49 CFR Part 107

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Part II

Department ofTransportationResearch and Special ProgramsAdministration

49 CFR Part 107, et al.Hazardous Materials: Requirement forDOT Specification Cylinders; ProposedRule

58460 Federal Register / Vol. 63, No. 210 / Friday, October 30, 1998 / Proposed Rules

DEPARTMENT OF TRANSPORTATION

Research and Special ProgramsAdministration

49 CFR Parts 107, 171, 172, 173, 177,178, and 180

[Docket No. RSPA–98–3684(HM–220)]

RIN 2137–AA92

Hazardous Materials: Requirements forDOT Specification Cylinders

AGENCY: Research and Special ProgramsAdministration (RSPA) DOT.ACTION: Notice of proposed rulemaking(NPRM) and public meeting.

SUMMARY: RSPA proposes to amendcertain requirements in the HazardousMaterials Regulations (HMR) toestablish four new DOT cylinderspecifications and to revise therequirements for maintenance,requalification, and repair of all DOTspecification cylinders. In addition,RSPA proposes to: revise therequirements for approval of cylinderrequalifiers, independent inspectionagencies, and nondomestic chemicalanalysis and tests; revise the cylinderrequalification, maintenance and repairrequirements; and to revise therequirements for hazardous materialsthat are authorized to be offered fortransportation in cylinders. Finally, thisNPRM incorporates a proposal toremove from use aluminum alloy 6351–T6 that was published in an advancenotice under Docket HM–176A andterminates that docket (RIN: 2131–AB51).

This action is being taken to—simplify the HMR for construction ofcylinders; provide for flexibility in thedesign, construction and use ofcylinders; recognize recent advances incylinder manufacturing andrequalification technologies; promotesafety though simplification of theregulations; reduce the need forexemptions; and facilitate internationalcommerce. The intended effect of thisaction is to enhance the safetransportation of hazardous materials incylinders.DATES: Comment Date: Comments mustbe received on or before January 28,1999.

Public Meeting Date: A publicmeeting will be held on December 8,1998; from 9:30 am to 4:00 pm. Anadditional meeting may be scheduled ifthere is substantial interest.ADDRESSES: Written Comments: Addresscomments to the Dockets ManagementSystem, U.S. Department ofTransportation, PL 401, 400 Seventh St.,

SW, Washington, DC 20590–0001.Comments should identify the docketnumber, RSPA 98–3684(HM–220), andshould be submitted in two copies.Persons wishing to receive confirmationof receipt of their comments shouldinclude a self-addressed stampedpostcard. The Dockets ManagementSystem is located on the Plaza Level ofthe Nassif Building, at the aboveaddress.

Public dockets may be reviewedbetween the hours of 10:00 a.m. to 5:00p.m., Monday thru Friday, excludingFederal holidays. In addition, commentscan be reviewed by accessing the DOTHomepage (http://www.dot.gov).Comments may also be submitted by E-mail to ‘‘[email protected]’’. In everycase, the comment should refer to theDocket number set forth above.

Public Meeting: The public meetingwill be held in Room 3200–3204 at theU.S. Department of Transportation’sNassif Building, 400 7th Street SW,Washington DC, 20590.FOR FURTHER INFORMATION CONTACT:Cheryl Freeman, telephone number(202) 366–4545, Office of HazardousMaterials Technology, or Ryan Posten,telephone number (202) 366–8553,Office of Hazardous MaterialsStandards, Research and SpecialPrograms Administration, U.S.Department of Transportation,Washington, DC 20590–0001.SUPPLEMENTARY INFORMATION:

I. BackgroundFederal hazardous material

transportation law (Federal hazmat law),49 U.S.C. 5101–5127, authorizes theSecretary of Transportation to regulatethe manufacture and continuingqualification of packagings used totransport hazardous materials incommerce, or packagings certified underFederal hazmat law for thetransportation of hazardous materials incommerce. The HMR, 49 CFR parts 171–180, contain requirements for themanufacture, use, and requalification ofcylinders subject to Federal hazmat law,including defining materials andmethods of construction, the frequencyand manner of inspection and testing,standards for cylinder rejection andcondemnation, cylinder marking andrecordkeeping, authorizations forpackaging hazardous materials incylinders, filling, loading, unloading,and carriage in transportation.

Historically, Federal authority toregulate the transportation ofcompressed gases was given to theformer Interstate CommerceCommission (ICC) through theTransportation of Explosives Act, 35Stat. 1135, section 233 (March 4, 1909),

which was later amended in 1921, at 41Stat. 1445, § 233. In 1911 the ICCadopted a series of ‘‘Shipping ContainerSpecifications,’’ among which the ICC 3specification for seamless steelcylinders was codified. That same year,the ICC 4 specification for a lap-weldedcylinder for anhydrous ammonia wasalso published. As the welding processimproved, from the riveted/brazedwelds to resistance welding and thenbutt welding by the metal-arc process,the ICC 4 Specification series wasexpanded to include the 4BA, the 4BW,and others. By 1914, two other cylinderspecifications were codified: the ICC 7specification for steel cylinders for lowpressure, nonliquefied gas, (which havecarried over to the present regulations,but not as specification 7) and the ICC8 specification for acetylene gascylinders, which still exists today withminor changes.

In 1930, the ICC implementedregulations for periodic inspection andtesting of cylinders; the regulations, asamended, were first published in theFederal Register on December 12, 1940(5 FR 4908). During the 1930’s and1940’s, the Compressed Gas Association(CGA) developed and refined the waterjacket test method for determining theserviceability of a cylinder. DuringWorld War II, there was a shortage ofhigh pressure gas cylinders. Because ofCGA’s work on steel wall stresslimitations, the ICC granted‘‘temporary’’ regulatory relief to increasethe gas carrying capacity of existingcylinders by allowing the cylinders tobe filled 10% over their marked servicepressures, and by marking thosecylinders with a plus, ‘‘+’’, mark. Tenyears later, the regulations were codifiedinto the Code of Federal Regulations (15FR 8261; Dec. 2, 1950). In 1967,pursuant to the Department ofTransportation Act, Pub. L. 89–670, 80Stat. 931, regulatory responsibility forthe transportation of dangerous articlesin commerce was transferred from theICC to DOT.

Through rulemaking and the issuanceof exemptions from the regulationsunder 49 CFR part 107, subpart B,materials other than steel (e.g.,aluminum and composite cylinders)now are authorized for use.Nevertheless, apart from thesubstitution of the ‘‘DOT’’ identifier forthe ‘‘ICC’’ identifier, many of today’sbasic requirements remain virtuallyunchanged from the time they were firstincorporated into the regulations.

Over the years, RSPA has receivednumerous petitions for rulemakingrequesting various changes to thecylinder requirements. CGA filed mostof these petitions that request changes to

58461Federal Register / Vol. 63, No. 210 / Friday, October 30, 1998 / Proposed Rules

the cylinder specifications. In 1969,CGA submitted a petition (P–69)containing six new proposals andrevising eight previously-filed petitions.Many of these 14 petitions werehandled in subsequent rulemakingssuch as Docket HM–69 adding a DOT 39non-reusable, non-refillablespecification cylinder (August 24, 1971;36 FR 16579), Docket HM–85 updatingthe DOT–4L cylinder materialproperties (Nov. 5, 1971; 36 FR 21287),and Docket HM–99 adding the DOT–3Tspecification cylinder (Aug. 15, 1973; 38FR 21989).

In 1981, RSPA adopted a DOT 3ALspecification under Docket HM–176 (46FR 62452). This new specification for aseamless aluminum cylinder, made ofdefinitely prescribed alloys, was basedin part on the petitions received fromindustry and an agency initiative toconsolidate and eliminate the need forseven exemptions authorizing themanufacture of seamless aluminumcylinders. In 1984, CGA petitioned (P–953) to include a welded stainless steelcylinder similar to the DOT–4BW. Atthat time, CGA proposed thedesignation ‘‘4SS’’ for the new stainlesssteel cylinder.

In 1990, CGA petitioned to add a new3F specification for a seamless steelcompressed gas cylinder designed for ahigh stress level similar to the DOT–3T,but with a stronger structural integritysimilar to the DOT–3AA cylinder. Theproposed 3FM specification provides fora greater efficiency in gas transportation.

The above-mentioned petitions weregiven full consideration in thedevelopment of this NPRM. Indeveloping this NPRM, RSPA workedclosely with the cylinder manufacturingand maintenance industries, and heldseveral meetings with CGA to obtainclarification of the CGA petitions. RSPAalso held public outreach meetings withindustry that were announced in theFederal Register. The industryproposals and petitions have beenrefined by RSPA based on RSPA’scompliance inspections and exemptionprogram, interpretations issued byRSPA, and certain industry consensusstandards and practices that haveproven to be safe. RSPA believes theproposals in this NPRM are consistentwith sound industry practice andincorporate modern manufacture andrequalification technology.

Some of the more significantproposals contained in this NPRM are:

1. The establishment of four newcylinder specifications that are moreperformance-oriented and the removalof several obsolete specifications. Theseproposed specifications are expressed inmetric units, require marking of the

cylinder with test pressure in place ofservice pressure, and are distinguishableby their specification designationmarkings.

2. The new specifications allowsgreater flexibility in the design andconstruction of metric-markedcylinders.

3. Independent inspection of allmetric-marked cylinders, both seamlessand welded.

4. Design qualification testing ofmetric-marked cylinders.

5. The requalification of metric-marked cylinders and certainnonmetric-marked cylinders usingthickness and shear wave ultrasonictesting in place of the volumetricpressure test.

6. Requiring any person who performsa requalification function that requiresmarking an inspection or retest date onthe cylinder to have approval from theAssociate Administrator for HazardousMaterials Safety (herein after referred toas the Associate Administrator).

7. Standardizing the requirements forthe repair and rebuilding of DOT 4series cylinders, other than the DOT 4L.

8. Allowing a 10-year interval forrequalification of DOT 3-series metric-marked cylinders used in certain typesof service.

9. Allowing a 15-year interval forrequalification of certain DOT 4-seriesmetric-marked cylinders used in certaintypes of service.

10. Allowing, upon approval by theAssociate Administrator, the applicationof requalification markings on cylindersby using alternative methods thatproduce durable legible marks.

11. Implementing valve damageprotection and puncture resistancecriteria for all DOT specificationcylinders used for Division 2.3 or 6.1materials in Hazard Zone B, andpuncture resistance criteria for those inHazard Zone A.

12. Discontinuing authorization for afilled cylinder with a specified servicelife from being offered for transportationin commerce after its service life hasexpired.

13. Providing filling pressures formetric-marked cylinders based oncritical temperature, test pressure, anddraft ISO Standard 11622.

14. Requiring that pressure reliefdevices on all metric-markedspecification cylinders be set at no lessthan test pressure. Requiring thatpressure relief devices on all 3-series,nonmetric-marked specificationcylinders be set at no less than testpressure from the first requalificationdue after the effective date of the finalrule.

II. New specification Standards forMetric-marked Cylinders

A. Consolidation of Cylinder StandardsAs discussed above, the current

cylinder requirements have their originin the early 1900’s. The regulations weredeveloped in a piecemeal fashion, withadjustments being made to addressparticular situations and problems on acase-by-case basis. This NPRMrepresents RSPA’s first comprehensivereview of the cylinder requirements.

RSPA proposes to establish four newcylinder specifications for seamless andwelded cylinders. These proposedcylinder specifications are moreperformance oriented and incorporateprovisions that recognize certaindomestic and international practices.Cylinders made to these specificationswould be marked in metric units andwould be distinguished by a uniquespecification marking that closelyapproximates the markings in draftInternational Standards Organization(ISO) and the European Committee forStandardization (CEN), TechnicalCommittee, entitled ISO/TC58/SC4 ‘‘GasCylinders Operational Requirements,’’based on CEN Standard EN 1089–1,‘‘Transportable gas cylinders—Gascylinder identification—Part 1:Stampmarking.’’

The new seamless cylinderspecifications are identified as DOT 3M,3ALM, and 3FM. The welded cylinderspecification is identified as the DOT4M. Eventually, RSPA anticipates thatthe DOT 3M specification will replacethe current DOT 3A, 3AA, 3AX, 3AAX,3B, and 3BN specifications. The DOT3ALM specification will replace the3AL specifications. The DOT 3FM willreplace the higher strength 3AA and the3T specifications. The DOT 4M willreplace the 4B, 4BA, 4BW, 4B240X,4B240ET, and 4E. In future rulemakings,RSPA plans to propose new metric-marked cylinder specifications toreplace the current specifications for theDOT 3E, 3HT, 4D, 4DA and 4DS; the 4L;the 8 and 8AL; and the DOT 39.

The basic specification requirements,those common to most metric-markedcylinders, are in proposed § 178.69. Thissection contains definitions, material ofconstruction, duties of the inspector,and criteria for all design andproduction qualification tests that maybe required by the individualspecifications. Proposed § 178.70contains requirements applicable toseamless cylinders. The individualspecifications, containing additionalrequirements, are in § 178.71 for theDOT 3M, § 178.72 for the DOT 3ALM,and § 178.73 for the DOT 3FM.Proposed § 178.81 contains


requirements applicable to DOT 4Mwelded cylinders.

In all cases where the new proposedspecifications differ, the newspecification requirements will have alevel of integrity that is equivalent to, orgreater than, the current nonmetricspecification requirements. Significantchanges from current requirements arediscussed further in this preamble.

B. Cylinder Filling LimitsCGA petitioned RSPA to change the

test pressure from 5/3 times servicepressure for currently authorized DOTspecification seamless cylinders to 3/2times service pressure for newlyconstructed DOT specification seamlesscylinders. In effect, the CGA proposalwould increase the filling limit for mostof the new seamless DOT specificationcylinders to that currently authorizedfor cylinders marked with a ‘‘+’’ sign(see 49 CFR 173.302(c)). In the historicaland technical information provided tosupport its petition, CGA stated:

I. BackgroundIn 1942 during the height of industrial

production for WWII, a shortage of highpressure gas cylinders developed. Theshortage was hampering the War effort. Thethree manufacturers of large size cylinderswere also forging shells and bombs and didnot have capacity to forge those and therequired quantities of high pressure steelcylinders.

The War Production Board brought thisconcern to the Compressed Gas Association(CGA) to seek a remedy for the shortage ofhigh pressure cylinders. One idea was to startup new production by spinning seamlesstubing, which was initiated by Cueno-Pressand Taylor Forge; but that would takemonths. An immediate ‘‘temporary’’ reliefwas conceived which was to increase gascarrying capacity by allowing an ‘‘overfill’’ ofexisting cylinders. After careful study, theincrease of 10% in filling pressure (i.e., from2015 to 2215 psi) was considered safe andtechnically sound because of theconservative design required by DOTSpecification 3A and of the existing highpressure cylinders produced thereto.

For example: A 10% increase in wall stressat the increased filling pressure maintainedthe operating stress well below the yieldpoint of the steel; and so, cyclic fatiguefailure would not become a factor for theductile, low strength steel. Furthermore, theoperating stress would still be far below theultimate tensile strength providing anadequate safety factor which related servicepressure to rupture pressure; and the onlyway the cylinder pressure of permanent gasescould reach burst pressure was byinvolvement in a fire.

By joint agreement between the WarProduction Board, Interstate CommerceCommission (ICC) and the Gas Industry, itwas decided to immediately allow a ‘‘10%overfill’’ for the existing cylinder fleet. Thiswas to be allowed for both flammable andnon-flammable permanent gases.

To make this effective required a change inthe ‘‘Regulations’’ covering ‘‘Charging ofCylinders with Non-liquefied CompressedGases’’ because it was to be applied toexisting cylinders as well as new production.Therefore, section 173.302 was changed and178 was not changed to cover cylinder designand production. Thus, a 10% increase in thegas carrying capacity of the existing cylinderfleet and new current production wasimmediately achieved. This had the effect ofadding 10% additional cylinders.

II. Technical Rationale for Allowing 10%Higher Fill Pressures

A. Introduction

The fleet of DOT 3 Series cylinders in useduring the war years performed safelywithout a service failure, notably from fatigueor gas pressure rupture. Thus, the carefullyconsidered decision to allow the chargingpressure to be increased by 10% wasconsidered to be proven safe and technicallyvalid.

The compressed gas industry monitoredperformance of their cylinder fleets andconcluded that the ‘‘temporary’’ over-fillingprocedure could safely become a permanentregulation. However, CGA decided torecommend certain controls to justifypermanent continuation of this change whicheffected the design safety factor. Thosecontrols are now contained in CFR Title 49,clause 173.302 (c) entitled ‘‘Special fillinglimits for Specification 3A, 3AA, 3AX, 3AAXand 3T cylinders’’.

The technical rationale for those controlswas: * * *

(1) ‘‘That such cylinders are equipped withfrangible disc safety relief devices (withoutfusible metal backing) having a burstingpressure not exceeding the minimumprescribed test pressure.’’

Rationale: This was to guarantee thatcylinder pressure from any source couldnever reach the cylinder design burstpressure. Therefore, lowering the ratio ofservice pressure to rupture pressure, wasmeaningless because the cylinders would beequipped with a ‘‘rupture port’’ which wouldvent the gas pressure at a pre-determinedpressure and prevent the cylinder from everreaching its ‘‘burst’’ pressure. * * *

(2) ‘‘That the elastic expansion shall havebeen determined at the time of the last testor retest by the water jacket method.’’

Rationale: In the 1930s and 1940s the CGAhad developed and refined the water jackettest method, and developed the mathematicalrelationship of wall stresses as measured bythe elastic expansion of individual cylinderdesigns. The average wall stress asdetermined by elastic expansion measured bythe water jacket hydrostatic test was limitedto a specified stress less than the permittedmaximum design stress. For example, 3AAdesign cylinders were to be rejected if theelastic expansion exceeded a valueequivalent to the strain developed at anaverage wall stress of 67,000 psi; whereas,the design wall stress limit in 178.37–10(b)is 70,000 psi. This 4% decrease in wall stresswas selected because elastic expansionmeasures the average effective wall thicknessand not the minimum. At the same time itwas concluded that a small increase (i.e., 4%)

in the stress at isolated areas of a cylindercould be safely tolerated to allow forlocalized damage or thinning; and a‘‘Maximum wall stress limitation’’ was set;e.g., 73,000 psi for 3AA design cylinders.This procedure of elastic expansion controlwas developed to further justify thepermanent use of the ‘‘10% overfill’’ byguaranteeing that such cylinders would becontrolled by limiting the loss of wallthickness so that the stress at service pressurewould be below the yield point of thecylinder steel. * * *

(3) ‘‘That either the average wall stress orthe maximum wall stress shall not exceed thewall stress limitations shown in thefollowing table.’’

Rationale: Wall stress limitations for bothaverage wall and isolated spots weredeveloped for each ‘‘class of steel’’ used forICC 3, DOT 3A, and DOT 3AA cylinderdesigns. (Much later DOT–3T was added.)These limits were selected from knownphysical properties of these steel classes; andwere set to assure that stress at operationpressures were: (1) well below yield pointand (2) that an adequate burst pressure toservice pressure ratio was obtained. Thisclause amplifies the preceding clause 2.

(4) ‘‘That an external and internal visualexamination made the time of test or retestshows the cylinder to be free from excessivecorrosion, pitting, or dangerous defects.’’

Rationale: The body of data and serviceexperience available within the CGA hadproven that the design criterion for DOT highpressure cylinders was eminently safe;especially as regards cycle life and rupture inservice. The only cause of cyclic or tensilerupture would be damage inflicted duringmanufacture or service. Thus, the visualinspection before and during use wasconsidered to be an essential safety measure,which continues to be true today.

(5) ‘‘That a plus sign (+) be addedfollowing the test date marking on thecylinder to indicate compliance withparagraphs (c) (2), (3) and (4) of this section.’’

Rationale: This was to force both thecylinder manufacturer and user to take aphysical act to signify their guarantee ofcompliance with the control methods. Thisalso was an easily discerned mark thatpermitted personnel to identify whichcylinders were satisfactory, safe and qualifiedfor charging to the ‘‘10% overfill’’.

B. Wall Stress and Safety Factors of Series 3DOT Cylinders

The most common high pressure cylinderin use in 1942 was the ICC–3A–2015 withsize of 9′′ O.D. x 51′′ long, rated at 220 cubicfeet oxygen capacity. This cylinder made ofnormalized intermediate manganese steelhad an ultimate tensile strength of about95,000 psi and had excellent ductility andgood charpy impact strength at ¥50°F. toassure safe fracture performance. The designstress at test pressure was 49,500 psi whichwith the 5/3 test pressure ratio allows a stressof 29,600 psi at 2015 psi service pressure.The yield point was about 69,000 psi (about0.73 x U.T.S.). Thus the service stress wasabout 50% of yield stress, which levelassured a long (virtually infinite) cycle life.The burst stress to service stress ratio (safetyfactor) was about 3.2 (95,000 ÷ 29,600).* * *


This ratio of operating stress compared toultimate strength was obviously aconservative design. The conservatism ismore obvious in view of the fact that thecylinders were seamless, forged, high qualitysteel pressure vessels which have no stressconcentration points in the longitudinalplane of major stress. Furthermore, they wereused in non-corrosive gas service and haveno source to increase the contained pressureduring use except by the small fluctuationsin ambient temperature or a fire. Thecylinders are also subjected to periodicrequalification. In view of these facts/dataand the excellent service record, the decisionwas made in 1942 to allow stress to increaseabout 32,600 psi at service pressure for the‘‘10% overfill’’. This equates to a workingstress to burst strength ratio of 2.9 (95,000 ÷32,600).

Thus the ‘‘10% overfill’’ was consideredtechnically appropriate and eminently safe asa way to increase the oxygen carryingcapacity from 220 CF to 244 CF. Thesecylinders have continued in service for over50 years with a perfect safety record asregards cyclic or pressure rupture in service.The same effective stress at test pressure canbe achieved by testing either at 5/3 of 2015or 3/2 of 2215. These pressures are 3358 and3323 which stresses the wall to 49,350 and48,720 psi respectively. This 1.2% differencein test pressure stress would beinconsequential with respect to cylindersafety. Therefore, the test pressure in theDOT 3A, 3AA, and 3T specifications cansafely be changed to 3/2 instead of 5/3service pressure. The following paragraphdescribes graphic presentation of thesituation with intermediate manganesenormalized and chrome-moly quenched andtempered, which represents virtually 100%of the 3A and 3AA cylinders in the U.S.* * *

It is proposed to write all the ‘‘10%overfill’’ into the design conditions for DOT3A, 3AX, 3AA, 3AAX, 3F (new) and 3T. Thiscan be accomplished by merely changing therequired test pressure from 5/3 x servicepressure to 3/2 x service pressure. For allintents and purposes, the cylinders would beexactly the same as discussed above. * * *

III. Conclusions

1. DOT 3A and 3AA cylinders have beenin use since 1942 (54 years) with a ratio oftest pressure to service pressure of 3/2. Attime of manufacture or retest, the cylindersare tested at 5/3 x service pressure; but theservice pressure is increased by 10% forfilling.

2. The 10% overfill pressure times 3/2results in a wall stress at test pressure only1% less than the requirement to test at 5/3times marked service pressure.

3. The 3/2 test pressure would result in acalculated minimum wall of barely 0.001inch less for a current cylinder with a 0.250wall minimum.

4. The tiny decrease in wall thickness andeffect of 1% lower stress at test pressurewould have no effect in overall cylindersafety.

5. The service record since 1942 (54 years)has been perfect as regards rupture under gaspressure and cyclic fatigue characteristic.

The change to 3/2 test versus 5/3 does notchange any measurable characteristic whichwould effect these failure modes.

6. The ASME Code uses a 3/2 test pressureto working pressure ratio.

7. Europe (18 countries) uses the 3/2 testto service pressure ratio.

IV. RecommendationThe minimum prescribed test pressure

shall be 3/2 times the marked servicepressure for all cylinders with a markedservice of 500 psi or greater for all Series 3steel cylinders. This should also beconsidered for cylinders made of nickel,aluminum or stainless steel.

In considering the issue of cylinderfilling limits, RSPA also reviewedtechnical information supplied bycylinder manufacturers and by holdersof exemptions that authorize either atest pressure of 3/2 times servicepressure or 10% overfill for materialsnot currently specified in 49 CFR173.302(c), the hazardous materialsinformation system data base forincidents involving ‘‘+’’ markedcylinders, and the work currently beingdone by the ISO and the United NationsGroup of Experts on the Transport ofDangerous Goods. After reviewing allthe available information, RSPA hasconcluded that from a transportationsafety perspective, there is no technicalreason or safety experience whichwould prohibit increasing the cylinderfilling limits for seamless cylinders tothose comparable to the levels currentlyauthorized in 49 CFR 173.302(c).Therefore, RSPA has accepted the CGAproposal to increase the filling limits fornew cylinders, in principle, but haschosen to limit the proposal forincreased filling limits to metric-markedDOT Specification cylinders.Additionally, RSPA has not changed therequirements in 49 CFR 173.302(c) forthe current DOT specification cylinders,but has moved them to proposed§ 173.302a(b).

With regards to existing cylinders,RSPA is considering a process foraccepting certain DOT specificationcylinders as meeting the new metricspecifications, but is still consideringvarious conversion criteria. RSPAsolicits comments from interestedpersons as to the interest and feasibilityof developing such a conversionprogram and, if feasible, specific criteriafor requalifying and conversion ofexisting cylinders.

C. Specification Markings on Metric-marked Cylinders

In the CGA submission to RSPA, itwas requested that cylinders be markedin bar rather than psig. Bar is aninternationally accepted metric unit forpressure in the compressed gas

industry. This change would help makemarking DOT specification cylindersconsistent with the practice in mostEuropean countries which are currentlymarking cylinders with the test pressureshown in bar.

While considering this request, RSPAreviewed its current markingrequirements as well as two draftdocuments on the subject of cylindermarking being considered by the ISOand the CEN. The documents are ISO/DIS 13769, ‘‘Gas cylinders—Stampmarking,’’ and CEN Standard EN 1089–1, ‘‘Transportable gas cylinders—Gascylinder identification—Part 1:Stampmarking.’’

Based upon this review, RSPAproposes to change the way DOTspecification cylinders are marked. Thenew marking scheme will change thenumber and sequence of marks requiredto be placed on DOT specificationcylinders by manufacturers and isconsistent with the sequence beingproposed by both ISO and CEN.However, RSPA does not proposed torequire all of the cylinder markscontained in either the ISO or CENdocuments. The proposed markingscheme will also make it easier toidentify those cylinders manufacturedto the proposed specifications.Additionally, the marking scheme issimilar to the type of marking schemecontained in the United NationsRecommendations for the Transport ofDangerous Good for non-bulkpackagings and intermediate bulkcontainers.

The proposed marking sequence, witheach element separated by a slash mark,is as follows:DOT SpecificationCountry of originManufacturer’s identificationSerial numberStamp for non-destructive testing (if

applicable)Minimum wall thicknessWater capacity (liters)Test pressure (bar)Identification of alloyTare weight (kg)Identification of inspection agencyTest dateREE (if applicable)

The most significant change is themarking of the new specificationcylinders with test pressure instead ofservice pressure. DOT specificationcylinders have always been designed totest pressure rather than servicepressure. Specifically, the stressformulas used to determine theminimum wall thickness of DOTspecification cylinders are calculated atthe minimum test pressure.


Additionally, as currently authorized in49 CFR 173.302(c), many cylinders usedto transport compressed gases which arenot liquefied, dissolved, toxic orflammable are filled to a pressure 10%in excess of their marked servicepressure and 49 CFR 173.304(f)specifies, with limited exceptions, thatthe pressure in the container at 130°Fshall not exceed 5/4 times the markedservice pressure. While marking the testpressure rather than the service pressurewill require the training of persons whofill cylinders, it should not have anyadverse safety effects sinceinadvertently filling a cylinder to themarked test pressure, in bar, wouldresult in the cylinder being filled to alower pressure than the currentlymarked service pressure in psig.Further, most cylinders are filled by aperson who uses a filling table thatshows the values already adjusted forchanges in temperature and elevation.RSPA envisions that cylinders markedwith test pressure will also be filled byusing filling tables.

III. Independent Inspection—New DOTSpecification Cylinders

A DOT specification cylinder is, andhas been for the past sixty years, awidely recognized standard for the safetransportation of compressed gases. Thiswide acceptance has resulted insignificant economic benefit to domesticindustry far beyond the value of thecylinders sold internationally. Marketdemand for gases and equipment hasincreased as a direct result of thereputation of the DOT cylinder forstrength, durability and quality.

Since the early 1900’s, cylindersmanufactured under DOT’s ‘‘highpressure’’ specifications have requiredindependent inspection, originallyreferred to as ‘‘disinterestedinspection.’’ Occasionally, RSPAreceives complaints from companiesabout costs of independent inspectionor claims that the companies’ employeesare as knowledgeable and qualified, ifnot more so, as the independentinspector. However, RSPA’s Office ofHazardous Materials Enforcement,through its compliance inspectionprogram, has found a higher level ofcompliance with the regulations wheninspection and certification functionsare carried out by an IndependentInspection Agency (IIA) instead of by anemployee of the manufacturingcompany. In order for DOT specificationcylinders to be acceptable for service inmost foreign countries, cylinders mustbe certified through an inspectionprocess which is not controlled by thecylinder manufacturer. Since 1977, allDOT specification cylinders

manufactured outside the United Statesunder the RSPA foreign cylinderapprovals program are required to beinspected and certified by an IIA.

In order to maintain the high level ofsafety established over the past 100years, to maintain the acceptability ofDOT specification cylinders worldwide,and to facilitate the harmonizationbetween domestic and foreign cylinderspecifications, RSPA is proposing thatall cylinders manufactured or rebuilt tothe new DOT metric-marked cylinderspecifications be subject to inspectionby an IIA. In effect, this would continuethe current DOT inspectionrequirements for seamless cylinders andextend the practice to welded cylinders.

IV. DOT Approval of CylinderRequalifiers

RSPA proposes that any person whorequalifies a DOT specification cylindermust be approved by the AssociateAdministrator prior to performing anyrequalification function that requires aninspection or retest date to be markedon the cylinder. The affected functionsinclude performance of a visualinspection, pressure test, ultrasonicthickness test, repair, or the rebuildingof cylinders. This proposal will enhancethe accountability of the cylinderrequalification process.

Currently, § 173.34(e)(13) permits acylinder used exclusively for certainliquefied gases to be requalified for useby performing an external visualinspection and marking the cylinderwith the test date and an ‘‘E’’. The ‘‘E’’indicates that the cylinder wasrequalified by external visual inspectionin accordance with CGA Pamphlet C–6rather than by a hydrostatic test. Aperson who performs only externalvisual inspections is not required toobtain an approval from, or registerwith, the Associate Administrator.Although current § 173.34(e)(13)requires these persons to maintainrecords, RSPA does not know who orhow many persons requalify and markcylinders with an inspection date andan ‘‘E’’, or the locations of their placesof business. Also, RSPA does not knowwhether these persons have theknowledge and skills necessary toperform the required functions,including use of required inspectionstandards.

RSPA inspectors have frequentlyobserved DOT specification cylinders,primarily in liquefied petroleum gasservice, that bear markings representingthat they were requalified for use. Themarkings reflected dates of recentrequalification by external visualinspection. One cylinder, marked withthe letter ‘‘E’’ and the date ‘‘6 98,’’ was

examined by RSPA personnel on June19, 1998, and found to be rusted to anextent that there is no doubt that therust formed long before the markedinspection date. Considering the amountof undisturbed rust on the cylinder, itwas apparent that the personrequalifying the cylinder did notproperly prepare it for inspection byfirst completely removing all rust fromthe exterior surface of the cylinder, asrequired by paragraph 3.1 of CGAPamphlet C–6, which was developed bythe compressed gas industry foradoption by reference as Federalregulations.

In reviewing the approach forresolving this issue, RSPA consideredfive options:

(1) Continue the current provisionthat allows persons who are not knownto RSPA to requalify cylinders byperforming visual inspections;

(2) Adopt a registration program thatwould require persons who performvisual requalification to be registeredwith RSPA and to mark their requalifieridentification numbers (RIN) on thecylinders they inspect;

(3) Adopt an approvals programrequiring that persons performingrequalifications of cylinders by visualinspection be approved by RSPA uponwritten application containingstatements regarding theirqualifications;

(4) Adopt an approvals program thatwould require persons performingvisual requalifications to be reviewed byan independent inspection agency; and

(5) Discontinue visual requalificationof cylinders, thereby requiring allaffected cylinders to be hydrostaticallyretested.

RSPA selected option 3 for this NPRMbecause it will not impose the burdenand added cost of employing anindependent inspection agency whileensuring the accountability of a personperforming visual requalifications andproviding RSPA the authority to revokeor suspend the person’s approval fordemonstrated non-compliance with therequalification requirements. Also, byrequiring a certification that anapplicant has the ability to performrequalifications, RSPA believes eachapplicant’s awareness of the importanceof compliance will be heightened. RSPAsolicits comments on these options andothers that RSPA may not haveconsidered.

V. Requalification MarkingsRSPA proposes to amend § 171.2(d) to

prohibit the misrepresentation of arequalification identification number(RIN) marking. Over the years, throughits compliance program, RSPA has been


in contact with dozens of individualswho did not perform the requiredhydrostatic tests, but stamped thecylinders as though each cylinder hadpassed the inspections and tests. Thesteel stamps used to mark the cylindersare readily available, low-cost andsimple to use. RSPA believes that theseand other factors (e.g., the high cost ofpurchasing and maintaining hydrostatictest equipment when compared to themere cost of obtaining a set of steelstamps) provide an economicinducement for some individuals toengage in fraudulent activities. Based onrecent enforcement data, this safetyproblem appears to be more widespreadthan RSPA originally thought. RSPA isconcerned about the number ofcylinders that are fraudulently stampedand then are used to transporthazardous materials in commerce.These cylinders, whose structuralintegrity has not been verified, posesubstantial risks to health, safety andproperty. When RSPA discovers thesesituations, RSPA publishes a safety alertnotice (see Notice No. 97–2, 62 FR19651; Notice No. 97–3, 62 FR 24548)and, where appropriate, refers thematter to the Department of Justice forpossible criminal prosecution (seeUnited States v. American OxygenCompany, et al., Docket No. 97–533(D.N.M.)).

RSPA is also soliciting comments onthe issue of what future method ormethods should be used to mark DOTspecification cylinders during therequalification process. Currently, aftera cylinder meets the requalificationstandards (e.g., passes a hydrostatic test,internal and external visualexaminations, etc.), the requalifierstamps the month and year of the testand its RIN on the cylinder. Thismarking is normally accomplished withsteel stamps (Note: currently under anexemption certain fiber-wrappedcylinders may be marked with labels.).Through this rulemaking, RSPA isevaluating the merits of new markingmethods for DOT specification cylindersfollowing the requalification process.

RSPA is considering incorporating anumber of marking options (e.g.,labeling, marking with a laser, replacingthe RIN with a symbol that is difficultto duplicate, etc.). RSPA is requestingcomments from the public as to thefeasibility, costs and benefits ofalternatives to the metal stampingmethod and whether the public believesthere is justification for RSPA adoptingan alternative method.

VI. Toxic GasesDivision 2.3 and 6.1, Hazard Zone A

and B toxic inhalation hazard (TIH)

materials present a substantial risk tothe public, transport workers andemergency responders even when smallquantities are released. For smallercylinders, shifting freight and droppingare major sources of package damageand releases of hazardous materials.Cylinders are sometimes dropped inhandling, resulting in valve damage orcylinder punctures. In a study ofHazardous Materials InformationSystem (HMIS) reports for the past 10years, RSPA found that over 30% of allreported cylinder incidents involvedvalve damage. Valve damage occurswhen valves are inadequately protectedby outer packagings or valve protectiondevices. Punctures most commonlyoccur when a cylinder is impacted byhandling equipment or other cargo or isdropped upon other cargo or handlingequipment. To reduce the probabilitythat a handling incident may result inthe release of a TIH material, RSPAproposes to expand the current drop testrequirement for cylinders containingTIH materials to include Hazard Zone Bmaterials and a performance test forcylinder puncture for TIH materials inHazard Zones A and B. These proposedperformance tests apply to barecylinders and cylinders packed instrong outside packagings.

The performance test for puncture isbased upon dropping a cylinder sevenfeet; the same height used in the droptest for cylinder valve protection. Theseven-foot drop height represents thetypical distance that an industrial gascylinder would encounter if it fell froma truck. RSPA chose an angle iron (2inch by 2 inch by 0.25 inch thick) as atypical penetrator. The majorparameters controlling cylinderpenetration are cylinder material, wallthickness, drop height and thecylinder’s gross weight. For consistency,RSPA proposes the cylinder weight bethe water-filled weight. To represent in-service stress conditions, the proposedtest is performed on the filled cylindercharged to service pressure fornonmetric-marked cylinders and 67% oftest pressure for metric-markedcylinders.

The puncture-performance test wouldbe required for metric-marked andnonmetric-marked cylinders. Tofacilitate implementation of thisrequirement for nonmetric-markedcylinders, RSPA is proposing a two-yearimplementation period. RSPA alsoproposes a table showing thresholdvalues of wall thickness for cylinders ofa particular specification, material, andwater-filled weight range. Cylindersmeeting the specified criteria with aminimum side wall thickness equal toor greater than the value specified in the

table would qualify under current§ 173.40(d)(1) without puncture testing.To minimize the testing burden, RSPAplans to perform puncture testing todevelop initial values for the table.RSPA is requesting that cylindermanufacturers and shippers assist RSPAin developing this table. RSPA is alsosoliciting comments on whether weldedcylinders and cylinders with wallthickness of 2.0 mm or less are used forthe transportation of Division 2.3 and6.1 Hazard Zone B, C, and D materials.RSPA will use this information tofurther develop the puncture testingthreshold table. When sufficient data isavailable, RSPA would consider thedevelopment of a graph or calculation asa more practical means to depict aminimum thickness threshold forpuncture resistance.

VII. Discontinuation of CertainCylinder Specifications

RSPA proposes to discontinue the useof the following DOT cylinderspecifications: 3C, 3D, 4, 4A, 4B240X,4B240FLW, 4C, 9, 25, 26, 33, 38, 40 and41. RSPA believes that these cylindersare obsolete and no longer in generaluse. Authorization to manufacture thesecylinders was removed from theregulations on September 11, 1980 (45FR 59887). Comments are solicited frompersons who may be using thesecylinders.

If the proposals contained in thisNPRM lead to publication of a final rule,RSPA proposes to provide a transitionperiod of five years from the effectivedate of the final rule for the continuedconstruction of cylinders made to thefollowing DOT specifications: 3A, 3AX,3AA, 3AAX, 3AL, 3B, 3T, 3BN, 4B,4BA, 4BW, 4B240ET, and 4E. RSPAbelieves a five-year transition period fornew construction of cylindersconforming to these specifications willreduce the burdens incurred by personsaffected by this proposal. Cylindersmade to these specifications would beauthorized for continued use as long asthey meet standards for periodicrequalification. Voluntary compliancewith the new metric or revisedrequirements would be authorized 90days following publication of the finalrule in the Federal Register.

