pt. 178, app. c 49 cfr ch. i (10–1–98 edition)

900

49 CFR Ch. I (10–1–98 Edition)Pt. 178, App. C

mass spectrograph. The test must be con-ducted for a period of time sufficient to evac-uate the chamber and to determine if thereis leakage into or out of the packaging. If he-lium gas is detected, the leaking packagingmust be automatically separated from non-leaking drums and the leaking area deter-mined according to the method prescribed in§ 178.604(d) of this subchapter. A packagingpasses the test if there is no leakage of he-lium.

(2) Pressure differential test. The packagingshall be restrained while either pressure or avacuum is applied internally. The packagingmust be pressurized to the pressure requiredby § 178.604(e) of this subchapter for the ap-propriate packing group. The method of re-straint must not affect the results of thetest. The test must be conducted for a periodof time sufficient to appropriately pressurizeor evacuate the interior of the packagingand to determine if there is leakage into orout of the packaging. A packaging passes thepressure differential test if there is nochange in measured internal pressure.

(3) Solution over seams. The packaging mustbe restrained while an internal air pressureis applied; the method of restraint may notaffect the results of the test. The exteriorsurface of all seams and welds must be coat-ed with a solution of soap suds or a waterand oil mixture. The test must be conductedfor a period of time sufficient to pressurizethe interior of the packaging to the specifiedair pressure and to determine if there isleakage of air from the packaging. A packag-ing passes the test if there is no leakage ofair from the packaging.

(4) Solution over partial seams test. For otherthan design qualification testing, the follow-ing test may be used for metal drums: Thepackaging must be restrained while an inter-nal air pressure of 48 kPa (7.0 psig) is applied;the method of restraint may not affect theresults of the test. The packaging must becoated with a soap solution over the entireside seam and a distance of not less thaneight inches on each side of the side seamalong the chime seam(s). The test must beconducted for a period of time sufficient topressurize the interior of the packaging tothe specified air pressure and to determine ifthere is leakage of air from the packaging. Apackaging passes the test if there is no leak-age of air from the packaging. Chime cutsmust be made on the initial drum at the be-ginning of each production run and on theinitial drum after any adjustment to thechime seamer. Chime cuts must be main-tained on file in date order for not less thansix months and be made available to a rep-resentative of the Department of Transpor-tation on request.

[Amdt. 178–97, 55 FR 52728, Dec. 21, 1990, asamended at 56 FR 66287, Dec. 20, 1991; 57 FR45466, Oct. 1, 1992]

APPENDIX C TO PART 178—NOMINAL ANDMINIMUM THICKNESSES OF STEELDRUMS AND JERRICANS

For each listed packaging capacity, thefollowing table compares the ISO Standard3574 nominal thickness with the correspond-ing ISO Standard 3574 minimum thickness.

Maximum capacity (L) ISO nomi-nal (mm)

Cor-respondingISO mini-

mum (mm)

20 ................................................... 0.7 0.6330 ................................................... 0.8 0.7340 ................................................... 0.8 0.7360 ................................................... 1.0 0.92120 ................................................. 1.0 0.92220 ................................................. 1.0 0.92450 ................................................. 1.9 1.77

[Amdt. 178–106, 59 FR 67522, Dec. 29, 1994]

PART 179—SPECIFICATIONS FORTANK CARS

Subpart A—Introduction, Approvals andReports

Sec.179.1 General.179.2 Definitions and abbreviations.179.3 Procedure for securing approval.179.4 Changes in specifications for tank

cars.179.5 Certificate of construction.179.6 Repairs and alterations.179.7 Quality assurance program.

Subpart B—General Design Requirements

179.10 Tank mounting.179.11 Welding certification.179.12 Interior heater systems.179.13 Tank car capacity and gross weight

limitation.179.14 Coupler vertical restraint system.179.15 Pressure relief devices.179.16 Tank-head puncture-resistance sys-

tems.179.18 Thermal protection systems.179.20 Service equipment; protection sys-

tems.179.22 Marking.

Subpart C—Specifications for PressureTank Car Tanks (Classes DOT–105, 109,112, 114, and 120)

179.100 General specification applicable topressure tank car tanks.

179.100–1 Tanks built under these specifica-tions shall comply with the requirementsof §§ 179.100, 179.101 and when applicable,§§ 179.102, 179.103, and 179.104.

179.100–3 Type.179.100–4 Insulation.

VerDate 14<DEC>98 09:51 Dec 30, 1998 Jkt 179200 PO 00000 Frm 00894 Fmt 8010 Sfmt 8010 Y:\SGML\179200T.XXX pfrm03 PsN: 179200T

901

Research and Special Programs Administration, DOT Pt. 179

179.100–6 Thickness of plates.179.100–7 Materials.179.100–8 Tank heads.179.100–9 Welding.179.100–10 Postweld heat treatment.179.100–12 Manway nozzle, cover and protec-

tive housing.179.100–13 Venting, loading and unloading

valves, measuring and sampling devices.179.100–14 Bottom outlets.179.100–16 Attachments.179.100–17 Closures for openings.179.100–18 Tests of tanks.179.100–19 Tests of safety relief valves.179.100–20 Stamping.179.101 Individual specification require-

ments applicable to pressure tank cartanks.

179.101–1 Individual specification require-ments.

179.102 Special commodity requirements forpressure tank car tanks.

179.102–1 Carbon dioxide, refrigerated liquid.179.102–2 Chlorine.179.102–4 Vinyl fluoride, inhibited.179.102–17 Hydrogen chloride, refrigerated

liquid.179.103 Special requirements for class 114A

* * * tank car tanks.179.103–1 Type.179.103–2 Manway cover.179.103–3 Venting, loading and unloading

valves, measuring and sampling devices.179.103–4 Safety relief devices and pressure

regulators.179.103–5 Bottom outlets.

Subpart D—Specifications for NonpressureTank Car Tanks (Classes DOT–103, 104,111AF, 111AW, and 115AW)

179.200 General specifications applicable tonon-pressure tank car tanks (ClassesDOT–103, 104, and 111).

179.200–1 Tank built under these specifica-tions must meet the requirements of§§ 179.200, 179.201 and when applicable§ 179.202.

179.200–3 Type.179.200–4 Insulation.179.200–6 Thickness of plates.179.200–7 Materials.179.200–8 Tank heads.179.200–9 Compartment tanks.179.200–10 Welding.179.200–11 Postweld heat treatment.179.200–13 Manway ring or flange, safety re-

lief device flange, bottom outlet nozzleflange, bottom washout nozzle flange andother attachments and openings.

179.200–14 Expansion capacity.179.200–15 Closures for manways.179.200–16 Gauging devices, top loading and

unloading devices, venting and air inletdevices.

179.200–17 Bottom outlets.

179.200–19 Reinforcements, when used, andappurtenances not otherwise specified.

179.200–21 Closures for openings.179.200–22 Test of tanks.179.200–23 Tests of safety relief valves.179.200–24 Stamping.179.201 Individual specification require-

ments applicable to non-pressure tankcar tanks.


179.201–2 Minimum plate thickness.179.201–3 Lined tanks.179.201–4 Material.179.201–5 Postweld heat treatment and cor-

rosion resistance.179.201–6 Manways and manway closures.179.201–8 Sampling device and thermometer

well.179.201–9 Gauging device.179.201–10 Water capacity marking.179.201–11 Insulation.179.202—179.202–22 [Reserved]179.220 General specifications applicable to

nonpressure tank car tanks consisting ofan inner container supported within anouter shell (class DOT–115).

179.220–1 Tanks built under these specifica-tions must meet the requirements of§§ 179.220, 179.221, and 179.222.

179.220–3 Type.179.220–4 Insulation.179.220–6 Thickness of plates.179.220–7 Materials.179.220–8 Tank heads.179.220–9 Compartment tanks.179.220–10 Welding.179.220–11 Postweld heat treatment.179.220–13 Inner container manway nozzle

and cover.179.220–14 Openings in the tanks.179.220–15 Support system for inner con-

tainer.179.220–16 Expansion capacity.179.220–17 Gauging devices, top loading and

unloading devices, venting and air inletdevices.

179.220–18 Bottom outlets.179.220–20 Reinforcements, when used, and

appurtenances not otherwise specified.179.220–22 Closure for openings.179.220–23 Test of tanks.179.220–24 Tests of safety relief valves.179.220–25 Stamping.179.220–26 Stenciling.179.221 Individual specification require-

ments applicable to tank car tanks con-sisting of an inner container supportedwithin an outer shell.



902

49 CFR Ch. I (10–1–98 Edition)§ 179.1

Subpart E—Specifications for Multi-UnitTank Car Tanks (Classes DOT–106Aand 110AW)

179.300 General specifications applicable tomulti-unit tank car tanks designed to beremoved from car structure for fillingand emptying (Classes DOT–106A and110AW).

179.300–1 Tanks built under these specifica-tions shall meet the requirements of§ 179.300, § 179.301 and when applicable,§ 179.302.

179.300–3 Type and general requirements.179.300–4 Insulation.179.300–6 Thickness of plates.179.300–7 Materials.179.300–8 Tank heads.179.300–9 Welding.179.300–10 Postweld heat treatment.179.300–12 Protection of fittings.179.300–13 Venting, loading and unloading

valves.179.300–14 Attachments not otherwise speci-

fied.179.300–15 Safety relief devices.179.300–16 Tests of tanks.179.300–17 Tests of safety relief devices.179.300–18 Stamping.179.300–19 Inspection.179.300–20 Reports.179.301 Individual specification require-

ments for multi-unit tank car tanks.179.302 [Reserved]

Subpart F—Specification for Cryogenic Liq-uid Tank Car Tanks and Seamless SteelTanks (Classes DOT–113 and 107A)

179.400 General specification applicable tocryogenic liquid tank car tanks.

179.400–1 General.179.400–3 Type.179.400–4 Insulation system and perform-

ance standard.179.400–5 Materials.179.400–6 Bursting and buckling pressure.179.400–7 Tank heads.179.400–8 Thickness of plates.179.400–9 Stiffening rings.179.400–10 Sump or siphon bowl.179.400–11 Welding.179.400–12 Postweld heat treatment.179.400–13 Support system for inner tank.179.400–14 Cleaning of inner tank.179.400–15 Radioscopy.179.400–16 Access to inner tank.179.400–17 Inner tank piping.179.400–18 Test of inner tank.179.400–19 Valves and gages.179.400–20 Pressure relief devices.179.400–21 Test of pressure relief valves.179.400–22 Protective housings.179.400–23 Operating instructions.179.400–24 Stamping.179.400–25 Stenciling.

179.401 Individual specification require-ments applicable to inner tanks for cryo-genic liquid tank car tanks.


179.500 Specification DOT–107A * * * *,seamless steel tank car tanks.

179.500–1 Tanks built under these specifica-tions shall meet the requirements of§ 179.500.

