e d ~ , ~ o m ~ n e ~ o r ~ d e~ces

~,.5 Supply lines shall have the maximum practical clearance ~om the engine e~amt system.

9-5.6 Supply lines shall be mounted, braced and supported to minimize vibration and protected against damage, corrosion or breakage due to strain or wear. A supply line shall be supported at least every 24 in. (610 ram).

9-5.7 A bend in piping or robing is prohibited where such a bend weakens the pipe or tub.ing.

S-5.8 A joint or connection shall be located in an accessible location.

S-6 Installation oLValves. o

9-6.1 . . . . . . , ~ , , ! ~ t , ~ . , ~ . . . . . , ~ , , . . . . . . . . . . . . . . . , , ~ . . . . . ~ . ~ , ,

• ~¢1 ~,~;.:=-'..:¢r. ~verg container sh~ll be eouinned with a manual or norroallv closed remotelv actuated shutoff-vaIv-e connected directly to th~ container. Remo/elv actuated valves shall be eouinved with a urovision to manually bleed the container. - " -

S-6.2 In addition to the valve required by 8-6.1, a manual shutoff valve shall be installed in an accessible location which will permit isolation of the container(s) from the remainder of the fuel system. The manual shutoffvalve shall have no more than a 90 ° rotation from oven m closed nositions.

S-6.2.1 The valve shall be securely mounted and shielded or installed in a protected location to minimize damage from vibration and unsecured objects.

3-6.2.2 The valve location shall be marked with the words "MANUAL SHUTOFF VALVE." Decals or stencUs are acceptable.

S-6.S A ~alve shall be provided in the system which automatically prevents the flow of gaseous fuel to the engine when the engine is not running even if the ignition is switched on.

S-6.4 When multiple fuel systems are installed on the vehicle, automatic valves shall be provided, as necessary, to shut off the fuei not being used.

Note: Electronic fuel iniectors are considered m be automatic valves.

9-6,5 The fueling system shall be equipped with a blackflow check valve which will prevent the returnflow of gas from the container(s) to the falling connection.

, 4 5

NFPA 52 - - A92 TCD

3.7 Installation of Pressure Gauges.

3.7.1 A pressure gauge located within a driver or passenger . compartment shall be installed in such a manner that no gas will flow through the gauge in the event of failure.

3-7.2 A pressure gauge installed outside a driver or passenger compartment shall b~ equipped with a limiting orifice, a shatter- proof dial lens and a body relief. . ,

3-7.3 Gauges shall be securely mounted, shielded and installed in a protected location to prevent damage from vibration and unsecured objects.

3.8 Instal lat ion o f Pressure Regulators.

5-8.1 An automatic pressure reducing ~ t o r ( s ) shall be installed to reduce the fuel container presmre to a level consistent with the ~,,~IJ~,~ v ~ . . ~ service pressure required by the gas-air mixer.

3.8.2 Means shall be provided to prevent regulator malfunctions due to refrigeration effecm.

3-8.3 Reguiamrs shall be installed so that their weight is not placed on, or supported by, the attached gaslines.

3-9 Insmliation of Fueling Connection.

3-9.1 A fueling connection receptacle complying with Section 2-12 shall be installed in each vehicle.

3.9.2 The fuel inf connection recenmcle sh~l be mounted to withstand the br~,akawav force s o e ~ i e d in 5-10.~.1. The recevmcie shall be installed in acc0rdance~.vith the manufacturer 's instr{tctions.

3-10 Wh'ing Installation

3-10.1 All wiring shall be secured and protected from abrasion and corrosion to the same standard as the original wiring on the yehicle.

3.10.2 All wiring shall be sized anti fuse protected With the fuse rating adequate to the current draw.

~-tO 11 LabeUng.

~-/0 11.1 A vehicle equipped with a CNO fuel system shall bear a the

S - ~ 11.1.1 T',,,~ A label readilvvisible and located in the ent, ine fgmpar tment shall include the following:

(a) CNG fueled vehicle,

(b) System weeid~vpr~em~ service pressure,

(c) Installer's name or company,

(d) Container retest date(s), or expiration date.

(e) Total container water volume in --~ L-,

3.10.1.2 A label located at the fuelin~ connection recentacie shall include the following:

(a~ CNG fueled vehicle. (b~ System working nressure. (c~ Container retest-date or exniration date.

Excention: If both labels are located in one of the above are~. the label~ can be combined into ~ ein~le label.

~-I0 11.2 Each vehicle shall be identified with a weather-resistant diamond-shaped label located on an exterior vertical or near vertical surface on the lower right rear of the vehicle (on the trunk lid of a vehicle so e~uipped, but not on the bumper of any vehicie) inboard from any omer markings. The label shaft be , r ~ , ~ , ~ e ' y a minimum of 4 3 /4 in. (120 nun) long by 3 1 /4 in. (83 ram) high. The marking shall consist of a border and the letters ~ O " [1 in. (95 nun) minimum height centered in the diamond] of silver o r white reflective luminous material on a blue background.

~-11 12 System Testing.

~-11 12.1 The complete assembly shall be leak tested using natural gas or inert gas (carbon dioxide or nitrogen or a mixture of these).

~ I 1 12.2 ,~f~,,. ;,~:~'.:=:.'~,,~ Before use. every connection shall be checked wlth a nonammonia soap solution or a leak detector instrument after the equipment fi connected and pressurized to its ~ - , ~ ~;~;,-.=.-,; service premure.

~-I 1 12.3 If the completed assembly is leak tested with natural gas, the testing shall be done under adequately ventilated conditions.

S - ~ 12.4 When a vehicle is involved in an accident or f i re causing damage to the CNG container, the CNO container shall be repla~ed or removed, inspected and retested in accordance with the document under which it was originally manufactured before being returned to service.

12.5 When a vehicle is involved in an accident or fire causing damage to an), p a n of the CNG fuel system, the system shall be repaired and retested (see 3.13~ before being returned to service.

3-12 1S Maintenance and Repair.

S - ~ 18.1 Damaged supply lines shall be replaced, not repaired.

S - ~ 18.2 The owner or user or both shall malnmi 9 all containers, container appurtenances, piping systems, venting systems and other components ln a safe condition. T h e above individual(s) shall be [em_ onsibl~ ~'gr yeri~in~ workin~ pressure and container r e ~ | t date or exoirafion date currenmess.

3.12.S Pressure relief devlces on cvlinder shall be maintained in accordance with CGA namohlet S-1.1

Prcssure relief devices on all other containers shall be maintained in accordan~f With the follqwin~:

(a~ Pressure relief device channels or other harts which could interfere with the functioning of the device sh'all also not be olu~zed bv naint or accumulation of dirt. - - -

~]~l Comnressed natural was containers shall be stored so as to avoid d a m ~ e .

(c~ Onlv 8ualified ~ersonnel shall be allowed to service nressure relief devlc~s.