VIII. Pressure Relief Device (PRD)Systems

In a previous rulemaking (see, DocketNo. HM–220A, 61 FR 26750, 26756;May 28, 1996), RSPA proposedvoluntary compliance with CGAPamphlet S–1.1, paragraph 9.1.1.1,which would require verification thatthe PRDs operate properly. RSPA madethis proposal based on the view that


over time certain components within aPRD will cease to function as designed.Thus, RSPA proposed adoptingparagraph 9.1.1.1 which would haverequired that the operation of the PRDbe verified. A number of commentersopposed this proposal citing its cost andthe lack of incident data supportingadoption of this requirement. Based onthe need to gather more data and reviewthe cost estimates submitted, RSPAwithdrew the proposal and agreed toconsider the proposal in a futurerulemaking. RSPA continues to evaluateadopting this industry standard.

Since publication of HM–220A finalrule, gas industry representatives haveexpressed the view that over time mostpolymers, used as seats in PRDs,vulcanize. Vulcanization prevents thedevices from functioning as designed.RSPA solicits information on thefollowing:

1. Data and comments on the cost,effectiveness and need for adoptingparagraph 9.1.1.1, in CGA Pamphlet S–1.1.

2. Additional incident data from Stateand local officials concerning incidentsthat involved compressed gas cylinderswhich may not have been reported toRSPA because the incident did notinvolve a hazardous materials carrier ordid not meet the reporting criteriaspecified in 49 CFR § 171.16.

3. Comments on the need to requirePRD manufacturers to certify aperformance range and period for theirdevices. Thus, a PRD would have toperform within specific limitsthroughout a specific life.

Public comments that address theseissues will be considered in a futurerulemaking.

IX. Related Rulemakings, Petitions forRulemaking, and SafetyRecommendations

Docket HM–176A (RIN 2131–AB51).RSPA proposes to amend § 178.46 toremove aluminum alloy 6351–T6 as anauthorized material for the manufactureof DOT 3AL seamless cylinders. InJanuary 1990, at RSPA’s urging,manufacturers of DOT 3AL cylindersvoluntarily discontinued the use ofaluminum alloy 6351–T6 becausecylinders made of this alloy aresusceptible to cracks that could result inleaks or ruptures.

On July 10, 1987, RSPA published inthe Federal Register a safety advisoryand advance notice of proposedrulemaking (ANPRM) (Docket No. HM–176–A; 52 FR 26027) to inform allpersons possessing DOT 3AL (49 CFR178.46) cylinders, made of aluminumalloy 6351 manufactured by Luxfer USALimited, that cracks had developedduring service which occasionallyresulted in leakage and loss of cylindercontents. In addition to the safetyadvisory, the notice identified thosecylinders at risk, suggested steps thatusers should take to minimize risks, andrequested industries’ commentsconcerning the extent of the problemand their suggestions on correctivemeasures.

RSPA received 31 comments frommanufacturers, distributors, andindustrial users of aluminum alloycylinders. Some commenters submittedfindings of studies for cylindersmanufactured with aluminum alloy6351, including sustained load cracking(SLC) behavior testing. The majority ofthe comments and findings concluded

that DOT 3AL cylinders made fromaluminum alloy 6351, includingcylinders authorized under exemptionDOT–E 7235, pose a greater probabilityof failure than other cylinders. Further,information available to RSPA revealsthat it is difficult to detect cracks inthese cylinders which adds to the risks.RSPA published several notices to alertpersons to the safety risk associatedwith cylinders manufactured to the DOT3AL specification or under exemptionDOT E–7235 and containing alloy 6351(50 FR 32944, August 15, 1985; 58 FR15895, March 24, 1993, 59 FR 38028,July 26, 1994). Thus, there is sufficientdata which demonstrates that this alloyis not suitable for the manufacture ofcompressed gas cylinders and that itshould be removed as an authorizedconstruction material.

Petitions for rulemaking. RSPA hasreceived numerous petitions forrulemaking requesting changes to thecylinder specifications and relatedcommodity and requalificationrequirements. These petitions were heldin abeyance and were considered in thedevelopment of this NPRM. Most of therequested changes are included in thisNPRM. Because of the proposals in thisNPRM to establish four new cylinderspecifications and to discontinueconstruction of cylinders to certaincurrent specifications, some of therequests for changes to the currentregulations are no longer warranted. Asummary of the petitions, with RSPA’scomment shown in brackets, are asfollows:

Petition No. Request

0095 ........................ Consolidate the DOT 3-series specifications to permit unified specifications. Filed by CGA [Proposed in §§ 178.69–178.73for metric-marked cylinders].

0154 ........................ Permit filling of non-toxic, nonliquefied flammable gases to 110% of the cylinder’s marked service pressure (including hy-drogen). Filed by CGA [Proposed in § 173.302b for metric-marked cylinders].

0312 ........................ Align rejection criteria of welded cylinder specifications to permit testing of second specimen from same lot if first speci-men fails. Filed by the Canadian Transport Commission [Proposed in § 178.81 for metric-marked cylinders].

0324 ........................ (Request same as P–0312). Filed by the Association of American Railroads.0457 ........................ Revise cylinder repair and rebuilding requirements. Filed by CGA [Proposed in § 180.211 for all cylinders].0553 ........................ Amend Part 178 to change cylinder lot size in each specification. Filed by CGA [Proposed in § 178.70 for seamless met-

ric-marked cylinders and in § 178.81 for metric-marked welded cylinders].0652 ........................ Revise § 173.302(c)(3) table to add a fifth class of steel for DOT 3 series cylinder tubes. Filed by CGA [Proposed in

§ 178.70 for metric-marked cylinders].0752 ........................ Amend the table in 178.37–5(a), by adding a column titled ‘‘Authorized Chemical analysis (designation 10B30).’’ Filed by

Pressed Steel Tank. (See DOT E 8311) [Proposed in § 178.70 for metric-marked cylinders].0823 ........................ Incorporate by reference CGA Pamphlets C–1 and C–5. (See also P–981). Filed by CGA [Incorporated by reference in

§ 171.7].0866 ........................ Revise required sequence for display of specification markings on seamless aluminum cylinders and allow use of new

marking techniques [Proposed in § 178.69 for metric-marked cylinders].0953 ........................ Establish a new specification for manufacture of new welded, stainless steel cylinders. (See E–4884). Filed by CGA [Pro-

posed in § 178.81 DOT 4M specification].1040 ........................ Revise § 173.304(c) and (d)(4) to expand specific gravities for LPG, at 42% filling density, from 0.504–510 to 0.497–

0.510. Filed by the National Propane Gas Association [Proposed in § 173.304b for metric-marked cylinders].1071 ........................ Permit use of DOT 3AL cylinders for any gas or gas mixture that is compatible with aluminum. Filed by CGA [Proposed

greater use DOT 3ALM cylinders in § 173.302b].


Petition No. Request

1082 ........................ Revise 173.302(f) to remove 5/6 filling pressure limitation applicable to DOT 3AL cylinders. Filed by CGA [Proposed in§ 173.301a for DOT 3AL cylinders and in § 173.301b for DOT 3ALM cylinders].

1087 ........................ Establish a new specification for seamless steel cylinders having a design stress of not more than 90,500 psi and a watercapacity of not more than 150 pounds. (E–9001, 9370, 10047). Filed by CGA [Included in proposed new DOT 3FMspecification in § 178.73].

1090 ........................ Require that a cylinder requalified by visual inspection must be marked with the retester’s identification number. Filed byCGA [Proposed in § 180.213].

1189 ........................ Establish a new low pressure welded stainless steel cylinder specification. Filed by CGA. Includes P–0953 [Proposed in§ 178.81 DOT 4M specification].

1229 ........................ Revise §§ 178.36 thru 178.60 to specify procedures for conducting tensile test. Filed by CGA [Proposed in § 178.69 formetric-marked cylinders].

1233 ........................ Permit nondestructive requalification testing of compressed natural gas (CNG) cylinders. Filed by FIBA [Proposed in§§ 178.69, 180.207 and 180.209 for metric-marked cylinders and certain nonmetric-marked cylinders].

1263 ........................ Revise § 173.34(e)(18) to permit the use of a permanent, non-transferrable label for retest and inspection markings on fireextinguishers. Filed by Amerex [Proposed in 180.213].

1277 ........................ Revise § 173.34(i)(4) to except DOT 4BW cylinders from heat treatment after replacement of nonpressure attachments.Filed by Manchester [Proposed in § 180.211 subject to certain conditions].

National Transportation Safety Board(NTSB) Safety Recommendations.I–92–001

Recommends that RSPA requireattachments to all DOT authorizedhazardous materials packagings bedesigned to minimize the risk ofpuncturing other hazardousmaterials packagings during anaccident situation. (Proposed in§ 173.301(m))

I–90–008Recommends that RSPA require

hazardous material cargo to besecured in transportation withadequate restraint systems toprevent ejection of cargo fromvehicles. (Proposed in § 177.840)

I–90–009Recommends that RSPA require

independent inspection of new andreconditioned low pressurecylinders that are consistent withpresent independent inspectionrequirements for high pressurecylinders [Proposed for 4Mcylinders in § 178.69.]

X. Cross Reference TableThe following table lists the proposed

paragraphs or sections and, whereapplicable, the corresponding paragraphor section contained in the currentHMR. In some cases, the crossreferences are to provisions which aresimilar to, but not identical with currentprovisions.

New section Old section

107.801107.803(a) .... 173.300a(a).

(b) ............. 173.300a, 173.34(e)(2)(ii)third sentence.

(c) intro ..... 173.300a(b).(c)(1) ......... (b)(2).(c)(2) ......... (b)(3).(c)(3) ......... (b)(6).(c)(4) ......... (b)(7).(c)(5) ......... (a).


(c)(6)(c)(7)(d) ............. (c), (i).

107.805(a) .... 173.34(e)(2)(ii).(b) ............. (e)(2)(ii).(c) .............. (e)(2)(ii)(A).(d) ............. (e)(2)(ii)(B).(e) ............. (e)(2)(ii)(B).(f)

107.807(a) .... 173.300b.(b) ............. (b).(c) .............. (g).

173.301(a)(a)(1) ......... 173.301(h).(a)(2) ......... 173.34(e)(1).(a)(3) ......... (e)(17).(a)(4) ......... (a)(2).(a)(5) ......... (e)(1)(ii).(a)(6) ......... 173.301(k).(a)(7)(a)(8)(a)(9)(a)(10) ....... 173.301(k).(b) ............. 173.34(c).(c) .............. 173.301(a).(d) ............. (b).(e) ............. 173.34(c).(f) .............. 173.301(d).(g) intro(g)(1) thru

(g) (3).173.301(g)(1) thru (g)(3).

(h) ............. (g).(i)(j) ............... (i).(k)(l) ............... (j).(m)

173.301a(a) .. 173.301(e).(b) ............. (e)(1).(c) .............. (e)(2).(d) ............. (f) .(e) ............. 173.34(b).

173.301b173.302(a) .... 173.302(a)(4), (a)(5)(i) thru

(iii).(b) ............. 173.302(a)(4), (a)(5)(i) thru

(iii).(c) .............. 173.301(e).(d) ............. 173.301(f).

173.302a(a)intro.

173.302(a).

(a)(1) ......... (a)(1).


(a)(2) ......... (a)(2).(a)(3) ......... (a)(4).(a)(4) ......... (a)(3).(a)(5) ......... (a)(4) – (5).(b) ............. (c).(c) .............. (f).(d) ............. (f).(e) ............. (d).

173.302b173.304(a) .... 173.304(a) intro, (a)(1).

(a)(1) ......... (a)(4).(a)(2)(a)(3)(b) ............. (b).(c) .............. (a) intro.(d) ............. (e).(e) ............. (f).

173.304a(a) .. 173.304(a).(c) .............. (c).(d) ............. (d) .(e) ............. (h).

173.304b173.315(p) .... 173.301(d)(5).180.201180.203180.205(a)

(b) ............. 173.34 (e)(2).(c) intro ..... (e)(1).(c)(1) ......... (e)(1).(c)(2)(c)(3) ......... (c)(3).(c)(4)(d)(e) ............. (e)(17).(f) .............. (e)(3).(g) ............. (e)(4).(h) ............. (e)(5).(i) ............... (e)(6).

180.207180.209(a) .... 173.34(e) intro.

(b) ............. (e)(16).(c) .............. (e)(9).(d) ............. (e)(10).(e) ............. (e)(11).(f) .............. (e)(12).(g) ............. (e)(13).(h) ............. (e)(14).(i) ............... (e)(18).(j) ............... (e)(19).(k)

180.211 ........ 173.34(g), (i) through (l).180.213 ........ 173.34(c), (e)(7).



180.215 ........ 173.34(e)(2)(v), (e)(8),(e)(13).

XI. Summary of Regulatory Changes bySection

Part 107, Subpart I

Section 107.801–107.807

This new subpart would containprocedures whereby persons may seekapproval from the AssociateAdministrator to be a cylinderrequalifer, an independent inspectionagency (IIA), or to have chemical testsor analysis performed outside theUnited States for DOT specificationcylinders manufactured outside theUnited States. These requirements arecontained currently in §§ 173.300a,173.34(e) and 173.300b, respectively.This new subpart would contain thespecific requirements. Currentrequirements in 49 CFR Subpart H ofPart 107 would be referenced forminimum content of an application, theRSPA office where an application is tobe filed, and the procedures that will beused to process or terminate anapplication for approval.

The criteria permit the selection ofany person or organization, foreign aswell as domestic, that is technicallycompetent to perform the prescribedfunctions and is free from undueinfluence by persons involved with thefabrication, ownership or movement ofthe cylinders that the applicant, ifapproved, would be called upon toevaluate and certify. Under thisproposal, RSPA would accept fortransportation in the United Statesforeign-made cylinders that are similarin construction to the proposed DOTmetric-marked cylinders. As part of thispolicy, if the United States recognizescylinders manufactured outside theUnited States and approved by a thirdparty inspector approved by anothergovernment, then equal treatment isexpected of that government relative tocylinders manufactured in the UnitedStates and approved by an IIA approvedby DOT. Therefore, a foreign third-partyinspector, who certifies cylindersmanufactured outside the United States,must submit a statement from thecompetent authority of the foreigngovernment stating that similarauthority is delegated to manufacturersof metric-marked cylinders in theUnited States and that no additionallimitations are imposed.

Proposed § 107.803 (current§ 173.300a) prescribes applicationprocedures for approval or renewal asan IIA. These procedures, contained

currently in § 173.300a, would alsopermit an IIA, upon approval by theAssociate Administrator, to performother functions relating to the cylinderrequalification requirements prescribedin Part 180.

Proposed § 107.805 (current§ 173.34(e)(2)) prescribes applicationprocedures for a person seeking anapproval to perform periodic cylinderrequalifications. The procedures wouldbe revised and broadened to apply toany person who performs a functionafter which the cylinder is required tobe marked with a date as discussed inPart IV of this preamble under theheading ‘‘DOT approval of cylinderrequalifiers’’. Because these provisionswould be expanded to apply to repairersand rebuilders, the terms ‘‘retester’’ and‘‘retester identification number’’ wouldbe replaced with the terms ‘‘requalifier’’and ‘‘requalifier identification number,’’respectively.

Proposed § 107.807 (current§ 173.300b) prescribes the applicationprocedures for issuance or renewal of anapproval to perform chemical analysesand tests outside the United States onDOT specification cylindersmanufactured outside the United States.

Part 171

Section 171.2Paragraph (d)(3) would be amended to

clarify that no one may mark arequalifier identification number on acylinder that has not been requalified inaccordance with the applicablerequirements.

Section 171.7This section would incorporate the

latest editions of previously approvedCGA Pamphlets, incorporate certainadditional ASTM and CGA standards,and add references to certainpublications of the American NationalStandards Institute (ANSI).

Section 171.8Definitions for ‘‘metric-marked

cylinder’’ and ‘‘nonmetric-markedcylinder’’ would be added.

Section 171.12Paragraph (b)(15) would be revised to

include references to § 171.12a(b)(13).

Section 171.12aOn August 18, 1998, RSPA issued a

notice of proposed rulemaking [DocketHM–215C; 63 FR 44312] whichproposed to revise paragraph (b)(13) toprovide reciprocity for certain Canadianspecification cylinders to be transportedwithin the United States. This HM–215C proposed change is reprinted herefor the benefit of readers.

Part 172

In the § 172.101 Table, in column (8b)for the entries ‘‘Cyanogen’’, ‘‘Germane’’,and ‘‘Iron Pentacarbonyl’’ would berevised to specify packagingauthorization sections that areconsistent with their toxic properties.

Part 173

Section 173.34

The provisions in this section wouldbe relocated to subpart I of part 107,§ 173.301 and subpart B of part 180, asappropriate, and § 173.34 would beremoved. All references to § 173.34 inthe HMR, approximately 150 in number,would be removed and replaced withthe appropriate section reference.

Section 173.40

The requirements for toxic materialspackaged in cylinders would be revisedto include an additional performancecriteria for puncture resistance. Therequirements in § 173.40 currentlyapply only to materials in Hazard ZoneA. All requirements except the controlson closures would be expanded toHazard Zone B materials. RSPA requestscomments on whether cylinders withHazard Zone B materials should berequired to meet the same closurerequirements required for Hazard ZoneA.

As discussed earlier in this preamble,DOT 3AL cylinders made of aluminumalloy 6351–T6 are susceptible tosustained load cracking (SLC) in theneck and shoulder area of the cylinderhead and, therefore, may leak intransportation. Leaks of ToxicInhalation Hazard (TIH) materials posea significant threat to health and safety.At least two major gas suppliers havevoluntarily stopped using thesecylinders in TIH gas services. Theproposed regulation will reduce the riskto health and safety associated with TIHmaterials leaking through cracks incylinders. RSPA proposes that thisregulation be imposed on the effectivedate of this rule. After that date,cylinders made of 6351 alloy may not befilled and offered for transportation inTIH service. Cylinders filled prior tothat date may be offered fortransportation and transported to theirultimate destination and, whennecessary, cylinders containing unusedgas may be returned to the person whofilled the cylinder.

Section 173.163

The requirements for nonmetric-marked cylinders containing hydrogenfluoride would be amended to requireultrasonic examination as the onlyauthorized requalification method. This


proposal is based on the fact that thepresence of moisture in a cylindercontaining hydrogen fluoride causesrapid corrosion of the cylinder wall.Since removal of all moisture afterhydrostatic testing is very difficult, thecurrent requirements authorize only theexternal visual inspection in lieu ofhydrostatic testing and internal visualinspection. At the time the requirementwas last amended, no other alternativeexamination was available to reliablyexamine the cylinder withoutintroducing moisture into the cylinder.An ultrasonic examination, to examinethe internal sidewall for defects, can beperformed without introducing moistureto the cylinder. This section also wouldbe amended to include metric-markedcylinders for use in hydrogen fluorideservice.

Section 173.192

The title of this section would berevised to reflect that requirements areapplicable to Hazard Zone A gases. Therestriction on aluminum cylinders byhighway and rail would be extendedbeyond arsine and phosphine to includeall Hazard Zone A gases. Paragraph (c)would be amended to authorizealternative leakage tests having anequivalent level of sensitivity as thecurrent water bath leakage test, uponwritten approval from the AssociateAdministrator. Currently withoutexception, cylinders containing anyamount of phosgene gas must besubjected to a water bath leakage testprior to offering them for transportation.

Section 173.198

An editorial change would be made toparagraph (a).

Section 173.226

Paragraph (a) would be revised toinclude only seamless specificationcylinders conforming to allrequirements of § 173.40. Currently,Division 6.1, Hazard Zone A materialsmay be shipped in any DOTspecification cylinder except 8, 8AL and39. RSPA believes that this must becorrected in order to require these highhazard materials to be transported incylinders with a higher level of safety.

Section 173.227

Paragraph (a) would be revised toinclude only seamless and weldedspecification cylinders conforming tothe requirements of § 173.40.

Section 173.228

Paragraph (a) would be amended toinclude metric-marked specificationcylinders and to require that cylindersused for bromine pentafluoride and

bromine trifluoride in Hazard Zones Aand B materials must conform to§ 173.40 as required for similarmaterials.

Sections 173.300a–173.300cThe provisions in these sections

would be relocated to new Subpart I ofPart 107 and §§ 173.300a, 173.300b and173.300c would be removed.

Sections 173.301–173.301bCurrent § 173.301 would be revised

and proposed §§ 173.301a and 173.301bwould be added. Section 173.301 wouldcontain the general shipperrequirements for the use of specificationcylinders that are currently in § 173.34and the standard requirements forcylinders that are currently in § 173.301.These requirements include generalprefill requirements, maintenance andlegibility of markings, PRD, valveprotection, manifolding of cylinders andthe charging of foreign cylinders. Aderivation table showing the relocationof the requirements appears in Part X ofthis preamble.

Certain other changes would be madeto § 173.301. The cargo tankmanifolding requirements that arecurrently in § 173.301(d) would beremoved and placed with other cargotank requirements in § 173.315.

Proposed paragraph (a)(6) wouldprohibit the offering for transportationand transportation in commerce of afilled cylinder having a specified servicelife after its service life has expired.This requirement will ensure cylindersthat may be unsafe are removed fromservice for transportation of hazardousmaterials.

Proposed paragraph (d) contains thegeneral prohibition, that is currentlycontained in paragraph (a), againstfilling a cylinder with gases that arecapable of combining chemically witheach other or with the cylinder materialso as to endanger its serviceability. Thisprovision would be expanded toprohibit the use of DOT 3AL cylindersmade of aluminum alloy 6351–T6 forgases having pyrophoric properties.Leaks of gases having pyrophoricproperties, such as, silane, would causespontaneous flame and pose asignificant threat to the health andsafety. A transition period of six monthsafter the effective date of the final rulewould be provided for cylinders filledprior to the specified date.

Proposed paragraph (f) contains PRDsystem and setting requirements. Thegeneral purpose of a hazardous materialpackaging is to prevent theunintentional release of a hazardousmaterial under normal conditions oftransportation, including mishandling

and minor traffic accidents. Also, thepackaging standards for cylinders aredesigned to prevent failure of a cylinderfrom over pressurization, particularly,when it retains substantial storedenergy. Thus, a balance must be setbetween competing interests for keepinga hazardous material, particularlyDivision 2.1 and 2.3 gases and Division2.2 gases with oxidizing properties, in apackaging and allowing such a materialto escape in order to prevent thepackaging from rupturing.

Under current regulations, the typeand setting of PRD systems areestablished by CGA Pamphlet S–1.1.CGA Pamphlet S–1.1 allows a PRDsetting to be 75% to 100% of testpressure of the cylinder. Based onRSPA’s analysis of the currentlyauthorized settings, a fully chargednonmetric-marked DOT–3 series gascylinder at 130 °F operating temperaturewill likely release hazardous gases whenthe PRDs, conforming to the authorizedtolerances on device function, are setbelow test pressure. RSPA believes thiscreates a serious threat to safety byallowing an improper balance betweenkeeping the hazardous material in thepackage and preventing the cylinderfrom rupturing. In contrast, RSPA doesnot believe this condition applies toDOT–4 series cylinders because theratio of test pressure to service pressureis 2:1 as compared to 1.67:1 for DOT–3 series cylinders.

To correct this condition, RSPA isproposing a PRD setting of 100% of themarked test pressure for metric-markedand nonmetric-marked DOT–3 seriescylinders. To allow users sufficient timeto change their nonmetric-markedcylinders to meet the new PRD settingrequirement, RSPA is proposing thateach cylinder be brought intocompliance at the first requalification ofthe cylinder after the effective date ofthe final rule.

RSPA believes a setting of 100% oftest pressure for a PRD is a reasonablebalance between keeping a gas in acylinder and preventing a cylinder fromrupturing in the event of a fire oroverfill. PRDs designed to release at notless than test pressure will eliminate thepossibility of gas release through therelief device at a temperature less thanor equal to 54 °C (130 °F). At the samecondition, test pressure, the factor ofsafety for cylinder rupture is 1.6. As aresult of discussions with gas shippers,RSPA believes many major shippers ofDOT–3 series cylinders are currentlysetting PRDs at 90–100% of testpressure for toxic and flammable gases.Because it is common practice for manyshippers of DOT–3 series cylinders toreplace the PRD at the time of a


cylinder’s requalification, RSPAbelieves the proposal will result inminimal incremental cost. For mostgases, RSPA believes the increased PRDsetting will not significantly impact theperformance of cylinders in bonfiretests. RSPA requests the following:

1. Data on the performance of PRDsset at test pressure in bonfire tests.

2. Comments on any gases orcylinders where a 100% of test pressuresetting could prevent a cylinder frompassing a bonfire test.

3. Comments on the need to requalifyPRDs in a bonfire test.

Proposed paragraph (h) would containthe cylinder valve protectionrequirements that are currently inparagraph (g). These requirementswould be revised to require aperformance-oriented approach to valveassembly protection. A six foot drop testwould be required to verify that eachcylinder valve (with or withoutprotection assembly) has sufficientstrength to survive falls incidental tohandling in transportation. Anacceptable drop test result would be thatno leakage occurs after the cylinder isdropped, although the cylinder mayshow damage. A similar drop test iscurrently required for all non-bulkperformance-oriented packagings toensure that the packages can withstandnormal conditions of transportation.RSPA believes that cylinders should beheld to at least the same level ofperformance as drums and fiberboardboxes. A period of five years is proposedin paragraph (h)(1)(i) to provide asmooth transition to meet thisperformance requirement.

Proposed paragraph (k) would beadded to permit foreign cylinders to beimported into the United States andtransported within a single port areasubject to certain conditions.

Proposed paragraph(m) would beadded to prohibit cylinder attachmentswith sharp features that may causedamage to other freight. This newprovision is in response to NTSBRecommendation I–92–001 with respectto cylinders. Attachments for otherhazardous material packaging types willbe addressed in a separate rulemakingaction.

Proposed § 173.301a would containthe current requirements pertaining tothe pressure in a nonmetric-markedcylinder at 70 °F and 130 °F. It wouldalso contain a grandfather provision thatis currently in § 173.34(b).

Proposed § 173.301b containsadditional general requirements formetric-marked cylinders used fornonliquefied (permanent) gases.Definitions would be added for ‘‘criticaltemperature,’’ ‘‘dissolved gas,’’ ‘‘filling

factor of liquefied compressed gas,’’‘‘high pressure liquefied compressedgas,’’ ‘‘low pressure liquefiedcompressed gas,’’ ‘‘permanent (non-liquefied compressed) gas,’’ ‘‘safetyfactor,’’ and ‘‘settled pressure.’’ Theseproposed definitions, which are used inISO Standard 11622, will provide forharmonization with the internationalstandards.

Sections 173.302–173.302bCurrent § 173.302 would be revised

and proposed §§ 173.302a and 173.302bwould be added. Proposed § 173.302prescribes the general requirements thatwould apply to filling a specificationcylinder with a nonliquefied(permanent) compressed gas.

Proposed 173.302a prescribesrequirements for filling a nonmetric-marked cylinder with a nonliquefiedcompressed gas, i.e., the currentrequirements in § 173.302. In addition,RSPA proposes to remove the 5⁄6 fillingpressure limitation for DOT 3ALcylinders in carbon monoxide service,in response to a CGA petition (P–1082).CGA furnished information to supportits conclusion that, although evidenceshows that carbon monoxide can causestress corrosion cracking in steelcylinders, there is no evidence thatcarbon monoxide causes corrosioncracking or carbonyl formation inaluminum cylinders.

Proposed § 173.302b prescribesrequirements for filling a metric-markedcylinder with permanent gas. Because ametric-marked cylinder is stamped withthe test pressure in bar, the fill pressureis calculated from the marked testpressure. The charge pressure for ametric-marked cylinder is 2⁄3 of the testpressure for seamless DOT 3M, 3FM and3ALM cylinders, and 1⁄2 of the testpressure for welded DOT 4M cylinders.The NPRM proposes a uniform standardwhich reduces the possibility ofoverfilling and allows the gas industryto ship an additional 1.5% gas. Becausethe NPRM proposes that the cylinder bemarked and charged in accordance withISO Standard 11622, it would facilitateshipments of hazardous material in DOTspecification cylinders internationally.

Section 173.304–173.304bCurrent § 173.304 would be revised

and proposed §§ 173.304a and 173.304bwould be added. Proposed § 173.304prescribes general requirements thatwould apply to filling a specificationcylinder with a liquefied gas.

Proposed § 173.304a prescribesspecific requirements for filling anonmetric-marked cylinder with aliquefied gas, i.e., the requirements thatare currently in § 173.304. Currently,

§ 173.304 limits the filling of a cylinderwith a liquefied compressed gas basedon the maximum expected operatingtemperature (130 °F) and the minimumspecific gravity of the liquid at 60 °F.The maximum filling densities for manygases are prescribed in a table thatwould be retained in the HMR in§ 173.304a for nonmetric-markedcylinders.

The current regulation defines aliquefied compressed gas to be partiallyliquid at an operating temperature of 20°C (68 °F) and authorizes a filling limitbased on a wide range of criticaltemperatures. Therefore, the safetyfactor derived from filling limits isconservative for some gases andmarginal for other gases. In addition, thecurrent regulations limit the internalvolume of a DOT–39 specificationcylinder to 75 cubic inches when usedfor liquefied petroleum gases. Thisrequirement is revised to apply to allliquefied flammable gases and appearsin proposed § 173.304a(a)(3). Inproposed § 173.304b for metric-markedcylinders, filling limits are based on themaximum operating temperature andfilling factor. Instead of a maximumfilling density table, the proposed fillinglimits are based on a filling factor whichis directly related to the criticaltemperature of the liquefied compressedgas. The proposed filling limits areapplicable to all liquefied compressedgases. Under the proposed filling limits,the filling factor is defined based on thecritical temperature and the operatingcondition of each individual gas.Therefore, the proposal enhances thelevel of safety and allows the gasindustry to fill the cylinders with moreproduct.

Section 173.334This section would be amended to

include metric-marked specificationcylinders.





Part 177

§ 177.840 Class 2 (Gases) MaterialsRSPA proposes to revise paragraph

(a)(1) to allow horizontal loading ofcylinders containing Class 2.2 materials.In addition, the horizontal loading ofClass 2.1 and Class 2.3 materials wouldbe permitted for cylinders designed sothat the inlet to the PRD is located in the


vapor space and provided that thecylinders are properly secured duringtransportation.

This paragraph also would require theuse of cylinder restraint systems toreduce the likelihood of the cylindersbeing ejected from the vehicle in eventof an accident. This proposal is basedon a NTSB Recommendation I–90–008,that urges RSPA to require hazardousmaterials packages to be secured withadequate cargo restraint systems toprevent their ejection from the vehicleduring transportation. NTSB made therecommendation following an accidentin Collier County, Florida that involveda number of cylinders, containing apoisonous by inhalation gas, beingejected from an overturned tractor-flatbed semitrailer. Considering thewide variation in cylinder sizes, and thevarious types of restraints that would berequired, RSPA solicits information onanticipated safety benefits and the costsof requiring the use of restraint systems,particularly on small businesses.

Part 178

Section 178.46

As discussed in Part IX of thispreamble, the tables in paragraph (b)(4)would be revised to remove aluminumalloy 6351 as an authorized material forthe manufacture of DOT 3AL seamlesscylinders. In addition, in Table 1,several changes would be made to thechemical composition limits for 6061alloy for consistency with limits statedin The Aluminum AssociationStandards and Data, 1993 edition. TheSi maximum that is currently stated as0.80% would be revised to read 0.8%,the Fe maximum that is currently statedas 0.70% would be revised to read0.7%, the Mg minimum that is currentlystated as 0.80% would be revised toread 0.8%, and the Mg maximum thatis currently stated as 1.20% would berevised to read 1.2%. Finally, Table 1limits the chemical composition of Pb(lead) and Bi(bismuth) to 0.01. RSPAproposes to change these limits to 0.005.

Section 178.69

This new proposed section containsgeneral design and manufacturingrequirements applicable to all metric-marked DOT specification cylinders.This proposed section contains much ofthe same information as the current§ 178.35, including compliance,inspection and analyses, duties ofinspector, PRDs, and markings;however, proposed § 178.69 is extendedto address definitions, authorizedmaterial, threads, and tests. Thus,§ 178.69 would simplify the regulationsin that all information common to

metric-marked cylinders will becentrally located, and will allow thesimplification and streamlining of theindividual cylinder specificationsproposed in §§ 178.71, 178.72, 178.73and 178.81.

Paragraph (b) will define commonterms for clarity and consistency. Theaddition of the new definition for‘‘volumetric expansion test’’ will clarifyRSPA’s meaning of the many terms usedby industry to describe pressure testing.

Paragraph (c) specifies therequirements for inspection andanalyses. RSPA proposes that all DOT 4-series metric-marked cylinders haveinspection and analyses performed byan independent inspection agency.

In paragraph (e), duties of theinspector, RSPA proposes a change toallow the inspector to obtain a certifiedcast or heat analysis from the cylindermanufacturer in addition to the materialproducer or supplier, as needed. Thecurrent regulations require the inspectorto verify that the material ofconstruction meets the requirements ofthe applicable specification by eithermaking a chemical analysis of each heatof material; obtaining a certifiedchemical analysis from the materialmanufacturer for each heat of material;or by making a check analysis of asample from each coil, sheet, or tube ifan analysis is not provided by thematerial manufacturer for each heat ofmaterial. These alternative methods forverifying compliance are somethingraised by independent inspectors torequire cylinder manufacturers toperform check analyses when readilyavailable information may be used. Theproposed regulation would allowcylinder manufacturers to use analysesobtained from the mill to verify thematerial conforms to standards for thecylinder specification.

Paragraph (f) specifies performance-oriented requirements for threads. Theserequirements would allow themanufacturer to design the threads inconformance with any appropriatestandard as long as certain thread shearstrength limits are met.

Paragraphs (h) and (i) list all tests thatapply to metric-marked cylinders. Anew approach for the metric-markedcylinders is the categorization of designqualification tests (paragraph (h) inaddition to production tests inparagraph (i)). These paragraphs includecriteria for each test as well asacceptance criteria. The individualcylinder specifications prescribe whichtests in § 178.69 apply to eachspecification, as well as any unique testrequirements or acceptable results.Centralizing all test information in onelocation reduces repetition in the

regulations and reduces the likelihoodof inconsistent requirements in thespecifications. The requirement thatnew metric-marked cylinders have cycletesting performed during designqualification incorporates currentindustry practice. RSPA believes thatthe cycle test is an important designperformance test that assesses cylinderfatigue life and, therefore also, proposesthis requirement for welded cylinders.

Paragraph (i)(12) containsrequirements for ultrasonic examination(UT); a non-destructive test methoddesigned to detect surface andsubsurface flaws and to measure thethickness of a cylinder and the size ofa flaw or crack. The UT equipment hasthe capability to detect the presence ofdiscontinuities on or even within thecylinder sidewall, shoulder, or bottom.UT would be required for all seamlessand some welded metric-markedcylinders at the time of manufacture.

Paragraph (k) prescribes markingrequirements. A significant change forthe new metric-marked cylinders ismarking with the test pressure, ratherthan service pressure, expressed in bar.To communicate vital information torequalifiers, metric-marked cylindersthat require UT examination duringrequalification must be marked ‘‘UT’’ aswell as with the minimum wallthickness. Other markings, such ascountry of origin, will be required formetric-marked cylinders; therebymaking them more acceptable fortransportation of hazardous materials ininternational commerce.

Paragraph (l) includes a prohibitionon coatings that may interfere withinspections and tests, or that allowmoisture to accumulate between thecylinder wall and the coating. Thisprovision is RSPA’s response topotential threats to safety associatedwith coating materials, such as vinyl,which promote corrosion.

Section 178.70

This proposed section groups thecommon requirements that apply to allDOT 3 series metric-marked seamlesscylinders (DOT 3M, DOT 3ALM, andDOT 3FM).

Paragraph (c) specifies materials for 3series cylinders. Authorized materialsare located in Appendix A, Table 1 forsteel and nickel and Table 2 foraluminum. The steel compositionsauthorized include two carbonmanganese type, one chrome moly typesteel, and one stainless steel type. Thealuminum composition is a 6061 alloy.These compositions are broad enough tocover most material specificationscurrently in use.


Paragraph (e) specifies wall thicknessrequirements. The current DOT 3AAXrequirement in § 178.37(a)(2)(i) thatadresses additional design loads due tobending is proposed in this generalsection for all DOT 3-series metric-marked cylinders. The inclusion of thisrequirement sets a precedent in theHMR by allowing manufacturers theflexibility to adapt any metric-markedcylinder specification to a ‘‘tube trailer’’type cylinder.

Section 178.71This section proposes the new DOT

3M metric-marked cylinderspecification. This specificationcombines aspects of the current DOT3A, 3AX, 3AA, 3AAX, 3B, and 3BNspecifications.

Proposed paragraph (c) authorizesconstruction using steel, stainless steel,and nickel. The carbon manganesecomposition authorized encompassesthe steel currently used for DOT 3Aspecification cylinders. The inclusion ofthe stainless steel composition for aseamless cylinder will eliminate theneed for many exemptions.


3ALM metric cylinder specification.This specification is very similar to thecurrent DOT 3AL except that aluminumalloy 6351 is not authorized as amaterial of construction.


3FM metric-marked cylinderspecification. The proposed DOT 3FMcylinder is designed to a high stresslevel similar to the DOT 3T, andincorporates the strong structuralintegrity of the DOT 3AA cylinder. Thisspecification meets many of therequirements of the ISO Standard 9809–2 cylinder, which should make itreadily acceptable in internationalcommerce. The authorized materials ofconstruction are Grade B, a chromemolybdenum type steel currentlyauthorized for 3T cylinders and Grade Ea new chrome molybdenum type steel.Steels such as Grade E with higherultimate strength levels (above 115,000psi) are currently authorized underexemption. Because the most criticalfailure mode is cracking, these cylinderswill be subjected to UT examination atthe time of manufacture andrequalification.

Section 178.81This section contains specific

requirements for the proposed DOT 4Mmetric-marked cylinder specification.This specification combines aspects of

the current DOT 4B, 4BA, 4BW,4B240ET, 4E, 4D, 4DA, 4DS and4AA480 specifications. The maximumdesign test pressure is 140 bar (2030psi). This represents a pressure of morethan double what is currentlyauthorized for welded cylinders, exceptthe DOT 4DA and 4DS specification,which have a maximum test pressure of1800 psi. Authorized materials wouldinclude aluminum alloy 5154 currentlyused for the DOT 4E specificationcylinder, as well as carbon, HSLA,stainless, and 4130X steels. For DOT 4Mspecification cylinders with a testpressure of 70 bar or more, the weldsmust be 100% radiographed to provideassurance of the joint quality.Manufacturers of DOT 4M specificationcylinders would have the option ofperforming an ultrasonic examination inlieu of the radiographic examination.

RSPA solicits comments on the needfor a higher performance weldedcylinder specification than what isproposed in this NPRM. Comments arealso requested as to whether such ahigher performance specification shouldbe distinguished from the lowerperformance by pressure, or by materialstrength, or some other performancestandard. RSPA is currently consideringa cylinder specification with a designtest pressure of either more than 140 bar(2030 psi) or with an ultimate tensilestrength of 830 Mpa (121,000 psi) orhigher.

Part 180

Part 180, Subpart CThis new subpart would prescribe

requirements for the continuingqualification, maintenance, repair andrebuilding of DOT specification andexemption cylinders. Most of therequirements are currently contained in§§ 173.34 and 173.301. Readers shouldrefer to the references under Part X ofthis preamble for the citation of thecorresponding provision that is similarto the current provision contained in theHMR. The proposed requirementsinclude DOT metric-marked cylinders.

Section 180.203This section contains definitions for

terms used throughout Subpart C. Someof these definitions are ‘‘commerciallyfree of corrosive components,’’‘‘condemn,’’ ‘‘defect,’’ ‘‘rejectedcylinder,’’ and ‘‘volumetric expansiontest.’’