179.500–3 Type and general requirements.179.500–4 Thickness of wall.179.500–5 Material.179.500–6 Heat treatment.179.500–7 Physical tests.179.500–8 Openings in tanks.179.500–10 Protective housing.179.500–11 Loading and unloading valves.179.500–12 Safety relief devices.179.500–13 Fixtures.179.500–14 Test of tanks.179.500–15 Handling of tanks failing in tests.179.500–16 Tests of safety relief devices.179.500–17 Marking.179.500–18 Inspection and reports.

APPENDIX A TO PART 179—PROCEDURES FORTANK-HEAD PUNCTURE-RESISTANCE TEST

APPENDIX B TO PART 179—PROCEDURES FORSIMULATED POOL AND TORCH-FIRE TEST-ING

AUTHORITY: 49 U.S.C. 5101–5127; 49 CFR part1.53.

SOURCE: 29 FR 18995, Dec. 29, 1964, unlessotherwise noted. Redesignated at 32 FR 5606,Apr. 5, 1967.

Subpart A—Introduction,Approvals and Reports

§ 179.1 General.

(a) This part prescribes the specifica-tions for tanks that are to be mountedon or form part of a tank car and whichare used for the transportation of haz-ardous materials in commerce.

(b) Except as provided in paragraph(c) of this section, tanks to which thispart is applicable, must be built to thespecifications prescribed in this part.

(c) Tanks built to specifications pre-dating those in this part may continuein use as provided in § 180.507 of thissubchapter.

(d) Any person who performs a func-tion prescribed in this part, shall per-form that function in accordance withthis part.

(e) When this part requires a tank tobe marked with a DOT specification


903

Research and Special Programs Administration, DOT § 179.4

(for example, DOT–105A100W), compli-ance with that requirement is the re-sponsibility of the tank builder. Mark-ing the tank with the DOT specifica-tion shall be understood to certifycompliance by the builder that thefunctions performed by the builder, asprescribed in this part, have been per-formed in compliance with this part.

(f) The tank builder should informeach person to whom that tank istransferred of any specification re-quirements which have not been met attime of transfer.

[Amdt. 179–17, 41 FR 38183, Sept. 9, 1976, asamended by Amdt. 179–50, 60 FR 49076, Sept.21, 1995]

§ 179.2 Definitions and abbreviations.(a) The following apply in part 179:(1) AAR means Association of Amer-

ican Railroads.(2) Approved means approval by the

AAR Tank Car Committee.(3) ASTM means American Society

for Testing and Materials.(4) DOT and Department means De-

partment of Transportation.(5) Definitions in part 173 of this

chapter also apply.(6) F means degrees Fahrenheit.(7) NGT means National Gas Taper

Threads.(8) NPT means American Standard

Tape Pipe Thread.(9) Psi means pounds per square inch

gauge.(10) Tank car facility means an entity

that manufactures, repairs, inspects,tests, qualifies, or maintains a tankcar to ensure that the tank car con-forms to this part and subpart F of part180 of this subchapter, that alters thecertificate of construction of the tankcar, that ensures the continuing quali-fication of a tank car by performing afunction prescribed in parts 179 or 180of this subchapter, or that makes anyrepresentation indicating compliancewith one or more of the requirementsof parts 179 or 180 of this subchapter.

(11) Tanks means tank car tanks.(b) [Reserved]

[29 FR 18995, Dec. 20, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21344, Nov. 6, 1971; Amdt. 179–50,60 FR 49076, Sept. 21, 1995; Amdt. 179–50, 61FR 33255, June 26, 1996; 63 FR 52850, Oct. 1,1998]

§ 179.3 Procedure for securing ap-proval.

(a) Application for approval of de-signs, materials and construction, con-version or alteration of tank car tanksunder these specifications, completewith detailed prints, must be submit-ted in prescribed form to the ExecutiveDirector—Tank Car Safety, AAR, forconsideration by its Tank Car Commit-tee and other appropriate committees.Approval or rejections of applicationsbased on appropriate committee actionwill be issued by the executive direc-tor.

(b) When, in the opinion of the Com-mittee, such tanks or equipment there-for are in compliance with effectiveregulations and specifications of theDepartment, the application will be ap-proved.

(c) When, in the opinion of the Com-mittee, such tanks or equipment there-for are not in compliance with effectiveregulations and specifications of theDepartment, the Committee may rec-ommend service trials to determine themerits of a change in specifications.Such service trials may be authorizedby the Department under the terms ofexemptions.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967 and amended by Amdt.179–41, 52 FR 36672, Sept. 30, 1987; 63 FR 52850,Oct. 1, 1998]

§ 179.4 Changes in specifications fortank cars.

(a) Proposed changes in or additionsto specifications for tanks must be sub-mitted to the Executive Director—Tank Car Safety, AAR, for consider-ation by its Tank Car Committee. Anapplication for construction of tanksto any new specification may be sub-mitted with proposed specification.Construction should not be starteduntil the specification has been ap-proved or an exemption has beenissued. When proposing a new specifica-tion, the applicant shall furnish infor-mation to justify a new specification.This data should include the propertiesof the lading and the method of loadingand unloading.

(b) The Tank Car Committee will re-view the proposed specifications at itsearliest convenience and report its rec-ommendations through the Executive


904

49 CFR Ch. I (10–1–98 Edition)§ 179.5

Director—Tank Car Safety to the De-partment. The recommendation will beconsidered by the Department in deter-mining appropriate action.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967 and amended by Amdt.179–41, 52 FR 36672, Sept. 30, 1987; 63 FR 52850,Oct. 1, 1998]

§ 179.5 Certificate of construction.(a) Before a tank car is placed in

service, the party assembling the com-pleted car shall furnish a Certificate ofConstruction, Form AAR 4–2 to theowner, the Department, and the Execu-tive Director—Tank Car Safety, AAR,certifying that the tank, equipment,and car fully conforms to all require-ments of the specification.

(b) When cars or tanks are covered inone application and are identical in alldetails are built in series, one certifi-cate will suffice for each series whensubmitted to the Executive Director—Tank Car Safety, AAR. One copy of theCertificate of Construction must befurnished to the Department for eachcar number of consecutively numberedgroup or groups covered by the originalapplication.

(c) If the owner elects to furnish theappurtenances such as valves and safe-ty devices, the owner shall furnish tothe Bureau of Explosives, and to theSecretary, Mechanical Division, AAR,a report in prescribed form, certifyingthat the appurtenances comply with allthe requirements of the specifications.

(d) When cars or tanks which are cov-ered on one application and are iden-tical in all details are built in series,one certificate shall suffice for each se-ries when submitted to the Secretary.One copy of the Certificate of Con-struction must be furnished to the Bu-reau of Explosives for each car numberof consecutively numbered group orgroups covered by the original applica-tion.

[Amdt. 179–10, 36 FR 21344, Nov. 6, 1971, asamended at 63 FR 52850, Oct. 1, 1998]

§ 179.6 Repairs and alterations.For procedure to be followed in mak-

ing repairs or alterations, see appendixR of the AAR Specifications for TankCars.

[Amdt. 179–10, 36 FR 21344, Nov. 6, 1971]

§ 179.7 Quality assurance program.(a) At a minimum, each tank car fa-

cility shall have a quality assuranceprogram, approved by AAR, that—

(1) Ensures the finished product con-forms to the requirements of the appli-cable specification and regulations ofthis subchapter;

(2) Has the means to detect any non-conformity in the manufacturing, re-pair, inspection, testing, and qualifica-tion or maintenance program of thetank car; and

(3) Prevents non-conformities fromrecurring.

(b) At a minimum, the quality assur-ance program must have the followingelements

(1) Statement of authority and re-sponsibility for those persons in chargeof the quality assurance program.

(2) An organizational chart showingthe interrelationship between man-agers, engineers, purchasing, construc-tion, inspection, testing, and qualitycontrol personnel.

(3) Procedures to ensure that the lat-est applicable drawings, design calcula-tions, specifications, and instructionsare used in manufacture, inspection,testing, and repair.

(4) Procedures to ensure that the fab-rication and construction materials re-ceived are properly identified and docu-mented.

(5) A description of the manufactur-ing, repair, inspection, testing, andqualification or maintenance program,including the acceptance criteria, sothat an inspector can identify the char-acteristics of the tank car and the ele-ments to inspect, examine, and test ateach point.

(6) Monitoring and control of proc-esses and product characteristics dur-ing production.

(7) Procedures for correction ofnonconformities.

(8) Provisions indicating that the re-quirements of the AAR Specificationsfor Tank Cars, Specification M–1002,apply.

(9) Qualification requirements of per-sonnel performing non-destructive in-spections and tests.

(10) Procedures for evaluating the in-spection and test technique employed,including the accessibility of the areaand the sensitivity and reliability of


905


the inspection and test technique andminimum detectable crack length.

(11) Procedures for the periodic cali-bration and measurement of inspectionand test equipment.

(12) A system for the maintenance ofrecords, inspections, tests, and the in-terpretation of inspection and test re-sults.

(c) Each tank car facility shall en-sure that only personnel qualified foreach non-destructive inspection andtest perform that particular operation.

(d) Each tank car facility shall pro-vide written procedures to its employ-ees to ensure that the work on thetank car conforms to the specification,AAR approval, and owner’s acceptancecriteria.

(e) Each tank car facility shall trainits employees in accordance with sub-part H of part 172 of this subchapter onthe program and procedures specifiedin paragraph (b) of this section to en-sure quality.

(f) Date of conformance. After July 1,1998, no tank car facility may manufac-ture, repair, inspect, test, qualify ormaintain tank cars subject to require-ments of this subchapter, unless it isoperating in conformance with a qual-ity assurance program and written pro-cedures required by paragraphs (a) and(b) of this section.

[Amdt. 179–50, 60 FR 49076, Sept. 21, 1995, asamended by Amdt. 179–50, 61 FR 33255, June26, 1996]

Subpart B—General DesignRequirements

§ 179.10 Tank mounting.

(a) The manner in which tanks areattached to the car structure shall beapproved. The use of rivets to secureanchors to tanks prohibited.

(b) [Reserved]

§ 179.11 Welding certification.

(a) Welding procedures, welders andfabricators shall be approved.

(b) [Reserved]

§ 179.12 Interior heater systems.

(a) Interior heater systems shall be ofapproved design and materials. If atank is divided into compartments, a

separate system shall be provided foreach compartment.

(b) Each interior heater system shallbe hydrostatically tested at not lessthan 13.79 bar (200 psi) and shall holdthe pressure for 10 minutes withoutleakage or evidence of distress.

[Amdt. 179–52, 61 FR 28678, June 5, 1996]

§ 179.13 Tank car capacity and grossweight limitation.

Tank cars built after November 30,1970, must not exceed 34,500 gallons ca-pacity or 263,000 pounds gross weighton rail. Existing tank cars may not beconverted to exceed 34,500 gallons ca-pacity or 263,000 pounds gross weighton rail.

[Amdt. 179–4, 35 FR 14217, Sept. 9, 1970]

§ 179.14 Coupler vertical restraint sys-tem.

(a) Performance standard. Each tankcar shall be equipped with couplers ca-pable of sustaining, without disengage-ment or material failure, vertical loadsof at least 200,000 pounds (90,718.5 kg)applied in upward and downward direc-tions in combination with buff loads of2,000 pounds (907.2 kg), when coupled tocars which may or may not be equippedwith couplers having this vertical re-straint capability.