(d) Onlv assemblies or original manufacturer 's naris shall b¢ used in the revalr of ~ressure relief devices unless the fnterchan~e ~f harm has-been 6roved bv suitable tests.

Chapter 4 CNG Compression, Storage and Dispensing Systems

4-1 Application. This chapter applies to the design, construction, install-aii6n, and operation of containers, pressure vessels, compres- sion equipment, buildings and structures, and associated equilsment used for storage and dispensing of CNO as an engine fuel in fleet and public dispensing operations.

4-2 System Component Qualification. System components shall comply with the appropriate provisions in Chapter ~ and with Secuons 4-5 through 4-1S.

4-3 General.

4-3.1 When served by a gas utility, the utility shall be notified of all CNG installations.

4-3.÷ 2 Equipment related m a compression, storage or dispensing installation shall beprotec ted to minimize the possibilities of physical damage andvandallsm. -.

4-3.4 ~ Control devices shall be installed so that internal or external icing or hydrate formation will not cause malfunction.

6

NFPA 52 - - A~2 TCD

4.8.~ 4 Vehicles shall not be considered a source of ignition wi~ respect to the provisions in this chapter.

Exception: Nehides containing fuel-fired equipment, e.g., recre- ational vehicles and catering trucks, shall be considered a source of ignition unless this .equipment is shut off completely before entering an area in which igniuon sources are prohibited.

4.8.5 ~-II.I Compression equipment shall be designed for use with CNG and for the pressure and temperatures to which it may be subjected under normal operating conditions. It shall have pressure relief devices which shall limit each stage pressure to the maximum allowable working pressure for the comuression cylinder and piping associated with that stage of compression. ,

4.8.6 =-I;.= When CNG compression equipment is operated unattended, it shall be equipped with a high discharge and low suction pressure automauc shutdown control.

4.8.7 ~-I~.,~ The fueling connection shall prevent escape of gas when the connector is not properly eugaged or becomes separated.

4.8.8 Engine driven comuressor installations shall conform, where annlicabl~, to NFPA 87. ~tandard for the Installation and Use of S~tionarv Combustion En~n¢0 ~md Gas "rgrbines.

4-8.9 Comnression eouinment shall incoroorate an automatic condensate system to hlifi~inate liouid carr:vover to the ~tora~e s v s t e m .

4-4 Siting.

4.4.1 CNG compression, storage and dispensing shall be located and conducted outdoors or indoors in compliance with 4.4.~ and'4-4.8.

4-4.2 Outdoors.

4.4.2.1 CNG storage containers charged with CN.G not connected foruse shall be located outdoors.

4-~ .2 .2 A facifiv/in which CNG compression, storage and dispensing equipment is sheltered by an enclosure constructed of noncombus- tible or limited2D combustible materials which has at least one side

redominantiy open and a roof designed for ventilation and persal of escaped gas shall be regarded as outdoors.

4-4.2.8 Compression, storage and dispensing equipment outdoors shall be located aboveground, not beneath electricpoweriines or where exposed by thew failure, and a minimum of 10 ft (8 m) from the nearest imoortant building or line of adjoining property which may be built upon or source o-f ignition.

4-4.2.4 Compression, storage and dispensing equipment outdoors shall be located not less than I0 ft (3 m) from the nearest public street or sidewalk line, and at least 50 ft (15 m) from the nearest rail of any railroa d main track.

4-4.2.5 A clear space of at least 8 ft (I m) shall be provided for access to all valves and fittings of multiple groups of containers.

44.2.6 Readily ignitabie material shall not be permitted within I0 ft ($ m) of any stauonary container.

/

44.2.7 The minimum separation between containers and aboveground tanks contmning flammable or combustible liqu/ds shall be 20 f~ (6 m).

4.4.2.8 During outdoor fueling operations,, the point of transfer (see definition) shall be located at [east I0 ft (8 m) from any imoortant building, mobile home, public sidewalk, highway, street, or-road and at feasts ft (I m) from storage containers.

Exception: At the discretion of the authority havingjurisdiction, the point of transfer n~y be located at a lesser distance from buildings or walls constructed of concrete or masonry materials, but at least I0 ft (3 m) from any building openings.

~-4.8 Indoors.

4-4.3.1 Compression, dispensing equipment and storage containers connected for use may be located inside of buildings reserced exclusively for these purposes or in rooms within or attached to buildings used for other purposes iri accordance with 4-4.8.

4-4.$.1.~ Storage shall 1~ limited to not more than 10,000 cuf t ( 2 8 3 m ) ofnahu-al gasin each building or room. .

Exceminn: CNG stored in vehicle mounted fuel sunDlv containers.

4-4.S.2 Buildings reserved exclusively for these purposes shah be constructed of noncombustible or limited-combustible materials. Windows and doors shall be located so as to be readily accessible in case of emergency.

Exception: Window glazing may be plastic.

. . . . . . . . . . . . . . . . 7 ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-4.3.2.1 Explosion venting shall be provided in exterior walls or roof only. Vents may consist of any one or any combination of the following, designed to reliev~ at a maximum mternal pressure of 25 lb per sq ft (125 kgper m ) a~d providing a venting area of not less than 1 sq ft per 81) cuf t (1 mZ per 9.4 m ~) of room volume:

(a) Walls of light material;

(b) Lightly fastened hatch covers;

(c) Lightly fastened, outward opening doors in exterior walls;

(d) Lightly fastened walls or roof.

Where applicable, snow loads shall be considered.

4-4.8.$ Rooms within or attached to other buildings shall be constructed of noncombustible or limited-combustible materials. Interior walls or partitions shall be continuous from floor to ceiling, shall be securely anchored and shall have a fire resistance rating Of at least 2 hours. At least one wall shall be an exterior wall. Windows and doors shall be located so as to be readily accessible in case of emergency.

Exception: Window glazing may be plastic.

4-4.8.3.1 Explosion venting shall be provided in accordance with 4-4.8.2.1.

4-4.3.8.2 Access to the room'shall be from outside the primary , structure.

Exception: If such access is not possible, access from within the primary structure is permitted provided such access is made through a barrier space having two vapor-sealing, self-closing fire doors suitable for instnllafion in a ~ having the fire remtance rating selected.

4-4.8.4 Indoor locations shall be ventilated utilizing air supply inlets and exhaust outlets arranged to provide air movement as uniformly as practical. Inlets shall be uniformly arranged on exterior walls near floor level Outlets shall be located at the high point of the room in exterior walls or the roof.

4-4.8.4.1 Ventilation shall be by a continuous mechanical ventilation system which shall shut down comoression eeuinment in the event of failure of the ventilation system-or by a me-ch]mical ventilation system activated by a continuous monitoring natural gas detection system when a gas concentration of not more than 20 percenf of the

• ~ J . V

4-4.8.4.2 The~ventiladon rate,shall be at least I cu if /minute per 12 cuft (I m~/min, per 12 m~) of room volume.

47

N F P A $2 - - A 9 2 T C D

Note: Th~ corresponds t9 ~ air chan~es p f r hour.