Section 180.205This section prescribes general

requirements for the continuingqualification and use of cylinders andfor each person performing a cylinderrequalification function.

Section 180.207

This section prescribes requirementsfor the periodic requalification ofmetric-marked specification cylinders.Proposed Table I specifies the periodicrequalification requirements. Thestandard requalification period is onceevery five years, with extendedrequalification periods provided forcylinders used exclusively to transportcertain gases. For example, when usedexclusively for noncorrosive, nontoxic(LC50 of not less than 5000 ppm) gases,DOT 3M, 3ALM, and 3FM specificationcylinders must be requalified at leastonce every ten years. Similarly, a DOT4M specification cylinder must berequalified at least once every 15 years.DOT 3M and 4M specification cylindersused exclusively as fire extinguishersand meeting the limitation of specialprovision 18 must be requalified at leastonce every twelve years, as currentlyrequired for nonmetric-marked DOTspecification cylinders used as fireextinguishers.

All DOT 3M, 3ALM, 3FM and 4Mspecification cylinders must berequalified using the ultrasonicexamination, instead of a volumetricexpansion test. A DOT 4M specificationcylinder, with a marked test pressure of70 bar or less and having a tensilestrength less than 830 Kpa (120,000 psi),may be subjected to a volumetricexpansion test in lieu of an ultrasonicexamination. Ultrasonic examinationimproves safety by automating theidentification and measurement of wallthickness, pitting and cracking. Itimproves the probability of detection forinternal pits and cracks over currentinternal visual inspection. Ultrasonicexamination also reduces inspectionand labor costs, cleaning costs andwaste water by allowing cylinderrequalification without removing thevalve and purging the cylinder’scontents, and without the deliberateintroduction of water into the cylinder.

Comments are invited on theproposed requirements for ultrasonicexamination of cylinders. RSPA alsosolicits information on industrypractices in this area, the costs andbenefits for using UT examinations andthe pass/fail criteria in Table II.

Section 180.209

This section prescribes requirementsthat are currently contained in§ 173.34(e) for the periodicrequalification of nonmetric-markedspecification cylinders. The current rulefor the requalification of most DOTspecification and exemption cylindersrequires a volumetric expansion test,external and internal visual inspections


which are not suitable for detecting aburied or internal crack.

In proposed paragraph (a)(1), note 2following the table requires detectionand measurement of the sidewall cracksin DOT 3T and 3HT cylinders at eachrequalification period by an approvednon-destructive test (NDT) method.Cracks in these cylinders can bedetected by using a suitable NDTmethod, such as acoustic emissions orappropriate shear wave ultrasonicexamination. Because the ultimatetensile strength (UTS) of DOT 3T and3HT cylinders are above 7,900 Mpa(155,000 psi), crack growth due to stresscorrosion and fatigue can occur duringnormal service. An undetected crackcan grow to a critical size and result ina catastrophic failure. Manufacturers ofspecificition DOT 3T and other highstrength exemption cylinders arerequired to perform UT examinations atthe time of manufacture.

Proposed paragraph (a)(2) allows fornonmetric-marked specificationcylinders to be ultrasonically examinedas an alternative requalification method.An external visual inspection isrequired to be conducted in conjunctionwith the UT examination. Therequalification period for nonmetric-marked cylinders is the same asrequired in Table I of this proposedsection.

Section 180.211This section prescribes repair, rebuild

and heat treatment requirementscurrently prescribed in §§ 173.34(g) thru173.34(l), with certain revisions. Theserequirements are standardized andsimplified.

Section 180.213This section contains marking

requirements presently contained in§ 173.34(e)(7), with certain revisions.

A new requirement for allspecification cylinders would be addedto identify the type of inspection, test,or work performed on a cylinder. Thisnew requirement would enableshippers, carriers, and enforcementpersonnel to readily determine the typeand date of each inspection or test, orwhether any repair or rebuilding workhas been performed on a cylinder.

The methods for marking cylinderswould permit stamping, engraving,scribing or any other method approvedin writing by the AssociateAdministrator for HMS. In response toa NPGA petition, RSPA also proposesallowing use of pressure sensitive labelsto display the requalification markingson fire extinguishers. However, RSPA isalso soliciting comments on whetherthere are any methods that should or

should not be authorized for applicationof requalification markings. Currently,after a cylinder passes therequalification volumetric expansiontest, internal and external visualexaminations, etc., the RIN holderstamps the month and year of the testand its RIN on the cylinder. Thismarking is normally accomplished withsteel stamps. However, RSPA hasgranted exemptions, such as E–11372,authorizing certain fire extinguishersand fiber-wrapped cylinders to displaythe requalification markings usinglabels. RSPA is considering whether toincorporate new marking methods forDOT specification cylinders followingthe requalification process.

RSPA requests comments on thefeasibility, costs and benefits ofalternative marking methods, andwhether affected persons believe thereis justification for RSPA to adoptalternative methods.

Section 180.215

This section contains the reportingand record retention requirementscurrently prescribed in § 173.34(e)(8),with certain revisions.

The retester authorization recordrequirements in current § 173.34(e)(8)(i)would be revised to include all cylinderrequalifiers who inspect, test, repair, orrebuild cylinders. In addition, proposedparagraph (d)(1) requires that recordscovering any work involving welding orbrazing repairs, or the building or reheattreatment of cylinders must be retainedby the cylinder requalifier for 15 years.The requalifier would be required toretain inspection and test records untilexpiration of the inspection orrequalification period or until thecylinder is again requalified, whicheveroccurs first. Records of any welding orbrazing repair, rebuilding or reheattreatment would be required to beretained for 15 years.

XII. Regulatory Analyses and Notices

A. Executive Order 12866 and DOTRegulatory Policies and Procedures

This proposed rule is considered asignificant regulatory action undersection 3(f) of Executive Order 12866and was reviewed by the Office ofManagement and Budget. The rule isconsidered significant under theRegulatory Policies and Procedures ofthe Department of Transportation (44 FR11034) because of public interest. Apreliminary regulatory evaluation isavailable for review in the docket.

B. Regulatory Flexibility Impact

GeneralThe Regulatory Flexibility Act (5

U.S.C. 601 et seq.) requires an agency toreview regulations to assess their impacton small entities unless the agencydetermines that a rule is not expected tohave a significant economic impact ona substantial number of small entities.RSPA is unable, at this time, to certifythat this proposed rule will not have asignificant impact on a substantialnumber of small entities. RSPA hasperformed an Initial RegulatoryFlexibility Analysis (IRFA) of thisproposed rule’s potential impact onsmall entities, and the assessment hasbeen placed into the public docket forthis rulemaking. Written publiccomments that clarify the degree ofpotential impacts on affected smallentities are requested.

IRFA SummaryThe Regulatory Flexibility Act is

concerned with identifying theeconomic impact of regulatory actionson small businesses and other smallentities. Unless alternative definitionshave been established by the agency inconsultation with the Small BusinessAdministration, the definition of ‘‘smallbusiness’’ has the same meaning asunder the Small Business Act. As RSPAhas established no special definition,the agency employs thresholdspublished under criteria in 13 CFR121.101, e.g., 500 employees forcylinder manufacturers (SIC 3443—Fabricated Plate Work (Boiler Shops)and SIC 3462 Iron and Steel Forgings).

Need for the proposed rule. Asindicated throughout the preamble tothis proposed rule, current requirementsfor the manufacture, use, andrequalification of cylinders can betraced to standards first applied in theearly 1900’s. The regulations weresubsequently revised in a piecemealfashion, with adjustments being made toaddress particular situations andproblems on a case-by-case basis. Thisnotice represents RSPA’s firstcomprehensive review of requirementspertaining to the transportation ofcompressed gases in cylinders andspheres. This action is being taken to:(1) Simplify requirements for theproduction of new cylinders, (2) provideflexibility in the design, constructionprocesses and permitted use ofcylinders, (3) adopt advancedtechnological processes and proceduresfor cylinder manufacturing andrequalification, (4) achieve an increasedlevel of safety through simplification ofthe rules and regulations, (5) reduce theneed to issue, and renew, exemptions


that permit variances from detailedspecifications concerning materials ofconstruction, design, and manufacturingprocesses, and (6) facilitate internationalcommerce in the transportation ofcompressed gases.

Objectives and legal basis for theproposed rule. The intended effect ofthis action is to reduce threats to health,safety and property in the transportationof hazardous materials, particularlyflammable, toxic and other compressedgases. Federal hazardous materialstransportation law (49 U.S.C. 5101 etseq.) directs the Secretary ofTransportation to prescribe regulationsfor the safe transportation of hazardousmaterials in intrastate, interstate andforeign commerce. Section 5103(b)specifies that the regulations shall applyto persons transporting hazardousmaterials in commerce; causinghazardous materials to be transported incommerce; or manufacturing,fabricating, marking, maintaining,reconditioning, repairing, or testing apackaging or container that isrepresented, marked, certified, or soldby such persons as qualified for use intransporting hazardous material incommerce.

Identification of potentially affectedsmall entities. 1. Businesses likely to bemost affected by this proposed rule aremanufacturers of specification DOT–3and DOT–4 series cylinders (SIC 3443and SIC 3462). Currently, RSPAestimates there are 40 manufacturers ofspecification DOT–3 and DOT–4 seriescylinders. Of that number,approximately 29 are ‘‘smallbusinesses’’ under the Small BusinessAct.

In the case of approximately eleven(11) manufacturers (five (5) of whom aresmall businesses) of high-pressure(specification DOT–3 series) cylindersthere should be little or no burdenattributed to requirements contained inthis proposed rule, as many of thesenew processes and technologicalinnovations have already been adoptedas part of their own quality managementprogram.

In addition to the above, there areanother twenty-nine (29) cylindermanufacturers (twenty-four (24) ofwhom are small businesses) identifiedin RSPA’s database of registeredmarkings for packaging manufacturers,and/or holders of exemptions thatauthorize the manufacture, marking,and sale of cylinders that do not fullyconform to specifications for the DOT–3 and DOT–4 series. Eight (8) of thesecylinder manufacturers (including five(5) that meet the criterion of a smallbusiness) are members of theCompressed Gas Association (CGA), one

of the primary initiators of petitions forrulemaking to revise the HMR forgreater consistency with regulations ofthe world’s leading industrial nations. Itis RSPA’s understanding that all CGAmembers support proposed revisionscontained in the CGA petitions.However, that leaves another twenty-one (21) non-CGA-member cylindermanufacturers, of which RSPA assumesat least 90% (approximately nineteen(19)) meet the SBA criterion for a smallbusiness, that would be affected by theproposed rule.

Some small entities may experiencean adverse economic impact attributedto the proposed rule’s prohibition on themanufacture of non-metric-markedspecification DOT–3 and DOT–4 seriescylinders after a future date (five yearsfrom the effective date of a final rule).Prior to that date, small entities would,at their own discretion, be permitted tomanufacture (1) non-metric-markedcylinders only, (2) metric-markedcylinders only, or (3) a combination ofnon-metric-marked cylinders andmetric-marked cylinders. However, afterthe phase-out date, these small entitiesmay manufacture DOT–3 and DOT–4cylinders conforming to metric-markedspecifications only.

RSPA anticipates that, upon review ofthese proposed requirements, somesmall entities currently producingspecification DOT–3 or DOT–4 seriescylinders may determine that it is noteconomically feasible to continue thisline of products. For example, RSPAestimates the average annual cost of theproposed requirement for anindependent inspection agency toobserve cylinder manufacturingoperations and processes at $59,286 perfacility. However, that average iscalculated on the basis of a wide rangeof costs for individual facilities thatproduce specification DOT–4 seriescylinders (e.g., $5,000 for an occasionalproduction run to $100,000 for amanufacturer that operates a dedicatedline). For manufacturers that produce arelatively large volume of thesecylinders the CGA estimates theadditional cost of manufacturingattributed to this provision will be anadditional 10¢ per cylinder. For acompleted 20-pound propane cylinderthat currently sells for approximately$25 (retail price), RSPA expects that theadded expense would not beprohibitively costly to the manufactureror to the ultimate consumer.

RSPA understands that theproduction of specification DOT–3 andDOT–4 cylinders by somemanufacturers that are small businessesoftentimes is but one of a wide-range ofpressure vessels, or other products, in

the company’s product line. Knowingthe importance of specification DOT–3and DOT–4 series cylinders to theviability of these small entities, iscritical to RSPA’s determination ofwhether this rule may have a significanteconomic impact on a substantialnumber of small manufacturingcompanies. Small entities are, therefore,specifically invited to providecomments on the economic impact ofthe proposed rule on their overalloperations.

2. In addition to cylindermanufacturers, there are approximately1,400 businesses currently engaged inthe periodic requalification of high-pressure cylinders. Here, also, RSPAconservatively estimates that at least 90percent of these requalifiers are smallbusinesses. This number includesbusinesses that manage large fleets ofcylinders, such as cylinders chargedwith propane to power forklift trucks,and for use by retail customers throughcylinder exchange programs. Still othercompanies, generally thought to fallwithin SIC 7389 (business services, notelsewhere classified), manage fleets ofcylinders used in (1) carbon dioxideservice for carbonated soft drinks, (2)fire extinguisher service, and (3)compressed air/oxygen breathingequipment used in recreational divingoperations, as well as by emergencyservices personnel, like firefighters. Allof these businesses are currentlyapproved to requalify cylinders throughperformance of the hydrostatic pressuretest.

The proposed rule would require eachbusiness to determine whether itshould: (1) upgrade test equipment fromthe hydrostatic type to ultrasonicexamination type to be able to servicethe older DOT specification cylindersand the new metric-marked cylinders,or (2) continue to maintain its currentlyinstalled hydrostatic test equipment andservice only the older DOT specificationcylinders (estimated to now number 300million, a majority of which may beexpected to remain in service well intothe next century) and the proposedDOT–4M metric-marked cylinder thathave a marked test pressure of ≤70 bar.

RSPA anticipates that some smallentities currently performingrequalification functions by thehydrostatic pressure test method maydetermine that investments in newultrasonic test equipment (requiring aninvestment currently estimated at $50-$80 thousand amortized over a period often (10) years) may not be economicallyfeasible, considering the comparativelysmall number of metric-markedcylinders (vs. the current size of thedomestic fleet of approximately 300


million cylinders) that will be producedbeginning perhaps as early as 1999, andfirst requiring periodic requalification in2004. Currently, five (5) of the eighteen(18) retester facilities currentlyperforming requalification of cylindersby ultrasonic examination, rather thanby hydrostatic pressure testing, underterms of special exemptions issued byRSPA are thought to meet the criterionfor a small business.

Although the ultrasonic examinationmethod initially involves a large capitalinvestment, it offers cost savings forbusinesses that own and/or usecylinders for the transportation ofcompressed gases. In addition,ultrasonic examination provides (1)substantial benefits for increased safety,(2) opportunities for reducing emissionsof hazardous materials to theenvironment, and (3) reducedcontamination of cylinders.

Commenters are specifically invitedto provide additional information withrespect to this proposed requirement forultrasonic testing of metric-markedcylinders and its potential impact onsmall entities. RSPA requests commentsfrom affected small entities regardingthe potential adverse impact thisproposed rule may have on theircylinder requalification operationsspecifically, and the overall viability oftheir enterprise should they determine itwould be economically prohibitive tocontinue to perform cylinderrequalification services.

3. Finally, there are literally hundredsof thousands of commercialestablishments that own and usecylinders manufactured tospecifications in the DOT–3 and DOT–4 series. Those business sectors includeagriculture; mining; construction;manufacturing; transportation,communications, electric, gas andsanitary services; wholesale trade; retailtrade; services; and many othernonclassifiable establishments. On thebasis of a Small BusinessAdministration estimate that of the 24million businesses located in the U.S.only 15,000 (.000625%) are large firms,RSPA concedes it is likely that over99% of the businesses that make use ofcompressed gases in DOT specificationcylinders are small businesses. (Source:SBA Office of Advocacy, Small BusinessAnswer Card 1998).

RSPA believes the proposed rules willgenerally have a small individual,though significant in the aggregate (i.e.,$10 million annually), positive benefitfor all of these businesses by making themetric-marked cylinders they buy orlease acceptable for trade and use inworldwide commerce. In addition, thosecylinders will be allowed to be charged

with a wider range of compressed gasesand other materials, and, in many cases,the period between periodicrequalification will be extended byseveral years, thereby resulting in costsavings attributed to less frequentinspections. For example, in the case ofa specification DOT–3AL aluminumcylinder, the 5 year retest cycle wouldbe extended to 10 years for thespecification DOT–3ALM. In time, theremay be as many as 1 million suchcylinders in carbon dioxide service forthe carbonated beverage industry alone.A single retest of this fleet of cylindersover a ten-year period vs. the currentfive-year period, at an average cost of$10 per cylinder, i.e., $10 million,would result in aggregate savings to thecylinder owners of $1 million per year.In the very competitive soft-drinkindustry, RSPA believes that the costsavings would be shared broadly.

To the extent that RSPA has failed torecognize potential impacts on thegeneral universe of small entities thatown or use cylinders, commenters areinvited to identify those impacts and themagnitude of their affect on smallentities.

Reporting and recordkeepingrequirements. This proposed rulecontains one new requirement forreporting and recordkeeping.Specifically, persons who requalifycylinders by a visual inspection, ascurrently authorized by § 173.34(e)(13),would, under proposed § 180.209(g), berequired to first obtain a requalificationidentification number (RIN) fromRSPA’s Associate Administrator forHazardous Materials Safety underprovisions of proposed § 107.805.Essential elements of the application forapproval include: (1) the name andaddress of the facility manager, (2)identification of the DOT specification/exemption cylinders that will beinspected at the facility, and (3) a signedand dated certification by the applicantthat the facility will operate incompliance with applicablerequirements of the HMR, and that thehazmat employees performinginspections have been properly trained,to include familiarization with theappropriate CGA C–6 series pamphletsconcerning the conduct of visualinspections.

An approval, if issued by theAssociate Administrator for HazardousMaterials Safety, would be effective fora maximum of five years, at which timethe approval holder would have to filea new application for approval. Otherthan the requirements for having to filean application for approval, andentering the four-digit RIN (in additionto the month, year and letter ‘‘E’’

currently required) on each cylinderrequalified by the visual inspectionmethod, there is no additionalregulatory burden associated with thisproposal.

While the actual number of facilitiescurrently operating under the exceptionprovided by § 173.34(e)(13) is unknown,RSPA assumes, on the basis of datacompiled by the Bureau of the Census,that the actual number is not more than6,691, of which 5,651 are retail dealersof bottled liquefied petroleum gases (SICCode 5984), 968 are merchantwholesalers of industrial gases, exceptliquefied petroleum gases (SIC Code5169), and 72 are entities identified asEPA-approved reclaimers of refrigerantgases.

On a per facility basis, RSPAestimates the cost of this reporting andrecordkeeping requirement would be$122.50 per five-year cycle. Thisestimate was calculated on the basis ofcost data submitted by RSPA to theOffice of Management and Budget insupport of an approval issued by OMB(2137–0022) concerning Testing,Inspection and Marking Requirementsfor Cylinders. RSPA does not see thisproposed regulatory requirement asinhibiting the ability of currentlyexcepted retesters to continue toprovide this cylinder requalificationservice to an extent that it threatens theviability of their primary business, i.e.,the sale of compressed gases inrelatively small units. RSPA specificallyinvites commenters to provide data thatsupports or refutes this estimate of thecosts of compliance with the newrequirement to obtain a retester(requalification) identification numberand its impact on small businessescurrently authorized to perform thisrequalification function without firsthaving to obtain an approval from theAssociate Administrator for HazardousMaterials Safety.

Related Federal rules and regulations.With respect to the production,permitted use, and periodicrequalification of cylinders used in thetransportation in commerce ofcompressed gases, there are no relatedrules and regulations issued by otherdepartments or agencies of the Federalgovernment.

Alternate proposals for smallbusinesses. The Regulatory FlexibilityAct directs agencies to establishexceptions and differing compliancestandards, when possible, for smallbusiness, while still meeting objectivesof the applicable regulatory statutes. Inthe case of manufacture, use, inspection,testing, retesting and requalification ofDOT specification cylinders incompressed gas service, RSPA believes


that it is not possible to establish suchdiffering standards and still accomplishthe objectives of Federal hazardousmaterials transportation law (49 U.S.C.5101–5127). RSPA further believes thatthe discussion in this NPRM as to theneed for regulatory action, issues raisedby many of the affected parties throughpetitions for rulemaking, applicationsfor exemption, and otherwise,effectively requires RSPA to apply oneset of requirements applicable to smalland large businesses alike.

While certain regulatory actions mayaffect the competitive situation of anindustry by imposing relatively greaterburdens on small-scale than on large-scale enterprises, RSPA does not believethat this will be the case with theproposed rule. The principal types ofcompliance expenditure effectivelyrequired by the proposed rule would beimposed on each cylinder representedthrough its specification markings asconforming to a DOT specification,whether manufactured by, used by, orserviced by a large or a small business.There are administrative efficiencyadvantages, and economies of scale,available to a large firm, but therequirements considered in thisrulemaking are intended to assure aminimum level of safety for packagingsused to contain hazardous materials thatpose high-order risks in transportation.Thus, no provisions may be waivedsimply on the basis that they would beburdensome to a small business.

At the same time, RSPA notes that theproposed rules were developed underthe assumption that small businessescomprise an overwhelming majority ofentities that would be compelled tocomply, particularly regardingpermitted use of cylinders and theirperiodic requalification for continueduse. For that reason, in its developmentof the proposed rules, RSPA consideredeach requirement and determined thisset represents the minimal requirementsnecessary for it to be able to assure anadequate level of safety intransportation.

For example, as an accommodation tosmall businesses, RSPA proposes to (1)permit facilities to continue to use theircurrently installed hydrostatic pressuretest equipment to retest non-metricmarked specification cylinders, millionsof which have been in service forseveral decades and may be expected tocontinue in service for many moredecades, and (2) permit therequalification of certain metric-markedcylinders, i.e., specification DOT–4Mwith a marked test pressure ≤70 bar.

Section 610 Review

Pursuant to section 610 of theRegulatory Flexibility Act (5 U.S.C.§ 610), RSPA has conducted a review ofcurrent requirements for themanufacture, use, and requalification ofcylinders. The purpose of this reviewwas to identify regulations that have asignificant economic impact on asubstantial number of small entities andto revise those regulations, whereappropriate. In proposing revisions tothe existing regulations, RSPA hasattempted to minimize the economicimpact on small business entities. It hasdone this, in part, by proposing toreduce from fifteen to four the numberof authorized DOT–3 and DOT–4 seriescylinder specifications, allowing greaterfill limits for metric-marked cylinders,and extending the time betweenperiodic requalification of metric-marked cylinders. Also, small business,such as boiler shops (SIC 3443), ironand steel forging shops (SIC 3462),merchant wholesalers of industrialgases, except liquefied petroleum gas(LPG) (SIC 5169), retail dealers of LPG(SIC 5984), and business services, notelsewhere classified (SIC 7389), willbenefit from the greater safety providedby this proposed rule. RSPA encouragessmall entities to comment on theeconomic impact of proposals containedin this NPRM.

First, RSPA examined whether thereis a continuing need for its cylinderregulations. Based on the variouscharacteristics of compressed gases (e.g.,flammability and toxicity) and theassociated risks that are involved in thetransportation of gases, RSPA recognizesthat there is a continuing need for itscylinder regulations. However, asdiscussed previously in this preamble,RSPA is in receipt of numerouspetitions for rulemaking concerning thecylinder regulations. Many of thesepetitions propose that RSPA incorporateaccepted industry practices and newtechnology (e.g., new marking methods).RSPA has accepted many of thesepetitions and is proposing toincorporate new technology where thenew technology achieves an equivalentor higher level of safety (e.g., ultrasonictesting). RSPA also reviewedexemptions issued under 49 CFR Part107 and has incorporated thoseexemption provisions that haveachieved a proven safety record.

In addition to the above, over theyears, the regulated community hasrequested that RSPA reduce thecomplexity of its cylinder regulations.RSPA addressed these concerns bymodifying the language used in theproposed rule, including a definition

section and changing the organizationalstructure of the cylinder regulations.RSPA also recognizes that marketconditions have changed dramaticallysince many of the existing rules werefirst adopted. Today, cylinders aremanufactured, used, and transported to,from, and between entities in the globalmarketplace. In recognition of thatworldwide sale and distribution ofcompressed gases in cylinders, RSPA isproposing to revise the HMR in amanner that is harmonious withinternational standards (e.g., metric-marked cylinders).

RSPA is confident that the proposedrule and existing cylinder regulations donot duplicate or conflict with otherFederal rules. In addition, conflicts withstate or local regulations are expresslyprovided for in Federal hazardousmaterials transportation law (49 U.S.C.§ 5125). Under this statutory authority,RSPA issues preemption determinationsas to whether a State, politicalsubdivision, or Indian tribe regulationor law, governing the transportation ofhazardous materials, is preemptedunder Federal law (see 49 C.F.R. Part107, Subpart C).

C. Executive Orders 12612 and 13084

This proposed rule has been analyzedin accordance with the principles andcriteria contained in Executive Orders12612 (‘‘Federalism’’) and 13084(‘‘Consultation and Coordination withIndian Tribal Governments’’). Becausethis proposed regulation would have nosubstantial direct effect on the States orthe relationship, or the distribution ofpower and responsibilities, between theFederal Government and the States,RSPA has determined that this rule doesnot have sufficient federalismimplications to warrant preparation of aFederalism Assessment. Because thisrule would not significantly or uniquelyaffect the communities of the Indiantribal governments, the funding andconsultation requirements of ExecutiveOrder 13084 do not apply.

Federal hazardous materialtransportation law contains expresspreemption provisions at 49 U.S.C. 5125that preempt State, local, and Indiantribe requirements if——

(1) Complying with a requirement ofthe State, political subdivision, orIndian tribe and Federal hazardousmaterial transportation law orregulations is not possible;

(2) The requirement of the State,political subdivision, or Indian tribe, asapplied or enforced, is an obstacle toaccomplishing and carrying out Federalhazardous material transportation lawor regulations; or


(3) The requirement of the State,political subdivision, or Indian tribeconcerns any of the following ‘‘coveredsubjects’’ and is not substantially thesame as a provision of Federalhazardous material transportation lawor regulations:

(A) The designation, description, andclassification of hazardous material;

(B) The packing, repacking, handling,labeling, marking, and placarding ofhazardous material;

(C) The preparation, execution, anduse of shipping documents related tohazardous material and requirementsrelated to the number, contents, andplacement of those documents;

(D) The written notification,recording, and reporting of theunintentional release in transportationof hazardous material; and

(E) The design, manufacture,fabricating, marking, maintenance,reconditioning, repairing, or testing of apackaging or container represented,marked, certified, or sold as qualifiedfor use in transporting hazardousmaterial.

This proposed rule concerns thepacking and handling of hazardousmaterials, and the design, manufacture,fabrication, marking, maintenance, andtesting of cylinders that are marked andcertified as qualified for use in thetransportation of hazardous materials. Ifso adopted as final, this rule wouldpreempt any State, local, or Indian triberequirements concerning these subjectsunless the non-Federal requirements are‘‘substantially the same’’ (see 49 CFR107.202(d)) as the Federal requirements.

Federal law (49 U.S.C. 5125(b)(2))provides that if DOT issues a regulationconcerning any of the covered subjects,DOT must determine and publish in theFederal Register the effective date ofFederal preemption. The effective datemay not be earlier than the 90th dayfollowing the date of issuance of thefinal rule and not later than two yearsafter the date of issuance.

RSPA requests comments on what theeffective date of the Federal preemptionshould be for the requirements in thisproposed rule that concern coveredsubjects.

D. Unfunded Mandates Reform Act of1995

This proposed rule would not imposeunfunded mandates under theUnfunded Mandates Reform Act of1995. It does not result in costs of $100million or more, in the aggregate, to anyof the following: State, local, or Indiantribal governments, or the private sector.This rule is the least burdensomealternative that achieves the objective ofthe rule.

E. Paperwork Reduction Act

Under regulations implementing thePaperwork Reduction Act of 1995, ‘‘* * * an agency may not conduct orsponsor, and a person is not required torespond to a collection of informationunless it displays a valid OMB controlnumber.’’ 5 CFR 1320.8(b)(iii)(6).

The information collection andrecordkeeping requirements in current§§ 173.34, 173.302(c) and 178.35pertaining to records prepared bypersons performing the requalification,repair, rebuild and use of cylinders andrequirements in current § 173.34pertaining to persons seeking approvalto requalify cylinders, were approved bythe Office of Management and Budget(OMB) under the provisions of 44 U.S.C.chapter 35 and assigned control number2137–0022, with an expiration date ofAugust 31, 1999. This information isused to verify that cylinders meet therequired manufacturing standards priorto being authorized for initial use, andthat once manufactured, the cylindersare maintained and used in compliancewith applicable requirements of theHMR as packagings for hazardousmaterials. In this proposed rule, theseinformation collection andrecordkeeping requirements for recordsare revised and are in §§ 178.35,178.69(e)(13), 180.205, 180.209,180.211, 180.213, and 180.215.

The information and recordkeepingrequirements in current §§ 173.300a and173.300b for persons seeking approvalto be an independent inspection agency,and for chemical analyses and tests ofDOT specification and exemptioncylinders conducted outside of theUnited States, were approved by OMBand assigned control number 2137–0557, with an expiration date of July 31,1999. The information is used toevaluate an applicant’s qualification toperform the applicable packagingfunctions and to ensure material ofconstruction used in cylinders madeoutside the United States are inaccordance with the applicablerequirements. In this proposed rule, theinformation collection andrecordkeeping requirements are in§§ 107.803, 107.805, 107.807 and180.205(c). The information collectionand recordkeeping requirements forpersons seeking approval as cylinderrequalifiers and approval to change acylinder’s service pressure are removedfrom OMB control number 2137–0022and being placed with the otherapproval requirements under OMBcontrol number 2137–0557. OMBcontrol number 2137–0557 includesinformation and recordkeepingrequirements for other than cylinders.

The estimates contained in thisproposed rule address only the cylinderprovisions.

Because this proposed rule wouldestablish certain new cylinderspecifications, broaden the approvalrequirements for affected persons whorequalify cylinders, and would relocatethe cylinder requalificationrequirements to other sections, revisionswould be made to the current burdenhour submission. RSPA has revised theburden estimates based on the proposalin this NPRM and will submit revisedburden estimates to OMB.

OMB Control Number 2137–0022

Affected Public: Cylinder requalifiers,repairers and rebuilders, and owners ofcertain DOT specification andexemption cylinders.

Annual Reporting and RecordkeepingBurden:

Number of Respondents: 500.Total Annual Responses: 5,000.Total Annual Burden Hours: 1,729.Total Annual Cost for Development

and Maintenance: $42,683.

OMB Control Number 2137–0557

Affected Public: Cylindermanufacturers, requalifiers, and personsseeking to change a cylinder’s servicepressure.

Annual Reporting and RecordkeepingBurden:

Number of Respondents: 2,027.Total Annual Responses: 2,027.Total Annual Burden Hours: 2,628.Total Annual Cost for Development

and Maintenance: $294,544.RSPA invites comments on these

revised information collectionestimates, including any paperworkburdens not already considered.Requests for a copy of these informationcollections should be directed toDeborah Boothe, Office of HazardousMaterials Standards, Room 8102, 400Seventh Street, SW, Washington, DC20590–0001. Telephone (202) 366–8553or 1–800–467–4922. Written commentsshould be received by the close of thecomment period indentified in theDATES section of this rulemaking andshould be addressed to the DocketsManagement System as identified in theADDRESSES section of this rulemaking.Comments must reference the docketnumber, RSPA 98–3684 (HM–220).

F. Regulation Identifier Number (RIN)

A regulation identifier number (RIN)is assigned to each regulatory actionlisted in the Unified Agenda of FederalRegulations. The Regulatory InformationService Center publishes the UnifiedAgenda in April and October of eachyear. The RIN contained in the heading


of this document can be used to cross-reference this action with the UnifiedAgenda.

List of Subjects

49 CFR Part 107

Administrative practice andprocedure, Hazardous materialstransportation, Packaging andcontainers, Penalties, Reporting andrecordkeeping requirements.

49 CFR Part 171

Exports, Hazardous materialstransportation, Hazardous waste,Imports, Incorporation by reference,Reporting and recordkeepingrequirements.

49 CFR Part 172

Hazardous materials transportation,Hazardous waste, Labeling, Packagingand containers, Reporting andrecordkeeping requirements.

49 CFR Part 173

Hazardous materials transportation,Packaging and containers, Radioactivematerials, Reporting and recordkeepingrequirements, Uranium.

49 CFR Part 177

Hazardous materials transportation,Motor vehicle safety, Packaging andcontainers, Reporting and recordkeepingrequirements.

49 CFR Part 178

Hazardous materials transportation,Packaging and containers, Reportingand recordkeeping requirements.

49 CFR Part 180

Hazardous materials transportation,Motor vehicle safety, Packaging andcontainers, Reporting and recordkeepingrequirements.

In consideration of the foregoing, title49, Chapter I, Subchapters A and C ofthe Code of Federal Regulations, areproposed to be amended as follows:

PART 107—HAZARDOUS MATERIALSPROGRAM PROCEDURES

1. The authority citation for Part 107would continue to read as follows:

Authority: 49 U.S.C. 5101–5127, 44701;Sec. 212–213, Pub. L. 104–121, 110 Stat. 857;49 CFR 1.45, 1.53.

§ 107.3 [Amended]2. In § 107.3, the definition of

‘‘Registration’’ would be amended byremoving the wording ‘‘registration withRSPA as a cylinder retester pursuant to49 CFR 173.34(e)(1), or’’.

3. Subpart I would be added to Part107 to read as follows:

Subpart I—Approval of IndependentInspection Agencies, Cylinder Requalifiers,and Non-domestic Chemical Analyses andTests of DOT Specification Cylinders

Sec.107.801 Purpose and Scope.107.803 Approval of independent

inspection agency.107.805 Approval of cylinder requalifiers.107.807 Approval of non-domestic

chemical analyses and tests.

Subpart I—Approval of IndependentInspection Agencies, CylinderRequalifiers, and Non-domesticChemical Analyses and Tests of DOTSpecification Cylinders

§ 107.801 Purpose and scope.(a) This subpart prescribes procedures

for—(1) A person who seeks approval to be

an independent inspection agency toperform cylinder inspections andverifications required by parts 178 and180 of this chapter;

(2) A person who seeks approval toengage in the requalification (i.e.,inspection, testing or certification),rebuild or repair of a cylindermanufactured in accordance with a DOTspecification under subchapter C of thischapter or under the terms of anexemption issued under this part;

(3) A person who seeks approval toperform the manufacturing chemicalanalyses and tests of DOT specificationor exemption cylinders outside theUnited States.

(b) No person may engage in afunction identified in paragraph (a) ofthis section unless approved by theAssociate Administrator in accordancewith the provisions of this subpart. Eachperson shall comply with the applicablerequirements in this subpart. Inaddition, the procedural requirementsin subpart H of this part apply to thefiling, processing and termination of anapproval issued under this subpart.

§ 107.803 Approval of independentinspection agency.

(a) General. Prior to performingcylinder inspections and verificationsrequired by parts 178 and 180 of thischapter, a person must apply to theAssociate Administrator for an approvalas an independent inspection agency. Aperson approved as an independentinspection agency is not a RSPA agentor representative.

(b) Criteria. No applicant for approvalas an independent inspection agencymay be engaged in the manufacture ofcylinders for use in the transportation ofhazardous materials, or be directly orindirectly controlled by, or have afinancial involvement with, any entitythat manufactures cylinders for use in

the transportation of hazardousmaterials, except for providing servicesas an independent inspector.

(c) Application information. Eachapplicant must submit an application inconformance with § 107.705 that mustcontain the information prescribed in§ 107.705(a). In addition, the applicationmust contain the following information:

(1) Name and address of eachmanufacturing facility where tests andinspections are to be performed and adetailed description of the inspectionand testing facilities to be used by theapplicant and the applicant’s ability toperform the inspections and to verifythe inspections required by part 178 ofthis chapter or under the terms of anexemption issued under this part.

(2) Name, address, and principalbusiness activity of each person havingany direct or indirect ownership interestin the applicant greater than threepercent and any direct or indirectownership interest in each subsidiary ordivision of the applicant.

(3) Name of each individual whomthe applicant proposes to employ as aninspector and will be responsible forcertifying inspection and test resultsand a statement of that person’squalifications.

(4) An identification or qualificationnumber assigned to each inspector whois supervised by a certifying inspectoridentified in (c)(3) of this section.

(5) A statement that the applicant willperform its functions independent of themanufacturers and owners of thecylinders.

(6) If the applicant’s principal place ofbusiness is in a country other than theUnited States—

(i) A copy of the designation from theCompetent Authority of that countrydelegating to the applicant an approvalor designated agency authority for thetype of packaging for which a DOTdesignation is sought; and

(ii) A statement from the CompetentAuthority of that country stating thatsimilar authority is delegated to otherIndependent Inspection Agencies whoare approved under this subpart andthat no condition or limitation will beimposed upon United States citizens ororganizations that is not required of itsown citizenry.

(7) The date and signature of theperson certifying the approvalapplication

(d) Facility inspection. Upon therequest of the Associate Administrator,the applicant shall allow the AssociateAdministrator or the AssociateAdministrator’s designee to inspect theapplicant’s facilities and records. Theperson seeking approval must bear thecost of RSPA’s inspection.


§ 107.805 Approval of cylinder requalifiers.(a) General. A person must meet the

requirements of this section to beapproved to inspect, test, certify, repair,or rebuild a cylinder in accordance witha DOT specification under subpart C ofpart 178 or subpart C of part 180 of thischapter or under the terms of anexemption issued under this part.

(b) Each applicant must arrange for anindependent inspection agency,approved by the AssociateAdministrator pursuant to this subpart,to perform a review of its inspection orrequalification operation. The personseeking approval must bear the cost ofthe inspection. A list of approvedindependent inspection agencies isavailable from the AssociateAdministrator at the address listed in§ 107.705. Assistance in obtaining anapproval may be requested from thesame address.

(c) Application for approval. If theinspection performed by anindependent inspection agency iscompleted with satisfactory results, theapplicant must submit a letter ofrecommendation from the independentinspection agency, an inspection report,and an application that must contain theinformation prescribed in § 107.705(a).In addition, the application mustcontain the following information: thename of the facility manager; the DOTspecification/exemption cylinders thatwill be inspected, tested, repaired, orrebuilt at the facility; a certification thatthe facility will operate in compliancewith the applicable requirements ofsubchapter C of this chapter; and thedate and the signature of the personmaking the certification.

(d) Issuance of requalifieridentification number (RIN). TheAssociate Administrator issues a RIN asevidence of approval to requalify DOTspecification/exemption cylinders if it isdetermined, based on the applicant’ssubmission and other availableinformation, that the applicant’squalifications and, when applicable,facility are adequate to perform therequested functions in accordance withthe criteria prescribed in subpart C ofpart 180 of this chapter.

(e) Expiration of RIN. Unlessotherwise provided in the issuance

letter, an approval expires five yearsfrom the date of issuance, provided thatthe applicant’s facility andqualifications are maintained at orabove the level observed at the time ofinspection by the independentinspection agency, or at the date of thecertification in the application forapproval, for facilities only performinginspections made under § 180.209(g) ofthis chapter.