(b) Test verification. Except as pro-vided in paragraph (d) of this section,compliance with the requirements ofparagraph (a) of this section shall beachieved by verification testing of thecoupler vertical restraint system in ac-cordance with paragraph (c) of this sec-tion.

(c) Coupler vertical restraint tests. Acoupler vertical restraint system shallbe tested under the following condi-tions:

(1) The test coupler shall be testedwith a mating coupler (or simulatedcoupler) having only frictional verticalforce resistance at the mating inter-face; or a mating coupler (or simulatedcoupler) having the capabilities de-scribed in paragraph (a) of this section;

(2) The testing apparatus shall simu-late the vertical coupler performanceat the mating interface and may notinterfere with coupler failure or other-wise inhibit failure due to force appli-cations and reactions; and


906

49 CFR Ch. I (10–1–98 Edition)§ 179.15

(3) The test shall be conducted as fol-lows:

(i) A minimum of 200,000 pounds(90,718.5 kg) vertical downward loadshall be applied continuously for atleast 5 minutes to the test coupler headsimultaneously with the application ofa nominal 2,000 pounds (907.2 kg) buffload;

(ii) The procedures prescribed inparagraph (c)(3)(i) of this section, shallbe repeated with a minimum verticalupward load of 200,000 pounds (90,718.5kg); and

(iii) A minimum of three consecutivesuccessful tests shall be performed foreach load combination prescribed inparagraphs (c)(3) (i) and (ii) of this sec-tion. A test is successful when a verti-cal disengagement or material failuredoes not occur during the applicationof any of the loads prescribed in thisparagraph.

(d) Authorized couplers. As an alter-native to the test verifications in para-graph (c) of this section, the followingcouplers are authorized:

(1) E double shelf couplers designatedby the Association of American Rail-roads’ Catalog Nos., SE60CHT, SE60CC,SE60CHTE, SE60CE, SE60DC, SE60DE,SE67CC, SE67CE, SE67BHT, SE67BC,SE67BHTE, SE67BE, SE68BHT, SE68BC,SE68BHTE, SE68BE, SE69AHTE, andSE69AE.

(2) F double shelf couplers designatedby the Association of American Rail-roads’ Catalog Nos., SF70CHT, SF70CC,SF70CHTE, SF70CE, SF73AC, SF73AE,SF73AHT, SF73AHTE, SF79CHT,SF79CC, SF79CHTE, and SF79CE.

[Amdt. 179–42, 54 FR 38797, Sept. 20, 1989]

§ 179.15 Pressure relief devices.Except for DOT Class 106, 107, 110, and

113 tank cars, tanks must have a pres-sure relief device, made of materialcompatible with the lading, that con-forms to the following requirements:

(a) Performance standard. Each tankmust have a pressure relief device,made of material compatible with thelading having sufficient flow capacityto prevent pressure build-up in thetank to no more than the flow ratingpressure of the pressure relief device infire conditions as defined in AppendixA of the Association of American Rail-roads Specifications for Tank Cars.

(b) Settings for reclosing pressure reliefdevices. (1) Except as provided in para-graph (b)(2) of this section, a reclosingpressure relief valve must have a mini-mum start-to-discharge pressure equalto the sum of the static head and gaspadding pressure and the lading vaporpressure at the following referencetemperatures:

(i) 46 °C (115 °F) for noninsulatedtanks;

(ii) 43 °C (110 °F) for tanks having athermal protection system incorporat-ing a metal jacket that provides anoverall thermal conductance at 15.5 °C(60 °F) of no more than 10.22 kilojoulesper hour per square meter per degreeCelsius (0.5 Btu per hour/per squarefoot/per degree F) temperature dif-ferential; and

(iii) 41 °C (105 °F) for insulated tanks.(2)(i) The start-to-discharge pressure

of a pressure relief device may not belower than 5.17 Bar (75 psig) or exceed33 percent of the minimum tank burstpressure.

(ii) Tanks built prior to October 1,1997 having a minimum tank burstpressure of 34.47 Bar (500 psig) or lessmay be equipped with a reclosing pres-sure relief valve having a start-to-dis-charge pressure of not less than 14.5percent of the minimum tank burstpressure but no more than 33 percent ofthe minimum tank burst pressure.

(3) The vapor tight pressure of a re-closing pressure relief valve must be atleast 80 percent of the start-to-dis-charge pressure.

(4) The flow rating pressure must be110 percent of the start-to-dischargepressure for tanks having a minimumtank burst pressure greater than 34.47Bar (500 psig) and from 110 percent to130 percent for tanks having a mini-mum tank burst pressure less than orequal to 34.47 Bar (500 psig).

(5) The tolerance for a reclosing pres-sure relief valve is ±3 psi for valveswith a start-to-discharge pressure of6.89 Bar (100 psig) or less and ±3 percentfor valves with a start-to-dischargepressure greater than 6.89 Bar (100psig).

(c) Flow capacity of pressure relief de-vices. The total flow capacity of eachreclosing and nonreclosing pressure re-lief device must conform to Appendix A


907


of the Association of American Rail-roads Specifications for Tank Cars.

(d) Flow capacity tests. The manufac-turer of any reclosing or nonreclosingpressure relief device must design andtest the device in accordance with Ap-pendix A of the Association of Amer-ican Railroads Specifications for TankCars.

(e) Combination pressure relief systems.A nonreclosing pressure relief devicemay be used in series with a reclosingpressure relief valve. The pressure re-lief valve must be located outboard ofthe nonreclosing pressure relief device.

(1) When a breaking pin device isused in combination with a reclosingpressure relief valve, the breaking pinmust be designed to fail at the start-to-discharge pressure specified in para-graph (b) of this section, and the re-closing pressure relief valve must bedesigned to discharge at not greaterthan 95 percent of the start-to-dis-charge pressure.

(2) When a rupture disc is used incombination with a reclosing pressurerelief valve, the rupture disc must bedesigned to burst at the start-to-dis-charge pressure specified in paragraph(b) of this section, and the reclosingpressure relief valve must be designedto discharge at not greater than 95 per-cent of the start-to-discharge pressure.A device must be installed to detectany accumulation of pressure betweenthe rupture disc and the reclosing pres-sure relief valve. The detection devicemust be a needle valve, trycock, ortell-tale indicator. The detection de-vice must be closed during transpor-tation.

(3) The vapor tight pressure and thestart-to-discharge tolerance is based onthe discharge setting of the reclosingpressure relief device.

(f) Nonreclosing pressure relief device.In addition to paragraphs (a), (b)(4), (c),and (d) of this section, a nonreclosingpressure relief device must conform tothe following requirements:

(1) Until October 1, 1998, anonreclosing pressure relief devicemust incorporate a rupture disc de-signed to burst at a pressure equal to100% of the tank test pressure, or 33%of the tank burst pressure. After thatdate, a nonreclosing pressure relief de-vice must incorporate a rupture disc

designed to burst at a pressure equal tothe greater of 100% of the tank pres-sure, or 33% of the tank burst pressure.

(2) The approach channel and the dis-charge channel may not reduce the re-quired minimum flow capacity of thepressure relief device.

(3) The nonreclosing pressure reliefdevice must be designed to preventinterchange with other fittings in-stalled on the tank car, must have astructure that encloses and clamps therupture disc in position (preventingany distortion or damage to the rup-ture disc when properly applied), andmust have a cover, with suitable meansof preventing misplacement, designedto direct any discharge of the ladingdownward.

(4) The nonreclosing pressure reliefdevice must be closed with a rupturedisc that is compatible with the ladingand manufactured in accordance withAppendix A of the AAR Specificationsfor Tank Cars. The tolerance for a rup-ture disc is +0 to ¥15 percent of theburst pressure marked on the disc.

(g) Location of relief devices. Eachpressure relief device must commu-nicate with the vapor space above thelading as near as practicable on thelongitudinal center line and center ofthe tank.

(h) Marking of pressure relief devices.Each pressure relief device and rupturedisc must be permanently marked inaccordance with the Appendix A of theAssociation of American RailroadsSpecifications for Tank Cars.

[Amdt. 179–52, 61 FR 28678, June 5, 1996, asamended by Amdt. 179–52, 61 FR 50255, Sept.25, 1996; 62 FR 51561, Oct. 1, 1997]

§ 179.16 Tank-head puncture-resist-ance systems.

(a) Performance standard. When theregulations in this subchapter requirea tank-head puncture-resistance sys-tem, the system shall be capable of sus-taining, without any loss of lading,coupler-to-tank-head impacts at rel-ative car speeds of 29 km/hour (18 mph)when:

(1) The weight of the impact car is atleast 119,295 kg (263,000 pounds);

(2) The impacted tank car is coupledto one or more backup cars that have atotal weight of at least 217,724 kg


908

49 CFR Ch. I (10–1–98 Edition)§ 179.18

(480,000 pounds) and the hand brake isapplied on the last ‘‘backup’’ car; and

(3) The impacted tank car is pressur-ized to at least 6.9 Bar (100 psi).

(b) Verification by testing. Compliancewith the requirements of paragraph (a)of this section shall be verified by full-scale testing according to appendix Aof this part.

(c) Alternative compliance by otherthan testing. As an alternative to re-quirements prescribed in paragraph (b)of this section, compliance with the re-quirements of paragraph (a) of this sec-tion may be met by installing full-headprotection (shields) or full tank-headjackets on each end of the tank carconforming to the following:

(1) The full-head protection (shields)or full tank-head jackets must be atleast 1.27 cm (0.5 inch) thick, shaped tothe contour of the tank head and madefrom steel having a tensile strengthgreater than 379.21 N/mm2 (55,000 psi).

(2) The design and test requirementsof the full-head protection (shields) orfull tank-head jackets must meet theimpact test requirements of Section 5.3of the AAR Specifications for TankCars.

(3) The workmanship must meet therequirements of Section C, Part II,Chapter 5 of the AAR Specifications forDesign, Fabrication, and Constructionof Freight Cars.


§ 179.18 Thermal protection systems.(a) Performance standard. When the

regulations in this subchapter requirethermal protection on a tank car, thetank car must have sufficient thermalresistance so that there will be no re-lease of any lading within the tank car,except release through the pressure re-lease device, when subjected to:

(1) A pool fire for 100 minutes; and(2) A torch fire for 30 minutes.(b) Thermal analysis. (1) Compliance

with the requirements of paragraph (a)of this section shall be verified by ana-lyzing the fire effects on the entire sur-face of the tank car. The analysis mustconsider the fire effects on and heatflux through tank discontinuities, pro-tective housings, underframes, metaljackets, insulation, and thermal pro-

tection. A complete record of eachanalysis shall be made, retained, andupon request, made available for in-spection and copying by an authorizedrepresentative of the Department. Theprocedures outlined in ‘‘Temperatures,Pressures, and Liquid Levels of TankCars Engulfed in Fires,’’ DOT/FRA/OR&D–84/08.11, (1984), Federal RailroadAdministration, Washington, DC(available from the National TechnicalInformation Service, Springfield, VA)shall be deemed acceptable for analyz-ing the fire effects on the entire sur-face of the tank car.