4-4.8.4.8 A ventilation system for a room within or attached to another building shall be separate from any ventilation system for the other building.

4-4.8.5 A gas detection system shall be equipped to sound an alarm when a maximum of ~ ~,~,=~.~ one f i f~ of the lower flammable limit is reached.

44.8.6 Reactivation of the ~ ,~ t , : , .w ,~ , f , . ~ , , . , shall be by manual restart conducted by trained personnel.

,,LL,~ ~ I I ~ . . ,v ly ,.;;~. TJ.I~ ~ . . . . . Buildings and rooms used for compression, storage and dispensing shall be classified in accor- dance with Table 5-12.1 for insudlad-ons of electrical equipment.

4-4.$.8 Sources of Itmifion. other than electrical as nermitted bv 5.4.8.7. shall be nrohibited.

4-4.8.8 9 Pressure relief devices on storage systems shall have safety relief device channels to convey escaping gas to outdoors and then upward to a safe area so as not to impinge upon buildings, other equipment or areas that could be occupied by the public - - e.g., side-~alh.

4-4.8.9 10 Access doors shall have warning signs with the words ~VARNINC,---NO SMOKINO--FLAMMABLE GAS." Such wording shall be in plainly legible bright red letters on a white _ .b .a~ r_ ound.

4-5 In~mn,tion of Containers and Container Appurtenances (Other than Pressure Relief Devices).

4-5.1 Storage containers shall be installed aboveground on stable, noncombustible foundations or in vanlt~ with ventilation and

Horizontal containers shall have no more than two points of support longitudinally. Where flooding may occur, they shall be securely anchored to prevent floating.

4-5.2 Containers shall be protected by painting or other equivalent means where necessary to inhibit corrosion. Horizontally installed containers shall not be in direct contact with each other.

Exception: Composite containers shall not be painted without prior permission of the container manufacturer.

4-6.3 Adequate means shall be provided to prevent the flow or accumulanon of flammable or combustible liquids under containers, such as by grading, pads or diversion curtn.

4.6 Installation of Pressure Relief Devices.

4-6.1 Pressure relief valves shall be so arranged that theywfll discharge to a safe area, and so that escaping gas will not impinge upon bfiildings, other equipment, or areas that could be occupied by the public. (See 4-4.$.8.)

4.6.2 Pressure relief valves on pressure vessels shall be installed so that an]~ discharge will be in a vertical position and shall be fitted with stumble raincaps.

4-6.8 A pressure relief device shall be provided in the transfer system to prevent overpressure in the vehide.

4.7 Installation of Pressure Regulators.

4.7.1 Regulators shall be designed, installed or protected so their operation will not be affectedby the elements (freezing rain, sleet, snow) or ice, mud or debris. This protection ma~, be integral with the regulator.

4-8 Installation of Pressure Gauges.

4-8.1 Gauges shall be installed to indicate compression discharge pressure, storage pressure, and fuel supply container fill pressure.

4.9 Installation of Piping and Hoses.

4.9.1 Piping and robing shall be run as directly as practical with adequate provisions for expansion, contraction,jarring, vibration, and setding. Exterior piping may be either buried or installed aboveground and shall be well supported and protected against

mechanical daxTxage. Undergroundpip ing shall be buried not less than 18 in. (457 nun) below the surfac~ o f the ground unless otherwise protected. Underground Piping shall be protected from corrosion in compliance wifli present recognized practices. Threaded pipe and fittings sh/d] not be used underground.

4-0.1.1 ~lanifolds connecfln~ fuel cpntalners shall be fabricated to minimize vibration and shall be installed in a ¢rotected locadon or shielded to nrevent darna~e from unsecured 6blects.

4~.1,2 A Dine threadj � int inf material lmnervious to the action of the naturdl ~as used in the s~tem shall be-aoolied m all male nine threads Drio-r to assemblv. ' . . . .

4-9.1.$ PiDin~ and fitdnt, s shall be clear and free from cuttin~ or th read in~-bu~ and scal~s, and the ends of all Dinin~ shall be- reamed. - " - -

4-9.1.4 A bend in Dinin~ or mbinu is Drohihited where such a bend weakens the Dive 6r-tubing.

4-9.1.5 A |oint or connection shall be located in an accessible location. -

4-9.9 Natm-al gas shall ~ no t be vented ;~ ; ~ :;.~o;p,~.~.;~ --:--.',:~ , ~,c ;-~,~ : , ~ to a safe point of discharge. Avent pipe or stack shall have the open end suitably protected m prevent entrance of rain, snow and solid material. Vertical vent pipes and stacks shall have provision for drainage.

4-9.3 The use of hose in an inst~!!~don is limited to:

(a) A vehide fueling hose;

(b) An inlet connection to compression equipment;

(c) A section of metallic hose not exceeding 36 in. (610 mm) in length in apipel ine to provide flexibility where necessary. Each section shall be so installed that it will be protected against mechani- cal damage and be readily visible for inspection. The manufacturer's identification shall be retained in each section.

4-10 Testing.

4-10.1 Piping, robing and hoses, and hose assemblies shall be leak tested after assembly to prove free from leaks at a pressure eoyal to at least the normal o ~ , ~ i . ~ ~ - ~ service pressure of that portion of the system.

4-10.2 Pressure relief valves shall be tested at least every five years.

4.11 Installation of Emergency Shutdown Equipment.

4.11.1 Manually operated container valves shall be provided for each container.

4-11.2 The fill line on a storaue container shall be eauiDoed with a back-flow check valve to nrevent dischara~ of namraft,~s-fi'om the container in case of line.-hose or fitfina, s-ruDture.

4-11.~ ~ A manually operated shutoff valve shall be installed in a manifold as close to a.container or group of containers as practical. This valve shall be downstream of the back-flow check valve referred to in 5-10.2.

4-11.S 4 Where excess-flow check valves are used, the closing flow shall be less than the flow rating of the piping system which would result from a pipeline rupture between the excess-flow valve and the equipment downstream of the excess2D flow check valve.

4-II.4 5 The fill line on storage containers shall be equipped with a back-flow check valve to prevent discharge of natural gas from the container in case of line, hose, or fittings rupture.

4.11.~ § Gas piping from an outdoor comnressor or storage svstem into a building shall be provided with shu~ffvaIves located outside the building.

4-11.67 A - m e s m - ~ An emergency manual shutdown c.f ~..~ ~c.~.p;~;~.~. ~cf~p~.~.~ device shall be provided at the dispensing area and also at a location remote from the dispensing area. This device, when activated, shall shut off the Dower sunDlv and t, as SUDDIv to the comnressor and the disnen~er. - - -

4 8

NFPA $2 ~ A92 TCD

4.11.6 7.1 Emergency shutdown devices shall be distinctly marked for easy recognition with a permanently affixed legible sign.

4.11.~8 Breakaway protection shall be provided in a manner such that, in the event of a pullaway, natural gas will cease to flow at any separation.