(f) Exceptions. Notwithstandingrequirements in paragraphs (b) and (c)of this section, a person who onlyperforms inspections in accordancewith § 180.209(g) of this chapter mustsubmit a request which, in addition tothe information prescribed in§ 107.705(a) contains; the facilitymanager for each location in whichrequalifications would be performed;the DOT specification/exemptioncylinders that will be inspected at thefacility; a certification that the facilitywill operate in compliance with theapplicable requirements of subchapter Cof this chapter; a certification that thepersons performing inspections havebeen trained and have the informationcontained in each applicable CGApamphlet incorporated by reference in§ 171.7 of this chapter that applies to therequalifiers activities; and the date andthe signature of the person making thecertification. Each person shall complywith the applicable requirements in thissubpart. In addition, the proceduralrequirements in subpart H of this partapply to the filing, processing andtermination of an approval issued underthis subpart.

§ 107.807 Approval of non-domesticchemical analyses and tests.

(a) General. A person who seeks tomanufacture DOT specification orexemption cylinders outside the UnitedStates must seek an approval from theAssociate Administrator to perform thechemical analyses and tests of thosecylinders outside the United States.

(b) Application for approval. Eachapplicant must submit an applicationthat must contain the informationprescribed in § 107.705(a). In addition,the application must contain thefollowing information: the name,address and a description of each

facility at which cylinders are to bemanufactured and chemical analysesand tests are to be performed; completedetails concerning the dimension,materials of construction, wallthickness, water capacity, shape, type ofjoints, location and size of openings andother pertinent physical characteristicsof each specification or exemptioncylinder for which approval is beingrequested, including calculations forcylinder wall stress and wall thicknesswhich may be shown on a drawing oron separate sheets attached to adescriptive drawing; the name of theindependent inspection agency to beused; and the date and the signature ofthe person making the certification.

(c) Facility inspections. Upon therequest of the Associate Administrator,the applicant shall allow the AssociateAdministrator for HMS or the AssociateAdministrator’s designee to inspect theapplicant’s cylinder manufacturing andtesting facilities and records, and mustprovide such materials and cylinders foranalyses and tests as the AssociateAdministrator may specify. Theapplicant or holder shall bear the costof the initial and subsequentinspections, analyses, and tests.

PART 171—GENERAL INFORMATION,REGULATIONS, AND DEFINITIONS

4. The authority citation for part 171would continue to read as follows:

Authority: 49 U.S.C. 5101–5127; 49 CFR1.53.

§ 171.2 [Amended]

5. In § 171.2, paragraph (d)(3) wouldbe amended by removing the wording‘‘retest or exemption markings’’ andadding in its place the wording ‘‘retest,exemption or requalificationidentification number (RIN) markings’’.

6. In § 171.7, in the table in paragraph(a)(3), new entries would be added inalphanumeric sequence to read asfollows:

§ 171.7 Reference material.

(a) * * *(3) Table of material incorporated by

reference. * * *

Source and name of material 49 CFR reference

* * * * * * *American Society for Nondestructive Testing, PO Box 28518, 1711 Arlingate Lane, Columbus,

OH 43228–0518ASNT Recommended Practice SNT–TC–1A, 1992 ................................................................ Part 178, subpart C, Appendix B.

* * * * * * *American Society for Testing and Materials


Source and name of material 49 CFR reference

* * * * * * *ASTM B 221–96 Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars,

Rods, Wire, Profiles, and Tubes.178.46(a)(4), Table 2.

ASTM B 221M–96 Standard Specification for Aluminum and Aluminum-Alloy ExtrudedBars, Rods, Wire, Profiles, and Tubes.

Part 178, Subpart C, Appendix A, Table 2, Alu-minum.

* * * * * * *ASTM E 10–96 Standard Test Method for Brinell Hardness of Metallic Materials ................. 178.69.ASTM E 18–94 Standard Test Methods for Rockwell Hardness and Rockwell Superficial

Hardness of Metallic Materials.178.70.

* * * * * * *ASTM E 165–95 Standard Test Method for Liquid Penetrant Examination ............................ 178.69.ASTM E 213–93 Standard Practice for Ultrasonic Examination of Metal Pipe and Tubing ... 178.71; 178.72; 178.73; Part 178, Subpart C,

Appendix B; 180.215.

* * * * * * *ASTM E 399–90e1 Standard Test Method for Plane-Strain Fracture Toughness of Metallic

Materials.178.73.

* * * * * * *ASTM E 709–95 Standard Guide for Magnetic Particle Examination ..................................... 178.69.ASTM E 797–95 Standard Practice for Measuring Thickness by Manual Ultrasonic Pulse-

Echo Straight-Beam Method.Part 178, Subpart C, Appendix B; 180.215.

* * * * * * *Compressed Gas Association, Inc.

* * * * * * *CGA Pamphlet C–1, Methods for Hydrostatic Testing of Compressed Gas Cylinders, 1996 178.69; 178.81; 180.205.

* * * * * * *CGA Pamphlet P–20, Standard for the Classification of Toxic Gas Mixtures, 1995 .............. 173.115.

* * * * * * *CGA Pamphlet S–7, Method for Selecting Pressure Relief Devices for Compressed Gas

Mixtures in Cylinders, 1996.173.301.

* * * * * * *

§ 171.7 [Amended]

7. In addition, in § 171.7, in the tablein paragraph (a)(3), the followingchanges would be made:

a. In the entry ASTM A240/A240M–94b, the wording ‘‘A240M–94b’’ wouldbe revised to read ‘‘A240M–96a.’’

b. The entry ASTM A 388–67 wouldbe removed.

c. In the entry ASTM B 557–84, incolumn 2, the reference ‘‘178.69;’’would be added, in numeric order.

d. In the entry ASTM E 8–89, thewording ‘‘E 8–89’’ would be revised toread ‘‘E 8–96a’’ and in column 2, thereferences ‘‘178.36; 178.37; 178.38;178.39;’’, ‘‘178.45;’’, ‘‘178.50; 178.51;’’,‘‘178.55;’’, ‘‘178.61;’’, and ‘‘178.68;’’would be removed and ‘‘178.69;’’ wouldbe added, in numerical order.

e. In the entry ASTM E 23–60, incolumn 1, the wording ‘‘E 23–60’’would be revised to read ‘‘E 23–96’’ andin column 2, the reference ‘‘178.69;’’would be added, in numeric order.

f. In the entry ASTM E 112–88, thewording ‘‘E 112–88’’ would be revisedto read ‘‘E 112–96’’ and in column 2, the

reference ‘‘;178.69’’ would be added, innumeric order.

g. In the entry ASTM E 290–92, incolumn 2, the references ‘‘;178.69;178.72’’ would be added, in numericorder.

h. In the entry CGA Pamphlet C–3, theyear ‘‘1975’’ would be revised to read‘‘1994’’ and in column 2, the references‘‘178.50; 178.51;’’, ‘‘178.54;’’, ‘‘178.61;’’,‘‘178.68’’ would be removed and‘‘178.69;’’, ‘‘178.81;’’, ‘‘180.211’’ wouldbe added, in numeric order.

i. In the entry CGA Pamphlet C–5, incolumn 2, the reference ‘‘173.302’’would be removed and ‘‘173.302a’’would be added, in its place.

j. In the entry CGA Pamphlet C–6, incolumn 2, the reference ‘‘173.34;180.519’’ would be removed and thereferences ‘‘173.198; 180.205; 180.209;180.211.’’ would be added, in its place.

k. In the entry CGA Pamphlet C–6.1,in column 2, the reference ‘‘173.34’’would be removed and the references‘‘180.205; 180.209’’ would be added, inits place.

l. In the entry CGA Pamphlet C–6.2,in column 2, the reference ‘‘173.34’’

would be removed and the reference‘‘180.205’’ would be added, in its place.

m. In the entry CGA Pamphlet C–6.3,in column 2, the reference ‘‘173.34’’would be removed and the references‘‘180.205; 180.209’’ would be added, inits place.

n. In the entry CGA Pamphlet C–8, incolumn 2, the reference ‘‘173.34’’ wouldbe removed and the reference ‘‘180.205’’would be added, in its place.

o. In the entry CGA Pamphlet C–11,in column 2, the reference ‘‘178.35’’would be removed and the references‘‘178.35; 178.69’’ would be added, in itsplace.

p. In the entry CGA Pamphlet C–12,in column 2, the reference ‘‘173.34;’’would be removed and the references173.301;’’ and ‘‘;180.205’’ would beadded, in numeric order.

q. In the entry CGA Pamphlet C–13,in column 2, the reference ‘‘173.34;’’would be removed and the references ‘‘;180.205;’’, and ‘‘180.209.’’ would beadded, in numeric order.

r. In the entry CGA Pamphlet C–14, incolumn 2, the reference ‘‘173.34’’ would


be removed and the reference ‘‘173.301’’would be added, in its place.

s. In the entry CGA Pamphlet S–1.1,in column 2, the reference ‘‘173.34’’would be removed and the references‘‘173.301; 173.304a.’’ would be added,in its place.

8. In § 171.8, definitions for ‘‘Metric-marked cylinder’’ and ‘‘Nonmetric-marked cylinder’’ would be added, inalphabetical order, to read as follows:

§ 171.8 Definitions and abbreviations.

* * * * *Metric-marked cylinder means a

cylinder manufactured to the DOT 3M,3ALM, 3FM or 4M specificationprescribed in §§ 178.69 through 178.81of this subchapter.* * * * *

Nonmetric-marked cylinder means acylinder manufactured to a DOTspecification prescribed in §§ 178.35through 178.68 of this subchapter thatwas in effect on [DATE PRIOR TOEFFECTIVE DATE OF THE FINALRULE].* * * * *

§ 171.8 [Amended]9. In addition, in § 171.8, in the

definition of ‘‘Filling density’’,paragraph (1) would be amended byrevising the reference‘‘§ 173.304(a)(2)Table Note 1’’ to read‘‘§ 173.304a(a)(2) Table Note 1’’.

10. In § 171.12, paragraph (b)(15)would be revised to read as follows:

§ 171.12 Import and export shipments.

* * * * *(b) * * *(15) Cylinders not manufactured to a

DOT specification must conform to therequirements of § 173.301(j) through (l)of this subchapter or, for Canadianmanufactured cylinders, to therequirements of § 171.12a(b)(13).* * * * *

11. In § 171.12a, in paragraph (b)(13)a new sentence would be added at theend of the paragraph, and paragraphs(b)(13)(i) through (b)(13)(v) would beadded to read as follows:

§ 171.12a Canadian shipments andpackagings.

* * * * *(b) * * *(13) * * * However, a cylinder made

in Canada that meets the followingconditions is authorized for thetransportation of a hazardous materialwithin the United States:

(i) The cylinder was manufactured onor after January 1, 1977;

(ii) During the manufacturing process,the cylinder was marked with anapproval number and an inspector’s

mark authorized by TDG or by itspredecessor, the Railway TransportCommittee of the Canadian TransportCommission (CTC), in its regulations forthe Transport of DangerousCommodities by Rail and was marked‘‘CTC’’ or ‘‘TDG’’;

(iii) The cylinder is in fullconformance with the specificationsprescribed by the TDG regulations;

(iv) The cylinder has been requalifiedunder a program authorized by theCanadian regulations or requalified inaccordance with subpart C of part 180of this subchapter within the prescribedrequalification period; and

(v) At the time the requalification isperformed, in addition to the markingsprescribed in § 180.211 of thissubchapter, the cylinder is marked‘‘DOT/’’ immediately before theCanadian specification marking.* * * * *

PART 172—HAZARDOUS MATERIALSTABLE, SPECIAL PROVISIONS,HAZARDOUS MATERIALSCOMMUNICATIONS, EMERGENCYRESPONSE INFORMATION, ANDTRAINING REQUIREMENTS



§ 172.101 [Amended]

13. Section 172.101, in the HazardousMaterials Table, the following changeswould be made:

a. For the entry ‘‘Cyanogen’’, inColumn (8b), the reference ‘‘192’’ wouldbe removed and ‘‘304’’ would be addedin its place.

b. For the entry ‘‘Germane’’, inColumn (8b), the reference ‘‘192’’ wouldbe removed and ‘‘302’’ would be addedin its place.

c. For the entry ‘‘Iron pentacarbonyl’’,in Column (8b), the reference ‘‘192’’would be removed and ‘‘226’’ would beadded in its place.

PART 173—SHIPPERS—GENERALREQUIREMENTS FOR SHIPMENTSAND PACKAGINGS


Authority: 49 U.S.C. 5101–5127, 44701; 49CFR 1.45, 1.53.

§ 173.34 [Removed]

15. Section 173.34 would be removed.16. Section 173.40 would be revised

to read as follows:

§ 173.40 General packaging requirementsfor toxic materials packaged in cylinders.

When this section is referenced for ahazardous material elsewhere in thissubchapter, the following requirementsare applicable to cylinders used for thatmaterial:

(a) Authorized cylinders. A cylindermust conform to one of thespecifications for cylinders in subpart Cof part 178 of this subchapter, exceptthat Specification 8, 8AL, and 39cylinders are not authorized. After[EFFECTIVE DATE OF THE FINALRULE] DOT 3AL cylinders made ofaluminum alloy 6351 may not be filledand offered for transportation ortransported with a Division 2.3, Zone Aor B material, a Division 6.1, Zone A orB material or any liquid that meets thedefinition of Division 6.1 and meetscriteria for Packing Group I, HazardZones A or B, as specified in § 173.133.

(b) Closures. Each cylinder containinga Hazard Zone A material must beclosed with a plug or valve conformingto the following:

(1) Each plug or valve must have ataper-threaded connection directly tothe cylinder and be capable ofwithstanding the test pressure of thecylinder;

(2) Each valve must be of the packlesstype with non-perforated diaphragm,except that for corrosive materials, avalve may be of the packed typeprovided the assembly is made gas-tightby means of a seal cap with gasketedjoint attached to the valve body or thecylinder to prevent loss of materialthrough or past the packing;

(3) Each valve outlet must be sealedby a threaded cap or threaded solidplug; and

(4) Cylinder, valves, plugs, outletcaps, luting and gaskets must becompatible with each other and with thelading.

(c) Additional handling protection.Each cylinder or cylinder overpackcombination offered for transportationcontaining a Division 2.3 or 6.1 HazardZone A or B material must meet thepuncture resistance and valve damageprotection performance requirements ofthis section. In addition to therequirements of this section, overpacksmust conform to the overpackprovisions of § 173.25.

(1) Puncture resistance. Each cylinderor cylinder overpack combination mustbe qualified under the punctureresistance test specified in § 178.69(h)(3)of this subchapter. However, a cylindermeeting the conditions in the followingtable is excepted from the punctureresistance test requirements of thissection and of § 178.69(h)(3) of thissubchapter:


1 Use of existing cylinders is authorized. Newconstruction is not authorized after [FIVE YEARSFROM EFFECTIVE DATE OF THE FINAL RULE],except that new construction of ICC–3 cylinders iscurrently not authorized.

DOT specification/ma-terial

Maximumwaterfilledgrossweight(lbs.)

Minimumwall thick-

ness(inch)

3A .............................. 215 0.1803AA ........................... 255 0.220

(2) Valve damage protection. Eachcylinder with a valve must be equippedwith a protective cap, other valveprotection device or an overpacksufficient to protect the valve fromdeformation, breakage or leakageresulting from a drop of 2.0 m (7 ft) ontoa non-yielding surface. Impact must beat an orientation most likely to causedamage.

(d) Interconnection. Cylinders maynot be manifolded or interconnected.

§ 173.115 [Amended]

17. In § 173.115, in paragraph (c)(2),in the last sentence, the wording ‘‘orCGA Pamphlet P–20’’ is addedimmediately following the word‘‘subpart’’.

18. In § 173.115, in paragraph (j), thereference ‘‘§ 173.304(a)(2)’’ would berevised to read ‘‘§ 173.304a(a)(2)’’.

19. Section 173.163 would be revisedto read as follows:

§ 173.163 Hydrogen fluoride.

Hydrogen fluoride (hydrofluoric acid,anhydrous) must be packaged inspecification 3, 3A, 3AA, 3B, 3BN, 3E,4A, or 3M cylinders; or Specification4B, 4BA, 4BW, or 4M cylinders, if theyare not brazed. Filling density may notexceed 85 percent of the cylinder’swater weight capacity. Metric-markedcylinders must be requalified byultrasonic examination in accordancewith § 180.207 of this subchapter.Nonmetric-marked cylinders must berequalified by ultrasonic examination inaccordance with § 180.209(a)(2) of thissubchapter.


§ 173.192 Packaging for certain toxicgases in Hazard Zone A.

When § 172.101 of this subchapterspecifies that a toxic material bepackaged under this section, onlyspecification cylinders are authorized,as follows:

(a) Specification 3A1800, 3AA1800,3AL1800, or 3E1800 cylinders; 3M,3ALM, or 3FM cylinders with a markedtest pressure of 200 bar (2900 psig);under the following conditions:

(1) Specification 3A, 3AA, 3AL, 3M,3ALM, or 3FM cylinders may notexceed 57 kg (125 pounds) watercapacity (nominal).

(2) Specification 3AL or 3ALMcylinders may only be offered fortransportation or transported byhighway and rail.

(b) Packagings must conform to therequirements of § 173.40.

(c) For cylinders used for phosgene:(1) The filling density may not exceed

125 percent;(2) A cylinder may not contain more

than 68 kg (150 pounds) of phosgene;and

(3) Each cylinder containing phosgenemust be tested for leakage before it isoffered for transportation or transportedand must show no leakage; this testmust consist of immersing the cylinderand valve, without the protection capattached, in a bath of water at atemperature of approximately 66’C(150’F) for at least 30 minutes, duringwhich time frequent examinations mustbe made to note any escape of gas. Thevalve of the cylinder must not beloosened after this test. Alternatively,each cylinder containing phosgene maybe tested for leakage by a methodapproved in writing by the AssociateAdministrator for Hazardous MaterialsSafety.

§ 173.198 [Amended]

21. In § 173.198, in paragraph (a), thereference ‘‘§ 173.34(e)’’ would berevised to read ‘‘§ 180.205 of thissubchapter’’.

22. In § 173.226, paragraph (a) wouldbe revised to read as follows:

§ 173.226 Materials poisonous byinhalation, Division 6.1, Packing Group I,Hazard Zone A.

* * * * *(a) In seamless specification cylinders

conforming to the requirements of§ 173.40.* * * * *

23. In § 173.227, paragraph (a) wouldbe revised to read as follows:

§ 173.227 Materials poisonous byinhalation, Division 6.1, Packing Group I,Hazard Zone B.

* * * * *(a) In packagings as authorized in

§ 173.226 and seamless and weldedspecification cylinders conforming tothe requirements of § 173.40.* * * * *


§ 173.228 Bromine pentafluoride orbromine trifluoride.

(a) The following packagings areauthorized:

(1) Specification 3A150, 3AA150,3B240, 3BN150, 4B240, 4BA240,4BW240 and 3E1800 cylinders;

(2) Specification 3M, 3ALM, 3FM,and 4M cylinders with a minimummarked test pressure of 25 bar (363psig).

(b) Material in Hazard Zones A and Bmust be transported in cylindersconforming to the requirements of§ 173.40, except that material in HazardZone A must be transported only inseamless specification cylinders.

(c) Cylinder valves must be protectedas specified in § 173.301(h). No cylindermay be equipped with any pressurerelief device.

§§ 173.300a, 173.300b, 173.300c[Removed]

25. In part 173, §§ 173.300a, 173.300b,and 173.300c would be removed.


§ 173.301 General requirements forshipment of compressed gases in cylindersand spherical pressure vessels.

(a) General qualifications for use ofcylinders. As used in this subpart, filledmeans an introduction or presence of ahazardous material in a cylinder. AClass 2 material (gas) offered fortransportation in a cylinder must beprepared in accordance with thissection and §§ 173.302 through 173.305.

(1) Compressed gases must be inmetal cylinders and containers built inaccordance with the DOT (and ICC, asshown) specifications, as shown in thisparagraph (a)(1), in effect at the time ofmanufacture, and marked as required bythe specification and the regulation forrequalification if applicable:

Packagings2P2QICC–31

3A1

3AA1

3AL1

3ALM3AX1

3A480X1

3AAX1

3B1

3BN1

3E3FM3HT3M3T1

4AA4804B1

4B240ET1

4BA1

4BW1

4D4DA


4DS4E1

4L4M88AL39

(2) A cylinder must be filled inaccordance with this part. Before eachfilling of a cylinder, the person fillingthe cylinder must visually inspect theoutside of the cylinder. A cylinder thathas a crack or leak, is bulged, has adefective valve or pressure relief device,or bears evidence of physical abuse, fireor heat damage, or detrimental rustingor corrosion may not be used unless itis properly repaired and requalified asprescribed in subpart C of part 180 ofthis subchapter.

(3) A cylinder that has previouslycontained a Class 8 material must berequalified in accordance with§ 180.205(e) of this subchapter.

(4) When a cylinder with a markedpressure limit is prescribed, anothercylinder made under the samespecification but with a higher markedpressure limit is authorized. Forexample, a cylinder marked ‘‘DOT–4B500’’ may be used when ‘‘DOT–4B300’’ is specified and a cylindermarked ‘‘DOT–3FM140’’ may be usedwhen ‘‘DOT–3FM70’’ is authorized.

(5) No person may fill a cylinderoverdue for periodic requalificationwith a hazardous material and then offerit for transportation. This requirementdoes not apply to a cylinder that wasfilled prior to the requalification duedate.

(6) After its authorized service life hasexpired, a cylinder may not be offeredfor transportation in commerce.

(7) For nonmetric-marked cylinders,the pressure of the hazardous material at55°C (131°F) must not exceed theservice pressure of the cylinder.Sufficient outage shall be provided sothat the cylinder will not be liquid fullat 55°C (131°F).

(8) Metric-marked cylinderscontaining permanent gases must befilled in accordance with § 173.302b.

(9) Metric-marked cylinderscontaining liquefied gases must be filledin accordance with § 173.304b.

(10) DOT 2P, 2Q, 3E, 3HT, spherical4BA, 4D, 4DA, 4DS, 39, and spherical4M cylinders must be shipped in strongoutside packagings. The strong outsidepackaging must conform to paragraph(h) of this section and to § 173.25.

(b) Cylinder markings. Requiredmarkings on a cylinder must be legibleand must meet the applicablerequirements of subpart C of part 180 ofthis subchapter. Additional informationmay be marked on the cylinder

provided it does not affect the requiredmarkings prescribed in the applicablecylinder specification.

(c) Toxic gases and mixtures.Cylinders containing toxic gases andtoxic gas mixtures that meet the criteriaof Division 2.3 Hazard Zone A or B mustconform to the requirements of § 173.40,CGA Pamphlets S–1.1 and S–7. DOT 39cylinders may not be used for toxicgases or toxic gas mixtures that meet thecriteria for Division 2.3 Hazard Zone Aor B.

(d) Gases capable of combiningchemically. A filled cylinder may notcontain any gas or material that iscapable of combining chemically withthe cylinder’s contents or with thecylinder material of construction so asto endanger the cylinder’s serviceability.After [EFFECTIVE DATE OF THEFINAL RULE] DOT 3AL cylinders madeof aluminum alloy 6351 may not befilled and offered for transportation withpyrophoric gases.

(e) Ownership of cylinder. A cylinderfilled with a hazardous materials maynot be offered for transportation unlessit was filled by the owner of thecylinder or with the owner’s consent.

(f) Pressure relief device systems. (1)Except as provided in paragraph (f)(6)and (f)(7) of this section, a cylinderfilled with a gas for transportation mustbe equipped with one or more pressurerelief devices sized and selected as totype, location and quantity and tested inaccordance with CGA Pamphlets S–1.1(compliance with paragraph 9.1.1.1 ofCGA Pamphlet S–1.1 is not required)and S–7. A pressure relief device isrequired on a DOT 39 cylinder and acylinder used for acetylene in solution,regardless of cylinder size or filledpressure. A DOT 39 cylinder used forliquefied Division 2.1 materials must beequipped with a metal pressure reliefvalve. Fusible pressure relief devices arenot authorized on a DOT 39 cylindercontaining a liquefied gas.

(2) When installed, a pressure reliefdevice must be in the vapor space of acylinder.

(3) For a metric-marked cylinder, thestart-to-discharge pressure of a pressurerelief device may not be less than themarked test pressure of the cylinder. Fora nonmetric-marked DOT–3 seriescylinder, from the first requalificationdue on and after [EFFECTIVE DATE OFTHE FINAL RULE,] the start-to-discharge pressure of the pressure reliefdevice, may not be less than theminimum required test pressure. Toensure that the relief device does notopen below its set pressure, theallowable tolerances for all the pressurerelief devices must range from zero toplus 10% of its setting. The pressure

relief device must be capable ofpreventing rupture of the normallyfilled cylinder when subjected to a firetest conducted in accordance with CGAPamphlet C–14, or in the case of anacetylene cylinder, CGA Pamphlet C–12.

(4) Before each filling of a cylinderequipped with a pressure relief device,the person filling the cylinder mustvisually inspect each pressure reliefdevice for corrosion, damage, rust,plugging of external pressure reliefdevice channels, and other mechanicaldefects such as extrusion of fusiblemetal. A cylinder with a defectivepressure relief device may not be used.

(5) Before a filled cylinder is offeredfor transportation from the cylinderfilling facility, the pressure relief devicemust be tested for leaks. A cylinder witha leaking pressure relief device may notbe offered for transportation.

(6) A pressure relief device is notrequired on——

(i) A cylinder 305 mm (12 inches) orless in length, exclusive of neck, and114 mm (4.5 inches) or less in outsidediameter, except:

(A) When filled with a liquefied gasfor which this part requires a servicepressure of 1800 psi or higher for anonmetric-marked cylinder, and a testpressure of 186 bar (2700 psi) or higherfor a metric-marked cylinder; or

(B) When filled with a nonliquefiedgas to a pressure less than 1800 psi fora nonmetric-marked cylinder and 124bar for a metric-marked cylinder.

(ii) A cylinder with a water capacityof less than 454 kg (1000 lbs) filled witha nonliquefied gas to a pressure of 21bar (300 psi) or less at 21°C (70°F).

(iii) A cylinder containing a Class 3 ora Class 8 material withoutpressurization unless otherwisespecified for the hazardous material.

(7) A pressure relief device isprohibited on a cylinder filled with aDivision 2.3 or a Division 6.1 materialin Hazard Zone A.

(g) Manifolding cylinders intransportation. (1) Cylinder manifoldingis only authorized under conditionsprescribed in this paragraph (g).Manifolded cylinders shall be supportedand held together as a unit bystructurally adequate means. Except forDivision 2.2 materials, each cylindermust be equipped with an individualshutoff valve that must be tightly closedwhile in transit. Manifold branch linesmust be sufficiently flexible to preventdamage to the valves which otherwisemight result from the use of rigid branchlines. Each cylinder must beindividually equipped with a pressurerelief device as required in paragraph (f)of this section. Pressure relief devices


on manifolded cylinders, filled with acompressed gas, must be arranged todischarge upward and unobstructed tothe open air in such a manner as toprevent any escaping gas fromcontacting personnel or any adjacentcylinders. Valves and pressure reliefdevices on manifolded cylinders, filledwith a compressed gas, must beprotected by framing or other methodwhich is equivalent to the valveprotection required in paragraph (h) ofthis section. Manifolding is authorizedfor cylinders containing the followinggases:

(i) Nonliquefied compressed(permanent)gases authorized by§ 173.302.

(ii) Liquefied compressed gases thatare authorized by § 173.304. Eachmanifolded cylinder, containing aliquefied compressed gas, must beseparately filled and means must beprovided to ensure that no interchangeof cylinder contents can occur duringtransportation.

(iii) Acetylene as authorized by§ 173.303.

(2) For the checking of tare weights orfor replacement of solvent, the cylindermust be removed from the manifold.This requirement is not intended toprohibit the filling of acetylenecylinders while manifolded.

(h) Cylinder valve protection. (1)Except for a cylinder meeting thefollowing conditions, a cylinder offeredfor transportation must meet theperformance requirements specified inparagraph (h)(2) of this section:

(i) A cylinder manufactured before[FIVE YEARS FROM EFFECTIVE DATEOF THE FINAL RULE.];

(ii) A cylinder containing only aDivision 2.2 material without a Division5.1 subsidiary hazard;

(iii) A cylinder containing a Class 9material or a Class 8 material onlycorrosive to metal;

(iv) A cylinder with a water capacityof 4.8 liters (293 cubic inches) or lesscontaining oxygen, compressed;

(v) A cylinder containing oxygen,refrigerated liquid (cryogenic liquid).

(2) Each cylinder valve assembly mustbe of sufficient strength or protectedsuch that no leakage occurs when acylinder with the valve installed isdropped 1.8 m (6 ft.) or more onto anon-yielding floor, impacting the valveassembly or protection device at anorientation most likely to cause damage.The cylinder valve assembly protectionmay be provided by any method thatmeets the performance requirement inthis paragraph (h)(2), examples include:

(i) Equipping the cylinder with asecurely attached metal cap.

(ii) Packaging the cylinder in a box,crate or other strong outside packagingconforming to the requirements of§ 173.25.

(iii) Constructing the cylinder suchthat the valve is recessed into thecylinder or otherwise protected.

(i) Cylinders mounted on motorvehicles or in frames. Seamless DOTspecification cylinders longer than twometers (6.5 feet) are authorized fortransportation only when horizontallymounted on a motor vehicle or in anISO framework or other framework ofequivalent structural integrity.Cylinders may be transported by rail incontainer on freight car (COFC) or traileron flat car (TOFC) service only underconditions approved by the AssociateAdministrator for Safety, FederalRailroad Administration. The cylindermust be configured as follows:

(1) Each cylinder must be fixed at oneend of the vehicle or framework withprovision for thermal expansion at theopposite end attachment;

(2) The valve and pressure reliefdevice protective structure must besufficiently strong to withstand a forceequal to twice the weight of the cylinderand framework assembly with a safetyfactor of four, based on the ultimatestrength of the material used; and

(3) Discharge from a pressure reliefdevice shall be arranged in such amanner to prevent any escaping gasfrom contacting personnel or anyadjacent cylinders.

(j) Non-specification cylinders indomestic use. Except as provided inparagraphs (k) and (l) of this section, afilled non-DOT specification cylinder,other than a DOT exemption cylinder,may not be offered for transportation ortransported to, from, or within theUnited States.

(k) Importation of foreign cylinders fordischarge within a single port area. Acylinder manufactured to other than aDOT specification that has beencertified as being in conformance withthe transportation regulations of anothercountry may be authorized upon writtenrequest to and approval by the AssociateAdministrator for Hazardous MaterialsSafety, for transportation within a singleport area, provided—

(1) The cylinder is transported in aclosed freight container;

(2) The cylinder is certified by theimporter to provide a level of safety atleast equal to that required by theregulations in this subchapter for acomparable DOT specification cylinder;and

(3) The cylinder is not refilled forexport unless in compliance withparagraph (l) of this section.

(l) Charging of foreign cylinders forexport. A cylinder manufacturedoutside the United States that was notmanufactured, inspected, tested andmarked in accordance with part 178 ofthis subchapter or a cylindermanufactured to other than a DOTspecification or exemption may be filledwith a gas in the United States andoffered for transportation andtransported for export, if the followingconditions are met:

(1) The cylinder has been requalifiedand marked with the month and year ofrequalification in accordance withsubpart C of part 180 of this subchapter,or has been requalified as authorized bythe Associate Administrator forHazardous Materials Safety.

(2) The maximum filling density andservice pressure for each cylinderconform to the requirements of this partfor the gas involved.

(3) The bill of lading or other shippingpaper shall identify the cylinder andshall carry the following certification:‘‘This cylinder has (These cylindershave) been qualified, as required, andfilled in accordance with the DOTrequirements for export.’’

(m) Sharp attachments. Attachmentsto cylinders filled for transportationmay not have sharp corners, edges, orany other features that are capable ofcausing puncture or damage to otherfreight. Attachments include allpermanent structural attachments, aswell as anything temporarily attached tothe cylinder, such as skids.

27. Section 173.301a would be addedto read as follows:

§ 173.301a Additional generalrequirements for shipment of nonmetric-marked cylinders.

(a) General. The requirements in thissection are in addition to therequirements in § 173.301 and apply tothe shipment of gases in nonmetric-marked cylinders.

(b) Authorized cylinders not markedwith a service pressure. For authorizedcylinders not marked with a servicepressure, the service pressure isdesignated as follows:

Specification markingService

pressurepsig

3 ................................................ 18003E .............................................. 18008 ................................................ 250

(c) Cylinder pressure at 21°C (70°F).The pressure in a cylinder at 21°C (70°F)may not exceed the service pressure forwhich the cylinder is marked ordesignated, except as provided in§ 173.302a(b). For certain liquefied


gases, the pressure at 21°C (70°F) mustbe lower than the marked servicepressure to avoid having a pressure at atemperature of 54.4°C (131°F) that isgreater than permitted.

(d) Cylinder pressure at 55°C (131°F).The pressure in a cylinder at 55°C(131°F) may not exceed 5⁄4 times theservice pressure, except:

(1) A cylinder filled with acetylene,liquefied nitrous oxide or carbondioxide.

(2) When a cylinder is filled inaccordance with § 173.302a(b), thepressure in the cylinder at 55°C (131°F)may not exceed 5⁄4 times the fillingpressure.

28. Section 173.301b would be addedto read as follows:

§ 173.301b Additional generalrequirements for shipment of metric-marked cylinders.

(a) Definitions. For purposes of thissubpart, the following definitions applyto Class 2 materials in metric-markedcylinders:

Critical temperature means thetemperature above which the substancecan not exist in the liquid state.

Dissolved gas means a gas which isdissolved under pressure in a liquidphase solvent. The solvent may besupported in a porous mass.

Filling factor of liquefied compressedgas means the mass of a gas, in kg (orpound), which can be filled into a 1 liter(61 cubic inches) water capacitycontainer. The filling factor of eachliquefied compressed gas must becalculated to meet all requirements of§ 173.304b.

High pressure liquefied compressedgas means a gas which has a criticaltemperature in the range from ¥10 °C(14 °F) to less than 70 °C (158 °F).

Low pressure liquefied compressedgas means a gas which has a criticaltemperature equal to or above 70 °C (158°F).

Permanent (non-liquefiedcompressed) gas means a gas other thanin solution, which has a criticaltemperature below ¥10 °C (14 °F).

Safety factor means the ratio of thecylinder burst pressure to its markedtest pressure. For example, a cylinderwith a marked test pressure of 180 bar(2610 psi) and a burst pressure of 340bar (4930 psi) and has a safety factor of1.89.

Settled pressure (formerly referred toas service pressure) means the pressureof the contents of the cylinder at 15 °C(59 °F).

(b) Pressure in cylinders containing apermanent gas. The pressure in a DOT3M, 3FM, 3ALM or 4M cylindercontaining a permanent gas must be asprescribed in § 173.302b.

(c) Pressure in cylinders containing aliquefied compressed gas. (1) Thepressure in a cylinder containing aliquefied compressed gas which hascritical temperature ranging from ¥10°C (14 °F) up to 70 °C (158 °F) may notexceed the cylinder’s marked testpressure or be liquid full at atemperature of 65 °C (149 °F).

(2) The pressure in a cylindercontaining a liquefied compressed gaswhich has a critical temperature greaterthan or equal to 70 °C (158 °F) may notexceed the cylinder’s marked testpressure or be liquid full at 54 °C(130 °F).

(d) Authorized gases for DOT 3FMcylinders. A DOT 3FM cylinder mayonly be used for gases free of corrodingcomponents with a dew point below¥49 °C (¥56 °F). A DOT 3FM cylinderis not authorized for hydrogen orhydrogen bearing gases (e.g., hydrogensulfide).


§ 173.302 Filling of cylinders with non-liquefied compressed gases.

(a) General requirements. A cylinderfilled with a non-liquefied compressedgas (except gas in solution) must beoffered for transportation in accordancewith the requirements of this sectionand §§ 173.301, 173.301a, 173.301b,173.302a, 173.302b and 173.305. Wheremore than one section applies to acylinder, the most restrictiverequirement must be followed.

(b) Aluminum cylinders in oxygenservice. Each aluminum cylinder filledwith oxygen must meet the followingconditions:

(1) Each cylinder must be equippedonly with brass or stainless steel valves;

(2) Each cylinder must have onlystraight threads in the opening;

(3) Each cylinder must be cleaned inaccordance with the requirements ofFederal Specification RR–C–901c,paragraphs 3.7.2, and 3.8.2. Cleaningagents equivalent to those specified inRR–C–901c may be used provided theydo not react with oxygen. One cylinderselected at random from a group of 200or less and cleaned at the same time,must be tested for oil contamination inaccordance with Specification RR–C–901c, paragraph 4.4.2.3, and meet thestandard of cleanliness specified; and

(4) The pressure in each cylinder maynot exceed 207 bar (3000 psig) at 21 °C(70 °F).

(c) Each authorized cylindercontaining oxygen which iscontinuously fed to tanks containinglive fish may be offered fortransportation and transported

irrespective of the provisions of§ 173.24(b)(1).

(d) Shipment of Division 2.1 materialsin aluminum cylinders are authorizedonly when transported by highway, rail,or cargo-only aircraft.

30. Section 173.302a would be addedto read as follows:

§ 173.302a Additional requirements forshipment of permanent (nonliquefied)compressed gases in nonmetric-markedcylinders.

(a) Detailed filling requirements.Nonliquefied compressed gases (exceptgas in solution) for which fillingrequirements are not specificallyprescribed in § 173.304a must beshipped, subject to the requirements inthis section and §§ 173.301, 173.301a,173.302 and 173.305 in nonmetric-marked cylinders, as follows:

(1) Specification 3, 3A, 3AA, 3AL, 3B,3E, 4B, 4BA and 4BW cylinders.

(2) DOT 3HT cylinders. Thesecylinders are authorized for aircraft useonly and only for nonflammable gases.They have a maximum service life of 24years from the date of manufacture. Thecylinders must be equipped withpressure relief devices only of thefrangible disc type which meet therequirements of § 173.301(f). Eachfrangible disc must have a rated burstingpressure which does not exceed 90percent of the minimum required testpressure of the cylinder. Discs withfusible metal backing are not permitted.Specification 3HT cylinders may beoffered for transportation only whenpacked in strong outer packagingsconforming to the requirements of§ 173.25.

(3) For a specification 39 cylinderfilled with a Division 2.1 material, theinternal volume may not exceed 75cubic inches.

(4) Specification 3AX, 3AAX, and 3Tcylinders are authorized for Division 2.1and 2.2 materials and for carbonmonoxide. DOT 3T cylinders are notauthorized for hydrogen. When used inmethane service, the methane must be anon-liquefied gas which has a minimumpurity of 98.0 percent methane andwhich is commercially free of corrodingcomponents.

(5) Aluminum cylinders made to DOTspecification 39 and 3AL are authorizedfor oxygen only under the conditionsspecified in § 173.302(b).

(b) Special filling limits forspecification 3A, 3AX, 3AA, 3AAX, and3T cylinders. A specification 3A, 3AX,3AA, 3AAX, and 3T cylinders may befilled with a compressed gas, other thana liquefied, dissolved, Division 2.3 or2.1 material, to a pressure 10 percent inexcess of its marked service pressure,provided:


(1) The cylinder is equipped with afrangible disc pressure relief devices(without fusible metal backing) having abursting pressure not exceeding theminimum prescribed test pressure.