(2) When the analysis shows the ther-mal resistance of the tank car does notconform to paragraph (a) of this sec-tion, the thermal resistance of thetank car must be increased by using asystem listed by the Department underparagraph (c) of this section or by test-ing a new or untried system and verify-ing it according to appendix B of thispart.

(c) Systems that no longer require testverification. The Department maintainsa list of thermal protection systemsthat comply with the requirements ofappendix B of this part and that nolonger require test verification. Infor-mation necessary to equip tank carswith one of these systems is availablein the Dockets Unit, Research and Spe-cial Programs Administration, 400 Sev-enth Street, SW., Washington, DC20590–0001.


§ 179.20 Service equipment; protectionsystems.

If an applicable tank car specifica-tion authorizes location of filling ordischarge connections in the bottomshell, the connections must be de-signed, constructed, and protected ac-cording to paragraphs E9.00 and E10.00of the AAR Specifications for TankCars, M–1002.

[Amdt. 179–50, 60 FR 49077, Sept. 21, 1995]

§ 179.22 Marking.

In addition to any other marking re-quirement in this subchapter, the fol-lowing marking requirements apply:


909

Research and Special Programs Administration, DOT § 179.100–6

(a) Each tank car must be marked ac-cording to the requirements in Appen-dix C of the AAR Specifications forTank Cars.

(b) Each tank car that requires atank-head puncture-resistance systemmust have the letter ‘‘S’’ substitutedfor the letter ‘‘A’’ in the specificationmarking.

(c) Each tank car that requires atank-head puncture-resistance system,a thermal protection system, and ametal jacket must have the letter ‘‘J’’substituted for the letter ‘‘A’’ or ‘‘S’’ inthe specification marking.

(d) Each tank car that requires atank-head puncture-resistance system,a thermal protection system, and nometal jacket must have the letter ‘‘T’’substituted for the letter ‘‘A’’ or ‘‘S’’ inthe specification marking.


Subpart C—Specifications forPressure Tank Car Tanks(Classes DOT–105, 109, 112,114 and 120)

§ 179.100 General specification appli-cable to pressure tank car tanks.

§ 179.100–1 Tanks built under thesespecifications shall comply with therequirements of §§ 179.100, 179.101and when applicable, §§ 179.102,179.103, and 179.104.

§ 179.100–3 Type.(a) Tanks built under this specifica-

tion shall be fusion-welded with headsdesigned convex outward. Except asprovided in § 179.103 or § 179.104 theyshall be circular in cross section, shallbe provided with a manway nozzle ontop of the tank of sufficient size to per-mit access to the interior, a manwaycover to provide for the mounting of allvalves, measuring and sampling de-vices, and a protective housing. Otheropenings in the tank are prohibited, ex-cept as provided in part 173 of thischapter, §§ 179.100–14, 179.101–1 (a) tableNote 10, 179.102 or § 179.103.

(b) [Reserved]

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21344, Nov. 6, 1971]

§ 179.100–4 Insulation.(a) If insulation is applied, the tank

shell and manway nozzle must be insu-lated with an approved material. Theentire insulation must be covered witha metal jacket of a thickness not lessthan 11 gauge (0.1196 inch) nominal(Manufacturers’ Standard Gauge) andflashed around all openings so as to beweather-tight. The exterior surface of acarbon steel tank, and the inside sur-face of a carbon steel jacket must begiven a protective coating.

(b) If insulation is a specification re-quirement, it shall be of sufficientthickness so that the thermal conduct-ance at 60 °F is not more than 0.075 Btuper hour, per square foot, per degree Ftemperature differential. If exteriorheaters are attached to tank, thethickness of the insulation over eachheater element may be reduced to one-half that required for the shell.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21344, Nov. 6, 1971; Amdt. 179–50,60 FR 49077, Sept. 21, 1995]

§ 179.100–6 Thickness of plates.(a) The wall thickness after forming

of the tank shell and heads must not beless than that specified in § 179.101, northat calculated by the following for-mula:

t = Pd / 2SE

where:d = Inside diameter in inches;E = 1.0 welded joint efficiency; except for

heads with seams=0.9;P = Minimum required bursting pressure in

p.s.i.;S = Minimum tensile strength of plate mate-

rial in p.s.i., as prescribed in § 179.100–7;t = Minimum thickness of plate in inches

after forming.

(b) If plates are clad with materialhaving tensile strength properties atleast equal to the base plate, the clad-ding may be considered a part of thebase plate when determining thickness.If cladding material does not have ten-sile strength at least equal to the baseplate, the base plate alone shall meetthe thickness requirement.

(c) When aluminum plate is used, theminimum width of bottom sheet oftank shall be 60 inches, measured onthe arc, but in all cases the width shall


910

49 CFR Ch. I (10–1–98 Edition)§ 179.100–7

be sufficient to bring the entire widthof the longitudinal welded joint, in-cluding welds, above the bolster.


§ 179.100–7 Materials.(a) Steel plate: Steel plate materials

used to fabricate tank shell andmanway nozzle must comply with oneof the following specifications with theindicated minimum tensile strengthand elongation in the welded condition.The maximum allowable carbon con-tent must be 0.31 percent when the in-dividual specification allows carbongreater than this amount. The platesmay be clad with other approved mate-rials.

Specifications

Minimum ten-sile strength

(p.s.i.) weldedcondition1

Minimum elon-gation in 2

inches (percent)welded condi-tion (longitu-

dinal)

AAR TC128, Gr. B ......... 81,000 19ASTM A 302, Gr. B ........ 80,000 20ASTM A 516 .................. 70,000 20ASTM A 537, Class 1 .... 70,000 23

1 Maximum stresses to be used in calculations.

(b) Aluminum alloy plate: Aluminumalloy plate material used to fabricatetank shell and manway nozzle must besuitable for fusion welding and mustcomply with one of the following speci-fications with its indicated minimumtensile strength and elongation in thewelded condition.

Specifications

Minimum ten-sile strength(p.s.i.) 0 tem-per, weldedcondition3 6


inches (per-cent) 0 tem-per, welded

condition (lon-gitudinal)

ASTM B 209, Alloy 50521 25,000 18ASTM B 209, Alloy 50832 38,000 16ASTM B 209, Alloy 50861 35,000 14ASTM B 209, Alloy 51541 30,000 18ASTM B 209, Alloy 52541 30,000 18ASTM B 209, Alloy 54541 31,000 18ASTM B 209, Alloy 56521 25,000 18

1 For fabrication, the parent plate material may be 0, H112,or H32 temper, but design calculations must be based onminimum tensile strength shown.

2 0 temper only.3 Weld filler metal 5556 must not be used.4 Maximum stress to be used in calculations.

(c) High alloy steel plate. (1) High alloysteel plate must conform to the follow-ing specifications:

Specifications


(p.s.i.) weldedcondition1


inches (percent)weld metal (lon-

gitudinal)

ASTM A240, Type 304L 70,000 30ASTM A240, Type 316L 70,000 30


(2)(i) High alloy steels used to fab-ricate tank must be tested in accord-ance with the following procedures inASTM Specification A262 titled,‘‘Standard Practices for Detecting Sus-ceptibility to Intergranular Attack inAustenitic Stainless Steel,’’ and mustexhibit corrosion rates not exceedingthe following:

Test procedures Material Corrosionrate i.p.m.

Practice B ............... Types 304L and 316L ... 0.0040Practice C ............... Type 304L ..................... 0.0020

(ii) Type 304L and 316L test speci-mens must be given a sensitizing treat-ment prior to testing.

(d) All attachments welded to tankshell must be of approved materialwhich is suitable for welding to thetank.

[Amdt. 179–10, 36 FR 21344, Nov. 6, 1971, asamended by Amdt. 179–32, 48 FR 27707, June16, 1983; Amdt. 179–47, 58 FR 50237, Sept. 24,1993; Amdt. 179–52, 61 FR 28679, June 5, 1996;Amdt 179–52, 61 FR 50255, Sept. 25, 1996]

§ 179.100–8 Tank heads.(a) The tank head shape shall be an

ellipsoid of revolution in which themajor axis shall equal the diameter ofthe shell adjacent to the head and theminor axis shall be one-half the majoraxis.

(b) Each tank head made from steelwhich is required to be ‘‘fine grain’’ bythe material specification, which is hotformed at a temperature exceeding 1700°F., must be normalized after formingby heating to a temperature between1550° and 1700 °F., by holding at thattemperature for at least 1 hour perinch of thickness (30-minute mini-mum), and then by cooling in air. If thematerial specification requires quench-ing and tempering, the treatment spec-ified in that specification must be usedinstead of the one specified above.

[29 FR 18995, Dec. 29, 1964. Redesignated, 32FR 5606, Apr. 5, 1967 and amended by Amdt.179–12, 39 FR 15038, Apr. 30, 1974]


911


§ 179.100–9 Welding.(a) All joints shall be fusion-welded

in compliance with the requirements ofAAR Specifications for Tank Cars, ap-pendix W. Welding procedures, weldersand fabricators shall be approved. Alsosee § 179.104.

(b) [Reserved]

§ 179.100–10 Postweld heat treatment.(a) After welding is complete, steel

tanks and all attachments weldedthereto must be postweld heat treatedas a unit in compliance with the re-quirements of AAR Specifications forTank Cars, appendix W.

(b) For aluminum tanks, postweldheat treatment is prohibited.

(c) Tank and welded attachments,fabricated from ASTM A 240 Type 304Lor Type 316L materials do not requirepostweld heat treatment, but these ma-terials do require a corrosion resist-ance test as specified in § 179.100–7(c)(2).

[Amdt. 179–10, 36 FR 21345, Nov. 6, 1971, asamended by Amdt. 179–47, 58 FR 50238, Sept.24, 1993; Amdt. 179–52, 61 FR 28679, June 5,1996]

§ 179.100–12 Manway nozzle, cover andprotective housing.

(a) Manway nozzles must be of ap-proved design of forged or rolled steelfor steel tanks or of fabricated alu-minum alloy for aluminum tanks, withaccess opening at least 18 inches insidediameter, or at least 14 inches by 18inches around or oval. Nozzle must bewelded to the tank and the opening re-inforced in an approved manner incompliance with the requirements ofAAR Specifications for Tank Cars, ap-pendix E, Figure E10.

(b) Manway cover shall be machinedto approved dimensions and be offorged or rolled carbon or alloy steel,rolled aluminum alloy or nickel whenrequired by the lading. Minimumthickness is listed in § 179.101. Manwaycover shall be attached to manway noz-zle by through or stud bolts not enter-ing tank, except as provided in§ 179.103–2(a).