• 4-11,~) A brealmwav device shall be installed at every disuensin~' VO~t- Such a devi~:e shall be arranged to senarate bv a ~orce not ~¢~t~er than 44 Ib (20 k ~ when applied in ~nv horizontal direction.

4-11.10 Control circuits shall be arranges such that when an emergency shutdown device is activate¢i or electric ~ v e r is cut off. svsteras wl~ich shut down shall remain down until n~anuallv activated or reset after a safe situation is restored.

4-I 1.11 Each underm~und suvnlv line between a a~as storage facility and a disc, enser at aTast.fiU sta-tibn shall have a seli~-closin~ ~ that

(a~ the ~ower sux>tdv to the dlsc, enser is cut off. or (b~ anv-emer~en-c~, shutdown device at the refuelin~ station is

activated. -

4-I 1.1~ A fast closing. %uarter turn" manual shht offvalve shall be ~ d e d at a fast fill-sta~on unstream of the breakawav device ferred to in 5-10.9. where i t ls readily accessible to a ~ r s o n

disDensin~ natural ~as unless. :

(a~ the self-clnsin~ valve referred to in 5-10.11 is located immedi- atelv unstream of the dispenser, or '

(b~ the disnenser is eo~n~ed with a sel~-closin~ valve that closes ¢0ch time the control ~ ~s turned to the "OFF ~ ~osition or an emer~encv device is activated.

4-12 Installation of Elecwical Equipment..

4-12.1 Electrical equipment shall be installed in accordance with ~FPA 70, National Electrical Code*, for Class I, Group D, Division I or 2 locations in accordance with Table 4.12.1.

Exception: Electrical equipment on internal combustion engines installed in accordance with NFPA 57.

NOTE: The electrical classification under Table 5-12.1 may be permitted to be reduced, or hazardous areas limited or eliminated, by adequate positive pressure ventilation from a source of clean air or inert ~as in conjunction with effective saf%,uards against ventflato-r failure bv nur~in~ methods r ecoun ted in I~'PA 496 Standard for Pur~¢~ ana l~essurized Encl6sures for Electrical Eouinment. Such chanses should be subject to approval by the Auth-ority Having Jurisdiction.

4-18 Stray or Impressed Currents and Bonding.

4.18.1 When stray or impressed currents are used or may be present on dispensing systems (such as cathodic protection), protective measures to prevent ignition shall be taken in accordance with API RP 2003, Protection Against Ignitions Arising Out of Static. Lighming, and Su~ay Currents. -

4-15.2 Static protection is not required when CHO h loaded or unloaded by conductive or nonconducdve hose, flexible metallic mbin~[, or pipe . connections where both halves of the metallic couplings are in contact.

4-14 Operation.

4-14.1 A cylinder shall not be charged in excess of the mmcimmn design pressure at normal tempe, ramre for that

cylinder. DOT and CTC ~ylinders shall be charged in accordance with DOT and TC regulations.

DOT and ~I 'C cylinders shall not be subjected tO pressure in excess of 125 percent of the marked service pressure even if on cooling it settles to the marked service pressure. Pressure vessels shall be char~ed in accordance with the reouirements of ASME Code. SectiOn VIII. Division I~

4.14.1.1 A fuel supply container shall not have a settled pressure above the , , , ,~,; ,~ p, ~ . , ~ c service uressure stamped on the container and displayed on a label ~ear the filling connection, corrected for the mnbient temperature at time o[filling.

4-14.2 CNO dispensing systems shall be equlp1~'d - to anmmadcally stop fuel flow when a fuel supply container reaches the temperature- corrected fill pressure. (See 4-6.SL

4-14.3 The transfer of CNG into a fuel supply container shall be performed in accordance with instructions hosted at the disDensin~

4.14.4 When C~G is bein K transferred to or from a motor vehicle, the engine shall be stopped.

4-14.5 During the transfer of CNG to or from cargo vehicles,.the hand or emergency brake of the vehicle shall be set and chocx blocks used to prevent rolling of the vehicle.

4.14.6 ~,:,:~L ~,~,;.~:'-,,.~; ~ . ;~ ~,: ~;~,~,~,:~ ~.~ Transfer systems shah ~e canable of denressurizin~ to facilitate disconnection d~ , , , :~ . , "--;,~ ~,:,,',,. ~ ,~.~.~,--,~;'-;~ ~,~,: - -~ . ,%'~,~ Bleed cofinections shall lead to a safe point of discharge.

4.14.7 CNG shall not be used" to operate any device or equipment which has not been designed or properly modified for CNG service.

4-14.8 Sources of ignition shall n o t b e p e r m i t t e d within 10 ft (S m) of any filling connection during a tranffer operation. (See 4-4.$.)

4.14.9 Warning signs with the words "STOP MOTOR," ~ O SMOKING," ,,~'~ . "" . . . . . . . . . . . . . . . . . . . : ; :D" ~ FLAMMABLE GAS" shall be posted at dispensing station and compressor a reas . . The location of signs shall be determined by_ local conditions u.ut me letterin_~ shall be [ar~_e enou_~h to be visible from each point ot transfer.

4.14.9 Warning signs with the words =STOP MOTOR", "NO SMOKING*, "FLAMMABLE GAS" shall be posted at dispensing

• station and compressor areas. The location of signs shall be determined by local conditions but the letterin~ shall be large enough to be visible and leuible from each ~oi~t o~ transfer.

4.15 Fire Protection.

4-15.1 A portable fire extinguisher having a rating of not less than 20-B:C shall be provided at ~ e dispensing area.

4-16 Maintenance.

4.16.1 Containers and their appurtenances, pip ingsy~tems, compression equipment, controls, and devices shal lbe maintained in proper operating condition. - "

4.16.2 After the original installation, vehicle fuelirlg hoses sh.all be examined visually at such intervals as are necessary to assure mat they are safe for use. Hose shall be tested for leaks ~,~. ~ . p ~ ~,; ~,~,:,-'.~,~; :~.~ ~=c~,,~.~ ~ / ~ . , ~ . ~ ; at'least annually and any unsafe l e d g e shall be reason for rejection.

4.16.8 While in transit, fueling hose and flexible metal hose on a cargo vehicle to be used in a transfer operation, including their .connections, shall be depressurized and protected from wear and mjury.

4-16.4 Pressure relief valves shall be maintained in proper operating condition. •

4-16.4.1 As a precaution to keeppressure relief devices in reliable operating condition, care shall be taken in the handling or storing o~compressed natural ~ . containers to avoid damage. Care shal l also be exercised to avmd plugging by paint or other dirt accumula- tion of pressure relief device c~annels or other parts which could interfere with the functioning of the device. On!~ qualified personnel shall be allowed to service pressure relief devices. Only assemblies or original manufacturer 's parts shall be used in the repair of pressure relief devices unless the interchange of parts has been proved by suitable tests.

4.17 Vehicle Fuelin~ A~nliances in commercial annlications,

4-17.1 Vehicle fuelinu anoliances (VFA~ shall not exceed a u m flow of 10 scan.' VFA.s shall be listed.