(2) The cylinder’s elastic expansionwas determined at the time of the lasttest or retest by the water jacket method.

(3) Either the average wall stress orthe maximum wall stress does notexceed the wall stress limitation shownin the following table:

Type of steel

Averagewall

stresslimitation

Maximumwall

stresslimitation

Plain carbon steelsover 0.35 carbonand medium man-ganese steels ........ 53,000 58,000

Steels of analysis andheat-treatmentspecified in spec.3AA ........................ 67,000 73,000

Steel of analysis andheat treatmentspecified in spec.DOT–3T ................. 87,000 94,000

Plain carbon steelsless than 0.35 car-bon made prior to1920 ....................... 45,000 48,000

(i) The average wall stress shall becomputed from the elastic expansiondata using the following formula:S = 1.7EE / KV—0.4PWhere:S = wall stress, pounds per square inch;EE = elastic expansion (total less

permanent) in cubic centimeters;K = factor × 10¥7 experimentally

determined for the particular typeof cylinder being tested or derivedin accordance with CGA PamphletC–5;

V = internal volume in cubic centimeter(1 cubic inch = 16.387 cubiccentimeters);

P = test pressure, pounds per squareinch.

(ii) The maximum wall stress shall becomputed from the formula:S = (P(1.3D2 + 0.4d2)) / (D2-d2)Where:S = wall stress, pounds per square inch;P = test pressure, pounds per square

inch;D = outside diameter, inches;d = D–2t, where t=minimum wall

thickness determined by a suitablemethod.

(iii) The formula in paragraph (b)(3)(i)of this section is derived from theformula in paragraph (b)(3)(ii) and thefollowing:EE = (PKVD2) / (D2-d2)

(iv) Compliance with average wallstress limitation may be determinedthrough computation of the elasticexpansion rejection limit in accordancewith CGA Pamphlet C–5 or through theuse of the manufacturer’s marked elasticexpansion rejection limit (REE) on thecylinder.

(4) That an external and internalvisual examination made at the time oftest or retest shows the cylinder to befree from excessive corrosion, pitting, ordangerous defects.

(5) That a plus sign (+) be addedfollowing the test date marking on thecylinder to indicate compliance withparagraphs (b) (2), (3), and (4) of thissection.

(c) Carbon monoxide. Carbonmonoxide must be offered in aspecification 3, 3A, 3AX, 3AA, 3AAX,3AL, 3E, or 3T cylinder having aminimum service pressure of 1,800 psig.The pressure in the cylinder may notexceed 1000 psig at 70° F., except thatif the gas is dry and sulfur free, thecylinder may be filled to five-sixths ofthe cylinder’s service pressure or 2000psig, whichever is less. A DOT 3ALcylinder is authorized only whentransported by highway, rail or cargo-only aircraft.

(d) Diborane and diborane mixtures.Diborane and diborane mixed withcompatible compressed gas must beoffered in a DOT 3AA1800 cylinder.The maximum filling density of thediborane may not exceed 7 percent.Diborane mixed with compatiblecompressed gas may not have a pressureexceeding the service pressure of thecylinder if complete decomposition ofthe diborane occurs. Cylinder valveassembles must be protected inaccordance with § 173.301(h).

(e) Fluorine. Fluorine must be offeredin a DOT 3A1000, 3AA1000, or 3BN400cylinder without a pressure relief deviceand equipped with a valve protectioncap. The cylinder may not be filled toover 400 psig at 70° F. and may notcontain over 6 pounds of gas.


§ 173.302b Additional requirements forshipment of permanent gases in metric-marked cylinders.

(a) General requirements. Permanentgases (except gas in solution) must beshipped, subject to this section and§§ 173.301, and 173.301b in a DOTspecification 3ALM, 3M, 3FM or 4Mcylinder.

(1) A cylinder with a marked testpressure greater than or equal to 35 bar(508 psi) is authorized for transportationof Division 2.1, 2.2, or 2.3 Hazard ZoneB,C or D gas.

(2) A DOT 3ALM, 3M, or 3FMcylinder with a marked test pressuregreater than or equal to 200 bar (2900psi) is authorized for transportation ofDivision 2.3 Hazard Zone A gases.

(3) The settled pressure for a DOT 3M,3FM or 3ALM cylinder may not exceedtwo-thirds of the cylinder’s marked testpressure.

(4) The settled pressure for a DOT 4Mcylinder and a DOT 3M cylinder madefrom nickel may not exceed one-half ofthe cylinder’s marked test pressure.

(5) A DOT 3FM cylinder exceeding454 kilogram (1000 pounds) watercapacity is authorized for drycompressed natural gas (scrubbed toremove acid gases). The cylinder maynot contain any liquefied gas and thegas must meet following conditions:

(i) Water content is less than or equalto 0.5 lb. per million cubic feet atstandard temperature and pressure(STP) (60° F., 30 inches Hg).

(ii) Hydrogen Sulfide and MercaptanSulfur in Natural Gas is less than orequal to 0.1 grain per 100 cubic feet.

(iii) Total Soluble Sulfides other thanHydrogen Sulfide must be less than orequal to 0.1 grain per 100 cubic feet atSTP.

(iv) Less than one percent by volumeof oxygen.

(v) Less than three percent by volumeof carbon dioxide.

(b) Pressure Limit. Pressure in acylinder containing a permanent gas at70 °C (158 °F) may not exceed thevalues in the following table:

Division

Percent-age of

cylinder’smarked

test pres-sure

2.3, Zone A ................................... 632.3, Zone B, C .............................. 702.1/5.1; 2.3, Zone D ...................... 782.2 ................................................. 100

(c) Fluorine. Fluorine must beshipped in DOT 3M or 4M cylinderswithout pressure relief devices. Thesettled pressure may not exceed 1⁄4 ofthe cylinder’s marked test pressure, orbe more than 28 bar (400 psig) at 21 °C(70 °F). The cylinder may not containover 2.7 kg (6 pounds) of gas.

(d) Carbon monoxide. A cylinderfilled with carbon monoxide may notexceed 1⁄3 of the cylinder’s marked testpressure, except that if the gas is dryand sulfur free, settled pressure may notexceed 1⁄2 of the cylinder’s marked testpressure.

(e) Diborane and diborane mixtures.Diborane and diborane mixed with acompatible compressed gas must be


shipped in a DOT 3M cylinder and thesettled pressure may not exceed 1⁄3 ofthe cylinder’s marked test pressure. Themaximum filling density of the diboranemay not exceed 7 percent. Diboranemixed with a compatible compressedgas may not have a settled pressureexceeding 2⁄3 of the cylinder’s markedtest pressure if complete decompositionof the diborane occurs. The cylindervalve must be protected in accordancewith § 173.301(h).


§ 173.304 Filling of cylinders with liquefiedcompressed gases.

(a) General requirements. Liquefiedcompressed gases (except gas insolution) must be shipped in accordancewith the requirements in this sectionand in §§ 173.301, 173.301a, 173.301b,173.304a, 173.304b and 173.305.

(1) DOT 3AL, 3ALM, 3FM and 4Mcylinders may not be used for anymaterial that has a primary or subsidiaryhazard of Class 8.

(2) Shipments of Division 2.1materials in aluminum cylinders areauthorized only when transported byhighway, rail or cargo-only aircraft.

(b) Filling limits. Except for carbondioxide, 1,1-Difluoroethylene (R–1132A), nitrous oxide and vinylfluoride, inhibited, the liquid portion ofa liquefied gas may not completely fillthe packaging at any temperature up toand including 54° C (130° F). The liquidportion of vinyl fluoride, inhibited, maycompletely fill the cylinder at 54° C(130° F) provided; the pressure at thecritical temperature does not exceed oneand one-fourth times the servicepressure of a nonmetric-markedcylinder; or the pressure at the critical

temperature does not exceed 83% of thetest pressure of a metric-markedcylinder.

(c) Mixture of compressed gas andother material. A mixture of compressedgas must be shipped in accordance with§ 173.305.

(d) Refrigerant gases. Refrigerant gaseswhich are nontoxic and nonflammableunder this part, must be offered fortransportation in cylinders prescribed in§§ 173.304a, 173.304b, or in DOT 2Pand 2Q containers (§§ 178.33, 178.33a ofthis subchapter). DOT 2P and 2Qcontainers must be packaged in a strongwooden or fiberboard box of suchdesign as to protect valves from injuryor accidental functioning underconditions incident to transportation.Pressure in the inside metal containersmay not exceed 6 bar absolute (87 psia)at 21° C (70° F). Each completed metalcontainer filled for shipment must beheated until its contents reach atemperature of 54° C (130° F) withoutevidence of leakage, distortion, or otherdefect. Each outside package must beplainly marked ‘‘INSIDE CONTAINERSCOMPLY WITH PRESCRIBEDSPECIFICATIONS.’’

(e) Engine starting fluid. Enginestarting fluid containing a flammablecompressed gas or gases must beshipped in a cylinder as prescribed in§ 173.304a, 173.304b, or as follows:

(1) Inside nonrefillable metalcontainers having a capacity not greaterthan 500 ml (32 cubic inches). Thecontainers must be packaged in strong,tight outer packagings. The pressure inthe container may not exceed 10 barabsolute (145 psia), at 54 °C (130 °F).However, if the pressure exceeds 10 barabsolute (145 psia), at 54 °C (130 °F), a

DOT 2P container must be used. In anyevent, the metal container must becapable of withstanding, withoutbursting, a pressure of one and one-halftimes the pressure of the content at 54°C (130 °F). The liquid content of thematerial and gas must not completelyfill the container at 54 °C (130 °F). Eachcontainer, filled for shipment, musthave been heated until its contentsreach a temperature of 54 °C (130 °F),without evidence of leakage, distortion,or other defect. Each outside shippingcontainer must be plainly marked,‘‘INSIDE CONTAINERS COMPLY WITHPRESCRIBED SPECIFICATIONS.’’

(2) [Reserved]33. Section 173.304a would be added

to read as follows:

§ 173.304a Additional requirements forshipment of liquefied compressed gases innonmetric-marked cylinders.

(a) Detailed filling requirements.Liquefied gases (except gas in solution),must be offered for transportation,subject to the requirements in thissection and §§ 173.301, 173.301a and173.304, in nonmetric-markedcylinders, as follows:

(1) Specification 3, 3A, 3AA, 3B, 3BN,3E, 4B, 4BA, 4B240ET, 4BW, 4E, 39,except that no Specification 4E or 39packaging may be filled and shippedwith a mixture containing a pyrophoricliquid, carbon bisulfide (disulfide),ethyl chloride, ethylene oxide, nickelcarbonyl, spirits of nitroglycerin, ortoxic material (Division 6.1 or 2.3),unless specifically authorized in thispart.

(2) The following requirements mustbe complied with for the gases named(for cryogenic liquids, see § 173.316):

Kind of gas

Maximum permittedfilling

density (percent)(See Note 1)

Containers marked as shown in this column or of the same type with higherservice pressure must be used except as provided in §§ 173.301(1),

173.301(a)(4) (see notes following table)

Anhydrous ammonia .............................. 54 ........................... DOT–4; DOT–3A480; DOT–3AA480; DOT–3A480X; DOT–4A480; DOT–3;DOT–4AA480; DOT–3E1800; DOT–3AL480.

Bromotrifluoromethane (R–13B1 or H–1301).

124 ......................... DOT–3A400; DOT–3AA400; DOT–3B400; DOT–4A400; DOT–4AA480; DOT–4B400; DOT–DOT–4BA400; DOT–4BW400; DOT–3E1800; DOT–39; DOT–3AL400.

Carbon dioxide (see notes 4, 7, and 8) 68 ........................... DOT–3A1800; DOT–3AX1800; DOT–3AA1800; DOT–3AAX1800; DOT–3;DOT–3E1800; DOT–3T1800; DOT–3HT2000; DOT–39; DOT–DOT–4L.

Carbon dioxide, refrigerated liquid (seeparagraph (e) of this section.) Chlo-rine (see Note 2).

125 ......................... DOT–3AL1800. DOT–3A480; DOT–3AA480; DOT–3; DOT–3BN480; DOT–3E1800.

Chlorodifluroethane (R–142b) or 1–Chloro–1, 4B150; DOT–4BA225;DOT–4BW225; DOT–1–difluoroethane (Note 8).

100 ......................... DOT–3A150; DOT–3AA150; DOT–3B150; DOT–3E1800; DOT–39, DOT–3AL150.

Chlorodifluoromethane (R–22) (seeNote 8).

105 ......................... DOT–3A240; DOT–3AA240; DOT–3B240; DOT– 4B240; DOT–4BA240; DOT–4BW240; DOT–4B240ET; DOT–4E240; DOT–39; DOT–41; DOT–3E1800;and DOT–3AL240.

Chloropentafluorethane, (R–115) ........... 110 ......................... DOT–3A225; DOT–3AA225; DOT–3B225; DOT–4A225; DOT–4BA225; DOT–4B225; DOT–4BW225; DOT–3E1800; DOT–39; and DOT–3AL225.

Chlorotrifluoromethane (R–13) (seeNote 8).

100 ......................... DOT–3A1800; DOT–3AA1800; DOT–3; DOT–3E1800; DOT–39; and DOT–3AL1800.


Kind of gas





Cyclopropane (see Note 8) .................... 55 ........................... DOT–3A225; DOT–3A480X; DOT–3AA225; DOT–3B225; DOT–4A225; DOT–4AA480; DOT4B225; DOT–4BA225; DOT–4BW225; DOT–4B240ET; DOT–3;DOT–3E1800; DOT–39;DOT–3AL225.

Dichlorodifluoromethane (R–12) (seeNote 8).

119 ......................... DOT–3A225; DOT–3AA225; DOT–3B225;DOT– 4A225; DOT–4B225; DOT–4BA225; DOT–4BW225; DOT–4B240ET; DOT–4E225;DOT–9; DOT–39;DOT–41; DOT–3E1800; and DOT–3AL225.

Dichlorodifluoromethane anddifluoroethane mixture (constant boil-ing mixture) (R–500)(Note 8).

Not liquid full at 130°F.

DOT–3A240; DOT–3AA240, DOT–3B240; DOT–3E1800; DOT–4A240; DOT–4B240; DOT–4BA240; DOT–4BW240; DOT–4E240; DOT–9, DOT–39.

1,1–Difluoroethane (R–152a) (see Note8).

79 ........................... DOT–3A150; DOT–3AA150; DOT–3B150;DOT–4B150; DOT–4BA225; DOT–4BW225; DOT–3E1800; DOT–3AL150.

1,1–Difluoroethylene (R–1132A) ............ 73 ........................... DOT–3A2200, DOT–3AA2200, DOT–3AX2200, DOT–3AAX2200, DOT–3T2200,DOT–39.

Dimethylamine, anhydrous ..................... 59 ........................... DOT–3A150; DOT–3AA150; DOT–3B150; DOT–4B150 DOT–4BA225; DOT–4BW225; ICC–3E1800.

Ethane (see Note 8) ............................... 35.8 ........................ DOT–3A1800; DOT–3AX1800; DOT–3AA1800; DOT–3AAX1800; DOT–3;DOT–3E1800; DOT–3T1800; DOT–39; DOT–3AL1800.

Ethane (see Note 8) ............................... 36.8 ........................ DOT–3A2000; DOT–3AX2000; DOT–3AA2000; DOT–3AAX2000; DOT–3T2000;DOT–39; DOT–3AL2000.

Ethylene (see Note 8) ............................ 31.0 ........................ DOT–3A1800; DOT–3AX1800 DOT–3AA1800; DOT–3AAX1800; DOT–3; DOT–3E1800; DOT–3T1800; DOT–39; and DOT–3AL1800 .

Ethylene (see Note 8) ............................ 32.5 ........................ DOT–3A2000; DOT–3AX2000; DOT–3AA2000; DOT–3AAX2000; DOT–3T2000;DOT–39; and DOT–3AL2000.

Ethylene (see Note 8) ............................ 35.5 ........................ DOT–3A2400; DOT–3AX2400; DOT–3AA2400; DOT–3AAX2400; DOT–3T2400;DOT–39; DOT–3AL2400.

Hydrogen chloride, anhydrous ............... 65 ........................... DOT–3A1800; DOT–3AA1800; DOT–3AX1800; DOT–3AAX1800; DOT–3;DOT–3T1800; DOT–3E1800.

Hydrogen sulfide (see Note 10) ............. 62.5 ........................ DOT–3A480; DOT–3AA480; DOT–3B480; DOT–14A480; DOT–4B480; DOT–4BA480; DOT–4BW480.; DOT–3E1800; DOT–3AL480.

Insecticide, gases liquefied (See Notes8 and 12).


DOT–3A300; DOT–3AA300; DOT–3B300; DOT–4B300; DOT–4BA300; DOT–4BW300; DOT–9; DOT–40; DOT–41; DOT–3E1800.

Liquefied nonflammable gases, liquidother than classified flammable, cor-rosive, toxic & mixtures or solutionthereof filled w/nitrogen carbon diox-ide, or air (see Notes 7 and 8).


Specification packaging authorized in paragraph (a)(1) of this section and DOT–3HT; DOT 4D; DOT–4DA; DOT–4DS.

Methyl acetylene–propadiene, mixtures,stabilized (see Note 5).


DOT–4B240 without brazed seams; DOT–4BA240 without brazed seams; DOT–3A240; DOT–3AA240; DOT–3B240; DOT–3E1800;DOT–4BW240; DOT–4E240; DOT–4B240ET;DOT–4;DOT–41; DOT–3AL240.

Methyl chloride ....................................... 84 ........................... DOT–3A225; DOT–3AA225; DOT–3B225; DOT–4A225; DOT–4B225; DOT–4BA225; DOT–4BW225; DOT–3; DOT–4; DOT–38; DOT–3E1800; DOT–4B240ET.

Cylinders complying with DOT–3A150; DOT–3B150; DOT–4A150, and DOT–4B150 manufactured prior to Dec. 7, 1936 are also authorized.

Methyl mercaptan ................................... 80 ........................... DOT–3A240; DOT–3AA240; DOT–3B240; DOT–4B240; DOT–4B240ET; DOT–3E1800; DOT–4BA240; DOT–4BW240.

Nitrosyl chloride ...................................... 110 ......................... DOT–3BN400 only.Nitrous oxide (see Notes 7, 8, and 11) 68 ........................... DOT–3A1800; DOT–3AX1800; DOT–3AA1800; DOT–3AAX1800; DOT–3;

DOT–3E1800; DOT–3T1800; DOT–3HT2000; DOT–39; DOT–3AL1800.Nitrous oxide, refrigerated liquid (see

paragraph (e) of this section.).DOT–4L.

Refrigerant gas, n.o.s. or Dispersantgas, n.o.s. (see Notes 8 and 13).


DOT–3A240; DOT–3AA240; DOT–3B240; DOT–3E1800; DOT–4A240; DOT–4B240; DOT–4BA240; DOT–4BW240; DOT–4E240; DOT–9; DOT–39; andDOT–3AL240.

Sulfur dioxide (see note 8) ..................... 125 ......................... DOT–3A225; DOT–3AA225; DOT–3B225; DOT–4A225; DOT–4B225; DOT–4BA225; DOT–4BW225; DOT–4B240ET; DOT–3; DOT–4; DOT–38; DOT–39;DOT–3E1800; and DOT–3AL225.

Sulfur hexafluoride ................................. 120 ......................... DOT–3A1000; DOT–3AA1000; DOT–3AAX2400; DOT–3; DOT–3AL1000; DOT–3E1800; DOT–3T1800.

Sulfuryl fluoride ...................................... 106 ......................... DOT–3A480; DOT–3AA480; DOT–3E1800; DOT–4B480; DOT–4BA480; DOT–4BW480.

Tetrafluoroethylene/inhibit ...................... 90 ........................... DOT–3A1200; DOT–3AA1200; DOT–3E1800.Trifluorochloroethylene, inhibited ........... 115 ......................... DOT–3A300; DOT–3AA300; DOT–3B300; DOT–4A300; DOT–4B300; DOT–

4BA300; DOT–4BW300; DOT–3E1800.Trimethylamine, anhydrous .................... 57 ........................... DOT–3A150; DOT–3AA150; DOT–3B150; DOT–4B150; DOT–4BA225; DOT–

4BW225; DOT–3E1800.Vinyl chloride (see Note 5) .................... 84 ........................... DOT–4B150 without brazed seams; DOT–4BA225 without brazed seams; DOT–

4BW225; DOT–3A150; DOT–3AA150; DOT–3E1800; DOT–3AL150.Vinyl fluoride, inhibited ........................... 62 ........................... DOT–3A1800; DOT–3AA1800; DOT–3E1800; DOT–3AL1800.


Kind of gas





Vinyl methyl ether, inhibited (see Note5).

68 ........................... DOT–4B150, without brazed seams; DOT–4BA225 without brazed seams;DOT–4BW225; DOT–3A150; DOT–3AA150; DOT–3B1800; DOT–3E1800.

Note 1: ‘‘Filling density’’ means the percent ratio of the weight of gas in a container to the weight of water that the container will hold at 60 °F.(1 lb of water=27.737 cubic inches at 60 °F.).

Note 2: Cylinders purchased after Oct. 1, 1944, for the transportation of chlorine must contain no aperture other than that provided in the neckof the cylinder for attachment of a valve equipped with an approved pressure relief device. Cylinders purchased after Nov. 1, 1935, and filledwith chlorine must not contain over 150 pounds of gas.

Note 3: [Reserved]Note 4: Special carbon dioxide mining devices containing a heating element and filled with not over 6 pounds of carbon dioxide may be filled

to a density of not over 85 percent, provided the cylinder is made of steel with a calculated bursting pressure in excess of 39,000 psi, be fittedwith a frangible disc that will operate at not over 57 percent of that pressure, and be able to withstand a drop of 10 feet when striking crosswiseon a steel rail while under a pressure of at least 3,000 psi. Such devices must be shipped in strong boxes or must be wrapped in heavy burlapand bound by 12-gauge wire with the wire completely covered by friction tape. Wrapping must be applied so as not to interfere with the function-ing of the frangible disc pressure relief device. Shipments must be described as ‘‘liquefied carbon dioxide gas (mining device)’’ and marked, la-beled, and certified as prescribed for liquefied carbon dioxide.

Note 5: All parts of valve and pressure relief devices in contact with contents of cylinders must be of a metal or other material, suitably treatedif necessary, which will not cause formation of any acetylides.

Note 6: [Reserved]Note 7: Specification 3HT cylinders for aircraft use only, having a maximum service life of 24 years. Authorized only for nonflammable gases.

Cylinders must be equipped with pressure relief devices only of the frangible disc type which meet the requirements of § 173.301(f) Each fran-gible disc must have a rated bursting pressure which does not exceed 90 percent of the minimum required test pressure of the cylinder. Discswith fusible metal backing are not permitted. Cylinders may be shipped only when packed in strong outside packagings.

Note 8: See § 173.301(a)(10).Note 9: [Reserved]Note 10: Each valve outlet must be sealed by a threaded cap or a threaded solid plug.Note 11: Must meet the valve and cleaning requirements in § 173.302(b).Note 12: For an insecticide gas which is nontoxic and nonflammable, see § 173.305(c).Note 13: For a refrigerant or dispersant gas which is nontoxic and nonflammable, see § 173.304(d).

(3) The internal volume of aSpecification 39 cylinder may notexceed 75 cubic inches for a liquefiedflammable gas.

(b) [Reserved](c) Verification of content in cylinder.

Except as noted in paragraph (d)(4) ofthis section, the amount of liquefied gasfilled into a cylinder must be by weightor, when the gas is lower in pressurethan required for liquefaction, apressure-temperature chart for thespecific gas may be used to ensure thatthe service pressure at 21° C (70° F)times 5/4 will not be exceeded at 54° C(130° F). The weight of liquefied gasfilled into the container also must bechecked, after disconnecting thecylinder from the filling line, by the useof a proper scale.

(d) Requirements for liquefiedpetroleum gas. (1) Filling densitylimited as follows:

Minimum specific gravity of liq-uid material at 60 °F

Maximumthe fillingdensity inpercent ofthe water-weight ca-

pacity of thecylinder

0.271 to 0.289 ........................... 26




0.290 to 0.306 ........................... 270.307 to 0.322 ........................... 280.323 to 0.338 ........................... 290.339 to 0.354 ........................... 300.355 to 0.371 ........................... 310.372 to 0.398 ........................... 320.399 to 0.425 ........................... 330.426 to 0.440 ........................... 340.441 to 0.452 ........................... 350.453 to 0.462 ........................... 360.463 to 0.472 ........................... 370.473 to 0.480 ........................... 380.481 to 0.488 ........................... 390.489 to 0.495 ........................... 400.496 to 0.503 ........................... 410.504 to 0.510 ........................... 420.511 to 0.519 ........................... 430.520 to 0.527 ........................... 440.528 to 0.536 ........................... 450.537 to 0.544 ........................... 460.545 to 0.552 ........................... 470.553 to 0.560 ........................... 480.561 to 0.568 ........................... 490.569 to 0.576 ........................... 500.577 to 0.584 ........................... 510.585 to 0.592 ........................... 520.593 to 0.600 ........................... 53




0.601 to 0.608 ........................... 540.609 to 0.617 ........................... 550.618 to 0.626 ........................... 560.627 to 0.634 ........................... 57

(2) Subject to § 173.301a(d), anyfilling density percentage prescribed inthis section is authorized to beincreased by 2 for liquefied petroleumgas in specification 3 cylinders or inspecification 3A cylinders marked for1,800 psig, or higher, service pressure.

(3) Liquefied petroleum gas must beshipped in specification cylinders asfollows:

(i) Specification 3, 3A, 3AA, 3B, 3E,3AL, 4B, 4BA, 4B240ET, 4BW, 4E, or 39cylinders. Shipments of flammablegases in 3AL cylinders are authorizedonly when transported by highway, railor cargo-only aircraft.

(ii) Additional containers may be usedwithin the limits of quantity andpressure as follows:

Type of containerMaximum ca-pacity cubic

inchesMaximum charging pressure—psig

DOT–2P or DOT–2Q (see Note 1) ........... 31.83 45 psig at 70 °F. and 105 psig at 130 °F. (see Note 2).


Type of containerMaximum ca-pacity cubic

inchesMaximum charging pressure—psig

DOT–2P or DOT–2Q (see Note 1) ........... 31.83 35 psig at 70 °F. and 100 psig at 130 °F.

Note 1: Containers must be packed in strong wooden or fiber boxes of such design as to protect valves from damage or accidental functioningunder conditions normally incident to transportation. Each completed container filled for shipment must have been heated until its contents reacha temperature of 130 °F., without evidence of leakage, distortion, or other defect. Each outside shipping container must be plainly marked ‘‘IN-SIDE CONTAINERS COMPLY WITH PRESCRIBED SPECIFICATIONS.’’

Note 2: A container must be equipped with a pressure relief device which will prevent rupture of the container and dangerous projection of aclosing device when exposed to fire.

(4) Verification of content. Cylinderswith a water capacity of 200 pounds ormore and for use with a liquefiedpetroleum gas with a specific gravity at60 °F. of 0.504 or greater may have thequantity of their contents determined byusing a fixed length dip tube gaugingdevice. The length of the dip tube shallbe such that when a liquefied petroleumgas, with a specific volume of 0.03051cu. ft./lb. at a temperature of 40 °F., isfilled into the container the liquid justreaches the bottom of the tube. Theweight of this liquid may not exceed 42percent of the water capacity of thecontainer which must be stampedthereon. The length of the dip tube,expressed in inches carried out to onedecimal place and prefixed with theletters ‘‘DT’’ shall be stamped on thecontainer and on the exterior ofremovable type dip tube; for thepurpose of this requirement the markedlength shall be expressed as the distancemeasured along the axis of a straight

tube from the top of the boss throughwhich the tube is inserted to the properlevel of the liquid in the container. Thelength of each dip tube shall be checkedwhen installed by weighing eachcontainer after filling except wheninstalled in groups of substantiallyidentical containers in which case oneof each 25 containers shall be weighed.The quantity of liquefied gas in eachcontainer must be checked by means ofthe dip tube after disconnecting fromthe filling line. The outlet from the diptube shall be not larger than a No. 54drill size orifice. A containerrepresentative of each day’s filling ateach charging plant shall have itscontents checked by weighing afterdisconnecting from the filling line.

(e) Carbon dioxide, refrigerated liquidor nitrous oxide, refrigerated liquid. (1)The following provisions apply tocarbon dioxide, refrigerated liquid andnitrous oxide, refrigerated liquid:

(i) DOT 4L cylinders conforming tothe provisions of this paragraph areauthorized.

(ii) Each cylinder must be protectedwith at least one pressure relief deviceand at least one frangible discconforming to § 173.301(f) andparagraph (a)(2) of this section. Therelieving capacity of the pressure reliefdevice system must be equal to orgreater than that calculated by theapplicable formula in paragraph 5.9 ofCGA Pamphlet S–1.1.

(iii) The temperature and pressure ofthe gas at the time the shipment isoffered for transportation may notexceed ¥18 °C (0 °F) and 20 bar (290psig) for carbon dioxide and ¥15.6 °C(+4 °F) and 20 bar(290 psig) for nitrousoxide. Maximum time in transit may notexceed 120 hours.

(2) The following pressure reliefdevice settings, design servicetemperatures and filling densities apply:

Pressure relief device setting maximum start-to discharge gauge pressure inbar (psig)

Maximum permitted filling density (percent by weight)

Carbon dioxide, refrigeratedliquid Nitrous oxide, refrigerated liquid

7.2 bar (105 psig) ............................................................................................. 108 ............................................ 10411.7 bar (170 psig) ........................................................................................... 105 ............................................ 10116 bar (230 psig) .............................................................................................. 104 ............................................ 9920 bar (295 psig) .............................................................................................. 102 ............................................ 9725 bar (360 psig) .............................................................................................. 100 ............................................ 9531 bar (450 psig) .............................................................................................. 98 .............................................. 8337 bar (540 psig) .............................................................................................. 92 .............................................. 8743 bar (625 psig) .............................................................................................. 86 .............................................. 80Design service temperature °C (°F) ................................................................. ¥196 °C (¥320 °F) ................. ¥196 °C (¥320 °F)


§ 173.304b Additional requirements forshipment of liquefied compressed gases inmetric-marked cylinders.

(a) General requirements. Liquefiedgases must be offered for transportation,subject to the requirements in thissection, §§ 173.301, 173.301b and173.304, in the following metric-markedcylinders: DOT 3M, 3FM, 3ALM, and4M. A filling factor must be calculatedfor each liquefied compressed gas tomeet the following conditions:

(1) The cylinder may not be liquid fullat 55 °C (131 °F). In addition, for a lowpressure liquefied compressed gas, thevapor space must be at least 5% of thecylinder internal volume at 50 °C (122°F).

(2) A cylinder with a marked testpressure greater than or equal to 35 bar(508 psi) is authorized for transportationof Division 2.1, 2.2, and 2.3, gasesHazard Zone B, C or D gas.

(3) A DOT 3ALM, 3M, or 3FMcylinder with a marked test pressuregreater than or equal to 200 bar (2900psi) is authorized for transportation of aDivision 2.3 Hazard Zone A gas.

(4) The pressure in a cylindercontaining a high pressure liquefiedcompressed gas at 65 °C (149 °F) or lowpressure liquefied compressed gas at 55°C (131 °F) may not exceed the valuesin the following table:

Division

Percentage ofcylinder’s

marked testpressure

2.3, Zone A ........................... 632.3, Zone B, C ...................... 702.1/5.1; 2.3, Zone D .............. 782.2 ......................................... 100


(5) Vapor pressure may not exceed, atthe maximum anticipated temperatureduring transportation, the cylinder’smarked test pressure.

(6) Cylinder valve and fittings must berated at or above the cylinder’s burstpressure. The suitability of the cylinder,valve and fitting materials must bechecked, at the maximum anticipatedtemperature during transportation, foroperation.

(b) A DOT 3FM cylinder may not beused for a material that has a primaryor subsidiary hazard of Class 8,hydrogen sulfide or other sulfidebearing compounds, carbon dioxide,carbon monoxide, atmospheric gaseswith a dew point above ¥50 °C (¥58°F), or any other material where theaddition of water may make the materialcorrosive.

(c) A DOT 3FM or 3ALM cylindermay not be used for reclaimedrefrigerant gases.

§ 173.305 [Amended]35. In § 173.305, paragraph (b) would

be amended by revising the reference‘‘173.301(e)’’ to read ‘‘173.301a(c)’’.

§ 173.306 [Amended]36. In 173.306, the following changes

would be made:a. Paragraph (d)(3)(ii) would be

amended by revising the reference‘‘§ 173.301’’ to read ‘‘§ 173.301a or§ 173.301b’’.

b. Paragraph (g)(5) would be amendedby revising the reference ‘‘§ 173.301(k)’’to read ‘‘§ 173.301(a)(10)’’.

37. In 173.315, in paragraph (a), inNote 2 following the table, the reference‘‘§ 173.301(d)’’ would be revised to read‘‘paragraph (p) of this section’’ andparagraph (p) would be added to read asfollows:

§ 173.315 Compressed gases in cargotanks and portable tanks.

* * * * *(p) Manifolding is authorized for

cargo tanks containing anhydrousammonia provided that each individualcargo tank is equipped with a pressurerelief valve or valves and gaugingdevices as required by paragraphs (h)and (i) of this section. Each valve shallbe tightly closed while the cargo tank isin transit. Each cargo tank must be filledseparately.


§ 173.334 Organic phosphates mixed withcompressed gas.

Hexaethyl tetraphosphate, parathion,tetraethyl dithio pyrophosphate,tetraethyl pyrophosphate, or otherDivision 6.1 organic phosphates(including a compound or mixture),

may be mixed with a non-flammablecompressed gas. This mixture must notcontain more than 20 percent by weightof organic phosphate and must bepackaged in specification 3A240,3AA240, 3B240, 4A240, 4B240,4BA240, or 4BW240 cylinders; or any3M, 3FM, or 4M cylinders with amarked test pressure of at least 25 bar(363 psig) or greater; meeting thefollowing requirements:

(a) Each cylinder may be filled withnot more than 5 kg (11.0 pounds) of themixture, to a maximum filling density ofnot more than 80 percent of the watercapacity;

(b) No cylinder may be equipped withan eduction tube or a fusible plug;

(c) No cylinder may be equipped withany valve unless the valve is a typeapproved by the AssociateAdministrator for Hazardous MaterialsSafety;

(d) Cylinders must be overpacked ina box, crate or other strong outsidepackaging conforming to therequirements of § 173.25 and arrangedto protect each valve or other closingdevice from damage. Except as providedin paragraph (e) of this section, no morethan four cylinders may be packed in astrong outside packaging. Each strongoutside packaging with its closingdevice protection must be sufficientlystrong to protect all parts of eachcylinder from deformation or breakage ifthe completed package is dropped 1.8 m(6 feet) onto a nonyielding surface andimpacted at the package’s weakestpoint;

(e) Cylinders may be packed in strongwooden boxes with valves or otherclosing devices protected from damage,with not more than twelve cylinders inone outside wooden box. An outerfiberboard box may be used when notmore than four such cylinders are to beshipped in one packaging. Valves mustbe adequately protected. Box and valveprotection must be of strength sufficientto protect all parts of inner packagingsand valves from deformation orbreakage resulting from a drop of at least1.8 m (6 feet) onto a nonyieldingsurface, impacting at the weakest point.


§ 173.336 Nitrogen dioxide, liquefied, ordinitrogen tetroxide, liquefied.

Nitrogen dioxide, liquefied, ordinitrogen tetroxide, liquefied, must bepackaged in specification cylinders asprescribed in § 173.192. Specificationcylinders prescribed in § 173.192 withvalve removed are authorized. Eachvalve opening must be closed by meansof a solid metal plug with taperedthread properly luted to prevent

leakages. Transportation in DOT 3ALand 3ALM cylinders is authorized onlyby highway or rail. Each cylinder mustbe cleaned in compliance with therequirements of Federal SpecificationRR–C–901c, paragraphs 3.7.2 and 3.8.2.Cleaning agents equivalent to thosespecified in RR–C–901b may be used;however, any cleaning agent must notbe capable of reacting with oxygen. Onecylinder selected at random from agroup of 200 or less and cleaned at thesame time must be tested for oilcontamination in accordance withSpecification RR–C–901c paragraph4.4.2.3 and meet the standard ofcleanliness specified therein.


§ 173.337 Nitric oxide.Nitric oxide must be packed in

Specification 3A1800, 3AA1800,3E1800, or 3AL1800 cylinders; or 3M,3ALM, or 3FM cylinders with a markedtest pressure of 200 bar (2900 psig) orgreater filled to a pressure of not morethan 52 bar (750 psi) at 21 °C (70 °F).Cylinders must be equipped with astainless steel valve and valve seatwhich will not be deteriorated bycontact with nitric oxide or nitrogendioxide. Cylinders or valves may not beequipped with pressure relief devices ofany type. Valve outlets must be sealedby a solid threaded cap or plug and aninert gasketing material. In addition—

(a) Transportation in 3AL or 3ALMcylinders is authorized only by highwayor rail.

(b) Each cylinder must be cleaned incompliance with the requirements ofFederal Specification RR–C–901c,paragraphs 3.7.2 and 3.8.2. Cleaningagents equivalent to those specified inRR–C–901c may be used; however, anycleaning agent must not be capable ofreacting with oxygen. One cylinderselected at random from a group of 200or less and cleaned at the same timemust be tested for oil contamination inaccordance with Specification RR–C–901C paragraph 4.4.2.3 and meet thestandard of cleanliness specifiedtherein.

PART 177—CARRIAGE BY PUBLICHIGHWAY


Authority: 49 U.S.C. 5101–5127, 49 CFR1.53.

42. In § 177.840, paragraph (a)(1)would be revised to read as follows:

§ 177.840 Class 2 (gases) materials.

* * * * *(a) * * *


(1) Cylinders. Cylinders containingClass 2 (gases) materials shall besecurely lashed in an upright position,loaded in racks, or packed in boxes orcrates and securely attached to themotor vehicle to prevent the cylindersfrom being shifted, overturned orejected from the vehicle. A cylindercontaining a Class 2 material may beloaded in a horizontal position providedthat the cylinder is designed so that theinlet to the pressure relief device islocated in the vapor space and thecylinder is properly secured and lashed.* * * * *

PART 178—SPECIFICATIONS FORPACKAGINGS

43. The authority citation for part 178would continue to read as follows:


§ 178.3 [Amended]44. In § 178.3, paragraph (a)(1) would

be amended by removing the wording‘‘DOT 4B240ET’’ and adding thewording ‘‘DOT 3M’’, in its place.

§ 178.35 [Amended]45. In § 178.35, the following changes

would be made:a. In paragraph (b) introductory text,

the wording ‘‘§ 173.300b of thissubchapter’’ would be revised to read‘‘subpart I of part 107 of this chapter’’.

b. In paragraph (b)(1), the wording‘‘§ 173.300a of this subchapter’’ wouldbe revised to read ‘‘subpart I of part 107of this chapter’’.

c. In paragraph (e), the wording‘‘§§ 173.34 and 173.301’’ would berevised to read ‘‘§ 173.301’’.

d. In paragraph (f)(2)(ii), theparenthetical wording ‘‘(§ 178.44)’’ and‘‘(§ 178.45)’’ would be removed.

46. In addition, in § 178.35, paragraph(f)(3) would be revised to read asfollows:

§ 178.35 General requirements forspecification cylinders.