(c) Except as provided in § 179.103,protective housing of cast, forged orfabricated approved materials must bebolted to manway cover with not lessthan twenty 3⁄4-inch studs. The shear-ing value of the bolts attaching protec-

tive housing to manway cover mustnot exceed 70 percent of the shearingvalue of bolts attaching manway coverto manway nozzle. Housing must havesteel sidewalls not less than three-fourths inch in thickness and must beequipped with a metal cover not lessthan one-fourth inch in thickness thatcan be securely closed. Housing covermust have suitable stop to preventcover striking loading and unloadingconnections and be hinged on one sideonly with approved riveted pin or rodwith nuts and cotters. Openings in wallof housing must be equipped with screwplugs or other closures.


§ 179.100–13 Venting, loading and un-loading valves, measuring and sam-pling devices.

(a) Venting, loading and unloadingvalves must be of approved design,made of metal not subject to rapid de-terioration by the lading, and mustwithstand the tank test pressure with-out leakage. The valves shall be boltedto seatings on the manway cover, ex-cept as provided in § 179.103. Valve out-lets shall be closed with approvedscrew plugs or other closures fastenedto prevent misplacement.

(b) The interior pipes of the loadingand unloading valves shall be anchoredand, except as prescribed in § 179.102 or§ 179.103, may be equipped with excessflow valves of approved design.

(c) Gauging device, sampling valveand thermometer well are not speci-fication requirements. When used, theyshall be of approved design, made ofmetal not subject to rapid deteriora-tion by the lading, and shall withstandthe tank test pressure without leakage.Interior pipes of the gauging device andsampling valve, except as prescribed in§ 179.102 or § 179.103, may be equippedwith excess flow valves of approved de-sign. Interior pipe of the thermometerwell shall be anchored in an approvedmanner to prevent breakage due to vi-bration. The thermometer well shall beclosed by an approved valve attachedclose to the manway cover, or other ap-proved location, and closed by a screwplug. Other approved arrangementsthat permit testing thermometer well


912

49 CFR Ch. I (10–1–98 Edition)§ 179.100–14

for leaks without complete removal ofthe closure may be used.

(d) An excess flow valve as referred toin this specification, is a device whichcloses automatically against the out-ward flow of the contents of the tankin case the external closure valve isbroken off or removed during transit.Excess flow valves may be designedwith a by-pass to allow the equali-zation of pressures.

(e) Bottom of tank shell may beequipped with a sump or siphon bowl,or both, welded or pressed into theshell. Such sumps or siphon bowls, ifapplied, are not limited in size andmust be made of cast, forged or fab-ricated metal. Each sump or siphonbowl must be of good welding qualityin conjunction with the metal of thetank shell. When the sump or siphonbowl is pressed in the bottom of thetank shell, the wall thickness of thepressed section must not be less thanthat specified for the shell. The sectionof a circular cross section tank towhich a sump or siphon bowl is at-tached need not comply with the out-of-roundness requirement specified inAAR Specifications for Tank Cars, ap-pendix W, W14.06. Any portion of asump or siphon bowl not forming a partof cylinder of revolution must havewalls of such thickness and be so rein-forced that the stresses in the wallscaused by a given internal pressure areno greater than the circumferentialstress which would exist under thesame internal pressure in the wall of atank of circular cross section designedin accordance with § 179.100–6(a). In nocase less than that specified in§ 179.101–1(a).

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21345, Nov. 6, 1971; Amdt. 179–40,52 FR 13046, Apr. 20, 1987; Amdt. 179–42, 54 FR38798, Sept. 20, 1989]

§ 179.100–14 Bottom outlets.

(a) Bottom outlets for discharge oflading is prohibited, except as providedin § 179.103–3. If indicated in § 179.101,tank may be equipped with a bottomwashout of approved construction. Ifapplied, bottom washout shall be in ac-cordance with the following require-ments.

(1) The extreme projection of the bot-tom washout equipment may not bemore than that allowed by appendix Eof the AAR Specifications for TankCars.

(2) Bottom washout shall be of cast,forged or fabricated metal and shall befusion-welded to the tank. It shall be ofgood weldable quality in conjunctionwith metal of tank.

(3) If the bottom washout nozzle ex-tends 6 inches or more from shell oftank, a V-shaped breakage groove shallbe cut (not cast) in the upper part ofthe outlet nozzle at a point imme-diately below the lowest part of the in-side closure seat or plug. In no casemay the nozzle wall thickness at theroot of the ‘‘V’’ be more than 1⁄4-inch.Where the nozzle is not a single piece,provision shall be made for the equiva-lent of the breakage groove. The nozzlemust be of a thickness to insure thataccidental breakage will occur at orbelow the ‘‘V’’ groove or its equivalent.On cars without continuous centersills, the breakage groove or its equiva-lent may not be more than 15 inchesbelow the tank shell. On cars with con-tinuous center sills, the breakagegroove or its equivalent must be abovethe bottom of the center sill construc-tion.

(4) The closure plug and seat shall bereadily accessible or removable for re-pairs.

(5) The closure of the washout nozzlemust be equipped with a 3⁄4-inch solidscrew plug. Plug must be attached byat least a 1⁄4-inch chain.

(6) Joints between closures and theirseats may be gasketed with suitablematerial.

(b) [Reserved]

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21345, Nov. 6, 1971; Amdt. 179–40,52 FR 13046, Apr. 20, 1987]

§ 179.100–16 Attachments.

(a) Reinforcing pads must be used be-tween external brackets and shells ifthe attachment welds exceed 6 linearinches of 1⁄4-inch fillet or equivalentweld per bracket or bracket leg. Whenreinforcing pads are used, they mustnot be less than one-fourth inch inthickness, have each corner rounded to


913


a 1-inch minimum radius, and be at-tached to the tank by continuous filletwelds except for venting provisions.The ultimate shear strength of thebracket-to-reinforcing pad weld mustnot exceed 85 percent of the ultimateshear strength of the reinforcing pad-to-tank weld.

(b) Attachments not otherwise speci-fied shall be applied by approvedmeans.


§ 179.100–17 Closures for openings.(a) Closures shall be of approved de-

sign and made of metal not subject torapid deterioration by the lading.Plugs, if used, shall be solid, with NPTthreads, and shall be of a length whichwill screw at least six threads insidethe face of fitting or tank.

(b) [Reserved]

§ 179.100–18 Tests of tanks.(a) Each tank shall be tested by com-

pletely filling tank and manway nozzlewith water or other liquid having simi-lar viscosity, at a temperature whichshall not exceed 100 °F during the test;and applying the pressure prescribed in§ 179.101. The tank shall hold the pre-scribed pressure for at least 10 minuteswithout leakage or evidence of distress.

(b) Insulated tanks shall be tested be-fore insulation is applied.

(c) Caulking of welded joints to stopleaks developed during the foregoingtest is prohibited. Repairs in weldedjoints shall be made as prescribed inAAR specifications for Tank Cars, ap-pendix W.

(d) Testing of exterior heaters is nota specification requirement.

§ 179.100–19 Tests of safety reliefvalves.

(a) Each valve shall be tested by airor gas for compliance with § 179.15 be-fore being put into service.

(b) [Reserved]

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, as amended at 62 FR51561, Oct. 1, 1997]

§ 179.100–20 Stamping.

(a) To certify that the tank complieswith all specification requirements,each tank shall be plainly and perma-nently stamped in letters and figuresat least 3⁄8 inch high into the metalnear the center of both outside headsas follows:

Example of requiredstamping

Specification .................................. DOT–105A100WMaterial ......................................... ASTM A 516Cladding material (if any) ............. ASTM A240–304Tank builder’s initials .................... CladDate of original test ...................... ABCCar assembler (if other than tank-

er builder).00–0000DEF

Water capacity .............................. 00000 lbs.

(b) [Reserved]

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21346, Nov. 6, 1971; Amdt. 179–52,61 FR 28679, June 5, 1996]

§ 179.100 Individual specification re-quirements applicable to pressuretank car tanks.

§ 179.101–1 Individual specification re-quirements.

In addition to § 179.100, the individualspecification requirements are as fol-lows:

DOT specifica-tion Insulation

Burstingpressure

(psi)

Minimumplate

thickness(inches)

Testpressure

(psi)

Manwaycover

thickness

Bottom out-let

Bottomwashout

Reference(179.***)

105A100ALW ... Yes ............. 500 5/8 100 2 2 1/2 No ............... No.105A200ALW ... Yes ............. 500 5/8 200 2 2 1/2 No ............... No.105A300ALW ... Yes ............. 750 5/8 300 2 2 5/8 No ............... No.105A100W ....... Yes ............. 500 3 9/16 100 2 1/4 No ............... No.105A200W ....... Yes ............. 500 3 9/16 200 2 1/4 No ............... No.105A300W ....... Yes ............. 750 1 11/16 300 7 2 1/4 No ............... No.105A400W ....... Yes ............. 1,000 1 11/16 400 7 2 1/4 No ............... No.105A500W ....... Yes ............. 1,250 1 11/16 500 2 1/4 No ............... No ............ 102–1, 102–2105A600W ....... Yes ............. 1,500 1 11/16 600 2 1/4 No ............... No ............ 102–4, 102–17109A100ALW ... Optional ...... 500 5/8 100 2 2 1/2 No ............... Optional.109A200ALW ... Optional ...... 500 5/8 200 2 2 1/2 No ............... Optional.109A300ALW ... Optional ...... 750 5/8 300 2 2 5/8 No ............... Optional.109A300W ....... Optional ...... 500 1 11/16 300 2 1/4 No ............... Optional.


914

49 CFR Ch. I (10–1–98 Edition)§ 179.102

DOT specifica-tion Insulation

Burstingpressure

(psi)

Minimumplate

thickness(inches)

Testpressure

(psi)

Manwaycover

thickness

Bottom out-let

Bottomwashout

Reference(179.***)

112A200W ....... Optional 4 .... 500 3 5 9/16 200 2 1/4 No ............... No.112A340W ....... Optional 4 .... 850 1 11/16 340 2 1/4 No ............... No.112A400W ....... Optional 4 .... 1,000 1 11/16 400 2 1/4 No ............... No.112A500W ....... Optional 4 .... 1,250 1 11/16 500 2 1/4 No ............... No.114A340W ....... Optional 4 .... 850 1 11/16 340 6 Optional ...... Optional ... 103114A400W ....... Optional 4 .... 1,000 1 11/16 400 6 Optional ...... Optional ... 103120A200ALW ... Yes ............. 500 5/8 200 2 2 1/2 Optional ...... Optional ... 103120A100W ....... Yes ............. 500 3 9/16 100 2 1/4 Optional ...... Optional ... 103120A200W ....... Yes ............. 500 3 9/16 200 2 1/4 Optional ...... Optional ... 103120A300W ....... Yes ............. 750 1 11/16 300 2 1/4 Optional ...... Optional ... 103120A400W ....... Yes ............. 1,000 1 11/16 400 2 1/4 Optional ...... Optional ... 103120A500W ....... Yes ............. 1,250 1 11/16 500 2 1/4 Optional ...... Optional ... 103

1 When steel of 65,000 to 81,000 p.s.i. minimum tensile strength is used, the thickness of plates shall be not less than 5/8inch, and when steel of 81,000 p.s.i. minimum tensile strength is used, the minimum thickness of plate shall be not less than 9/16 inch.