49

N F P A $2 - - A.92 T C D

Table 5-12.1 Electr ical Ins ta l l a t ions

Locat ion Division *Containers (other t h a n mounted 2 fuel supply containers)

Area con ta in ing compression, J; . . . . . " " " and anci l la ry equipment : Outdoors 1 Outdoors 2

equ ipmen t Indoors 1 Indoors 2

Exten t of Classified Area Within 10 ft (3.0 m) of conta iner

Up to 5 ft (L5 m) from equipment From 5 to 15 ft (1.5 to 4.6 m) from

Up to 5 ft (1.5 m) from equipment Beyond 5 ft (1.5 m) from equipment

• 7~ ~ . .~ , . . .~ Dispensing r~ . . . . *~"'~ ~ Equipment : Outdoors** 1 TT-- , . 5 ft tl ~ .~.~ ~ . . . . ;.., ~r ' ~ ' V i v v % . L . V ~ L ~ ] J - J -O~x~ .,~v.=..=.,.=.v v.=,

t r a n ; f c r Inside d ispenser enclosure Outdoors** 2 From 5 0 to t~ 20 i~ (1.5 to 4.6

m) from "-;- '* "¢ * . . . . ¢~.- +h~ d i spense r

• The classified area shall not extend beyond an unpierced wall, roof, or solid vapor t igh t partition..

• * Refer to Figure A-5-12 for an i l lus t ra t ion of classified areas in and around d i spensers .

5O /

N F P A $2 - - A 9 2 T C D

4-17.2 The inst~ll~don of VFA's shall be exemnt from the reouire- ments of Section 4-2. 4..3.4-4. 4-6 and 4-8 thmti~h 4-16. The VFA shall be exemot from sections 9-5 thru 9-10. -

4-17.S Storage for use with aVFA shall comply with the provisions 9f

4-17.4 The inst~ll~tion of VFA's shah comnlv with the reouirements of Chanter 5. other than was flow. -

4-17.5 Where more than one VFA are located in a common area. soacin~ between the VFA's shall not be less than S feet tmless ~ermi(ted in the installation instructions.

4-17.6 Unless soeciflcallv nern~itted in the inst~ll~don instructions. multinle VFA's ~hail n o t b e manifolded tot~ther on the d i schar~ side. - - -

4 - 1 7 . 7 VFA's shall not be installed within I0 ft of any storage.

Excention: Storage in the vehicle fuel sunnlv container.

Chapter 5 Residential Fueling Facility

5-1 Scope.

5-1.1 A residential fueling facility (RFF) is an assembly used for the compression and delivery of natural gas into vehicles with its associated equipment and piping. The capacity o f a RFF shall not exceed 5 SCFM of natural gas. Storage of-CNG, except in the vehicle fuel supply container, is prohibi ted.

5-1.9 This chaptel" applies to the design, construction, installation, and operation o f a RFF as defined in 5-1.1.

5-1.3 The provisions of this chapter shall apply to al/residential refueling in~t~n~tions except wiiere prohiblfed by local laws.

' 5-9 System Component Qualifications.

5-9.1 System components not hart of a listed fuelin~ annliimce shall comply with the appropriate p~ovisions in Chapter ~. - -

5.2.9 Fuelin~ annliances shah be listed.

5-2.3 VFA's shah be exemnt for the recmirements for 4-2.4-3. 4-4. 4-6 and 4.8 through 4-16 and 2-5 through ~ .

5-3 General . '

5-3.1 AH eqm~pment related to a RFF installation shall be ~ , ~ - ~ , ~ . . . . . ,,,.,,~.~ ~ p;~,~,~ .'.,,,,, orotected to minimize the nossibilities o fph~ica l damage and vandalism. This requirement inay be met by enclosing the compressor package in an enclosure, similar to a central air conditioner.

5-S.9 All equipment related ~ a RFF installation shall be designed for the pressure, temperature, and service expected.

5-3.3 Vehicles shall be considered as unc!~-,~it~ed electrically with respect _to A~,, de 5_0() o fNTPA 70] National F...lect~'i'_c~d .C~.de. _ . . . .

Excention: Vehicles contalninf fuel-fired eouinment, e.~.. recre. ation-al vehicles, shall be considered a sourc~ of itmifion ~nless this eeuinment is shut off comnletelv before en te r in~an area in which it, i~ifion sources are nrohib i ted .

5-3.4 Natural ~ shall not be vented to the atmosphere under normal ope ra 'on .

Excention: Leakage of 1.0 standard ins of ~ shall be nermitted to be released to the-atmosnhere per fillin~ d-urln~ disco~neftion of the fuelin~ hose.

5-8.5 Unless specifically permitted in the installation insumcttons of a listed VFA, multiple VFA's shall not be manifolded together on the discharge side.

5-3.6 Where more 'than one VFA are installed in a common area,' spacing between the VFA's shall not be less than 3 feet unless the installation instructions of a listed VFA permit spacing less than 3 feet.

Installation.

5-4.1.1 Approv~ of residential refueling installations shall be obtained r:/om the authority havingjuduUction and the natural gas distribution company.

5-4.1.2 The prim a~y concern for the location of the refueling system shall be based solel}, upon its satety, whether it be indoors or outdoors. CNO compression and disl~_nsi~, g should be located and conducted outdoors wherever practicable." However, when not practicable, e.g., inclement weather is common, c o m p r e ~ o n and dispensing can be located indoors.

5-4.1.8 All RFF equipment shall be installed in accordance with the equipment manufacturer 's instructions. ,

5-4.1.4 The RFF shall have a nameplate marked with minimum and maximum g~_ inlet pressure and flow rate, gas outlet maximum pressure and electri~.al requirements.

5-4.2 Indoor Inst~ll~tlons.

5-4.9.1 Where it is necessary . to install the compression equipment and refueling connection indoors, the compression units]tall be mounted to or otherwise located adjacent to an outside wall to facilitate the rapid venting of released iuases. The room or garage shall be considered for an acceptable site when the compressor enclosure is vented to the outside,

5-4.9.2 When the RFF or the vehicle being fueled is located indoors, a gas detector set to operate at one fifth the lower limit of fl~mm~bil- iV/of natural gas shall be installed in the ro~m. The detector shall be located within 6 inches of the ceiling or highest point in the room. The detector shall stop the compressor and operate an audible or visual alarm.

5-4.3 Outdoor Instal l~ons.

5-4.$.1 The RFF shall be installed on a firm noncombustible support ,to prevent undue stress on piping and conduit.

5-5 Inst~!!~tion of Pressure Relief Valves.

5-5.1 Pressure relief valves shall have pressure valve ~.~--.,~',~ ~ to convey escaping gas to outdoors and then upwards to a safe area so as not to impinge on buildings, other equipment, or areas that could be occupied by the public, e.g., sidewalks.

5-6 Installation of Pressure Gauges.