* * * * *(f) * * *(3) Marking exceptions. A DOT 3E

cylinder is not required to be markedwith an inspector’s mark or a serialnumber.* * * * *

§§ 178.36, 178.37, 178.38, 178.39, 178.45[Removed]

47. In subpart C, §§ 178.36, 178.37,178.38, 178.39, and 178.45 would beremoved.

48. In § 178.46(a)(4), in Table 2, theentry ‘‘6351-T6’’ would be removed andTable 1 would be revised to read asfollows:

§ 178.46 Specification 3AL seamlessaluminum cylinders.

(a) * * *(4) * * *

TABLE 1.—ALUMINUM[Heat or Cast Analysis for Aluminum; similar to ‘‘Aluminum Association 1 ’’ Alloy 6061 Chemical Analysis in Weight Percent 2]

Simin/max

Femax

Cumin/max

Mnmax

Mgmin/max

Crmin/max

Znmax

Timax

Pbmax

Bimax

Other

AlEachmax

Totalmax

0.40/0.8 ........................................................ 0.7 0.15/0.4 0.15 0.8/1.2 0.04/0.35 0.25 0.15 0.005 0.005 0.05 0.15 Bal.

1 The ‘‘Aluminum Association’’ refers to ‘‘Aluminum Standards and Data 1993’’, published by the Aluminum Association Inc.2 Except for ‘‘Pb’’ and ‘‘Bi’’, the chemical composition corresponds with that of Table 1 of ASTM B221 for Aluminum Association alloy 6061.

* * * * *

§§ 178.50, 178.51 and 178.55 [Removed]49. Sections 178.50, 178.51, and

178.55 would be removed.


be amended by revising the wording‘‘Table 1 of Appendix A to this part’’ toread ‘‘Table 1 of Appendix A to thissubpart’’.


be amended by revising the wording‘‘Table 1 of Appendix A to this part’’ toread ‘‘Table 1 of Appendix A to thissubpart’’.

§ 178.61 [Removed]52. Section 178.61 would be removed.

§ 178.68 [Removed]53. Section 178.68 would be removed.54. Section 178.69 would be added to

Subpart C to read as follows:

§ 178.69 Applicability and design criteriafor all metric-marked DOT specificationcylinders.

(a) Applicability. The definitions andgeneral requirements prescribed in

paragraphs (b) through (g) of this sectionapply to the manufacture of cylinders tothe DOT 3M, 3ALM, 3FM and 4Mspecifications prescribed in §§ 178.70through 178.81. The requirements fordesign qualification tests andproduction tests and verificationsprescribed in paragraphs (h) and (i) ofthis section apply only when requiredby the individual specification. Allspecification requirements areminimum requirements.

(b) Definitions. For purposes of thissubpart—

Associate Administrator means theAssociate Administrator for HazardousMaterials Safety.

Design qualification tests means aseries of tests, including the cycle, burstand puncture resistance test, thatmeasure the structural integrity of acylinder design or significant designchange.

Heat treatment means heating andcooling a solid metal or alloy in such away as to obtain desired conditions orproperties. In addition:

(1) Quench and temper heat treatmentmeans the process of heat treating andcooling cylinders by liquid quenching.The liquid must have a cooling rate ofless than 80 percent of that of water.

The temperature on quenching shall beappropriate for the material ofconstruction but may not exceed 957°C(1750°F).

(2) Normalizing heat treatment meansheating a ferrous alloy to a suitabletemperature above its transformationtemperature, not to exceed 957°C(1750°F), and then cooling it in air toambient temperature.

(3) Annealing heat treatment meansheating to and holding at a suitabletemperature and then cooling tofacilitate cold working.

(4) Stress relieving heat treatmentmeans heating to a suitable temperature,holding long enough to reduce residualstresses and then cooling slowly enoughto minimize the development of newresidual stresses.

Lot means a group of cylinderssuccessively produced in a work shift ofnot more than 10 hours of continuousoperation having—

(1) The same specified size andconfiguration, within the parameters of‘‘significant change’’ to an originaldesign as defined in this section;

(2) The same specified material ofconstruction (i.e. cast or heat);

(3) The same process of manufacture;and


(4) Been subjected to similarconditions of time, temperature, coolingrate, and atmosphere during heattreatment.

Plugged cylinder is a cylinder with apermanent end closure achieved by theinsertion of a threaded plug.

Proof pressure test means a pressuretest by interior pressurization withoutthe determination of the cylinder’sexpansion.

Settled pressure, (formerly referred toas service pressure) means the pressureof the contents of the cylinder at 15 °C(59 °F).

Significant change to an originaldesign means—

(1) A 10 percent or greater change incylinder wall thickness, test pressure ordiameter;

(2) A 30 percent or greater change inwater capacity or base thickness;

(3) Any change in specified material;(4) An increase in the diameter of

openings of over 100 percent; or(5) Any change in the number of

openings.Spun cylinder is a cylinder with an

end closure that has been welded by thespinning process.

Volumetric expansion test means apressure test by interior pressurizationto measure a cylinder’s expansion byusing the water jacket or directexpansion methods.

(1) Water jacket method means avolumetric expansion test to determinea cylinder’s total and permanentexpansion by measuring the differencebetween the volume of water thecylinder externally displaces at testpressure and the volume of water thecylinder externally displaces at ambientpressure

(2) Direct expansion method means avolumetric expansion test to calculate acylinder’s total and permanentexpansion by measuring the amount ofwater forced into a cylinder at testpressure, adjusted for thecompressibility of water, as a means ofdetermining the expansion.

(c) Inspection and analyses.Inspection and analyses must be incompliance with the following:

(1) Inspections and verifications, asrequired, must be performed by ahazmat employee of an independentinspection agency that has beenapproved in writing by the AssociateAdministrator in accordance with§ 107.803 of this chapter.

(2) Chemical analyses and tests mustbe made in the United States or at afacility located outside the United Statesthat is approved in writing by theAssociate Administrator in accordancewith § 107.807 of this chapter and underthe supervision of an independent

inspection agency approved under§ 107.803 of this chapter.

(d) Authorized material and materialidentification. (1) Material ofconstruction must be of uniform quality.

(2) Materials with seams, cracks,laminations or other defects likely toweaken the finished cylinder may notbe used.

(3) Materials must be identified withthe heat or cast code by a suitablemethod during manufacture. If the heator cast identification is permanentlystamped on the cylinder, it must bestamped in an area other than thesidewall of the cylinder.

(e) Duties of the inspector. Theinspector shall determine that eachcylinder conforms to the requirementsin this section and the applicableindividual specification. In makingthese determinations, the inspectorshall:

(1) Verify that all procedures forobtaining and reporting the chemicalanalysis are in accordance with theappropriate requirements of ASTMChemical Analysis Test Methods andthat the chemical analysis is inconformance with the individualspecification by—

(i) Obtaining a certified cast or heatanalysis from the material producer,supplier, or from the cylindermanufacturer, for each heat or cast ofmaterial; or

(ii) Peforming or obtaining a check(solid metal) analysis, when such checkanalysis is required;

(2) Witness that the applicable designqualification tests prescribed inparagraph (h) of this section for eachnew cylinder design or a significantchange to an original design have beenperformed with satisfactory results;

(3) Select samples for all tests;(4) Select samples for the check

analysis, when performed;(5) Verify that identification of

material is proper;(6) Verify that the manufacturer

makes a complete internal inspection ofthe cylinder body before closing theends;

(7) Verify that wall thickness wasmeasured and that the specifiedminimum thickness is met;

(8) Verify that the heat treatment isproper;

(9) Witness each test (except thatresults of the hardness test and the grainsize test may be verified);

(10) Verify by gauge that threads arein conformance with the specification;

(11) Verify that each cylinder ismarked in accordance with theapplicable specification;

(12) Verify that gauges and testequipment are properly calibrated;

(13) Prepare a report containing, at aminimum, the information required bythe applicable provisions of this subpartand the information listed in CGAPamphlet C–11 and provide the reportto the manufacturer and, upon request,to the purchaser. The inspector mustretain the reports required by thissection and the applicable individualspecification for 15 years from theoriginal test date on the cylinder. Eachreport must be legible and in English;and

(14) Certify that all cylindersrepresented by the test report meet allapplicable requirements of thespecification through inspection,verification, or any other action requiredto assure compliance.

(f) Threads. Threads must conform tothe following:

(1) Each thread must be clean cut,even, without checks and to gauge.

(2) Taper threads must conform to oneof the following—

(i) American Standard Pipe Thread(NPT) type must conform to therequirements of Federal Standard H–28,Section 7 (FED–STD–H28/7A);

(ii) National Gas Taper thread (NGT)type must conform to the requirementsof Federal Standard H–28 Sections 7(FED–STD–H28/7A), and 9 (FED–STD–H28/9A);

(iii) Other taper threads conforming toother standards may be used providedthe total thread shear strength is not lessthan that specified for NPT threads.

(3) Straight threads must conform toone of the following—

(i) National Gas Straight Thread (NGS)type must conform to the requirementsof Federal Standard H–28, Sections 7(FED–STD–H28/7A), and Section 9(FED–STD–H28/9A);

(ii) Unified Thread (UN) type mustconform to the requirements of FederalStandard H–28, Section 2 (FED–STD–H28/2B);

(iii) Controlled Radius Root Thread(UNJ) type must conform to therequirements of Federal Standard H–28,Section 4 (FED–STD–H28/4);

(iv) Other straight thread typesconforming to other standards may beused provided the requirements ofparagraph (f)(4) of this section are met.

(4) All straight threads must have atleast 4 engaged threads, a tight fit, andcalculated shear strength of at least 10times the shear stress at the test pressureof the cylinder. Shear strength must becalculated by using the appropriatethread shear area in accordance withFederal Standard H–28 Section 2,Appendix B (FED–STD–H28/2BAppendix B). Gaskets are required toprevent leakage.


(g) Pressure relief devices andprotection for valves, pressure reliefdevices, fittings and connections. (1)Pressure relief devices on cylindersmust conform to the requirements of§ 173.301(f) of this subchapter.

(2) Protection for valves, pressurerelief devices, fittings and connectionsmust conform to the requirements of§ 173.301(h)(2) of this subchapter.

(h) Design qualification tests. Eachcylinder design and each cylinderdesign having a ‘‘significant change’’from the original design must besubjected to the design qualificationtests prescribed in this paragraph (h).

(1) Cycle test. The cycle test must beperformed on a cylinder after it haspassed the volumetric expansion test, bysubjecting it to successive hydraulicpressurization and depressurizationcycles. The rate of cycling may notexceed 10 cycles per minute.

(i) The lower cyclic pressure may notexceed 10 percent of the upper cyclicpressure. The upper cyclic pressuremust be at least equal to the prescribedminimum test pressure.

(ii) The test cylinder must besubjected to a pressure exceeding 90percent of the upper cyclic pressure forat least 20 percent of the duration ofeach cycle.

(iii) The cycle test must be performedon at least three representative samplesof each design or any significant changeto an original design.

(iv) All cylinders used in the cycletest must be rendered incapable ofholding pressure following completionof the cycle test.

(2) Burst test. The burst test must beperformed on a representativecompleted cylinder selected at randomafter heat treatment by hydraulicallypressurizing the cylinder to failure. Therate of pressurization may not exceed 14bar (200 psi) per second. Burst testing ofeach design or any significant change toa previously tested design must beperformed on at least 3 representativecylinders.

(3) Puncture resistance test. Eachcylinder design type intended for thetransportation of Division 2.3 gases orDivision 6.1 liquids in Hazard Zones Aand B must pass the following test.Cylinders that are shipped in anoverpack must be tested in theoverpack.

(i) The puncture resistance test mustbe performed on three representativecylinders selected at random after heattreatment. The cylinder must be filledwith water and pressurized to 2⁄3 themarked test pressure at 21° C (70° F).The cylinder must be tested on itssidewall, supported on an unyieldingsupport and tied down so that there is

no movement during impact. Thepuncturing probe must consist of a 2inch x 2 inch x 1⁄4 inch angle iron, itsend sawed off at 90° to form a sharpcorner. The probe must have a weightattached that is equivalent to the weightof the cylinder including the heaviestmaterial to be shipped. The probe mustbe dropped from a minimum height of2.1m (7 feet) from the top surface of thecylinder, perpendicular to the cylinder’slongitudinal centerline, and mustimpact the cylinder sidewall on the topof the cylinder. The sharp corner of theangle iron must impact the centerline ofthe cylinder. (See Figure 1 of thissection.)

(ii) There must be no leakage as aresult of the impact. The cylinder mustbe leak tested, using compressed gascharged to 2/3 of the marked testpressure.

(4) Acceptable test results. Acceptabledesign qualification test results are asprescribed in the individual cylinderspecification.

(i) Production tests and verifications.When the individual specificationrequires a particular production test tobe performed, the test must beconducted on the finished cylinder asprescribed in this paragraph (i). Unlessotherwise noted in this section,acceptable test results are prescribed inthe individual cylinder specification.Any lot not meeting acceptable testresults must be rejected:

(1) Flattening or bend test. Flatteningor bend tests must be performed, on arepresentative completed cylinderselected at random or, if authorized bythe individual specification on a testring, after heat treatment. Each test ringused for the test must meet therequirements of paragraph (i)(7) of thissection.

(i) During the flattening test, thecylinder or test ring must be flattenedbetween wedge-shaped knife edges withthe longitudinal axis of the cylinder atapproximately 90 degrees to the knifeedges. For steel and nickel cylinders,the knife edges must have a 60 degreeincluded angle and be rounded to a 13mm (1/2 inch) radius. For aluminumcylinders, see § 178.72(i)(4).

(ii) A bend test in accordance withASTM E 290 may be substituted for theflattening test. Two test pieces cut froma sidewall ring or rings shall be tested.The width shall be the greater of 25 mm(1 inch) or four times the thickness ofthe test specimen. A load shall beapplied to the inside surface of the testpiece by a mandrel at the mid-lengthuntil the interior edges are no furtherapart than the mandrel diameter. Forsteel cylinders the mandrel shall not be

greater than four times the actual wallthickness.

(iii) For a cylinder with a watercapacity of 454 kg (1,000 pounds) orless, the flattening or bend test must beperformed on a cylinder selected fromeach lot.

(iv) For a cylinder with a watercapacity exceeding 454 kg (1,000pounds), the flattening or bend test mustbe performed on a cylinder or on a testring out of each lot when cylinders areheat treated in a batch furnace, or fromone cylinder or test ring out of each fourhours or less of production when thecylinders are heat treated in acontinuous furnace.

(v) A retest using one additional set ofspecimens is authorized if a test wasconsidered improper due to thepresence of a fault in the equipment orspecimen preparation. Retest specimensmust be taken from this same cylinderif space permits or from anotherrandomly selected cylinder in the samelot.

(2) Grain size. For cylinders madefrom nickel, preparation andexamination of the specimen and grainsize calculation must be as prescribed inASTM E 112.

(3) Hardness test. Apparatus andprocedures must be in conformancewith ASTM E 18 for Rockwell C scale(HRC) hardness number or ASTM E 10for Brinell hardness number (HBS).

(4) Impact test. The impact test mustbe performed on specimens taken fromthe cylinder or, if authorized by theindividual specification, from a testring, after heat treatment. Each test ringused for the test must meet therequirements of paragraph (i)(7) of thissection. Impact specimens must beprepared and tested in accordance withASTM E 23 and the specificrequirements in the individualspecification. A cylinder or a test ringneed represent only one of the heats inthe lot, provided the other heats in thelot were heat treated under the sameconditions and have previously beentested and have passed the tests.

(i) For a cylinder with a watercapacity of 454 kg (1,000 pounds) orless, the specimens must be taken fromone cylinder or test ring out of each lot.

(ii) For a cylinder with a watercapacity exceeding 454 kg (1,000pounds), the specimens must be takenfrom one cylinder or test ring out ofeach batch when cylinders are heattreated in a batch furnace, or from onecylinder or test ring out of each 4 hoursor less of production when cylinders areheat treated in a continuous furnace.

(5) Leakage test. Spun cylinders mustbe tested for leakage by subjecting theinside of the finished bottom to a


pressure of not less than 1⁄2 of thecylinder’s marked test pressure. Thebottom must be clean and free from allmoisture. Pressure must be applied,using dry gas, over an area of at least sixpercent of the total area of the bottombut not less than 19 mm (3⁄4 inch) indiameter including the closure. Therequired pressure must be applied for atleast one minute, during which time theoutside of the bottom under test must becovered with water or other suitableleak detecting fluid and closelyexamined for indication of leakage. Theleakage test must be performed prior tothe closing of the cylinder. The cylindermay not show any evidence of leakage.

(6) Magnetic particle and liquidpenetrant examinations. The apparatusand procedures for the magnetic particleexamination, wet or dry method, mustconform to ASTM E 709. The apparatusand procedures for the liquid penetrantinspection must conform to ASTM E165.

(7) Mechanical tests. Unless otherwisespecified in the individual cylinderspecification, a mechanical test must beperformed on a minimum of twospecimens taken at least 160 degreesapart from a representative completedcylinder which is selected at randomafter pressure testing and heattreatment. For cylinders more than 2meters (6.5 feet) long, the mechanicaltest may be performed on a test ringwhich has been heat treated with thecompleted cylinders. The test ring mustbe at least 61 cm (24 inches) long andmust have its ends covered during heattreatment so as to simulate the heattreatment process of the finishedcylinder it represents. Each test ringused for the test must be of the samespecification material, diameter andthickness as the finished cylinder itrepresents. A test cylinder or test ringneed represent only one of the heats inthe lot provided the other heats in thelot have previously been tested andhave passed the tests.

(i) Specimens must conform to thefollowing:

(A) The long axis of the specimenmust be parallel to the longitudinal axisof the cylinder.

(B) The tensile specimen reducedsection may not be flattened. However,the grip ends may be flattened to within25 mm (1 inch) of each end of thereduced section.

(C) Temperatures generated duringthe preparation of a specimen may notexceed 204 °C (400 °F) for steel ornickel, or 121 °C (250 °F) for aluminum.

(ii) The tensile strength, yieldstrength, and elongation of the materialmust be determined as follows:

(A) The yield strength in tension mustbe the stress corresponding to apermanent strain of 0.2 percent of thegauge length.

(B) For steel and nickel, the yieldstrength must be determined by the‘‘offset’’ method or the extension under-load method described in ASTM E 8.For aluminum material, the yieldstrength must be determined by the‘‘offset’’ method or the extension underload method as described in ASTM B557.

(C) The cross-head speed of thetesting machine may not exceed 3 mm(1⁄8 inch) per minute during thedetermination of yield strength,however, any test speed may be useduntil one-quarter of the specified tensilestrength is reached.

(D) The specimens must be taken fromone cylinder selected from each lot.

(E) When the length of the cylinderdoes not permit securing straightspecimens, then specimens may betaken in any location or direction andmay be straightened or flattened cold,by pressure only, not by blows. Theinspector’s report must indicate that thespecimens were taken and prepared inthis manner.

(F) The size of the specimen must beone of the following—

(1) gauge length of 50 mm (2 inches)and a maximum width of 38 mm (1.5inches);

(2) gauge length of 200 mm (8 inches)and a maximum width of 38 mm (1.5inches); or

(3) gauge length of at least 24 timesspecimen actual thickness and amaximum width of 6 times actualthickness, provided that the cylinderwall is not over 4.7 mm (3⁄16 inch) thick.

(G) For a cylinder with a watercapacity exceeding 454 kg (1,000pounds):

(1) The specimens must be taken fromone cylinder or test ring out of eachbatch when cylinders are heat treated ina batch furnace or from one cylinder ortest ring out of each 4 hours or less ofproduction when cylinders are heattreated in a continuous furnace.

(2) The size of the specimen must beas prescribed in the individualspecification.

(iii) A retest using one additional setof specimens is authorized if a test wasconsidered improper due to a fault inthe equipment or specimen preparation.Retest specimens must be from the samecylinder if space permits, or fromanother randomly selected cylinderfrom the same lot.

(8) Mechanical tests of welds. (i)Tensile test: Specimens must beprepared in accordance with and meetthe requirements of CGA Pamphlet C–3.

Should any specimen from the first testfail to meet the requirements, a secondtest may be performed taken from threeadditional cylinders selected at randomfrom the same lot. If either of theadditional specimens fails to meet therequirements of CGA Pamphlet C–3, theentire lot must be rejected.

(ii) Guided bend test: Specimens mustbe prepared in accordance with andmeet the requirements of CGA PamphletC–3.

(iii) Alternate guided-bend test: Thistest may be used as an alternative to theguided bend test specified in paragraph(i)(8)(ii) of this section and must beperformed in accordance with CGAPamphlet C–3. The specimen shall bebent until the elongation at the outersurface, adjacent to the root of the weld,between the lightly scribed gaugelines—‘‘a’’ to ‘‘b’’, shall be at least 20percent, except that this percentage maybe reduced for steels having a tensilestrength in excess of 340 MPa (50,000psi), as provided in table 4 of § 178.81.

(9) Production burst test. Whenrequired by a particular specification,must be performed on at least onecylinder from each lot. A cylinder usedin the cycle test may be used for theproduction burst test. If a cylinder failsthe production burst test, a secondsample of three cylinders from the samelot must be selected by the independentinspector. If any of these testedcylinders fail, the lot must be rejected.

(10) Proof pressure test. The pressurefor the proof pressure test must be atleast equal to the marked test pressureand must be maintained for at least tenseconds, and sufficiently longer, asnecessary, to assure there is no leakageand no drop in pressure. The cylindermay show no evidence of leakage ordistortion.

(11) Radiographic examination.Radiographic examination of cylindersmust conform to the techniques andacceptability criteria set forth in CGAPamphlet C–3. When fluoroscopicexamination is used, permanent filmrecords need not be retained.

(12) Ultrasonic examination. Theultrasonic examination must beperformed on the cylindrical section ofthe completed cylinder after it haspassed the volumetric expansion test.Testing must be in accordance withAppendix B of this subpart.

(13) Volumetric expansion test. Afterheat treatment, each cylinder must besubjected to an internal pressure at leastequal to the marked test pressure. Thewater jacket method must be performedin accordance with paragraph 4 andAppendices A and B of CGA PamphletC–1. An alternative test procedure, suchas direct expansion, may be used when


approved in writing by the AssociateAdministrator. If the required testpressure can not be maintained due tofailure of test apparatus, the cylindermust be rejected or the test must berepeated at a pressure increased by 10percent of the test pressure or 7 bar (100psi) whichever is lower. Only tworetests are authorized. The permanentexpansion measured at zero gaugepressure may not exceed 10 percent ofthe total measured expansion at testpressure.

(j) Rejected cylinders. When a lot ofcylinders is rejected, and reheattreatment may correct the cause ofrejection, the lot may be reheat treatedand retested as if it were a new lot.

(1) Volumetric expansion test: Reheattreatment of rejected cylinders thatfailed due to excessive permanentexpansion is authorized.

(2) Magnetic particle, liquid penetrantand ultrasonic examinations: Anycylinder rejected because of cracks maynot be requalified.

(k) Markings. Required markings onthe cylinder must be in accordance withthe following:

(1) Each cylinder must be legibly andpermanently marked by stamping on theshoulder, top head or neck. The depthof marking must ensure that the wallthickness measured from the root of thestamping to the interior surface is equal

to or greater than the prescribedminimum wall thickness.

(2) For a DOT–4M specificationcylinder the required markings must bestamped plainly and permanently onthe shoulders, top head, neck, valveboss, valve protection sleeve, collar, orsimilar part permanently attached to thetop of the cylinder. For cylinders that donot exceed 11.3 kg (25 pounds) watercapacity, the marking may be on thefootring permanently attached to thecylinder.

(3) The required markings specified inthis paragraph (k) (3) must be stampedon the cylinder in the sequence shownin items 1 through 12, with noadditional information interspersed, asillustrated in the following example:

DOT–3M/USA/M1234/SN123456/UT/200BAR/IA01/98–09/250/5.8/SS/56.5

Where:1. DOT 3M = DOT specification number.2. USA = country of manufacture.3. M1234 = symbol of manufacturer

assigned by the AssociateAdministrator.

4. SN123456 = manufacturer’s serialnumber.

5. UT = stamp for non-destructiveultrasonic examination, ifapplicable.

6. 200BAR = test pressure (bar).7. IA01 = Independent Inspection mark.

8. 98–09 = date of test (year and month).9. 250 = water capacity (liters).10. 5.8 = minimum guaranteed wall

thickness (millimeters).11. SS = identification of alloy

(SS:stainless steel, NI:Nickel, AL:Aluminum CS: Carbon Steel).

12. 56.5 = tare weight (kilograms).

(4) Required markings must be at least6 mm (0.250 inch) high, except thatcylinders having an inside diameter lessthan 102 mm (4 inches) may havemarkings that are at least 3 mm (0.116inch) high.

(5) Stamping on the side wall isprohibited.

(6) No other markings may conflictwith the required markings.

(7) Other variations in stampingrequired marks is authorized only whennecessitated by lack of space or asapproved in writing by the AssociateAdministrator.

(l) Coatings. Coatings on a cylinder’sexterior or interior walls are authorized,except that the coating must not causemarkings to be illegible, obscure defects,or allow moisture to be trapped betweenthe cylinder wall and the coating. Anycoating that may prevent adequatevisual inspection or ultrasonicexamination is prohibited.

BILLING CODE 4910–60–P


Figure 1 to § 178.69


55. Section 178.70 would be added toSubpart C to read as follows:

§ 178.70 General requirements for DOT 3series metric-marked seamless cylinders.

(a) DOT specifications 3M (§ 178.71),3ALM (§ 178.72), and 3FM (§ 178.73)cylinders must meet the requirementscontained in this section, § 178.69, andthe requirements of the applicableindividual specification contained in§§ 178.71 through 178.73.

(b) Lot size. In no case may a lotexceed 200 cylinders, but any cylinderprocessed for use in the requireddestructive testing need not be countedas being one of the 200.

(c) Authorized material andidentification of material. All tubing,billet, sheet, plate or cast stock must bein conformance with one of thespecifications in Table 1 or 2 ofAppendix A of this subpart. Theinspector may require a check analysisto establish the heat or cast analysiswhen necessary to meet therequirements of § 178.69(c)(2). Thematerial may not be used if the resultsof such analysis indicatesnonconformance with the requirementsof the material specification.

(d) Manufacture. (1) Each cylindermust be of seamless construction withintegrally formed heads and bottoms.

(2) The manufacturing process mustbe capable of producing a cylinder thatis free from defects likely to weaken thefinished cylinder. For a cylinder with awater capacity of more than 454 kg(1000 pounds), permanent closuresformed by spinning are prohibited andintegral heads must be concave topressure.

(3) Dirt and scale must be removed topermit proper inspection. Each cylindermust have a smooth and uniform finish.Fissures, laps, tears, or other defects thatare likely to weaken the finishedcylinder are not acceptable. Thethickness of the treated areas must bemeasured and may not be less than theprescribed minimum sidewallthickness. Machining or other treatmentof the cylinder to eliminate defects mustbe completed before heat treatment andvolumetric expansion testing.

(4) Head and bottom configurationsmust be as follows:

(i) Bottoms of bumped-back cylindersmust have a minimum thickness of notless than two times the prescribedminimum sidewall thickness. Suchbottom thickness must be measuredwithin an area bounded by a linerepresenting the points of contactbetween the cylinder and the floor whenthe cylinder is in a vertical position.

(ii) For heads and bottoms concave topressure, the inside shape must be

hemispherical, ellipsoidal, ortorispherical with a major to minor axisnot exceeding 2 to 1, or a dished shapefalling within these limits. Such headsand bottoms must be at least theprescribed minimum wall thickness ofthe cylindrical shell, except as follows:

(A) The thickness at the point ofclosure of spun cylinders must be atleast 2 times the prescribed minimumsidewall thickness.

(B) The thickness of thehemispherical bottoms on cylindersformed from sheet or plate must be atleast 90 percent of the prescribedminimum sidewall thickness.

(5) Welding or brazing for anypurpose is prohibited on cylindersmanufactured in accordance with thissection.

(6) Plugged cylinders are notauthorized.

(e) Wall thickness. The followingrequirements apply:

(1) The minimum wall thickness for acylinder must be the greater of thethickness as determined by thisparagraph (e), or as required by theindividual specification.

(2) For the minimum wall thicknesscalculations, the following formula mustbe used:S = [P(1.3D2+0.4d2)]/(D2¥d2)Where:S = Wall stress in Mpa (psi).P = Minimum test pressure in bar (psi),

as prescribed for the volumetricexpansion test, but not less than 31bar (450 psi).

D = Outside diameter in mm (inches).d = Inside diameter in mm (inches).

(3) A steel cylinder longer than 2meters (6.5 feet) must meet thefollowing additional requirements if thecylinder is horizontally supported at itstwo ends. The load of the cylinderconsists of the weight per unit length, innewtons per millimeter, of thecylindrical portion filled with water andpressurized to the prescribed minimumtest pressure. The wall thickness mustbe increased when necessary to meet thefollowing requirements:

(i) The sum of 2 times the maximumtensile stress at the mid-point of theunsupported length, due to bending (seeparagraph (e)(3)(ii) of this section), plusthe maximum longitudinal stress in thesame area, due to the hydrostaticpressure (see paragraph (e)(3)(iii) of thissection), may not exceed 80 percent ofthe minimum yield strength of the steelas determined by the mechanical testsprescribed in § 178.69(i)(7) and theapplicable individual specification.

(ii) The following formula must beused to calculate the maximum tensilestress due to bending—

S = MC/IWhere:S = tensile stress in MPa.M = bending moment in newton-mm =

.125Wl2.C=radius (D/2) of cylinder in mm.I=Moment of inertia=.04909 (D4¥d4) in

mm4.W=weight in newtons per mm of

cylinder length full of water.l=length of cylinder in mm.D=outside diameter in mm.d=inside diameter in mm.

(iii) The following formula must beused to calculate the maximumlongitudinal tensile stress due tovolumetric expansion test pressure—S(MPa)=[A1P/10A2]Where:S=tensile strength in MPa.A1=internal area in cross section of the

cylinder in mm2.A2=area of metal in cross section of the

cylinder in mm2.P=volumetric expansion test pressure in

bar.(f) Openings. Openings are not

permitted on the side wall and must becentered on the heads. Openings maynot exceed the smaller of one-half of thecylinder’s outside diameter or 200 mm(8 inches). All openings must be circularand threaded.

(g) Heat treatment. After forming,cylinders must be uniformly andproperly heat treated under similarconditions of time, temperature, coolingrate and atmosphere prior to all tests.The furnace temperature must becontrolled to assure a uniform processand have sufficient instrumentation tocontrol performance.


§ 178.71 Specification 3M; seamless steel,nickel and stainless steel metric-markedcylinders.

(a) General requirements and testpressure. Each DOT specification 3Mcylinder must meet the generalrequirements contained in §§ 178.69and 178.70 and the specificrequirements contained in this section.The design test pressure must be no lessthan 15 bar (218 psi).

(b) Duties of the inspector. In additionto the duties prescribed in § 178.69(e),an inspector must verify that the grainsize in a 3M cylinder manufacturedfrom nickel is in accordance withparagraph (h)(6) of this section.

(c) Authorized materials andidentification of materials. Materialsmust be in accordance with thefollowing:

(1) All tubing, billet, sheet, plate orcast stock must be in conformance with


Grade A, C, or D material specified inTable 1 of Appendix A of this subpart.

(i) Grade A material is authorized forsteel cylinders.

(ii) Grade C material is authorized forstainless steel cylinders.

(iii) Grade D material is authorized fornickel cylinders.

(d) Manufacture. Spun closures fornickel cylinders are prohibited.

(e) Wall thickness. (1) For cylinderswith a test pressure less than 93 bar(1350 psi), the minimum wall must besuch that the wall stress at theprescribed minimum test pressure doesnot exceed 165 MPa (24,000 psi) forcylinders made from Grade A or Cmaterial and in no case may the wallthickness be less than 2mm (.078 inch).

(2) For cylinders with a test pressureof 93 bar (1350 psi) or more, theminimum wall must be such that thewall stress at the prescribed minimumtest pressure does not exceed thefollowing:

(i) 380 MPa (55,000 psi) for cylindersmade from Grade A material;

(ii) 235 MPa (34,000 psi) for cylindersmade from Grade C material.

(3) For cylinders made from Grade Dmaterial, the minimum wall must besuch that the wall stress at theprescribed minimum test pressure doesnot exceed 100 MPa (15,000 psi), or 50percent of the minimum tensile strengthas determined by the mechanicalproperties tests prescribed in§ 178.69(i)(7).

(f) Heat treatment. A cylinder madefrom:

(1) Grade A material must be heattreated by normalizing at a metaltemperature most suitable for thematerial, and air cooled. Liquidquenching is not authorized.Intermediate manganese steel may begiven a quench and temper heattreatment.

(2) Grade C material does not requireheat treatment.

(3) Grade D material does not requireheat treatment. If the cylinder is heattreated, the furnace atmosphere duringheat treatment must be sulfur-free andneutral or reducing.

(g) Design qualification tests. Thefollowing design qualification testsdescribed in § 178.69 apply:

(1) Cycle test. Cylinders representativeof the design must withstand, withoutdistortion or failure, at least 10,000pressurizations.

(2) Burst test. Representativecylinders of each design must meet thefollowing—

(i) For nickel cylinders the testcylinders must withstand at least 2times test pressure.

(ii) For steel cylinders the testcylinders must withstand at least 1.6times test pressure.

(h) Production tests and verification.The following examinations and testsapply. Unless otherwise noted in thissection, acceptable results areprescribed in § 178.69.

(1) Volumetric expansion test.(2) Leakage test for spun cylinder.(3) Ultrasonic examination in

accordance with ASTM E 213 formeasurement of sidewall defects: Anycylinder having a discontinuity greaterthan two times in length and 10 percentin depth of the designed minimum wallthickness or any discontinuity greaterthan 15% of the minimum designedwall thickness in depth must berejected.

(4) Mechanical test: The yield strengthmay not exceed 73 percent of the tensilestrength for steel cylinders, or 50percent of the tensile strength for nickelcylinders. Elongation must be at least 20percent for a 50mm (2-inch) gaugelength specimen or at least 10 percentin other cases. In this instance, aflattening test or bend test is required.If elongation is at least 40 percent forthe 50mm (2-inch) gauge lengthspecimen, or at least 20 percent in othercases, a flattening test or bend test is notrequired.

(5) Flattening or bend test: Steelcylinders must withstand flattening tosix times wall thickness withoutcracking; nickel cylinders mustwithstand flattening to four times wallthickness without cracking. Bend testspecimens must be free of crackingwhen deformed around a mandrel notgreater in diameter than 4 times the wallthickness for steel or 2 times the wallthickness for nickel.

(6) Grain size verification: For nickelcylinders, a specimen must be takenfrom the sidewall of a representativecylinder from each lot. The diameter ofthe average grain cross section may notexceed 0.065 mm (0.0026 inch). Thecorresponding ASTM micro-grain sizenumber is 5.0. When the grain size inthe test cylinder exceeds this limit, thelot must be rejected.

(7) Magnetic particle or liquidpenetrant examination: Magneticparticle or liquid penetrant inspectionmust be performed on each cylinderconstructed of intermediate manganesesteel after heat treatment to determinethe presence of quenching cracks.Cracked cylinders must be rejected.

(i) Rejected cylinders. Nickelcylinders, rejected for unacceptablegrain size, may be reheat treated.Thereafter, the reheat treated cylindersmust pass all prescribed tests includingverification of acceptable grain size.


§ 178.72 Specification 3ALM; seamlessaluminum metric-marked cylinders.

(a) General requirements. Each DOTSpecification 3ALM seamless aluminumcylinder must meet the generalrequirements contained in §§ 178.69,178.70 and the specific requirementscontained in this section.

(b) Capacity. The water capacity maynot exceed 454 kg (1,000 pounds).

(c) Duties of the inspector. In additionto the duties prescribed in § 178.69(e),the inspector must verify compliancewith the provisions in paragraph (d) ofthis section, either by inspection or byobtaining the material manufacturer’scertificate of inspection.

(d) Authorized material andidentification of materials. Only thealuminum alloy specified in Table 2 ofAppendix A to this subpart isauthorized. Material must be identifiedwith the heat or cast code by a suitablemethod that will identify the alloy. Caststock must have uniform isotropic grainstructure not to exceed 500 micronsmaximum.

(e) Manufacture. Only the extrusionprocess is authorized. Closures formedby spinning are prohibited. The cylinderbottom must be concave to pressure.The thickness of the cylinder base maynot be less than the side wall thickness.The bottom of the cylinder must have aninside shape that is torispherical,hemispherical or ellipsoidal, where thedish radius is no greater than 1.2 timesthe inside diameter of the shell. Theknuckle radius may not be less than 12percent of the inside diameter of theshell. The interior base contour maydeviate from the true torispherical,hemispherical or ellipsoidalconfiguration, provided that—

(1) Any area of deviation isaccompanied by an increase in basethickness;

(2) All radii of merging surfaces areequal to or greater than the knuckleradius; and

(3) Each design has been qualified bysuccessfully passing the cycling andburst tests specified in paragraph (h) ofthis section.

(f) Wall thickness. The minimum wallthickness must be such that the wallstress at the prescribed minimum testpressure does not exceed 80 percent ofthe minimum yield strength nor 67percent of the minimum tensile strengthof the cylinder material as determinedby the mechanical properties testsprescribed in § 178.69(i)(7), but in nocase may the minimum wall thicknessbe less than 4mm (0.156 inch).


(g) Heat treatment. Prior to any test,each cylinder must be subjected to asolution heat treatment and agingtreatment appropriate for the type ofaluminum used.

(h) Design qualification tests. Thefollowing design qualification testsdescribed in § 178.69 apply:

(1) Cycle test. Cylinders representativeof the design must withstand, withoutdistortion or failure, at least 10,000pressurizations to the prescribedminimum test pressure.

(2) Burst test. Cylinders representativeof the design, must have a minimumburst of 1.6 times test pressure.

(i) Production tests and verifications.The following examinations and testsapply. Unless otherwise noted in thissection, acceptable results areprescribed in § 178.69.

(1) Volumetric expansion test.(2) Ultrasonic examination. The

examination must be performed inaccordance with ASTM E 213 formeasurement of sidewall defects. Anycylinder having a discontinuity greaterthan two times in length and 5 percentin depth of the design minimum wallthickness must be rejected.

(3) Mechanical tests. Mechanical testsmust be performed as follows: The twotensile specimens must be one of thefollowing: Flat specimen, 50 mm (2-inch) gauge length; Flat specimen, 24tgauge length by 6t width; or Roundspecimen, 4D gauge length withdiameter ‘‘D’’. When the cylindersidewall is greater than 5 mm (3⁄16-inch),a retest without reheat treatment usingthis ‘‘4D’’ specimen is authorized if thetest using the 2-inch specimen fails tomeet elongation requirements. The 4Dspecimen must meet requirements ofASTM E 8. Tensile strength must be atleast 260 Mpa (38000 psi). Yieldstrength must be at least 240 Mpa(35,000 psi). Elongation must be at least14 percent for 50 mm (2-inch) gaugelength specimen, at least 10 percent for24t by 6t specimen, and at least 14percent for the ‘‘4D’’ specimen.