2 When approved material other than aluminum alloys are used, the thickness shall be not less than 2 1/4 inches.3 When steel of 65,000 p.s.i. minimum tensile strength is used, minimum thickness of plates shall be not less than 1/2 inch.4 Tank cars not equipped with a thermal protection or an insulation system used for the transportation of a Class 2 (com-

pressed gas) material must have at least the upper two-thirds of the exterior of the tank, including manway nozzle and all appur-tenances in contact with this area, finished with a reflective coat of white paint.

5 For inside diameter of 87 inches or less, the thickness of plates shall be not less than 1/2 inch.6 See AAR specifications for tank cars, Appendix E, E4.01 and § 179.103–2.7 When the use of nickel is required by the lading, the thickness shall not be less than two inches.

[Amdt. 179–52, 61 FR 28679, June 5, 1996]

§ 179.102 Special commodity require-ments for pressure tank car tanks.

(a) In addition to §§ 179.100 and 179.101the following requirements are applica-ble:

(b) [Reserved]

§ 179.102–1 Carbon dioxide, refrig-erated liquid.

(a) Tank cars used to transport car-bon dioxide, refrigerated liquid mustcomply with the following special re-quirements:

(1) All plates for tank, manway noz-zle and anchorage of tanks must bemade of carbon steel complying withASTM Specification A 516, Grades 55,60, 65, or 70, or AAR SpecificationTC128–78, Grade B. The ASTM A516plate must also meet the Charpy V–Notch test requirements of ASTM A20–79b (see table 16) in the longitudinal di-rection of rolling. The TC128 platemust also meet the Charpy V–Notchenergy absorption requirements of 15ft-lb minimum average for 3 specimensand 10 ft-lb minimum for one specimenat minus 50 °F in the longitudinal di-rection of rolling in accord with ASTMSpecification A 370. Production-weldedtest plates prepared as required byW4.00 of AAR Specifications for TankCars, appendix W, must include impacttest specimens of weld metal and heat-

affected zone. As an alternate, anchorlegs may be fabricated of stainlesssteel, ASTM Specification A 240 Types304, 304L, 316 or 316L for which impacttests are not required.

(2)–(6) [Reserved](b) [Reserved]

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21347, Nov. 6, 1971; Amdt. 179–28,46 FR 49906, Oct. 8, 1981; 46 FR 55266, Nov. 9,1981; Amdt. 179–32, 48 FR 50440, 50441, Nov. 1,1983; 49 FR 42736, Oct. 24, 1984; Amdt. 179–45,55 FR 52728, Dec. 21, 1990; Amdt. 179–52, 61 FR28680, June 5, 1996]

§ 179.102–2 Chlorine.

(a) Each tank car used to transportchlorine must comply with all of thefollowing:

(1) Tanks must be fabricated fromcarbon steel complying with ASTMSpecification A 516, Grade 70, or AARSpecification TC–128, Grade A or B.

(2)–(3) [Reserved](b) [Reserved]

[Amdt. 179–7, 36 FR 14697, Aug. 10, 1971; Amdt.179–10, 36 FR 21346, Nov. 6, 1971, as amendedby Amdt. 179–25, 44 FR 20433, Apr. 5, 1979;Amdt. 179–40, 52 FR 13046, Apr. 20, 1987; Amdt.179–45, 55 FR 52728, Dec. 21, 1990; Amdt. 179–52,61 FR 28680, June 5, 1996]


915


§ 179.102–4 Vinyl fluoride, inhibited.

Each tank used to transport vinylfluoride, inhibited, must comply withthe following special requirements:

(a) All plates for the tank must befabricated of material listed in para-graph (b)(2) of this section, and appur-tenances must be fabricated of mate-rial listed in paragraph (b)(1) or (b)(2)of this section.

(1) Stainless steel, ASTM Specifica-tion A240, Type 304, 304L, 316 or 316L, inwhich case impact tests are not re-quired; or

(2) Steel complying with ASTM Spec-ification A516; Grade 70; ASTM Speci-fication A537, Class 1; or AAR Speci-fication TC128, Grade B, in which caseimpact tests must be performed as fol-lows:

(i) ASTM Specification A516 and A537material must meet the Charpy V-notch test requirements, in longitu-dinal direction of rolling, of ASTMSpecification A20.

(ii) AAR Specification TC128 mate-rial must meet the Charpy V-notchtest requirements, in longitudinal di-rection of rolling, of 15 ft.-lb. minimumaverage for 3 specimens, with a 10 ft.-lb. minimum for any one specimen, atminus 50 °F. or colder, in accordancewith ASTM Specification A 370.

(iii) Production welded test platesmust—

(A) Be prepared in accordance withAAR Specifications for Tank Cars, ap-pendix W, W4.00;

(B) Include impact specimens of weldmetal and heat affected zone preparedand tested in accordance with AARSpecifications for Tank Cars, appendixW, W9.00; and

(C) Meet the same impact require-ments as the plate material.

(b) Insulation must be of approvedmaterial.

(c) Excess flow valves must be in-stalled under all liquid and vaporvalves, except safety relief valves.

(d) A thermometer well may be in-stalled.

(e) Only an approved gaging devicemay be installed.

(f) A pressure gage may be installed.(g) Aluminum, copper, silver, zinc, or

an alloy containing any of these metalsmay not be used in the tank construc-

tion, or in fittings in contact with thelading.

(h) The jacket must be stenciled, ad-jacent to the water capacity stencil,

MINIMUM OPERATING TEMPERA-TURE l °F.(i) The tank car and insulation must

be designed to prevent the vapor pres-sure of the lading from increasing fromthe pressure at the maximum allowablefilling density to the start-to-dischargepressure of the safety relief valve with-in 30 days, at an ambient temperatureof 90 °F.

[Amdt. 179–32, 48 FR 27707, June 16, 1983, asamended at 49 FR 24317, June 12, 1984; 49 FR42736, Oct. 24, 1984; Amdt. 179–45, 55 FR 52728,Dec. 21, 1990; Amdt. 179–52, 61 FR 28680, June5, 1996]

§ 179.102–17 Hydrogen chloride, refrig-erated liquid.

Each tank car used to transport hy-drogen chloride, refrigerated liquidmust comply with the following specialrequirements:

(a) The tank car must comply withSpecification DOT–105J600W and be de-signed for loading at minus 50 °F. orcolder.

(b) All plates for the tank must befabricated of material listed in para-graph (b)(2) of this section, and appur-tenances must be fabricated of mate-rial listed in paragraph (b)(1) or (b)(2)of this section.

(1) Stainless steel, ASTM Specifica-tion A240, Type 304, 304L, 316, or 316L,in which case impact tests are not re-quired; or

(2) Steel complying with ASTM Spec-ification A516, Grade 70; ASTM Speci-fication A537, Class 1; or AAR Speci-fication TC128, Grade B, in which caseimpact tests must be performed as fol-lows:

(i) ASTM Specification A516 and A537material must meet the Charpy V-notch test requirements, in longitu-dinal direction of rolling, of ASTMSpecification A20.

(ii) AAR Specification TC128 mate-rial must meet the Charpy V-notchtest requirements, in longitudinal di-rection of rolling of 15 ft.-lb. minimumaverage for 3 specimens, with a 10 ft.-lb. minimum for any one specimen, atminus 50 °F. or colder, in accordancewith ASTM Specification A 370.


916

49 CFR Ch. I (10–1–98 Edition)§ 179.103

(iii) Production welded test platesmust—

(A) Be prepared in accordance withAAR Specifications for Tank Cars, ap-pendix W, W4.00;

(B) include impact test specimens ofweld metal and heat affected zone pre-pared and tested in accordance withAAR Specifications for Tank Cars, ap-pendix W, W9.00; and

(C) meet the same impact require-ments as the plate material.

(c) Insulation must be of approvedmaterial.

(d) Safety relief valves must betrimmed with monel or other approvedmaterial and equipped with a frangibledisc of silver, polytetrafluoroethylenecoated monel, or tantalum. Each safetyrelief device shall have the space be-tween the frangible disc and the reliefvalve vented with a suitable auxiliaryvalve. The discharge from each safetyrelief valve must be directed outsidethe protective housing.

(e) Loading and unloading valvesmust be trimmed with Hastelloy B orC, monel, or other approved material,and identified as ‘‘Vapor’’ or ‘‘Liquid’’.Excess flow valves must be installedunder all liquid and vapor valves, ex-cept safety relief valves.

(f) A thermometer well may be in-stalled.

(g) Only an approved gaging devicemay be installed.

(h) A sump must be installed in thebottom of the tank under the liquidpipes.

(i) All gaskets must be made of, orcoated with, polytetrafluoroethyleneor other approved material.

(j) The tank car tank may beequipped with exterior cooling coils ontop of the tank car shell.

(k) The jacket must be stenciled, ad-jacent to the water capacity stencil,

MINIMUM OPERATING TEMPERATURE l°F.

(l) The tank car and insulation mustbe designed to prevent the pressure ofthe lading from increasing from thepressure at the maximum allowablefilling density to the start-to-dischargepressure of the safety relief valve with-

in 30 days, at an ambient temperatureof 90° F.

[Amdt. 179–32, 48 FR 27708, June 16, 1983, asamended at 48 FR 50441, Nov. 1, 1983; 49 FR24317, June 12, 1984; 49 FR 42736, Oct. 24, 1984;Amdt. 179–45, 55 FR 52728, Dec. 21, 1990]

§ 179.103 Special requirements forclass 114A * * * tank car tanks.

(a) In addition to the applicable re-quirements of §§ 179.100 and 179.101 thefollowing requirements shall be com-plied with:

(b) [Reserved]

§ 179.103–1 Type.(a) Tanks built under this section

may be of any approved cross section.(b) Any portion of the tank shell not

circular in cross section shall havewalls of such thickness and be so rein-forced that the stresses in the wallscaused by a given internal pressure areno greater than the circumferentialstresses which would exist under thesame internal pressure in the wall of atank of circular cross section designedin accordance with paragraphs § 179.100–6 (a) and (b), but in no case shall thewall thickness be less than that speci-fied in § 179.101.

(c) [Reserved](d) Valves and fittings need not be

mounted on the manway cover.(e) One opening may be provided in

each head for use in purging the tankinterior.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–50, 60 FR 49077, Sept. 21, 1995]

§ 179.103–2 Manway cover.(a) The manway cover must be an ap-

proved design.(b) If no valves or measuring and

sampling devices are mounted onmanway cover, no protective housing isrequired.


§ 179.103–3 Venting, loading and un-loading valves, measuring and sam-pling devices.

(a) Venting, loading and unloadingvalves, measuring and sampling de-vices, when used, shall be attached to a


917


nozzle or nozzles on the tank shell orheads.

(b) These valves and appurtenancesmust be grouped in one location and,except as provided in § 179.103–5, mustbe equipped with a protective housingwith cover, or may be recessed intotank shell with cover. An additionalset grouped in another location may beprovided. Protective housing withcover, when used, must have steel side-walls not less than three-fourths inchin thickness and a metal cover not lessthan one-fourth inch in thickness thatcan be securely closed. Underframesills are an acceptable alternate to theprotective housing cover, provided thearrangement is of approved design. Forfittings recessed into tank shell, pro-tective cover must be metal and notless than one-fourth inch in thickness.