,5-6.1 For measurement and test purposes, pressure gauges may be installed but are not required.

5-7 Pressure Regulation.

5-7.1 A RFF shall be equipped to automatics]lly stop fuel flow when container(s) reach temperature corrected fill pressure.

5-8 Piping and Hose.

5.8.1 All piping and hose from the outlet of the compressor shall be supplied as part of the RFF.

5-8.9 All gas piping to the RFF shall be installed in accordance with NFPA 54,National Fuel Gas Code.

5-8.3 The use of hose in an installation is ~ , A restricted to:

(a] A fuelin~ hose that shall be limited to a maximum lenmh of 95 "ft and shall !~ sunoorted above the f loor /mound level or otherwise nrotected from n~chanical damage from ~brasion and bein~ driven over, and

~.~ ~ . A maximum of S ft (1 m) in lenmh when used m nrevent abrasion damage, resulfin~ from vihratior~ on the inlet andTor outlet.

(c) A section of metallic hose not exceeding 36 inches in length in a pipeline to provide flexibility where necessary. Each section shall

5 1

N F P A 52 ~ A92 T C D

be so installed that it will be protected against mechanical damage and be readily visible for inspection. The manufacturer's identgfica-

, don shall be retained in each section.

(d) Hose used for pressure relief device channels may exceed 36 in. (0.9 m)

. _ t _ 1 . . . . . . . . . [ . v ~ . ~ I ~ A ~ ~ 8 ~ i ~ A ~ 6 •

5-8.$ ~ ' ~ : v ; ~ ; . % , , ~ ' . ' . ~ t , ~ , - ' - ~ :-~ Transfer .s~stems shall be canable_ of to permit dep reuurkin g m facilim~ h'i,: I;,-ic. ~.%~.. disconnecdon. :JFhese Bleed connections shall lead to a safe point of discharge.

5-9 Testing.

~9.1 All p.iping and tubing shall .be tested a i~r assembly.to prove ee from leaks at a pressure equa~ to the mammum w o ~ n g

~,;~u,-~ ~ of that portion of thesystem.

5-10 Installation of Fanergency Shutdown Equipment.

5-10.1 A RFF shall be equipped with emergency manual shutdown of.the .g-as su_pply .and electric power, x ne emergency, e~ectrical swltch ~hall ~ at least 5 ft (1.5 m) from the RFFand in view of the RFF.

5-I0.9 Break-away protection shall be provided in a manner such ~_at, ~ . ~ e event o~a pull-away, natur~ gas will cease to flow a~m W

5-10.~.1 A breakawavdevice shai] be installed at every dis~ensin~ noint. Such a device shall be arranged to senarate b~; a force no~ gl'~ater than ~4 lbs (90 kf~ when a~pUed in any horizontal dirfction.

5-11 Operation.

5-11.1 A RFF shall be operated in accordance with the manufacturer's instructions.

5-11.2 A fuel supply container shad not be charged in excess of its maximum allowable ~ , ~ , ~ g ~,~,=~==--c service ~ressure at normal temperature. DOT and CTC containers shall be charged in accordance with DOT and CTC regulations.

5-11.$ When CNG is being transferred to a motor vehicle, the engine shall be stopped.

5-1.2 Maintenance and Inspection.

5-19.1 All RFF equipment shall be inspected and maintained in accordance with the manufacturer's instructions.

5-19.9 After installation, all hoses shall be examined visually as part of this "inspection. Hoses that are kinked or worn shall be repla~ed.

5-19.$ All safety relief valves shall be maintained in proper operating condition, in accordance with manufacturer's/supp]ier's recommen- dation.

Chapter 6 Referenced Publications

6-I The following documents or pordous thereof are referenced within this standard and shall be considered part of the require- ment~ of this document. The edition indicated for each re~erence is the current edition as of the date of the NFPA issuance of this document.

6-1.1 NFPAPublications. NadonalFireProtecfionAssuciadon, I Batterymarch Park, P.O. Box 9101, Quincy, MA 09269-9101.

NFPA $4-1988, National Fuel Gas Code.

N'FPA 70-1990, National Electrical Code.

NFPA 220-1985, Standard on Types of Building Construction.

NFPA 259-1987, Standard Test Method for Potential Heat of Building Materials.

6-1.2 Other Publications.

6-1.2.1 The following publications are available from the American 1So0~le7v/. of Mechardcal Engineers, 345 East 47th St., New York, NY

ANSI/ASME B$I.$ (1987), American National Standard Code for Chemical Plant and Petroleum Refinery Piping.

Boiler and Pressure Vessel Code Section VIII (1986). ~

6-1.2.2 The followingpublications are available from the American Society for Testing andMateriais, 1916 Race St., Philadelphia, PA 191OS.

A-47-1984, Specification for Malleable Iron C, asdng~

A-$95-1986, Specification for Ferriti¢ Ductile Iron Pressure- Retaining Castings for Use at Elevated Temperatures.

A-536-1984, Specification for Ductile Iron Castings.

E-I$6-1982, Standard Method of Test for Behavior of Materials in a Vertical Tube Furnace at 750"C.

6-1.2.$ The followinl~ publications are available from the Com- pressed Gas Associauon, Inc., 12SSJefferson Davis Highway, Arlington, VA 22202.

Pressure Relief Device Standards:

S-I.I, Cylinders for Compressed Gases (1979).

S-1.9, Cargo and Portable Tanks for Compressed Gases (1980).

S-I.S, Compressed Gas Storage Containers (1980).

6-1.9.4 US DOT and CTC container data is available from the US Department of Transportation, 400 7th St., SW, Washington, DC 90590 and the Canadmn Transport Commission~ Transport Canada Building, Place de V'dle, Ottawa, Ontario, K1A ON 5.

6-1.2.5 The followingpublication is available from the American Petroleum Institute, ]~I01 L St., NW, Washington, DC 200S7.

RP 2003, Protecdon Against Ignitions Arising Out of Static, Lightning and Stray Currents, Fourth Edition, 1989.

Appendix A Explanatory Material

This Appendix is not a part of the requirements of this NFPA document, but is included for information purposes only.

A-1 Properties of CNG.

A-l-1 Natural gas is a flammable gas. It is colorless, tasteless and nontoxic. It is a light gas, weighing about two-thirds as much as air. As used in the s~tems covered by this standard, it tends to rise and diffuses rapidly m air when it escapes from the system.

A-I-9 Natural gas burns in air with a luminous flame. At arran- spheric pressure, the ignition temperature of natural mixtures has been reported to be as low as 900*F (489 C).'°'~" The flammable limits of natural ~ mixtures at atmospheric pressure are about 5 percent to 15 percent by volume natural gas.

A-I-$ Natural gas is nontoxic but can cause anoxia (asphyxiation) when it displaces the normal 91 percent oxygen in air in a confined area without adequate ventilation.