(4) Flattening and bend test. Aflattening or bend test must beperformed as follows:

(i) The flattening test must beperformed by placing the test cylinderbetween wedge-shaped knife edgeshaving a 60 degree included angle, androunded in accordance with thefollowing table. The longitudinal axis ofthe cylinders must be at an angle of 90degrees to the knife edges during thetest. The test cylinder must withstandflattening to 9 times wall thicknesswithout cracking. The table follows:

TABLE.—FLATTENING TEST

Cylinder wall thicknesses(inches)

Roundedradius

(inches)

Under 0.150 .............................. 0.5000.150 to 0.249 ........................... 0.8750.250 to 0.349 ........................... 1.5000.350 to 0.449 ........................... 2.1250.450 to 0.549 ........................... 2.7500.550 to 0.649 ........................... 3.5000.650 to 0.749 ........................... 4.125

(ii) An alternate bend test, inaccordance with ASTM E 290 using amandrel diameter not more than 6 timesthe wall thickness, is authorized. Thistest may be used to qualify a lot that hasfailed the flattening test. Reheattreatment is not required for this test. Ifused, this test must be performed on 2samples from one cylinder taken atrandom out of each production lot. Thetest specimens shall remain uncrackedwhen bent inward around a mandrel inthe direction of curvature of thecylinder wall, until the interior edgesare at a distance apart not greater thanthe diameter of the mandrel.


§ 178.73 Specification for DOT 3FM;seamless steel metric-marked cylinders.

The construction of a cylinder to thisspecification also meets the requirementof draft ISO 9809–2, Transportation ofSeamless Steel Gas Cylinders—DesignConstruction and Testing—Part 2:Quenched and Tempered Steel withTensile Strength Greater Than or Equalto 1100 MPa.

(a) General requirements anddefinitions. Each Specification DOT3FM seamless steel cylinder must meetthe general requirements contained in§§ 178.69, 178.70 and the specificrequirements contained in this section.

(b) Authorized material andidentification of materials. All tubing,billet or cast stock must conform toGrade B or Grade E material specified inTable 1 of Appendix A of this subpart.

(c) Manufacture. Closures formed byspinning are prohibited.

(d) Wall thickness. The minimumwall thickness must be such that thewall stress at the prescribed minimumtest pressure does not exceed the lesserof 483 Mpa (70,000 psi) for Grade Bmaterial or 624 MPa (90,500 psi) forGrade E material, or 67 percent of theminimum tensile strength as determinedfrom the mechanical properties testsprescribed in paragraph 178.69(i)(7), butin no case may the minimum wallthickness be less than 1.5 mm (.058inch).

(e) Heat treatment. Each cylindermust be suitably quench and temper

heat treated and held at thattemperature for a suitable period oftime. Each cylinder must then be aircooled under conditions recommendedfor the steel. The minimum temperingtemperature of the metal must be at least570 °C (1058 °F).

(f) Design qualification tests. Thefollowing design qualification testsdescribed in § 178.69 apply:

(1) Cycle test. Cylinders representativeof the design must withstand, withoutdistortion or failure, at least 10,000pressurizations to the prescribedminimum test pressure.

(2) Burst test. Cylinders representativeof the design, must have a minimumburst of 1.6 times the marked testpressure.

(g) Production tests and verifications:The following examinations and testsapply. Unless otherwise noted in thissection, acceptable results areprescribed in § 178.69.

(1) Volumetric expansion test.(2) Ultrasonic examination. The

examination must be performed inaccordance with ASTM E 213 for themeasurement of sidewall defects. Anycylinder having a discontinuity greaterthan 24 mm (1 inch) in length and adepth greater than 5 percent of thedesign minimum wall thickness must berejected.

(3) Hardness test. A hardness testmust be performed on the cylindricalsection of each cylinder after heattreatment. The tensile strengthequivalent of the hardness numberobtained from the test may not be morethan 1,140 MPa (166,000 psi). Thehardness number may not exceed 37HRC or 344 HBS. If the hardnessnumber is exceeded, then the lot mustbe rejected.

(4) Mechanical tests. (i) Specimen sizemust be gauge length 50 mm (2 inches)and a maximum width of 38 mm (1.5inches). For cylinders over 454 kg (1,000pounds) water capacity, specimens maybe the Standard Round TensionSpecimen as specified in ASTM A–370(0.357 inches minimum diameter).

(ii) Elongation must be at least 16percent for the 50 mm (2 inches) gaugelength specimen. Tensile strength maynot exceed 1,069 MPa (155,000 psi). Forround specimens, the minimumelongation must be at least 15 percent.

(5) Impact tests. (i) Three specimensmust be impact tested per lot. Eachspecimen must be taken from thesidewall of the cylinder or test ring. Theaxis of the specimen must beperpendicular to the longitudinal axis ofthe cylinder, with the axis of the notchin the ‘‘T–L’’ orientation as illustrated infigure 3 of ASTM E 399. Each specimenmust be Charpy V-Notch type, size 10


mm (.40 inch) × 5 mm (.20 inch) or 4mm (.16 inch).

(ii) For cylinders over 454 kg (1,000pounds) water capacity, the axis of thespecimen must be parallel to thelongitudinal axis of the cylinder, withthe axis of the notch in the ‘‘L–C’’orientation as illustrated in figure 3 inASTM E 399. Each specimen must beCharpy V-Notch type, size 10 mm (.40

inch) × 10 mm (.40 inch) if cylinderthickness permits. When only a reducedsize specimen can be obtained, it mustbe the largest standard size obtainablebut not smaller than 10 mm (.40inch) × 5 mm (.20 inch).

(iii) For cylinders constructed ofGrade E material, the Charpy V-Notchimpact properties for the threespecimens must be tested at minus 50°C

(minus 60°F), or colder; and the valuesobtained may be not less than the valuesshown in the following table. Forcylinders constructed of Grade Bmaterial, the Charpy V-Notch impactproperties for the three specimens mustbe tested at minus 50°C (minus 60°F ),or colder; and the values obtained mustnot be less than the values shown in thefollowing table:

Size of specimen(mm)

Average value for acceptancefor 3 specimens

Minimum value for acceptancefor one specimen only of the 3

specimens

(ft-lb) (j/cm2) (ft-lb) (j/cm2)

Grade B10.0 × 10.0 .......................... 25 42 20 3410.0 × 7.5 ............................ 21 48 17 3910.0 × 5.0 ............................ 17 58 14 47

Grade E10.0 × 5.0 ............................ 15 50 12 4010.0 × 4.0 ............................ 12 40 9.5 32


§ 178.81 Specification for DOT 4M; Weldedmetric-marked cylinders.

(a) General. DOT specification 4Mcylinders must meet the requirementscontained in this section and § 178.69.

(1) The design test pressure for DOTspecification 4M cylinders must be lessthan or equal to 140 bar (2030 psi).

(2) [Reserved](b) Lot size. For cylinders

manufactured under the provisions ofthis section, in no case may a lot sizeexceed 500.

(c) Authorized materials andidentification of materials. For analuminum cylinder only AluminumAssociation alloy 5154 is authorized.For a steel cylinder, stock must conformto a material listed in Table 1 as follows:



(d) Manufacture. (1) A DOT–4Mspecification cylinder must bemanufactured only by a processspecifically authorized by and conformto the applicable requirements of thissection.

(2) The manufacturing process mustproduce cylinders that are free ofdefects which are likely to weaken thefinished cylinder. Heads must beseamless, hemispherical or ellipsoidalin shape with the major diameter notmore than two times the minordiameter, or a dished shape fallingwithin these limits. For heads concaveto pressure, the minimum headthickness may not be less than 90percent of the required thickness of thesidewall. For heads convex to pressure,the minimum thickness must be not lessthan two times the required thickness ofthe sidewall. The bottom thicknessesmust be measured within an areabounded by a line representing thepoints of contact between the cylinderand floor when the cylinder is in avertical position. For cylinders with awall thickness less than 2.5 mm (0.100inch), the ratio of tangential length tooutside diameter may not exceed 4.0.

(3) Welding processes and machineoperators shall meet qualificationstandards and comply with operatingprocedures specified in CGA PamphletC–3.

(i) Circumferential seams must be buttwelded with one member offset (jogglebutt) or lapped with minimum overlapof at least four times wall thickness.Other butt joints must be authorized inwriting by the Associate Administrator.Fillet weld beads must be flat or convexand the leg of any fillet weld subjectedto shear stress must be at least 1.3 timesthe shell wall thickness. For spheres,the maximum joint efficiency for designcalculations is 0.85. Heat affected zonesare considered to extend a distance ofsix times the wall thickness from thecenter line of the weld.

(ii) Longitudinal seams must havecomplete penetration, and must be freefrom undercuts, overlaps or abruptridges or valleys. Misalignment ofmating butt edges must not exceed 0.166of the wall thickness or 0.8 mm (0.031-inch), whichever is less. For cylinderswith nominal wall thickness up to andincluding 3.2 mm (0.125 inch), jointsmust be tightly butted. When wallthickness is greater than 3.2 mm (0.125inch), the joint must be gapped withmaximum distance equal to one-half thewall thickness or 0.8 mm (0.031 inch)whichever is less.

(iii) The joint efficiency is 1.0, .90 or.75, as appropriate, for welded jointdescribed in paragraph (i)(6) of thissection.

(iv) The tensile strength of weldedjoints must be equal to or greater thanthe minimum required tensile strengthof the shell material of the finishedcylinder.

(v) Attachments may not be welded tothe sidewall of the cylinder. Welding ofattachments must be completed prior toall pressure tests and prior to heattreatment when required. Attachmentsmust be made of weldable material of analloy which is compatible with thecylinder. The carbon content for steelattachments may not exceed 0.25percent.

(e) Wall thickness. The minimum wallthickness of a DOT 4M cylinder must bethe greater of the thickness asdetermined by the following criteria:

(1) The minimum wall thickness for acarbon steel, HSLA steel or stainlesssteel cylinder with an outside diametergreater than 127 mm (5 inches) must be2.0 mm (0.078 inch) and for analuminum cylinder with an outsidediameter greater than 127 mm (5 inches)must be 4 mm (0.156 inch).

(2) The minimum wall thickness for acarbon steel, HSLA steel or stainlesssteel cylinder with an outside diameterless than or equal to 127 mm (5 inches)must be 1.5 mm (.058 inch) and for analuminum cylinder 2.5 mm (0.097 inch).

(3) Each cylinder must have a wallthickness such that the wall stresscalculated at test pressure using theformula listed in paragraph (e)(4)(i) and(ii) of this section may not exceed thefollowing allowable stresses at testpressure:

(i) For DOT 4M cylinders made fromHSLA steel, 260 Mpa (37,000 psi).

(ii) For DOT 4M cylinders made fromcarbon steel, 165 Mpa (24,000 psi).

(iii) For DOT 4M cylinders made fromaluminum alloy 5154, 138 Mpa (20,000psi).

(iv) For DOT 4M cylinders made from4130X steel, 255 Mpa (70,000 psi).

(v) For DOT 4M cylinders made fromstainless steel cylinders, 410 Mpa(60,000 psi).

(4) For minimum wall thicknesscalculations, one of the followingformula must be used:

(i) For cylinders that are cylindrical inshape:S(MPa) = (P(1.3D2 + .4d2))/E(10(D2–d2))Where:S = Wall stress in MPa.P = Minimum test pressure in bar, as

prescribed for the hydrostatic test.D = Outside diameter in mm.d = Inside diameter in mm.E = Joint efficiency of the longitudinal

seam.(ii) For cylinders that are spherical in

shape:

S(MPa) = PD / 40tEWhere:S = wall stress in MPa.P = Minimum prescribed test pressure in

bar.D = Outside diameter in mm.t = Minimum wall thickness in mm.E = weld efficiency factor.

(f) Openings. Openings must conformto the following:

(1) Openings are permitted in headsonly. The opening must be circular orelliptical.

(2) Openings must be provided withadequate fittings, bosses or pads,integral with or securely attached to thecylinder by welding. Each fitting, bossor pad must be compatible with thecylinder material. Method of attachmentmust be the same as the method ofconstruction.

(3) When more than one openingexists in the head or bottom of thecylinder, these openings must beseparated by ligaments of at least threetimes the average of their holediameters.

(g) Heat treatment. When a completedcylinder is required to be heat treated,each cylinder in a lot must be uniformlyand properly heat treated under similarconditions of time, temperature, coolingrate and atmosphere prior to all tests.The furnace temperature for heattreatment must be controlled on acontinuous basis by use of automatedinstrumentation to control performance.

(1) Heat treatment must follow allforming and welding operations.

(2) Each completed cylinder must beheat treated, as follows:

(i) Quench and temper heat treatmentis authorized only for a DOT 4Mcylinder made from 4130X steel.

(A) Tempering must be accomplishedby reheating the quenched cylinder to atemperature below the transformationrange, and holding at that temperaturefor at least one hour per 25 mm (1 inch)of thickness, based on the shellthickness of the cylinder. Each cylindermust then be air cooled under uniformconditions.

(B) The tempering temperature of the4130X steel must be at least 538 °C(1000 °F).

(ii) Stress relieving heat treatment forHSLA steel and carbon steel cylindersmust be at a temperature of at least 593°C (1100 °F).

(iii) Normalizing heat treatment forHSLA steel and carbon steel cylindersmust be at a temperature of at least 870°C (1600 °F).

(iv) Heat treatment is not required fora stainless steel.

(v) For an aluminum alloy 5154cylinder, heat treatment is not required.


(h) Design qualification tests. Thefollowing design qualification testdescribed in § 178.69 apply. Burst test:five representative cylinders of eachdesign, or any significant change to apreviously tested design, must be bursttested. Each test cylinder must achievethe minimum burst pressure asspecified in Table 2 of paragraph (i) ofthis section without leakage or rupture.

(i) Production tests. The followingexaminations and tests apply. Unlessotherwise noted in this section,procedures and acceptable results areprescribed in § 178.69.

(1) Pressure test. Pressure testing mustconform to the frequency, schedules andpressures as specified in Table 2 of thisparagraph (i).

(2) Leak test. Each fully assembledcylinder must be subjected to a gasleakage test, using a dry inert gas, at onehalf the design test pressure while thecylinder is immersed in water, bycoating it with a leak detecting solution,or by an alternate test method approvedby the Associate Administrator. Table 2follows:

TABLE 2

DOT spec. Lot size

Volumetric 1 expansion test

Proof testpressure 3

Minimumburst

pressure 4Test pressure(TP)Maximum per-mitted PVE/

TVE 2

4M 5 .............................................................................. 500 As marked ................. 10% @ TP ................ 2 x TP

1 At least one cylinder per lot must be subjected to volumetric expansion test. If each cylinder is subjected to the volumetric expansion test theproof test is not required.

2 PVE = permanent volumetric expansion; TVE = total volumetric expansion.3 Each cylinder must be proof tested at the TP.4 One cylinder per lot must be pressurized to destruction; minimum burst is expressed in multiples of TP.5 See §§ 173.302b and 173.304b of this subchapter for fill (service) pressure of DOT 4M cylinders.

(3) Mechanical tests. Mechanical testsmust be taken from a minimum of twosample cylinders per lot selected atrandom after pressure test and heattreatment, if required. Test specimensmust be taken as depicted in figures 1through 5 of Appendix C of this subpartfor the specific design utilized forconstruction.

(i) For cylinders and spherical shapeswhich are not of sufficient size to securetest specimens, an alternate testingprotocol must be approved in writing bythe Associate Administrator.

(ii) A test cylinder need representonly one of the heats of material ofconstruction in the lot, provided thatother heats in the lot have been testedand passed when heat treated undersimilar conditions.

(iii) If, due to welded attachments onthe heads, there is insufficient surfacefrom which to take specimens,specimens may be taken from a cylinderprepared as a test cylinder which doesnot have the attachments but is the sameas the other cylinders in the lot and isheat treated with the lot it represents.

(iv) Minimum elongations arespecified in Table 3 or Table 4 of thisparagraph (i), as appropriate.

(v) Acceptable results. The yieldstrength may not exceed 73 percent oftensile strength for carbon steel and 80percent of tensile strength for aluminumalloy 5154.

(4) Flattening test. A flattening testmust be performed on a test cylinderselected from each lot. Cylinders mustbe flattened, without cracking, betweenknife edges as specified in § 178.69(i)(1)to six times the wall thickness for steelcylinders and ten times the wall

thickness for aluminum cylinders. Theminimum distance is to be measuredbetween the knife edges or plates whilethe specimens are under compression.For spherical shapes, flattening is to beperformed on a press, between parallelsteel plates with the welded seam atright angles to the plates. Alternatively,a test ring cut from the sphere whichincludes the weldment and at least oneinch of material on each side may becrushed between parallel steel plateswith welded seam at right angles to theplates. Any projecting appurtenancesmay be removed prior to flattening.Removal must not produce atemperature exceeding 204 °C (400 °F).

(5) Burst test. For production testingone cylinder selected at random fromeach lot must be burst tested. Each testcylinder must achieve the minimumburst pressure as specified in Table 2 ofthis paragraph (i) without leakage orrupture.

(6) Joint efficiency. (i) The jointefficiency is 1.0 when all weld seams,both longitudinal and circumferential,are completely radiographicallyexamined and defects removed. Weldrepair areas must be reinspected toconfirm that defects have been removedand the repaired area is of acceptableweld quality.

(ii) The joint efficiency is 0.90 whenone cylinder from the first 10production cylinders and one cylinderfrom each 100 consecutively weldedcylinders thereafter are completelyradiographically examined and show nodefects. When defects are found in thesample cylinder all cylinders weldedsince the last acceptable sampling must

be inspected completely and defectsremoved and repaired. When weldingoperations are suspended for more thanfour hours one cylinder must beinspected completely from the first 10production cylinders after resumptionof welding.

(iii) The joint efficiency is 0.75 whenthere is no radiographic weldexamination.

(iv) A cylinder which is less than 21.4kg (48 lbs) water capacity and testpressure less than 34.5 bar (500 psig)manufactured to a two piece design hasa joint efficiency of 1.0 and requires noradiographic examination.

(v) Radiographic examination isrequired for DOT 4M cylindersconstructed from 4130X steel and allDOT 4M cylinders with design testpressure equal to or greater than 70 bar(1015 psi). Radiographic examinationmust be performed on all welded jointswhich are subjected to internal pressure.

(vi) As an alternative to radiographicexamination, an ultrasonic examinationmay be used in accordance withAppendix B of this subpart.

(7) Mechanical test of welds. Testsmust be performed on specimens taken,as illustrated in Figure 1 through 5 ofAppendix C of this subpart, from acylinder chosen at random from eachlot. Acceptable results:

(i) Tensile test results must meetacceptance criteria specified in CGAPamphlet C–3 with specimen failure ata stress of not less than two times thewall stress at test pressure, calculatedusing the actual wall thickness.

(ii) Guided bend test results mustmeet acceptance criteria specified inCGA Pamphlet C–3.


(iii) Alternate guided bend test resultsmust meet acceptance criteria specified

in CGA Pamphlet C–3 and§ 178.69(i)(8)(iii). Tables 3 and 4 follow:

TABLE 3.—ELONGATION

Material

Minimum elongation (in percent)

Gauge length× width ((50mm x ≤38

mm)(2 inch x≤1.5 inch))

Gauge length× width 1 ((200

mm × ≤38mm)(8 inch ×

≤1.5 inch))

Gauge lengthof 24t ×

Width 1 of 6t

Aluminum, alloy 5154 ................................................................................................................... 12 12 12Steel (tensile strength <3447 MPA (50,000 psi)) ........................................................................ 40 20 20

Note 1: A gauge length of at least 24 times shell thickness and a width of not greater than six times shell thickness is authorized when cyl-inder wall is not greater than 4.7 mm (0.188 inch) thick.

TABLE 4.—ALTERNATE MINIMUM ELONGATION

Alternate minimum elongation (in percent)

Shell tensile strength

Having tensile strength >3447 MPA (50,000 psi)

MPA PSI

Gauge length× width ((50mm × ≤38

mm) (2 inch ×≤1.5 inch))

Gauge length× width 1 ((200

mm × ≤38mm)(8 inch ×

≤1.5 inch))

Gauge lengthof 24t × width1

of 6t

≤3964 ............................................................... ≤57500 ............................................................ 38 19 19≤4482 ............................................................... ≤65000 ............................................................ 36 18 18≤5000 ............................................................... ≤72500 ............................................................ 34 17 17≤5520 ............................................................... ≤80000 ............................................................ 32 16 16

Note 1: A gauge length of at least 24 times shell thickness and a width of not greater than six times shell thickness is authorized when cyl-inder wall is not greater than 4.7 mm (0.188 inch) thick.

(j) [Reserved](k) Cylinder Rejection. Each test

cylinder or each lot represented by a testcylinder that does not meet theacceptable test results must be rejected.When a lot of cylinders is rejected, dueto failure of the mechanical, flattening,or weld test, the lot may be reheat

treated and retested as if it were a newlot. Reheat treatment is limited to twotimes.

(l) Leakage test. A spun cylinderrejected under paragraph (i)(2) of thissection must be scrapped, condemnedor rendered incapable of holdingpressure.

(m) Repairs. A repair of weld seamsis authorized using the same process asthat used for the original welding. Arewelded cylinder must be reheattreated and pass all prescribed tests.

60. Appendices A, B and C would beadded to Subpart C of Part 178 to readas follows:

Appendix A to Subpart C of Part 178—Specifications for Steel, Nickel and Aluminum

TABLE 1.—STEEL AND NICKEL—HEAT ANALYSIS—CHEMICAL COMPOSITION IN WEIGHT PERCENT[For grades A–E, incidental elements to be within the limits specified in the AISI Manual 1for Semifinished Steel Products.]

Grade Type of material Cmin/max

Mnmin/max

Pmax

Smax

Simin/max

Crmin/max

Momin/max

Nimin/max

Bmin/max

Fe

A ......... Carbon 3 Manganese ....................... 0.10/0.50 —/1.75 0.035 0.025 —/0.30 .................... .................... .................... ............ Bal.B ......... Chrome Moly Type ........................... 0.25/0.50 0.40/1.05 0.035 0.025 0.15/0.35 0.80/1.15 0.15/0.25 .................... ............ Bal.C ........ Stainless 2 ......................................... —/0.080 —/2.00 0.035 0.030 —/1.00 16.0/20.0 2.00/3.00 8.0/15.0 ............ Bal.D ........ Nickel ................................................ .................... .................... ............ ............ .................... .................... .................... 99.0/— ............ Bal.E ......... Chrome 4 Moly Type ......................... 0.32/0.38 0.60/1.05 0.015 0.010 0.15/0.35 0.80/1.15 0.15/0.25 .................... ............ Bal.

1 The AISI manual referenced in the heading means ‘‘American Iron and Steel Institute’’ Steel Products Manual—Alloy, Carbon, and High Strength Low alloy Steels;Semifinished: dated March 1986.

2 The minimum for molybdenum (2.00) shown, applies only to Stainless Steel type 316.3 Forging or drawing quality steel required; rimmed steel not authorized.4 Forging or drawing quality steel required; produced to predominantly fine grain practice.

TABLE 2.—ALUMINUM—HEAT OR CAST ANALYSIS FOR ALUMINUM; SIMILAR TO ‘‘ALUMINUM ASSOCIATION’’ 1 ALLOY 6061 CHEMICALANALYSIS IN WEIGHT PERCENT 2

Simin/max

Femax

Cumin/max

Mnmax

Mgmin/max

Crmin/max

Znmax

Timax

Pbmax

Bimax

Other

AlEachmax

Totalmax

0.40/0.80 0.70 0.15/0.40 0.15 0.80/1.20 0.04/0.35 0.25 0.15 0.005 0.005 0.05 0.15 Bal.

1 The ‘‘Aluminum Association’’ refers to ‘‘Aluminum Standards and Data 1993’’, published by the Aluminum Association Inc.


2 Except for ‘‘Pb’’ and ‘‘Bi’’, the chemical composition corresponds with that of Table 1 of ASTM B221M for Aluminum Association alloy 6061.

MECHANICAL PROPERTIES

[Aluminum in conformance with the specifica-tion in Table 2 above, thermally treated to‘‘T6’’ temper]

Tensilestrength mini-mum (Mpa) 1

Yield strengthminimum(Mpa) 1

Elongation,percent mini-mum, for 2inch or 4D 2

sizespecimen

262 241 14 3

1 MPA x 145 = psi.2 ‘‘D’’ represents specimen diameter. When

the cylinder is over 3/16 inch thick, a retestwithout reheat treatment, using the 4D speci-mens is authorized, if the test using the 2 inchsize specimen fails to meet elongation require-ments.

3 ‘‘10 percent’’ minimum elongation is au-thorized, when using a 24t x 6t test specimenif the cylinder sidewall is not over 3/16 inchthick.

Appendix B To Subpart C of Part 178—Ultrasonic Examination of Cylinders

Ultrasonic examination (UT) includesstraight beam pulse echo testing thatmeasures 100 percent of the cylinder’ssidewall thickness and angle beam (shearwave) pulse echo that identifies andmeasures cracks, pits, laminations, laps, andother defects.

a. UT equipment. The UT equipment shallconsist of a pulse-echo test instrument thatis capable at a minimum, of generating,receiving, and presenting high energy pulsesin an A-scan presentation on a display. Itmust have a minimum frequency of 1.0 MHZand a minimum frequency range of 1.0 to 5.0MHZ.

1. The UT equipment must continuallymonitor the acoustic coupling to assure100% cylinder sidewall coverage during thetesting and automatically terminate thetesting if the coupling is lost. The equipmentalso must be capable of providing a linearpresentation of crack depth. The equipmentcalibration must be verified for each type ofcylinder to be examined using the calibrationstandard in paragraph b of this Appendixprior to testing. At a minimum, theequipment calibration must be verified at thebeginning of each work shift, not to exceed10 continuous hours.

2. The UT equipment must have multiplefocused array transducers to perform bothstraight beam and angle beam testing of thecylinder sidewall and sidewall to basetransition. A straight-beam search unitconsists of a piezoelectric crystal mounted toa fixture that is perpendicular to thelongitudinal axis of the cylinder. A shearwave search unit consists of piezoelectriccrystals mounted to a fixture that are angledat 45° or 60° to the longitudinal axis of thecylinder sidewall. The frequency and angleof each search unit must be determinedduring calibration based on material,diameter, and wall thickness of the cylinder.A proper search unit must be selected toobtain a good resolution and a minimumaccuracy of +/-5% of the defect depth. Asearch unit frequency of 2.25 MHZ to 10.0MHZ must be used. The equipment usedmust be calibrated to detect a discontinuity25.4 mm (1 inch) in length and a depth of5 percent of the prescribed minimum wallthickness.

b. Calibration standard. A cylinder used asa calibration standard must be of the samediameter (+/¥10%), surface finish,metallurgical type, and specification as thecylinders to be tested, for example, a DOT3FM calibrated cylinder must be used for3FM cylinders. The calibration cylinder mustbe machined with features that simulatedefects such as pits, fatigue cracks, andreduced wall thickness. The size of the defectfeature shall be approximately the same asthe applicable pass-fail criteria identified inTable II of § 180.207 of this subchapter forrequalification of metric-marked cylinders, asidentified in Table II of § 180.209 of thissubchapter for requalification of nonmetric-marked cylinders or as identified in theapplicable cylinder specification. Theminimum wall thickness and defect sizes inthe calibration cylinder must be confirmedby mechanical measurements and certifiedby a non-destructive testing (NDT) Level IIIin UT. The size of the defect features in thecalibration cylinder shall be measured everyfive years to confirm that the defect sizeshave not been changed. A certificationstatement signed by a person certified to NDTLevel III in UT must be maintained for eachcalibration standard and made available forreview, upon request, by an authorized RSPArepresentative.

c. Couplant. The same couplant must beused for both calibration and actual testing.

d. UT procedure and reportingrequirements. The UT procedure andreporting requirements used must be inaccordance with ASTM E 797 for wallthickness measurement and ASTM E 213 forsidewall defect measurement. The UTprogram must be approved in writing by theAssociate Administrator.

1. The surface of the cylinder to beinspected shall be free of extraneous loosematerial such as scale, loose paint, and dirt.

2. The rotational speed of the cylinderunder examination may not exceed therotational speed used during calibration.

3. The UT results must be evaluated inaccordance with pass-fail criteria identifiedin Table II of § 180.207 of this subchapter forrequalification of metric-marked cylinders, asidentified in Table II of § 180.209 of thissubchapter for requalification of nonmetric-marked cylinders or as identified in theapplicable cylinder specification.

e. Personnel Qualifications andResponsibilities: Each facility where testing isto be performed must be under themanagerial direction of a Senior ReviewTechnologist (SRT).

1. The SRT must define the overall testprogram, provide supervisory training andtechnical guidance to operators, review andcertify test results and maintain proof ofqualifications for each ‘‘qualified tester’’. TheSRT must have a Level III, UT Certification,in accordance with the ASNT RecommendedPractice SNT–TC–1A and a thoroughunderstanding of this subchapter pertainingto the qualification and use of DOT cylinders.

2. The person performing cylinder testing,the ‘‘qualified tester’’, must be at a minimuma qualified Level II, UT in accordance withASNT–TC–1A. The ‘‘qualified tester’’ mayperform system startup, calibrate the system,and review and validate the test results.

3. A person with Level I certification mayperform a system startup, check calibration,and perform UT only under the directguidance, supervision, and observation of aLevel II or Level III Operator.

4. Each ‘‘qualified tester’’ must havewritten procedures for conducting UT, foroperation of equipment, a copy of thissubchapter, proof of qualifications, andrecords of all tests performed at the facilitywhere testing is performed.






BILLING CODE 4910–60–C


PART 180—CONTINUINGQUALIFICATION AND MAINTENANCEOF PACKAGINGS



62. Subpart C would be added to Part180 to read as follows:

Subpart C—Qualification, Maintenance andUse of Cylinders

Sec.180.201 Applicability.180.203 Definitions.180.205 General requirements for

requalification of cylinders.180.207 Requirements for requalification of

metric-marked specification cylinders.180.209 Requirements for requalification of

nonmetric-marked specificationcylinders.

180.211 Repair, rebuilding and reheattreatment of nonmetric-marked DOT–4series specification cylinders.

180.213 Requalification markings.180.215 Reporting and record retention

requirements.

Subpart C—Qualification, Maintenanceand Use of Cylinders

§ 180.201 Applicability.

This subpart prescribes requirements,in addition to those contained in Parts107, 171, 172, 173 and 178 of thischapter, applicable to any personresponsible for the continuingqualification, maintenance, or periodicrequalification of DOT specification andexemption cylinders.

§ 180.203 Definitions.

In addition to the definitionscontained in §§ 171.8 and 178.69 of thissubchapter, the following definitionsapply to this subpart:

Associate Administrator meansAssociate Administrator for HazardousMaterials Safety.

Commercially free of corrosivecomponents means a hazardous materialhaving a dew point at or below minus46.7 °C (minus 52 °F) at 101kPa (1atmosphere) and free of material thatwill adversely react with the cylinder(e.g. chemical stress corrosion).

Condemn means a determination thata cylinder is unserviceable for thecontinued transportation of hazardousmaterials in commerce and that thecylinder may not be restored by repair,rebuilding, requalification or any otherprocedure.

Defect means an imperfection thatrequires removal of a cylinder fromservice.

Elastic expansion means thetemporary increase in a cylinder’s

volume, due to application of pressure,which is lost when pressure is released.

Filled means an introduction orpresence of a hazardous material in acylinder.

Non-corrosive service means ahazardous material that is not corrosiveto the materials of construction of acylinder (including valve, pressurerelief device, etc.) when moisture isintroduced into the cylinder.

Over-heated means a condition inwhich any part of a cylinder has beensubjected to a temperature in excess of176 °C (350 °F).

Over-pressurized means a conditionin which a cylinder has been subjectedto an internal pressure in excess of 30%of its test pressure.

Permanent expansion means thepermanent increase in a cylinder’svolume after the test pressure is released(permanent expansion = total expansionminus elastic expansion).

Proof pressure test means a pressuretest by interior pressurization withoutthe determination of the cylinder’sexpansion.

Rebuild means the replacement of apressure part (e.g. a wall, head orpressure fitting) by welding.

Rejected cylinder means a cylinderthat can not be used for thetransportation of a hazardous materialin commerce without repair, rebuild orrequalification.

Repair means a procedure forcorrection of a rejected cylinder andmay involve welding.

Requalification means the completionof a visual inspection and or the test(s)that are required to be performed on acylinder to determine its suitability forcontinued service.

Requalification identification numberor RIN means a code assigned by DOTto uniquely identify a cylinderrequalification, repair or rebuildingfacility.

Test pressure means the pressure usedfor the requalification of a cylinder.

Total expansion means the totalincrease in a cylinder’s volume due toapplication of the test pressure.

Visual inspection means an internalor external visual examination, or both,performed as part of the cylinderrequalification process.

Volumetric expansion test means apressure test by interior pressurizationto measure a cylinder’s expansion byusing the water jacket or directexpansion methods:

(1) Water jacket method means avolumetric expansion test to determinea cylinder’s total and permanentexpansion by measuring the differencebetween the volume of water thecylinder externally displaces at test

pressure and the volume of water thecylinder externally displaces at ambientpressure.

(2) Direct expansion method means avolumetric expansion test to calculate acylinder’s total and permanentexpansion by measuring the amount ofwater forced into a cylinder at testpressure, adjusted for thecompressibility of water, as a means ofdetermining the expansion.

§ 180.205 General requirements forrequalification of cylinders.

(a) General. Each cylinder used for thetransportation of hazardous materialsmust be an authorized packaging. Toqualify as an authorized packaging, eachcylinder must conform to this subpart,the applicable requirements specified inpart 173 of this subchapter, and theapplicable requirements of subpart C ofpart 178 of this subchapter.

(b) Persons performing requalificationfunctions. No person may represent thata repair or requalification of a cylinderhas been performed unless that personholds a current approval issued underthe procedural requirements prescribedin subpart I of part 107 of this chapter.No person may mark a cylinder with aRIN and a requalification date orotherwise represent that a DOTspecification or exemption cylinder hasbeen requalified unless all applicablerequirements of this subpart have beenmet. A person who requalifies cylindersshall maintain, at each location at whichit inspects, tests or marks cylinders, therecords prescribed in § 180.215.

(c) Periodic requalification ofcylinders. Each cylinder bearing a DOTspecification marking must berequalified and marked as specified inthe Requalification Table in thissubpart. Each cylinder bearing a DOTexemption number must be requalifiedand marked in conformance with thissection and the terms of the applicableexemption. No cylinder may be chargedor filled with a hazardous material andoffered for transportation in commerceunless that cylinder has beensuccessfully requalified and marked inaccordance with this subpart. Acylinder may be requalified at any timeduring the month and year that therequalification is due. However, acylinder that was charged or filledbefore the requalification became duemay remain in service until it has beenemptied.

(1) Each cylinder that successfullypasses requalification specified in thissection must be marked in accordancewith § 180.213.

(2) Each cylinder that failsrequalification must be:


(i) Rejected and may be requalified inaccordance with § 180.211; or

(ii) Condemned in accordance withparagraph (i) of this section.

(3) For nonmetric-marked DOTspecification cylinders, the markedservice pressure may be changed uponapplication to the AssociateAdministrator and receipt of writtenprocedures.

(4) For a metric-marked cylinder, thestart-to-discharge pressure of a pressurerelief device must not be less than themarked test pressure of the cylinder. Fora nonmetric-marked DOT–3 seriescylinder, the start-to-discharge pressureof a pressure relief device must be setto not less than 100% of the minimumrequired test pressure at the firstrequalification due on and after[EFFECTIVE DATE OF THE FINALRULE]. To ensure that the relief devicedoes not open below its set pressure, theallowable tolerances for all the pressurerelief devices must range from zero toplus 10% of its setting.

(d) Conditions requiring test andinspection of cylinders. Without regardto any other periodic requalificationrequirements, a cylinder must be testedand inspected in accordance with thissection prior to further use if—

(1) The cylinder shows evidence ofdented, corroded, cracked or abradedareas, leakage, thermal damage or anyother condition that might render itunsafe for use in transportation.

(2) The cylinder has been in anaccident and has been damaged to anextent that may adversely affect itslading retention capability.

(3) The cylinder has been over-heatedor over-pressurized.

(4) The Associate Administratordetermines that the cylinder may be inan unsafe condition.

(e) Cylinders containing Class 8materials. A cylinder that previouslycontained a Class 8 material may not beused to transport a Class 2 material incommerce unless the cylinder is—

(1) Visually inspected, internally andexternally, in accordance withparagraph (f) of this section and theinspection is recorded as prescribed in§ 180.215;

(2) Requalified in accordance withthis section, regardless of the date of theprevious requalification;

(3) Marked in accordance with§ 180.213;

(4) Decontaminated and thedecontamination removes all significantresidue or impregnation of the Class 8material.

(f) Visual inspection. Except asotherwise provided in this subpart, eachtime a cylinder is pressure tested, itmust be given an internal and external

visual inspection. When a pressure testis not performed, the cylinder must begiven an external visual inspection.

(1) The visual inspection must beperformed in accordance with thefollowing CGA Pamphlets: C–6 for steeland nickel cylinders; C–6.1 for seamlessaluminum cylinders; C–6.2 for fiberreinforced exemption cylinders; C–6.3for low pressure aluminum cylinders;C–8 for DOT 3HT cylinders, and C–13for DOT 8 series cylinders.

(2) Each cylinder with a vinyl orplastic coating must have the coatingcompletely removed prior to performingthe visual inspection.

(3) Each cylinder subject to visualinspection must be approved, rejectedor condemned according to the criteriain the applicable CGA pamphlet.

(4) In addition to other requirementsprescribed in this paragraph, DOT 3ALcylinders must be inspected forevidence of sustained load cracking inthe neck and shoulder area inaccordance with the cylindermanufacturer’s writtenrecommendations which have beenapproved in writing by the AssociateAdministrator.

(g) Pressure test. Unless otherwiseexcepted, the pressure test must beconducted in accordance with theprocedures in paragraphs 4, 5 and 6 andAppendices A and B of CGA PamphletC–1. Bands and other removableattachments must be loosened orremoved before testing so that thecylinder is free to expand in alldirections.

(h) Cylinder rejection. A cylindermust be rejected when, after a visualinspection, it meets a condition forrejection under the visual inspectionrequirements of paragraph (f) of thissection.

(1) A cylinder that is rejected may notbe marked as meeting the requirementsof this section.

(2) The requalifier shall notify thecylinder owner, in writing, that thecylinder has been rejected and, unlessrequalified as provided in § 180.211,may not be filled with a hazardousmaterial for transportation in commercewhere use of a specification packagingis required.

(3) A rejected nonmetric-markedcylinder with a service pressure of lessthan 900 psig may be requalified andmarked if the cylinder is repaired orrebuilt and subsequently inspected andtested in conformance with—

(i) The visual inspection requirementsof paragraph (f) of this section;

(ii) Part 178 of this subchapter andthis part;

(iii) Any exemption covering themanufacture, requalification, and or useof that cylinder; and

(iv) Any approval required under§ 180.211.