(c) When tank car is used to trans-port liquefied flammable gases, the in-terior pipes of the loading, unloading,and sampling valves must be equippedwith excess flow valves of approved de-sign except when quick closing internalvalves of approved design are used.When the interior pipe of the gagingdevice provides a means for the passageof lading from the interior to the exte-rior of the tank, it must be equippedwith an excess flow valve of approveddesign or with an orifice not exceeding0.060 inch.


§ 179.103–4 Safety relief devices andpressure regulators.

(a) Safety relief devices and pressureregulators must be located on top ofthe tank near the center of the car ona nozzle, mounting plate or recess inthe shell. Through or stud bolts, ifused, must not enter the tank.

(b) Metal guard of approved designmust be provided to protect safety re-lief devices and pressure regulatorsfrom damage.

[Amdt. 179–10, 36 FR 21348, Nov. 6, 1971]

§ 179.103–5 Bottom outlets.(a) In addition to or in place of the

venting, loading and unloading valves,measuring and sampling devices as pre-scribed in § 179.103–3, tanks may be

equipped with approved bottom outletvalves. If applied, bottom outlet valvesmust meet the following requirements:

(1) On cars with center sills, a ballvalve may be welded to the outside bot-tom of the tank or mounted on a pad ornozzle with a tongue and groove ormale and female flange attachment,but in no case shall the breakagegroove or equivalent extend below thebottom flange of the center sill. Oncars without continuous center sills, aball valve may be welded to the outsidebottom of the tank or mounted with atongue and groove or male and femaleflange attachment on a pad attached tothe outside bottom of the tank. Themounting pad must have a maximumthickness of 21⁄2 inches measured on thelongitudinal centerline of the tank.The valve operating mechanism mustbe provided with a suitable locking ar-rangement to insure positive closureduring transit.

(2) When internal bottom outletvalve is used in liquefied flammablegas service, the outlet of the valvemust be equipped with an excess flowvalve of approved design, except when aquick-closing internal valve of ap-proved design is used. Protective hous-ing is not required.

(3) Bottom outlet must be equippedwith a liquid tight closure at its lowerend.

(b) Bottom outlet equipment must beof approved design and must meet thefollowing requirements:

(1) The extreme projection of the bot-tom outlet equipment may not be morethan allowed by appendix E of the AARSpecifications for Tank Cars. All bot-tom outlet reducers and closures andtheir attachments shall be secured tocar by at least 3⁄8-inch chain, or itsequivalent, except that bottom outletclosure plugs may be attached by 1⁄4-inch chain. When the bottom outletclosure is of the combination cap andvalve type, the pipe connection to thevalve shall be closed by a plug, cap, orapproved quick coupling device. Thebottom outlet equipment should in-clude only the valve, reducers and clo-sures that are necessary for the attach-ment of unloading fixtures. The perma-nent attachment of supplementary ex-terior fittings must be approved by theAAR Committee on Tank Cars.


918

49 CFR Ch. I (10–1–98 Edition)§ 179.200

(2) To provide for the attachment ofunloading connections, the dischargeend of the bottom outlet nozzle or re-ducer, the valve body of the exteriorvalve, or some fixed attachment there-to, shall be provided with one of thefollowing arrangements or an approvedmodification thereof. (See appendix E.Fig. E17 of the AAR Specifications forTank Cars for illustrations of some ofthe possible arrangements.)

(i) A bolted flange closure arrange-ment including a minimum 1-inch NPTpipe plug (see Fig. E17.1) or includingan auxiliary valve with a threaded clo-sure.

(ii) A threaded cap closure arrange-ment including a minimum 1-inch NPTpipe plug (see Fig. E17.2) or includingan auxiliary valve with a threaded clo-sure.

(iii) A quick-coupling device using athreaded plug closure of at least 1-inchNPT or having a threaded cap closurewith a minimum 1-inch NPT pipe plug(see Fig. E17.3 through E17.5). A mini-mum 1-inch auxiliary test valve with athreaded closure may be substitutedfor the 1-inch pipe plug (see Fig E17.6).If the threaded cap closure does nothave a pipe plug or integral auxiliarytest valve, a minimum 1-inch NPT pipeplug shall be installed in the outletnozzle above the closure (see Fig.E17.7).

(iv) A two-piece quick-coupling de-vice using a clamped dust cap must in-clude an in-line auxiliary valve, eitherintegral with the quick-coupling deviceor located between the primary bottomoutlet valve and the quick-coupling de-vice. The quick-coupling device closuredust cap or outlet nozzle shall be fittedwith a minimum 1-inch NPT closure(see Fig. E17.8 and E17.9).

(3) The valve operating mechanismmust be provided with a suitable lock-ing arrangement to insure positive clo-sure during transit.

(4) If the outlet nozzle extends 6inches or more from shell of tank, a V-shaped breakage groove shall be cut(not cast) in the upper part to the out-let nozzle at a point immediately belowthe lowest part of value closest to thetank. In no case may the nozzle wallthickness at the roof of the ‘‘V’’ bemore than 1⁄4-inch. On cars withoutcontinuous center sills, the breakage

groove or its equivalent may not bemore than 15inches below the tankshell. On cars with continuous centersills, the breakage groove or its equiva-lent must be above the bottom of thecenter sill construction.

(5) The valve body must be of a thick-ness which will insure that accidentalbreakage of the outlet nozzle will occurat or below the ‘‘V’’ groove, or itsequivalent, and will not cause distor-tion of the valve seat or valve.

[Amdt. 179–10, 36 FR 21348, Nov. 6, 1971, asamended by Amdt. 179–40, 52 FR 13046, Apr.20, 1987; Amdt. 179–41, 52 FR 36672, Sept. 30,1987; Amdt. 179–50, 60 FR 49077, Sept. 21, 1995;Amdt. 179–52, 61 FR 28680, June 5, 1996; Amdt.179–53, 61 FR 51342, Oct. 1, 1996]

Subpart D—Specifications for Non-Pressure Tank Car Tanks(Classes DOT–103, 104, 111AF,111AW, and 115AW)

§ 179.200 General specifications appli-cable to non-pressure tank cartanks (Classes DOT–103, 104, and111).

§ 179.200–1 Tank built under thesespecifications must meet the re-quirements of §§ 179.200, 179.201and when applicable § 179.202.

§ 179.200–3 Type.Tank built under these specifications

must be circular in cross section, withformed heads designed convex outward.When specified in § 179.201–1, the tankmust have at least one manway or oneexpansion dome with manway, andsuch other external projections as areprescribed herein. When the tank is di-vided into compartments, each com-partment must be treated as a separatetank.

[Amdt. 179–10, 36 FR 21348, Nov. 6, 1971]

§ 179.200–4 Insulation.(a) If insulation is applied, the tank

shell and expansion dome when usedmust be insulated with an approvedmaterial. The entire insulation mustbe covered with a metal jacket of athickness not less than 11 gauge (0.1196inch) nominal (Manufacturer’s Stand-ard Gauge) and flashed around all open-ings so as to be weather tight. The ex-terior surface of a carbon steel tank


919


and the inside surface of a carbon steeljacket must be given a protection coat-ing.

(b) If insulation is a specification re-quirement, it shall be of sufficientthickness so that the thermal conduct-ance at 60 °F is not more than 0.225 Btuper hour, per square foot, per degree Ftemperature differential, unless other-wise provided in § 179.201–1. If exteriorheaters are attached to tank, thethickness of the insulation over eachheater element may be reduced to one-half that required for the shell.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21349, Nov. 6, 1971; Amdt. 179–50,60 FR 49078, Sept. 21, 1995]

§ 179.200–6 Thickness of plates.(a) The wall thickness after forming

of the tank shell, dome shell, and of 2:1ellipsoidal heads must be not less thanspecified in § 179.201–1, nor that cal-culated by the following formula:

t =Pd

SE2where:d = Inside diameter in inches;E = 0.9 Welded joint efficiency; except E=1.0

for seamless heads;P = Minimum required bursting pressure in


rial in p.s.i. as prescribed in § 179.200–7;t = Minimum thickness of plate in inches

after forming.

(b) The wall thickness after formingof 3:1 ellipsoidal heads must be not lessthan specified in § 179.201–1, nor thatcalculated by the following formula:

t =Pd

SE1.83

2×

where:d = Inside diameter in inches;E = 0.9 Welded joint efficiency; except E=1.0



rial in p.s.i. as prescribed in § 179.200–7;t = Minimum thickness of plate in inches

after forming.

(c) The wall thickness after formingof a flanged and dished head must benot less than specified in § 179.201–1, nor

that calculated by the following for-mula:

t =PL

SE

5

6where:

E = 0.9 Welded joint efficiency; except E=1.0for seamless heads;

L = Main inside radius to which head isdished, measured on concave side in inches;

P = Minimum required bursting pressure inp.s.i.;

S = Minimum tensile strength of plate mate-rial in p.s.i. as prescribed in § 179.200–7;

t = Minimum thickness of plate in inchesafter forming.

(d) If plates are clad with materialhaving tensile strength properties atleast equal to the base plate, the clad-ding may be considered a part of thebase plate when determining thickness.If cladding material does not have ten-sile strength at least equal to the baseplate, the base plate alone must meetthe thickness requirements.

(e) For a tank constructed of longitu-dinal sections, the minimum width ofbottom sheet of the tank must be 60inches measured on the arc, but in allcases the width must be sufficient tobring the entire width of the longitu-dinal welded joint, including welds,above the bolster.

(f) For a tank built of one piece cy-lindrical sections, the thickness speci-fied for bottom sheet must apply to theentire cylindrical section.

(g) See § 179.200–9 for thickness re-quirements for a compartmented tank.

[Amdt. 179–10, 36 FR 21349, Nov. 6, 1971]

§ 179.200–7 Materials.

(a) Plate material used to fabricatethe tank and, when used, expansiondome or manway nozzle material, mustmeet one of the following specifica-tions with the indicated minimum ten-sile strength and elongation in thewelded condition.

(b) Carbon steel plate: The maximumallowable carbon content must be 0.31percent when the individual specifica-tion allows carbon content greaterthan this amount. The plates may beclad with other approved materials:


920

49 CFR Ch. I (10–1–98 Edition)§ 179.200–8

Specifications


(p.s.i.) weldedcondition 1


inches (per-cent) weld

metal (longitu-dinal)

AAR TC 128, Gr. B ............ 81,000 19ASTM A 516, Gr. 70 .......... 70,000 20


(c) Aluminum alloy plate: Aluminumalloy plate must be suitable for weld-ing and comply with one of the follow-ing specifications:

Specifications

Minimum ten-sile strength(p.s.i.) weld-

ed condi-tion 3 6

Minimumelongation in

2 inches(percent) 0

temper weldmetal (longi-

tudinal)

ASTM B 209, Alloy 50521 ..... 25,000 18ASTM B 209, Alloy 50832 ..... 38,000 16ASTM B 209, Alloy 50861 ..... 35,000 14ASTM B 209, Alloy 51541 ..... 30,000 18ASTM B 209, Alloy 52541 ..... 30,000 18ASTM B 209, Alloy 54541 ..... 31,000 18ASTM B 209, Alloy 56521 ..... 25,000 18

1 For fabrication, the parent plate material may be 0, H112,or H32 temper, but design calculations must be based onminimum tensile strength shown.