A-1-4 Natural gas is not a unique, specific substance with a common composition at all times and in ali'places. While, as noted in the de.F~ition of Compressed Natural ~as in Section 1-5, natural gas consists principally of methane, it also contains ethane, small amounts of propane, butane and higher hydrocarbons and may contain srnan amounts of nitrogen, carbon dioxide, hydrogen sulfide and helium. The quandty of nitrogen, carbon diomde, hydrogen sulfide and helium wi/] vary from zero to a few percent depending upon the source, seasonal effects, etc.

A-l-4.1 As distributed in the extensive gas transmission and distribudon piping network in the United States and Canada, " natural gas also contains water vapor. This ~ipel ine quality" gas can contain up to 7 Ib or more of water per million cuf t ofgas.

A-1-4.9 Some constituents of natural gas, especially carbon dioxide ahd hydrogen sulfide in the presence of liqdi_d water, can oe corrosive to carbon steel and the corrosive effect is increased by pressure. The pressures used in CNG systems covered by NFPA 59 are substantial and well above those used in transmission and distribution piping and in other natural gas consuming equipment.

5 2

N F P A $2 - - A92 T C D

As excessive corrosion can lead to sudden explosive rupture of a A.1-4.6 The principal objective of the r e s e a r c h _ p r ~ was to container, this hazard must be controlled. .aenne n.amrm gas conmmmam concentration 1[mi.~ necessary ~.

msure mat inpRnal corrosion of CNu containers does not consumte As a result of such a failure in a cylinder comprising one of several a hazard over the lifetimes of the containers. A secondary objective

such in a robe wailer in 1978, the US Department of Transportation included definition of the effects of materials variables, conm~mer has specified CNO composition for CNG bein.~ transported in fabrication procedures, and other CNG system parameu~rs on interstate commerce. The limits for carbon dioxide,~hydrogen internal corrosion of CNO containers and conliiner materials. sulfide and water are very low, e.g., the Hmit for water ~s 0.5-1b per Accomplishment_of ~ e research program objectives permitted the

t~omrmttee to oe~ne me limiting concemrauons of corrosive million cu ft. contaminants in CNG necessary, to prevent corrosion or corrosion-

remtea oamage to vehicle fuel and storage containers. A-I-4.8 There is a substantial body of opinion on the Commiuee that the DOT stipulated composiuon is'intentionally conservative A.1.4.7 P ava .gr_/a_ph 2-2.1 as a control of the amount of hydrogen ana would requl?e expensive, sophisticated ~ conditioning equipment tobe used. This view is supported by experience of up to sulfide and shlfi-des, water, carbon dioxide and oxygen ~efle~ts a 15 years' duration with no failure of elther storage or fuel supply Committee consensus that if the water content is lh~ited the other conmine~ in CNG vehicle applications. Th. is experience has L~e iy potentially corrosive constituents should not be a major concern. oeen wire caruon steel cylina&s fabricate¢l to DOT SA or SAA specification and, therefore, relatively subject to internal corrosion if A-2 Vehicle Fuel Systems. the conditions are present.

A-2-I A typical vehicle fuel system consists of one or more (if more A-1-4,4 .Corrosion protection can also be addressed by the use of than one, the containers are manifolded together) fuel supply matertats which are corrosion resistant. A number of'exemptions containers holdin, g CNG at high l~ressure and fitted with pressure ana special permits nave been issued by DOT and CTC for ;~yiinders relief devices anu manual shutoffvalves, a filling connecuon with a made of materials other than carbon steel. However, the impetm check valve to prevent flow back out of the connection, a manual for these materials has come from other considerations, principally valve downstream from the container valve or valves, a valve which lighter weight, will automatica.]ly, close if the engine stops for any reason, a pressure

regutator to reduce fuel supply container pressure to a low engine ~p~;~:'..~,~ ~,~-,~,: service nressure, a gas -~ mi.xer to produce a nammame mixture ana a [~ressure gauge to show fuel supply A-1-4.5 The Committee encour~, ed the conduct of a research

program to explore this gas quah'ty/material matter and the research work was performed by Southwest Research Institute in San container pressure. Antonio, l exas , funding was provided by the New York State A-2-2 Systems are designed to operate at fuel su~p~ container ~nergy ttesearcn and Development Authority (NYSERDA), the New YorkGas Group (N'YUAS), and the U.S. Department of Energy pressures of 2400, 3000 or 3600 psi (16.5 MPa, 20.6 MPa or 25 MPa).

Fueiing co .nnections are designed to accommodate compatible (DOE). The Committee gratefully acknowredges both the f~ancial filling nozzlos suitable only f6r the proper pressure. support of N~SERDA, ~ and DOE, and the cooperation and coniributions of man aKement , eng~eering, and operating person- A-2.3 ~..el sup.ply containers are installed on either the outside of nel of the gas transmis~on companies, gas distribution companies,

, and CNO container manufacturers who supplied technical data, me vehicle or m~ide the vehicle. If inside, all connections m the used gas cylinders, test materials, and test gases for this research containers are either external to a driver or passenger compartment

or inside a compartment th__at is gastight witli respect .to a d/'iver or program, passenger compartment. l l ' te compartment is venteO to outside the '

vehicle.

A.2-4

p--...

Required for each container

r - - 1

. ,

Typical Vehicle Fuel System

5 3

NFPA 52 ~ A92 TCD

A-~ Fueling Systems.

A-S-1 A typical fueling system consists of one or more compressors takln~ suction from a natural gas transmission or distribution pipeline or a building pi~ping.system connected to a transmission or distribution pipeline vath the compressor discharging into either one or more storage containers or to a dispensing system, and a dispensing system consisting of a hose and nozzle and sometimes a meter. Where a storage container is present, it discharges to a dispensing system.

A-,~2 Where storage containers are used, the system is known as a "fast-fill" system with a vehicle tilting time of about 3-5 minutes. Where storage containers are not used, the system is known as a "slow-fill" system and filling times can be several hours.

A-3-3 The suction pressure for compressors ranges from about 2-500 psig (13.7 kPa-8.4 MPa) with most being under 60 psig (40 kPa). The delivery pressure is more than the vehicle system pressure but less than 5000 psi (35 MPa), wit h most around 3600 psi (25 MPa).

A-3.4 CNG is stored in two types of storage systems - - bulk storage and cascade storage. They differ in the manner in which the CNO is withdrawn from them.

A-S-4.1 Bulk storage of CNG can be accomplished with one large container or a number of smaller containers manifolded together. As vehicles draw CNG from bulk storage, all containers draw down (reduce in pressure).at the same rate.

Bulk storage provides less "available" CNG storage than the cascade system.

A.5-4.2 Storage containers arranged in a cascade can provide more "available" CNG storage than a bulk system for the same size containers. A brief description of the operation of a typical cascade system is as follows:

A cascade is usually arranged in at least three banks of containers with the containers in any one bank manifolded together so that each bank acts as one large container. The b a n ~ are separated by automatic switching valves. The valve sequencing is conwoHed automatically by a sequencing control pane l

The cascade banks are initiatly filled with CNO in sequence by the compressor to the normal , ~ / , ~ ; ~ , ~ / , ; ~ , ~ service nressure of the system. The highest pressure bank is refilled first ("Bknk 1"), followed by successively lower pressure banks ("Bank 2," "Bank 3," etc.). This sequence is called "priority fi11." -

Vehicles can then be fueled from the cascade, beginning with Bank (for a three-bank cascade).