(i) Cylinder condemnation. (1) Acylinder must be condemned when—

(i) The cylinder meets a condition forcondemnation under the visualinspection requirements of paragraph (f)of this section;

(ii) The cylinder leaks through itswall;

(iii) Evidence of cracking exists to theextent that the cylinder is likely to beweakened appreciably;

(iv) A DOT specification cylinder(including 4M), other than a DOT 4Ealuminum cylinder or an exemptioncylinder, permanent expansion exceeds10 percent of total expansion;

(v) A DOT 3HT cylinder—(A) Yields an elastic expansion

exceeding the marked rejection elasticexpansion (REE) value during thepressure test. A cylinder made beforeJanuary 17, 1978, and not marked withan REE in cubic centimeters near themarked original elastic expansion mustbe so marked before the next test date.The REE for the cylinder is 1.05 timesits original elastic expansion;

(B) Shows evidence of denting orbulging; or

(C) Bears a manufacture or an originaltest date older than twenty-four years orafter 4,380 pressurizations, whicheveroccurs first. If a cylinder is refilled, onaverage, more than once every otherday, an accurate record of the numberof rechargings must be maintained bythe cylinder owner or the owner’s agent;

(vi) A DOT 4E or 4M aluminumcylinder’s permanent expansion exceeds12 percent of total expansion;

(vii) A DOT exemption cylinder’spermanent expansion exceeds the limitin the applicable exemption, or thecylinder meets another criterion forcondemnation in the applicableexemption;

(viii) An aluminum or an aluminum-lined composite exemption cylinder isexposed to a temperature exceeding 177°C (350 °F); or

(ix) A DOT specification cylinderrequalified by ultrasonic examinationthat exceeds the minimum rejectioncriteria set forth in Table II of § 180.207or § 180.209, as applicable.

(2) When a cylinder is required to becondemned, the requalifier shall stampa series of X’s over the DOTspecification number and the markedpressure or stamp ‘‘CONDEMNED’’ onthe shoulder, top head, or neck using asteel stamp. Alternatively, at thedirection of the owner, the requalifiermay render the cylinder incapable of


holding pressure. In addition, therequalifier shall notify the cylinderowner, in writing, that the cylinder iscondemned and may not be filled withhazardous material for transportation incommerce where use of a specificationpackaging is required.

(3) No person may remove orobliterate the ‘‘CONDEMNED’’ marking.

§ 180.207 Requirements for requalificationof metric-marked specification cylinders.

(a) Each metric-marked cylinder thatbecomes due for periodic requalificationas specified in Table I of this sectionmust be inspected, tested, and markedin conformance with the requirements

of this subpart. The ultrasonicexamination must meet therequirements in Table II of this section.The recordkeeping requirements for anultrasonic examination must be inaccordance with § 180.215. Theultrasonic examination procedures andequipment must be approved by theAssociate Administrator and meet therequirements set forth in Appendix B ofSubpart C of Part 178 of this subchapter.Other nondestructive examinations(NDE) may be used only if approved inwriting by the Associate Administrator.

(b) Except as otherwise provided,DOT 3FM, 3ALM and 3M cylinders

must have 100% of the cylindricalsection tested by straight-beam andangle-beam. For a DOT 4M cylinderwith a marked test pressure greater than70 bar or tensile strength greater than orequal to 830 Kpa (120,000 psi), 100% ofthe cylindrical section must be tested bystraight-beam and angle-beam. For aDOT 4M cylinder with a marked testpressure of 70 bar or less and tensilestrength less than 830 Kpa (120,000 psi),100% of the cylindrical section must betested by straight beam if an ultrasonicexamination is performed.

Tables to § 180.207

TABLE I TO § 180.207.—REQUALIFICATION OF METRIC-MARKED CYLINDERS

Interval period(years)

Test ofinspection Specifications

Type of service

First subseq.

External visualinspection.

DOT–3M, 3FM, 3ALM, 4M ....... External visual inspections in accordance with the applicableCGA pamphlet must be performed in conjunction with the ul-trasonic examination.

.................... ....................

INTERNAL andEXTERNALVISUAL IN-SPECTION.

DOT–4M ................................... Except as otherwise provided, the internal and external visualinspections must be performed in conjunction with the pres-sure test and in accordance with the applicable CGA pam-phlet.

.................... ....................

Ultrasonic EX-AMINATION.

DOT 3M, 3FM, 3ALM, 4M ........ All, except cylinders used exclusively for the material listedbelow:.

5 5

DOT 3M, 3FM, 3ALM ............... (1) Nonliquefied or liquefied, noncorrosive, nontoxic (the LC50of the lading is not less than 5000 ppm) gases that are com-mercially free from corrosive components, and in cylindersprotected externally by a suitable corrosion-resistant coating.A coating on a stainless steel or aluminum cylinder is op-tional.

(2) Class 3 (flammable) liquids without pressurization that arenontoxic (except 6.1 PG III) and are commercially free fromcorroding components.

(3) Class 8 (corrosive) liquids without pressurization that arenontoxic (except 6.1 PG III) and do not meet the criteria of§ 173.137(c)(2) of this subchapter. See restriction in§ 180.205(e).

10 10

DOT 3M .................................... Anhydrous ammonia commercially free from corrosive compo-nents, and in cylinders protected externally by a suitable cor-rosion-resistant coating.

10 10

DOT 4M (DOT 4M cylinderswith a test pressure of 70 baror less may be tested by avolumetric expansion test).

(1) Nonliquefied or liquefied, noncorrosive, nontoxic (the LC50of the lading is not less than 5000 ppm) gases that are com-mercially free from corrosive components, and in cylindersprotected externally by a suitable corrosion-resistant coating.A coating on a stainless steel or aluminum cylinder is op-tional.

(2) Class 3 liquids without pressurization that are nontoxic (ex-cept 6.1 PG III) and are commercially free from corrosivecomponents.

15 15

(3) Class 8 (corrosive) liquids without pressurization that arenontoxic (except 6.1 PG III) and do not meet the criteria of§ 173.137(c)(2) of this subchapter. See restriction in§ 180.205(e).

DOT 3M and 4M (DOT 4M cyl-inders with a test pressure of70 bar or less may be testedby a volumetric expansiontest).

Specification cylinders used exclusively as fire extinguishersand meeting the limitations in special provision 18 in§ 172.102(c)(1) of this subchapter.

12 12


TABLE II TO § 180.207.—CRITERIA FOR PERIODIC ULTRASONIC EXAMINATION OF METRIC MARKED CYLINDERS

DOT specification

Coveragearea of

cylinder bystraight

beam (lon-gitudinalwave)

Coveragearea of

cylinder byanglebeam(shearwave)

Rejectablecrack depthin sidewall(% of wallthickness)

Rejectablecrack lengthin sidewall(multiple ofwall thick-

ness)

Rejectablecrack size inthe circum-

ferentialwelded joint

(depth ×length)

Rejectablepit size diam-

eter (D) ×depth

Rejectedarea for re-duced wall

thickness (t)reduced wallt=any value

less than de-sign min.

wall t1D=diameterof the cyl-

inder

3FM ....................................................... 100% ofsidewall.

100% ofsidewall.

10% of WallThickness ....

4 times WallThickness ....

NA ............... 3 mm × 1⁄3 ofthe De-signedWall Thick-ness.

161 mm2 or0.002D2.

3ALM ..................................................... 100% ofsidewall.

100% ofsidewall.




323 mm2 or0.004D2.

3M .......................................................... 100% ofsidewall.

100% ofsidewall.




323 mm2 or0.004D2.

4M with a marked test pressure >70bar or tensile strength ≥830 MPa.

100% ofsidewall.

100% ofsidewall.



10% of WallThick(Depth)and 2times ofWall Thick,(Length).

3 mm × 1⁄3 ofthe De-signedWall Thick-ness.

323 mm2 or0.004D2.

4M with a marked test pressure ≤70bar or tensile strength <830 MPa.

100% ofsidewall.

NA ........... NA ............... NA ............... NA ............... NA ............... 323 mm2 or0.004D2.

1 Term wall thickness in this table means the minimum design wall thickness provided in the manufacturers inspection report.

§ 180.209 Requirements for requalification of nonmetric-marked specification cylinders.

(a) Periodic qualification of cylinders. (1) Each nonmetric-marked cylinder that becomes due for periodic requalification,as specified in the following table, must be requalified and marked in conformance with the requirements of thissubpart. The recordkeeping requirements must be in accordance with § 180.215. Table I follows:

TABLE I.—REQUALIFICATION OF NONMETRIC-MARKED CYLINDERS 1

Specification under which cylinder was made 2 Minimum test pressure (p.s.i.) 3 Test period (years)

DOT–3 ............................................................... 3,000 p.s.i. ........................................................ 5.DOT–3A, 3AA ................................................... 5/3 times service pressure, except noncorro-

sive service (see § 180.209(g)).5, 10, or 12 (see § 180.209 (b), (f), (h) and (j)).

DOT–3AL .......................................................... 5/3 times service pressure ............................... 5 or 12 (see 180.209(j)).DOT–3AX, 3AAX .............................................. 5/3 times service pressure ............................... 5.3B, 3BN ............................................................. 2 times service pressure (see § 180.209(g)) .... 5 or 10 (see § 180.209(f)).3E ...................................................................... Test not required.3HT ................................................................... 5/3 times service pressure ............................... 3 (see § 180.209(i) and 180.213(c)).3T ...................................................................... 5/3 times service pressure ............................... 5.4AA480 ............................................................. 2 times service pressure (see § 180.209(g)) .... 5 or 10 (see § 180.209(e)(14)).4B, 4BA, 4BW, 4B–240ET ................................ 2 times service pressure, except non-corrosive

service (see § 180.209(g)).5, 10 or 12 (see § 180.209(e), (f) and (j)).

4D, 4DA, 4DS ................................................... 2 times service pressure .................................. 5.DOT–4E ............................................................ 2 times service pressure, except non-corrosive

service (see § 180.209(g)).5.

4L ...................................................................... Test not required8, 8AL ................................................................ ........................................................................... 10 or 20 (See § 180.209(i)).Exemption Cylinder Foreign cylinder (see

§ 173.301(j) for restrictions on use.See current exemption as marked on the cyl-

inder, but not less than 5/3 of any service orworking pressure marking.

See current exemption 5 (see § 180.209(k)and § 180.213(d)(iii)).

1 Any cylinder not exceeding two inches outside diameter and less than two feet in length is excepted from hydrostatic test.2 After January 1, 2005, DOT–3T and 3HT specification cylinders must be inspected by a non-destructive testing method approved by the As-

sociate Administrator.3 For cylinders not marked with a service pressure, see § 173.301(e)(1) of this subchapter.


(2) In lieu of a hydrostatic pressuretest (i.e. volumetric expansion or proofpressure tests) as required by thissection, each DOT specification cylinderthat becomes due for periodicrequalification, as specified in Table I ofparagraph (a)(1) of this section, may berequalified by using one of the followingmethods:

(i) Ultrasonic examination: Ultrasonicexamination must be in conformancewith the requirements of the AppendixB of Subpart C of part 178 of thissubchapter and Table II of paragraph(a)(2) of this section. Minimum wall

thickness of each cylinder examined byUT must be equal to or greater than thedesign minimum wall thickness. Foreach cylinder, the minimum wallthickness data from the cylindermanufacturer’s inspection report mustbe available and used during UTexamination. An external visualinspection in accordance with theapplicable CGA pamphlet is required tobe performed in conjuction with theultrasonic examination. Therecordkeeping requirements for anultrasonic examination must be inaccordance with § 180.215. The marking

requirements for an ultrasonicexamination must be in accordance with§ 180.213.

Note to paragraph (a)(2)(i): The testinterval for the requalification of anonmetric-marked DOT specificationcylinder subjected to UT examination is thesame as specified in Table I of paragraph(a)(1) of this section. The ultrasonicexamination only replaces the hydrostaticpressure test.

(ii) Other nondestructiveexaminations (NDE) as approved inwriting by the Associate Administrator.Table II follows:

TABLE II.—CRITERIA FOR PERIODIC ULTRASONIC EXAMINATION OF NON-METRIC MARKED CYLINDERS

DOT spec

Coveragearea of cyl-

inder bystraight

beam (longi-tudinal wave)

Coveragearea of cyl-

inder byangle beam(shear wave)

Rejectabledefect depthin sidewall(% of wallthickness)

Rejectabledefect lengthin sidewall(multiple ofwall thick-

ness)

Rejectablepit size diam-

eter (D) ×depth

Rejectedarea for re-duced wall

thickness (t)reduced wallt = any valueless than de-

sign min.wall t1 D =diameter ofthe cylinder

3T ............................................................................. 100% ofsidewall.

100% ofsidewall.



3 mm × 1⁄3 ofthe De-signedWallThickness.

161 mm2 or0.002D2.

3AL (mfg. after 1989) .............................................. 100% ofsidewall.

100% ofsidewall.




323 mm2 or0.004D2.

3AA,3A, 3AX, 3AAX ................................................ 100% ofsidewall.

100% ofsidewall.




323 mm2 or0.004D2.

4B,4BA,4BW4D,4DS,4DA ....................................... 100% ofsidewall.

NA ............... NA ............... NA ............... 3 mm × 1⁄3 ofthe De-signedWall Thick-ness.

323 mm2 or0.004D2.

1 Term wall thickness in this table means the minimum design wall thickness provided in the manufacturers inspection report.

(b) DOT–3A or 3AA cylinders. (1) Acylinder conforming to specificationDOT–3A or 3AA with a water capacityof 125 pounds or less that is removedfrom any cluster, bank, group, rack, orvehicle each time it is filled, may berequalified every ten years instead ofevery five years, provided the cylindermeets all of the following—

(i) The cylinder was manufacturedafter December 31, 1945;

(ii) The cylinder is used exclusivelyfor air, argon, cyclopropane, ethylene,helium, hydrogen, krypton, neon,nitrogen, nitrous oxide, oxygen, sulfurhexafluoride, xenon, permitted mixturesof these gases (see § 173.301(d) of thissubchapter), and permitted mixtures ofthese gases with up to 30 percent by

volume of carbon dioxide, provided thatthe gas has a dew point at or belowminus (52°F) at 1 atmosphere;

(iii) Before each refill, the cylinder isremoved from any cluster, bank, group,rack or vehicle and passes the hammertest specified in CGA Pamphlet C–6;

(iv) The cylinder is dried immediatelyafter hydrostatic testing to remove alltraces of water;

(v) The cylinder is not used forunderwater breathing; and

(vi) Each cylinder is stamped with afive-pointed star at least one-fourth ofan inch high immediately following thetest date.

(2) If, since the last requiredrequalification, a cylinder has not beenused exclusively for the gasesspecifically identified in paragraph

(b)(1)(ii) of this section, but currentlyconforms with all other provisions ofparagraph (b)(1) of this section, it maybe requalified every 10 years instead ofevery five years, provided it is firstrequalified and examined as prescribedby § 173.302a(b)(2), (3) and (4) of thissubchapter.

(3) Except as specified in (b)(2) of thissection, if a cylinder, marked with astar, is filled with a compressed gasother than as specified in paragraph(b)(1)(ii) of this section, the starfollowing the most recent test date mustbe obliterated. The cylinder must berequalified five years from the markedtest date, or prior to the first filling witha compressed gas, if the required five-year requalification period has passed.


(c) DOT 4-series cylinders. A DOT 4-series cylinder, except 4L cylinders, thatat any time shows evidence of a leak orof internal or external corrosion,denting, bulging or rough usage to theextent that it is likely to be weakenedappreciably; or that has lost five percentor more of its official tare weight mustbe requalified before being refilled andoffered for transportation. (Refer to CGAPamphlet C–6 or C–6.3, as applicable,regarding cylinder weakening.) Aftertesting, the actual tare weight must berecorded as the new tare weight.

(d) Cylinders 12 pounds or less withservice pressures of 300 psi or less. Acylinder of 12 pounds or less watercapacity authorized for service pressureof 300 psi or less must be given acomplete external visual inspection atthe time periodic requalificationbecomes due. External visual inspectionmust be in accordance with CGAPamphlet C–6 or C–6.1. The cylindermay be hydrostatically tested without awater jacket and without determiningtotal and permanent expansions. Thetest is successful if the cylinder, whenexamined under test pressure, does notdisplay a defect described in§ 180.205(i)(1)(ii) or (iii).

(e) Proof pressure test. A cylindermade in compliance with specificationDOT 4B, DOT 4BA, DOT 4BW, DOT 4Ethat is used exclusively for anhydrousdimethylamine; anhydrousmethylamine; anhydroustrimethylamine; methyl chloride;liquefied petroleum gas;methylacetylene-propadiene stabilized;or dichlorodifluoromethane,difluoroethane, difluorochloroethane,chlorodifluoromethane,chlorotetrafluoroethane,trifluorochloroethylene, or mixturethereof, or mixtures of one or more with

trichlorofluoromethane; and that iscommercially free from corrodingcomponents and protected externally bya suitable corrosion-resistant coating(such as galvanizing or painting) may berequalified every 12 years instead ofevery five years. Alternatively, thecylinder may be subjected to internalhydrostatic pressure of at least twotimes the marked service pressurewithout determination of expansion, butthis latter type of test must be repeatedevery seven years after expiration of thefirst 12-year period. When subjected tothe latter test, the cylinder must becarefully examined under test pressureand removed from service if a leak orother harmful defect exists. A cylinderrequalified by the proof pressure testmethod must be marked after a test oran inspection with the appropriate RINand the date of requalification orreinspection on the cylinder followedby an ‘‘S’’.

(f) Poisonous materials. A cylinderconforming to specification DOT–3A,DOT–3AA, DOT–3B, DOT–4BA orDOT–4BW having a service pressure of300 psi or less that is used exclusivelyfor methyl bromide, liquid; mixtures ofmethyl bromide and ethylenedibromide, liquid; mixtures of methylbromide and chlorpicrin, liquid;mixtures of methyl bromide andpetroleum solvents, liquid; or methylbromide and nonflammable,nonliquefied compressed gas mixtures,liquid; that is commercially free ofcorroding components, and that isprotected externally by a suitablecorrosion resistant coating (such asgalvanizing or painting) and internallyby a suitable corrosion resistant lining(such as galvanizing) may be testedevery 10 years instead of every fiveyears, provided that a visual internal

and external examination of thecylinder is conducted every five years inaccordance with CGA Pamphlet C–6.The cylinder must be examined at eachfilling, and rejected if a dent, corrodedarea, leak or other condition indicatespossible weakness.

(g) Visual inspections. A cylinderconforming to a specification listed inthe table in this paragraph and usedexclusively in the service indicatedmay, instead of a periodic hydrostatictest, be given a complete external visualinspection at the time periodicrequalification becomes due. Externalvisual inspection must be in accordancewith CGA Pamphlet C–6 or C–6.3, asapplicable. When this inspection is usedinstead of hydrostatic pressure testing,subsequent inspections are required atfive-year intervals after the firstinspection. Inspections must be madeonly by persons holding a current RINand the results recorded and maintainedin accordance with § 180.215. Recordsshall include: date of inspection (monthand year); DOT specification number;cylinder identification (registeredsymbol and serial number, date ofmanufacture, and owner); type ofcylinder protective coating (includingstatement as to need of refinishing orrecoating); conditions checked (e.g.,leakage, corrosion, gouges, dents or digsin shell or heads, broken or damagedfootring or protective ring or firedamage); disposition of cylinder(returned to service, returned tocylinder manufacturer for repairs orcondemned). A cylinder passingrequalification by the external visualinspection must be marked inaccordance with § 180.213.Specification cylinders must be inexclusive service as follows:

Cylinders made in compliance with— Used exclusively for—

DOT–3A, DOT–3AA, DOT–3A480X, DOT–4AA480 ................................ Anhydrous ammonia of at least 99.95% purity.DOT–3A, DOT–3AA, DOT–3A480X, DOT–3B, DOT–4B, DOT–4BA,

DOT–4BW.Butadiene, inhibited, which is commercially free from corroding compo-

nents.DOT–3A, DOT–3A480X, DOT–3AA, DOT–3B, DOT–4AA480, DOT–4B,

DOT–4BA, DOT–4BW.Cyclopropane which is commercially free from corroding components.

DOT–3A, DOT–3AA, DOT–3A480X, DOT–4B, DOT–4BA, DOT–4BW,DOT–4E.

Fluorinated hydrocarbons and mixtures thereof which are commerciallyfree from corroding components.

DOT–3A, DOT–3AA, DOT–3A480X, DOT–3B, DOT–4B, DOT–4BA,DOT–4BW, DOT–4E.

Liquefied hydrocarbon gas which is commercially free from corrodingcomponents.

DOT–3A, DOT–3AA, DOT–3A480X, DOT–3B, DOT–4B, DOT–4BA,DOT–4BW, DOT–4E.

Liquefied petroleum gas which is commercially free from corrodingcomponents.

DOT–3A, DOT–3AA, DOT–3B, DOT–4B, DOT–4BA, DOT–4BW, DOT–4E.

Methylacetylene-propadiene, stabilized, which is commercially freefrom corroding components.

DOT–3A, DOT–3AA, DOT–3B, DOT–4B, DOT–4BA, DOT–4BW ........... Anhydrous mono, di, trimethylamines which are commercially free fromcorroding components.

DOT–4B240, DOT–4BW240 .................................................................... Ethyleneimine, inhibited.

(h) Cylinders containing anhydrous ammonia. A cylinder made in compliance with specification DOT–3A, DOT–3A480X, or DOT–4AA480 used exclusively for anhydrous ammonia, commercially free from corroding components, andprotected externally by a suitable corrosion-resistant coating (such as painting) may be requalified every 10 years insteadof every five years.


(i) Requalification of DOT 8 series cylinders. (1) Each owner of a DOT 8 series cylinder used to transport acetylenemust have the cylinder shell and the porous filler requalified in accordance with CGA Pamphlet C–13. Requalificationmust be performed in accordance with the following schedule:

Date of cylinder manufactureShell (visual inspection) requalification Porous filler requalification

Initial Subsequent Initial Subsequent

Before January 1, 1991 ........ Before January 1, 2001 ........ 10 years ................................ Before January 1, 2011 ........ Not required.On or after January 1, 1991 10 years 1 .............................. 10 years ................................ 3 to 20 years 2 ....................... Not required.

1 Years from date of cylinder manufacture.2 For a cylinder manufactured on or after January 1, 1991, requalification of the porous filler must be performed no sooner than 3 years, and

no later than 20 years, from the date of manufacture.

(2) Unless requalified and marked inaccordance with CGA Pamphlet C–13before October 1, 1994, an acetylenecylinder must be requalified by a personwho holds a current RIN.

(3) If a cylinder valve is replaced, acylinder valve of the same weight mustbe used or the tare weight of thecylinder must be adjusted tocompensate for valve weightdifferential.

(4) The person performing a visualinspection, or requalification mustrecord the results as specified in§ 180.215.

(5) The person performing a visualinspection, or requalification must markthe cylinder as specified in § 180.213.

(j) Cylinders used as a fireextinguisher. Only DOT specificationcylinders used as fire extinguishers andmeeting Special Provision 18 in§ 172.102(c)(1) of this subchapter maybe requalified in accordance with thisparagraph (j).

(1) A DOT specification 4B, 4BA,4B240ET or 4BW cylinder may be testedas follows:

(i) For a cylinder with a watercapacity of 12 pounds or less byvolumetric expansion test using thewater jacket method or by proofpressure test. A requalification must beperformed 12 years after the original testdate and at 12-year intervals thereafter.

(ii) For a cylinder having a watercapacity over 12 pounds—

(A) By proof pressure test. Arequalification must be performed 12years after the original test date and at7-year intervals; or

(B) By volumetric expansion test usingthe water jacket method. Arequalification must be performed 12years after the original test date and at12-year intervals thereafter.

(2) A DOT specification 3A, 3AA, or3AL cylinder must be requalified byvolumetric expansion test using thewater jacket method. A requalificationmust be performed 12 years after theoriginal test date and at 12-yearintervals thereafter.

(k) Requalification of foreign cylindersfilled for export.

(1) A cylinder manufactured outsidethe United States, other than asprovided in § 171.12a of thissubchapter, that has not beenmanufactured, inspected, tested andmarked in accordance with part 178 ofthis subchapter may be filled withcompressed gas in the United States,and shipped solely for export if it meetsthe following requirements, in additionto other requirements of this subchapter:

(i) It has been inspected, tested andmarked (with only the month and yearof test) in conformance with theprocedures and requirements of thissubpart or the Associate Administratorhas authorized the filling company tofill foreign cylinder under an alternativemethod of qualification; and

(ii) It is offered for transportation inconformance with the requirements of§ 173.301(l) of this subchapter.

(2) [Reserved]

§ 180.211 Repair, rebuilding and reheattreatment of nonmetric-marked DOT–4series specification cylinders.

(a) General requirements for repairand rebuilding. Any repair or rebuildingof a DOT 4B, 4BA or 4BW cylinder mustbe performed by a person holding anapproval as specified in § 107.805 ofthis chapter. A person performing arebuild function shall be considered amanufacturer subject to therequirements of § 178.2(a)(2) andsubpart C of part 178 of this subchapter.The person performing a repair, rebuild,or reheat treatment must record the testresults as specified in § 180.215. Eachcylinder that is successfully repaired orrebuilt must be marked in accordancewith § 180.213.

(b) General repair requirements. Anyrepair of a cylinder must be made inaccordance with the following:

(1) The repair and the inspection ofthe work performed must be made inaccordance with the requirements of thecylinder specification.

(2) The person performing the repairshall use the procedure, equipment, andfiller metal or brazing material asauthorized by the approval issued under§ 107.805 of this chapter.

(3) Welding and brazing shall beperformed on an area free fromcontaminants.

(4) A weld defect, such as porosity ina pressure retaining seam, shall becompletely removed before rewelding.Puddling may be used to remove a welddefect only by the tungsten inert gasshielded arc process.

(5) After removal of a non-pressureattachment and before its replacement,the cylinder shall be given a visualinspection in accordance with§ 180.205(f).

(6) Reheat treatment of DOT–4B, 4BAor 4BW specification cylinders afterreplacement of non-pressureattachments is not required when thetotal weld material does not exceed 8inches. Individual welds must be atleast three inches apart.

(7) After repair of a DOT 4B, 4BA or4BW cylinder, the weld area is to beleak tested at the service pressure of thecylinder.

(8) Repair of weld defects must be freeof cracks.

(9) When a non-pressure attachmentwith the original cylinder specificationmarkings is replaced, all markings mustbe transferred to the attachment on therepaired cylinder.

(10) Walls, heads or bottoms ofcylinders with defects or leaks in basemetal may not be repaired, but may bereplaced as provided for in paragraph(d) of this section.

(c) Additional repair requirements for4L cylinders. (1) Repairs to a DOT 4Lcylinder are limited to the following:

(i) The removal of either end of theinsulation jacket to permit access to thecylinder, piping system, or neck tube.

(ii) The replacement of the neck tube.At least a 13 mm (0.51 inch) piece of theoriginal neck tube must be protrudingabove the cylinder’s top end. Theoriginal weld attaching the neck tube tothe cylinder must be sound and thereplacement neck tube must be weldedto this remaining piece of the originalneck tube.

(iii) The replacement of material suchas, but not limited to, the insulatingmaterial and the piping system within


the insulation space is authorized. Thereplacement material must beequivalent to that used at the time oforiginal manufacture.

(iv) Other welding procedures whichare qualified by CGA Pamphlet C–3, andnot excluded by the definition ofrebuild, are authorized.

(2) After repair, the cylinder must be:(i) Pressure tested in accordance with

the specifications under which thecylinder was originally manufactured;

(ii) Leak tested before and afterassembly of the insulation jacket usinga mass spectrometer detection system;and

(iii) Tested for heat conductivityrequirements.

(d) General rebuilding requirements.(1) The rebuilding of a cylinder must bemade in accordance with the followingrequirements:

(i) The person rebuilding the cylindermust use the procedures and equipmentas authorized by the approval issuedunder § 107.805 of this chapter.

(ii) After removal of a non-pressurecomponent and before replacement ofany non-pressure component, thecylinder must be visually inspected inaccordance with CGA Pamphlet C–6.

(iii) The rebuilder may rebuild a DOT4B, 4BA or 4BW cylinder having a watercapacity of 20 pounds or greater byreplacing a head of the cylinder using acircumferential joint. When this weldjoint is located at other than an originalwelded joint, a notation of thismodification shall be shown on theManufacturer’s Report of Rebuilding in§ 180.215(d)(2). Weld joint must be onthe cylindrical section of the cylinder.

(iv) Any welding and the inspectionof the rebuilt cylinder must be inaccordance with the requirements of theapplicable cylinder specification andthe following requirements:

(A) Rebuilding of any cylinderinvolving a joint subject to internalpressure may only be performed byfusion welding;

(B) Welding shall be performed on anarea free from contaminants; and

(C) A weld defect, such as porosity ina pressure retaining seam, shall becompletely removed before rewelding.Puddling may be used to remove a welddefect only by the tungsten inert gasshielded arc process.

(2) Any rebuilt cylinder must be—(i) Heat treated in accordance with

paragraph (f) of this section;(ii) Subjected to a volumetric

expansion test on each cylinder asspecified in CGA Pamphlet C–1,paragraphs 4 or 5, and Appendices Aand B. The results of the tests mustconform with the applicable cylinderspecification;

(iii) Inspected and have test datareviewed to determine conformancewith the applicable cylinderspecification; and

(iv) Made of material that conforms tothe specification. Determination ofconformance shall include chemicalanalysis, verification, inspection andtensile testing of the replaced part.Tensile tests must be performed on thereplaced part after heat treatment by lotsdefined in the applicable specification.

(3) A record of rebuilding must becompleted for each cylinder rebuilt inthe format presented in § 180.215(d).

(4) Rebuilding a cylinder with brazedseams is prohibited.

(5) When an end with the originalcylinder specification markings isreplaced, all markings must betransferred to the rebuilt cylinder.

(e) Additional rebuildingrequirements for DOT–4L cylinders. (1)The rebuilding of a DOT 4L cylinder is:

(i) Substituting or adding material inthe insulation space not identical to thatused in the original manufacture of thatcylinder;

(ii) Making a weld repair not toexceed 150 mm (5.9 inches) in length onthe longitudinal seam of the cylinder or300 mm (11.8 inches) in length on acircumferential weld joint of thecylinder; or

(iii) Replacing the outer jacket.(2) Reheat treatment of cylinders is

prohibited.(3) After rebuilding, each inner

containment vessel must be proofpressure tested at 2 times its servicepressure. Each completed assemblymust be leak-tested using a massspectrometer detection system.

(f) Reheat treatment. (1) Prior toreheat treatment, each cylinder must begiven a visual inspection, internally andexternally, in accordance with§ 180.205(f).

(2) Cylinders must be segregated inlots for reheat treatment. The reheattreatment and visual inspection must beperformed in accordance with thespecification for the cylinders except asprovided in paragraph (f)(4) of thissection.

(3) After reheat treatment, eachcylinder in the lot must be subjected toa volumetric expansion test and meetthe acceptance criteria in the applicablespecification or be scrapped.

(4) After all welding and heattreatment, a test of the new weld mustbe performed as required by the originalspecification. The test results must berecorded in accordance with § 180.215.

§ 180.213 Requalification markings.(a) General. Each cylinder that has

been requalified in accordance with this

subpart with acceptable results must bemarked as specified in this section.Required markings may not be altered orremoved.

(b) Placement of markings. Eachcylinder must be plainly andpermanently marked into the metal ofthe cylinder as permitted by theapplicable specification. Unlessauthorized by the cylinder specification,marking on the cylinder sidewall isprohibited.

(1) Required specification markingsmust be legible so as to be readilyvisible at all times. Markings that arebecoming illegible may be remarked onthe cylinder as provided by the originalspecification. The markings may beplaced on any portion of the upper endof the cylinder excluding the sidewall.No steel stamping, engraving, orscribing may be made in the sidewall ofthe cylinder unless specificallypermitted in the applicable cylinderspecification. A metal plate if used,must be attached as provided by theoriginal specification.

(2) Markings of previous tests may notbe obliterated, except when the spaceoriginally provided for requalificationdates becomes filled, additional datesmay be added as follows:

(i) All preceding test dates may beremoved by peening provided that—

(A) Permission is obtained from thecylinder owner;

(B) The minimum wall thickness ismaintained in accordance withmanufacturing specifications for thecylinder; and

(C) The original manufacturing testdate is not removed.

(ii) When the cylinder is fitted with afootring, additional dates may bemarked on the external surface of thefootring.

(c) Marking method. The depth ofmarkings may be no greater than thatspecified in the applicable specification.The markings must be made bystamping, engraving, scribing or anymethod approved in writing by theAssociate Administrator.

(1) A cylinder used as a fireextinguisher (§ 180.209(j)) may bemarked by using a pressure sensitivelabel.

(2) For a DOT 3HT cylinder, the testdate and RIN must be applied by low-stress steel stamps to a depth no greaterthan that prescribed at the time ofmanufacture. Stamping on the sidewallis not authorized.

(d) Requalification markings. (1) Eachcylinder that has successfully passedrequalification must be marked with theRIN set in a square pattern, between themonth and year of the requalificationdate. The first character of the RIN must


appear in the upper left corner of thesquare pattern; the second in the upperright; the third in the lower right, andthe fourth in the lower left. Example: Acylinder requalified in September 1998,and approved by a person who has beenissued RIN ‘‘A123’’, would be markedplainly and permanently into the metalof the cylinder in accordance withlocation requirements of the cylinderspecification or on a metal platepermanently secured to the cylinder inaccordance with paragraph (b) of thissection:

(2) Upon a written request, variationfrom the marking requirement may beapproved by the AssociateAdministrator.

(3) Exception. A cylinder subject tothe requirements of § 173.301(l) of thissubchapter may not be marked with aRIN.

(e) Size of markings. The size of themarkings must be at least 6.35 mm (1⁄4in.) high, except that RIN charactersmust be at least 3.18 mm (1⁄8 in.) high.

(f) Illustrations of the requiredmarking information for metric-markedcylinders and exemption cylinders afterrequalification are as follows:

(1) Ultrasonic examination:

(2) Volumetric expansion test:

(g) Illustrations of the requiredmarking information for nonmetric-marked cylinders and exemptioncylinders after requalification are asfollows:

(1) 5-year volumetric expansion test;10-year volumetric expansion test(cylinders conforming to § 180.209(f)and (h)); or 12-year volumetricexpansion test(fire extinguishersconforming to § 173.309(b) of thissubchapter and cylinders conforming to§ 180.209(e)and § 180.209(g)):

(2) 10-year volumetric expansiontest(cylinders conforming to§ 180.209(b)):

(3) Special filling limits up to 10% inexcess of the marked service pressure(cylinders conforming to § 173.302a(b)of this subchapter):

(4) Proof pressure test (fireextinguishers conforming to§ 173.309(b) of this subchapter andcylinders conforming to § 180.209(e)):

(5) 5-year external visual inspection(cylinders conforming to § 180.209(g)):

(6) Requalification after a repairprocedure and volumetrically tested(cylinders conforming to § 180.211):

(7) Requalification after a repairprocedure and proof pressure tested(cylinders conforming to § 180.211):

(8) Requalification after a rebuildingprocedure:

(9) DOT 8 series cylinder shellreinspection only:

(10) DOT 8 series cylinder shell andporous filler reinspection:

§ 180.215 Reporting and record retentionrequirements.

(a) Facility records. A person whorequalifies, repairs or rebuilds cylindersshall maintain the following recordswhere the requalification is performed:

(1) Current RIN issuance letter;(2) If the RIN has expired and renewal

is pending, a copy of the renewalrequest;

(3) Copies of notifications to AssociateAdministrator required under § 107.805of this subchapter;

(4) Current copies of those portions ofthis subchapter that apply to its cylinderrequalification and marking activities atthat location;

(5) Current copies of all exemptionsgoverning exemption cylindersrequalified or marked by the requalifierat that location; and

(6) The information contained in eachapplicable CGA or ASTM standardincorporated by reference in § 171.7 ofthis subchapter that applies to therequalifier’s activities. This informationmust be the same as contained in theedition incorporated by reference in§ 171.7 of this subchapter.

(b) Requalification records. Dailyrecords of visual inspection, pressuretest, and ultrasonic examination, asapplicable, must be maintained by theperson who performs the requalificationuntil either the expiration of therequalification period or until thecylinder is again requalified, whicheveroccurs first. A single date may be usedfor each test sheet, provided each test onthe sheet was conducted on that date.Ditto marks or a solid vertical line maybe used to indicate repetition of thepreceding entry for the followingentries: date; actual dimensions; ifpresent, manufacturer’s name orsymbol; if present, owner’s name orsymbol and test operator. Blank spacesmay not be used to indicate repetitionof a prior entry. The records mustinclude the following information:

(1) Pressure test records. For each testto demonstrate calibration, the date;serial number of the calibrated cylinder;calibration test pressure; total, elasticand permanent expansions; and legibleidentification of test operator. The testoperator must be able to demonstratethat the results of the daily calibrationverification correspond to thehydrostatic tests that were performed onthat day. The daily verification ofcalibration(s) may be recorded on thesame sheets as, and with, test recordsfor that date.

(2) Pressure test and visual inspectionrecords. The date of requalification;serial number; DOT specification orexemption number; marked pressure;actual dimensions; if present,


manufacturer’s name or symbol; ifpresent, owner’s name or symbol; resultof visual inspection; actual testpressure; total, elastic and permanentexpansions; percent permanentexpansion; disposition, with reason forany repeated test, rejection orcondemnation; and legibleidentification of test operator. For eachcylinder marked pursuant to§ 173.302a(b)(5) of this subchapter, thetest sheet must indicate the method bywhich any average or maximum wallstress was computed. Records must bekept for all completed, as well asunsuccessful tests. The entry for asecond test under CGA Pamphlet C–1after a failure to hold test pressure, must

indicate the date of the earlierinspection or test.

(3) Wall stress. Calculations of averageand maximum wall stress pursuant to§ 173.302a(b)(3) of this subchapter, ifperformed;

(4) Calibration certificates. The mostrecent certificate of calibration must bemaintained for each calibrated cylinder.

(5) Ultrasonic examination records.The information prescribed in ASTM E797 or ASTM E 213 as applicable.

(c) Repair, rebuilding or reheattreatment records. (1) Records coveringwelding or brazing repairs, rebuilding orreheat treating shall be retained for aminimum of fifteen years by theapproved facility.

(2) A record for rebuilding, inaccordance with § 180.211(d), must becompleted for each cylinder rebuilt. Therecord must be clear, legible, andcontain the following information:

Cylinder Identification

Original Manufacturer llllllllllCylinder Specification Number and ServicePressure llllllllllllllllCylinder Serial Number lllllllllDate at Original Manufacturer lllllllOther Identification Marks llllllll

Chemical Analysis of Replacement Parts

Parts Being Replaced lllllllllllHeat Identification llllllllllllSteel Manufactured by llllllllllAnalysis Performed by llllllllll

C P S Si Mn Ni Cr Mo Cu Al Zn

Record of Physical Test of Replacement Parts

Yield PSI Tensile PSI Elongation in inches Reduction in area % Weld bend Weld tensile

Record of Volumetric Expansion Test

Calculated volumetric capacity of the cylinder being rebuilt-llllllll lbs.

Actual testpressure Total expansion Permanent

expansionPercent of total to

permanentVolumetriccapacity

(Permanent expansion may not exceed 10%of the total expansion) (Volumetric capacityof a rebuilt cylinder must be within plus orminus 3% at the calculated capacity)

I certify that this rebuilt cylinder isaccurately represented by the data above and

complies with all of the requirements inSubchapter C of 49 CFR.Repair Technician llllllllllllDate llllllllllllllllllCompany Representative lllllllllDate llllllllllllllllll

Issued in Washington D.C. on October 15,1998, under authority delegated in 49 CFRPart 106, Appendix A.Alan I. Roberts,Associate Administrator for HazardousMaterials Safety.[FR Doc. 98–28118 Filed 10–26–98; 10:46am]BILLING CODE 4910–60–P

Documents

49 CFR Part 107