If there is insufficient CNG in Bank 3 to pressurize the vehicle fuel supply container(s), Bank 8 will be valved off and Bank 2 wili "top up--the vehicle container (s). Successive vehicles witl draw from Banks 3 and 2 as above', until Bank I is required to "top up" the vehicle container(s). When Bank I pressure is reduced to a preset value, the compressor will bypass the cascade and fill the vehicle directly. At the completion of the last vehicle fill, the compressor will continue running, and refill the cascade by priority fill

Cascade valving can be arranged to provide more available storage than the system described.

A-~-18.

I Before a CNG vehicle is returned into service followin~ an accident which caused damage or dislocation to the CNG'fuel system, or followln~ the reualr or replacement of any Dart of a CNG fuel system that is fubiect t~ contaiffer oressure, the sv:stem shall be tested in comnliance ~vith section ~-11."

2 Prior m ~ain tenance or repair o f a CNG fi~l lystem:

fa~ The sunnlv of CNG should be shut off before commencin~ the work by c~l~sln~ the shut-offvalves and oneradnar the enn4_ne ~ n t l the e n ~ n e stons rfinnin~ and ensure that the valve~remain~shut off throu~hout th~ e n t r e i~oDeratve neriod.

fb~ CNG should not be vented indoors

(c~ Unon comDleton of the work. leak test the CNG fuel sys~m in accord~ce with-the reaulrements of 8-11.

S Prior m makin~ repairs m ~asoline related eouinment on a CNG vehicle, to other thkn the CNO-fuel system, the fo-ll6win~ should be done:

(a~ orior m removal of the natural was mixer, shut of f the suoolv of CNG bv closin~ the shut offv'alves ana ooe ra tn~ the engine uhfil the engine a~ofis runnin~ and ensure that the valves r enn in off throu~ho~lt th~ entire iKo_nerative period: and

(b) upon comoleflon of the work. replace the natural was mixer in its ori~r[nal location without anv c h a n ~ or adiusunent i~fore the CNG s-hut-offvalves are reooened. -

4 Prior to makin~ collision renalrs on a CNG vehicle to other than the CNG fuel svste-m shall the f~llowin~ should be done:

(a~ close the shutoffvalve at the outlet of the CNG container before commencin~ the work and ensure that the valve remains off throughout htl# entire inoperative period: and

(b~ The CNG vehicle owner or ov, erator should be instructed to take the vehicle to a vehicle connexion center for insvection of the CNG fuel system before the shut offvalve referenced]n (a~ above is reooened.

A-4 Container Capacity.

A-4-1 Containers are described by their liq.uld capacity, and the design and allowable ~ serwce nressures. The liquid capacity (cuf t of water) is the volume of liquid-that would be req .uired to fill the container. The allowable . . . . . . . . . . . . . . . . . . serwce Dres~lre is the maximum pressure at which ~ e q o n ~ d n e r should be operating. From the liquid capacity and allowable w0rking / , ~ , ~ service pressure, the gas storage capacity can be calculated.

A-4-2 The amount of gas being stored in a cylinder can be calcu- lated by applying the ~d~-'eal gas law" taking account of the "com- pressihility factor" (or "supercompressibility") of the specific gas being stored.

A-4.2.1 The ideal gas law states that, if the absolute pressure of a certain volume of gas is doubled, the volume will decrease to half (at a. constant temperature). However, natural gas . . . . does not follow the ideal gas ]aw exactly. The term "supercompressthility," as It relates to naturkl gas, simply indicates that more nafiu'0.1 gas can be stored in a Oven volume' [below about 5,000 psig (~5 MPa)] than would be indicated by the ideal gas law.

A-4.5.1 Where soace is at a nremium or not available, consideration should be a'iven -to installatibn of storage containers on a roof nlgde of noncom~bustble material at fuelinar stations. A.5-2.2 For information on standarcl~ for listin~ fuelin~ annliances see AGA Reouirements for Natural Gas Vehicle- (NGV~-F~e-lin~ Annllances. No. 2-90 (November 1. 1990h

5 4

,~ N F P A 52 - - A 9 2 T C D

Dispensing Area ........ °oooooo

Class l, Div. 1

Class l, Div. 2

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......................... °°°"" ........ ~ .............. "1:

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::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: : W ::::::::::::::::::::::::::::::

iiiiiii~ilili{iiiiiiii~iiiii~ii~ilH~iii~i~iiiiiiiiiiiiiiiiiii: k.21,..O..=ii~iiiiiiiiiiiii~iiiiiiiiiiii~. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . o . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

•.:.....:..:.:......~:;~1~:~:~:.~;~:~1~1.~1~:~:~:.::....~.-.~........~...1.:.:.:.~:~:~1~:.:L 1".1"'.1".'''1.1{"

iiiiiiiiii~iiii~iiiiiiiiii~iiiii~iiiiiii~ii~iiiii~iiiiiiii ~ %~iiiiiiiiiiiiiiiiii!iiiiiiiiii{ilH}iiil '

" " " " ' ~ " T " V ; ' ~ " ' " F : ' } : ' " " :~ . ~ " V ~ ' " ' ~ " } " " " . . ' " ' V : " " i :: :: 1:1 ;:: .':: :::: :: I;; ;:: ::;: :: ;:; I:: ;;: I;, k s . :1; :.*I ::I I:: ::: ;:*" I:; 1:; ::1 :I: ::: I;:::: :;: ::1 :I: ::::: I :-': 1::: I I: I:: I: ::: .......... 0 ................................. . ........................................................................ *::::::::1::1:111:::11::1:::::1:::1:::::::::I:1111:1::1::1 ::::::::::::.*:: ::: ::: ::: ::: :::::1::11:::::::1:::::: ::: ::: 1:

::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

:!!!!!i!!ii!!~!!!!!!!!!!~!ii!~!!!!!!!!!!!i!!ii!!!!!!!!!iiiii!!!!!!!!i!ii!!!!!!!!!!!!ii!!i!!!!!!i!!i!i!!!!!!!!!!!: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

~..1..:.:..:...!!......:~...:..:...:::::::::;~.:......~.~...:...1!!.......::T.....!....i..i~ii.:........:i!!..:....~

~:.....::....1.::..:.:.....:...:...:.:.[~....:......:::.~T.....:..:{.T.~iiiii~T...1~:. ........................ o .......... o ......................................... ..,:.....- -.:- -.:" :-...::--~.:--..'- ........::-..'- -!-..:....:-- v---. !!- !~----:::,-

Classified areas in and around dispensers as detailed in Table 5-12.1

F i g u r e A-5-12.

55