2 0 temper only.3 Weld filler metal 5556 must not be used.4 Maximum stresses to be used in calculations.

(d) High alloy steel plate: High alloysteel plate must comply with one ofthe following specifications:

Specifications

Minimum ten-sile strength(p.s.i.) weld-ed condition 1

Minimumelongation in

2 inches(percent)

weld metal(longitudinal)

ASTM A 240, Type 304 ......... 75,000 30ASTM A 240, Type 304L ....... 70,000 30ASTM A 240, Type 316 ......... 75,000 30ASTM A 240, Type 316L ....... 70,000 30

1 Maximum stresses to be used in calculations.2 High alloy steel materials used to fabricate tank and ex-

pansion dome, when used, must be tested in accordance withPractice A of ASTM Specification A 262 titled, ’Standard Prac-tices for Detecting Susceptibility to Intergranular Attack inAustenitic Stainless Steels.’ If the specimen does not passPractice A, Practice B or C must be used and the corrosionrates may not exceed the following:

Test procedure Material Corrosionrate i.p.m.

Practice B .................... Types 304, 304L, 316,and 316L.

0.0040

Practice C ................... Type 304L .................. .0020

Type 304L and Type 316L test specimens must be given asensitizing treatment prior to testing. (A typical sensitizingtreatment is 1 hour at 1250 F.)

(e) Nickel plate: Nickel plate mustcomply with the following specifica-tion:

Specifications

Minimumtensile

strength(p.s.i.)welded

condition 1

Minimumelongationin 2 inches(percent)

weld metal(longitu-

dinal)

ASTM B 16222 .............................. 40,000 20

1 Maximum stresses to be used in calculations.2 When used as cladding for carbon steel plate, low-carbon

nickel is required.

(f) Manganese-molybdenum steel plate:Manganese-molybdenum steel platemust be suitable for fusion welding andcomply with the following specifica-tion:

Specifications

Minimumtensile


condition 1


weld metal(longitu-

dinal)

ASTM A 302, Gr. B ........................ 80,000 20


(g) All parts and items of construc-tion in contact with the lading must bemade of material compatible withplate material and not subject to rapiddeterioration by the lading, or be coat-ed or lined with suitable corrosion re-sistant material.

(h) All external projections whichmay be in contact with the lading andall castings, forgings, or fabricationsused for fittings or attachments totank and expansion dome, when used,in contact with lading must be made ofmaterial to an approved specification.See AAR Specification for Tank Cars,appendix M, M4.05 for approved mate-rial specifications for castings for fit-tings.

[Amdt. 179–10, 36 FR 21349, Nov. 9, 1971; 36 FR21893, Nov. 17, 1971, as amended by Amdt.179–28, 46 FR 49906, Oct. 8, 1981; Amdt. 179–40, 52FR 13046, Apr. 20, 1987; Amdt. 179–52, 61 FR28680, June 5, 1996]

§ 179.200–8 Tank heads.(a) All external tank heads must be

an ellipsoid of revolution in which themajor axis must equal the diameter ofthe shell and the minor axis must beone-half the major axis.

(b) Internal compartment tank headsmay be 2:1 ellipsoidal, 3:1 ellipsoidal, orflanged and dished to thicknesses asspecified in § 179.200–6. Flanged anddished heads must have main inside ra-dius not exceeding 10 feet, and inside


921


knuckle radius must not be less than33⁄4 inches for steel, alloy steel, or nick-el tanks, and not less than 5 inches foraluminum alloy tanks.

[Amdt. 179–10, 36 FR 21350, Nov. 6, 1971]

§ 179.200–9 Compartment tanks.(a) When a tank is divided into com-

partments, by inserting interior heads,interior heads must be inserted in ac-cordance with AAR Specifications forTank Cars, appendix E, E7.00, and mustcomply with the requirements specifiedin § 179.2011–1. Voids between compart-ment heads must be provided with atleast one tapped drain hole at theirlowest point, and a tapped hole at thetop of the tank. Top hole must beclosed, and the bottom hole may beclosed, with not less than three-fourthsinch nor more than 11⁄2-inches solidpipe plugs having NPT threads.

(b) When the tank is divided intocompartments by construction eachcompartment as a separate tank, thesetanks shall be joined together by a cyl-inder made of plate, having a thicknessnot less than that required for the tankshell and applied to the outside surfaceof tank head flanges. The cylinder shallfit the straight flange portion of thecompartment tank head tightly. Thecylinder shall contact the head flangefor a distance of at least two times theplate thickness, or a minimum of 1inch, whichever is greater. The cyl-inder shall be joined to the head flangeby a full fillet weld. Distance fromhead seam to cylinder shall not be lessthan 11⁄2 inches or three times the platethickness, whichever is greater. Voidscreated by the space between heads oftanks joined together to form a com-partment tank shall be provided with atapped drain hole at their lowest pointand a tapped hole at top of tank. Thetop hole shall be closed and the bottomhole may be closed with solid pipeplugs not less than 3⁄4 inch nor morethan 11⁄2 inches having NPT threads.


§ 179.200–10 Welding.(a) All joints shall be fusion-welded

in compliance with the requirements ofAAR Specifications for Tank Cars, ap-

pendix W. Welding procedures, weldersand fabricators shall be approved.

(b) Welding is not permitted on or toductile iron or malleable iron fittings.


§ 179.200–11 Postweld heat treatment.After welding is complete, postweld

heat treatment must be in compliancewith the requirements of AAR Speci-fications for Tank Cars, appendix W,when specified in § 179.201.1.

[Amdt. 179–10, 36 FR 21350, Nov. 6, 1971]

§ 179.200–13 Manway ring or flange,safety relief device flange, bottomoutlet nozzle flange, bottom wash-out nozzle flange and other attach-ments and openings.

(a) These attachments shall be fusionwelded to the tank and reinforced in anapproved manner in compliance withthe requirements of appendix E, figure10, of the AAR Specifications for TankCars.

(b) The opening in the manway ringmust be at least 16 inches in diameterexcept that acid resistant linedmanways must be at least 18 inches indiameter before lining.

(c) The manway ring or flange, shallbe made of cast, forged or fabricatedmetal. The metal of the dome, tank, ornozzle must be compatible with themanway ring or flange, so that theymay be welded together.

(d) The openings for the manway orother fittings shall be reinforced in anapproved manner.

[Amdt. 179–40, 52 FR 13047, Apr. 20, 1987]

§ 179.200–14 Expansion capacity.(a) Tanks shall have expansion capac-

ity as prescribed in this subchapter.This capacity shall be provided in thetank for Class DOT–111A cars, or in adome for Class DOT–103 and 104 typecars.

(b) For tank cars having an expan-sion dome, the expansion capacity isthe total capacity of the tank anddome combined. The capacity of thedome shall be measured from the insidetop of shell of tank to the inside top ofdome or bottom of any vent pipe pro-jecting inside of dome, except that


922

49 CFR Ch. I (10–1–98 Edition)§ 179.200–15

when safety relief device is applied toside of dome, the effective capacity ofthe dome shall be measured from top ofsafety relief device opening inside ofdome to inside top of shell of tank.

(c) The opening in the tank shellwithin the dome shall be at least 29inches in diameter. When the openingin the tank shell exceeds 30 inches indiameter, the opening shall be rein-forced in an approved manner. This ad-ditional reinforcement may be accom-plished by the use of a dome opening ofthe flued-type as shown in appendix E,Figure E 10C of the AAR Specificationfor Tank Cars or by the use of reinforc-ing as outlined in Appendix E, E3.04and Figures E10K and E10L. When theopening in the tank shell is less thanthe inside diameter of the dome, andthe dome pocket is not closed off in anapproved manner, dome pocket drainholes shall be provided in the tankshell with nipples projecting inside thetank at least 1-inch.

(d) The dome head shall be of ap-proved contour and shall be designedfor pressure on concave side.

(e) Aluminum alloy domes: (1) Thedome shell thickness shall be cal-culated by the formula in § 179.200–6(a).

(2) The dome head may be an ellip-soid of revolution in which the majoraxis shall be equal to the diameter ofthe dome shall and the minor axis shallbe one-half the major axis. The thick-ness in this case shall be determined byusing formula in § 179.200–6(a).

(3) The dome head, if dished, must bedished to a radius not exceeding 96inches. Thickness of dished dome headmust be calculated by the formula in§ 179.200–6(c).

(4) Tank shell shall be reinforced bythe addition of a plate equal to orgreater than shell in thickness and thecross sectional area shall exceed metalremoved for dome opening, or tankshell shall be reinforced by a seamlesssaddle plate equal to or greater thanshell in thickness and butt welded totank shell. The reinforcing saddle plateshall be provided with a fluid openinghaving a vertical flange of the diame-ter of the dome for butt welding shellof dome to the flange. The reinforcingsaddle plate shall extend about thedome a distance measured along shellof tank at least equal to the extension

at top of tank. Other approved designsmay be used.

(f) For thickness of carbon or alloysteel domes, see § 179.201–2.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21350, Nov. 6, 1971; Amdt. 179–28,46 FR 49906, Oct. 8, 1981; Amdt. 179–52, 61 FR28680, June 5, 1996]

§ 179.200–15 Closures for manways.

(a) Manway covers must be of ap-proved type.

(b) Manway covers shall be designedto provide a secure closure of themanway.

(c) Manway covers must be of ap-proved cast, forged, or fabricated met-als. Malleable iron, if used, must com-ply with ASTM A47–68, Grade 35018.Cast iron manway covers must not beused.

(d) All joints between manway coversand their seats shall be made tightagainst leakage of vapor and liquid byuse of gaskets of suitable material.

(e) For other manway cover require-ments see § 179.201–1.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21350, Nov. 6, 1971; Amdt. 179–37,50 FR 11066, Mar. 19, 1985]

§ 179.200–16 Gauging devices, top load-ing and unloading devices, ventingand air inlet devices.

(a) When installed, these devicesshall be of an approved design whichwill prevent interchange with anyother fixture, and be tightly closed.Unloading pipes shall be securely an-chored within the tank. Each tank orcompartment may be equipped withone separate air connection.

(b) When the characteristics of thecommodity for which the car is author-ized are such that these devices mustbe equipped with valves or fittings topermit the loading and unloading ofthe contents, these devices, includingvalves, shall be of an approved design,and be provided with a protective hous-ing except when plug or ball typevalves with operating handles removedare used. Provision shall be made forclosing pipe connections of valves.


923


(c) A tank may be equipped with avacuum relief valve of an approved de-sign. Protective housing is not re-quired.

(d) When using a visual gauging de-vice on a car with a hinged manwaycover, an outage scale visible throughthe manway opening shall be provided.If loading devices are applied to permittank loading with cover closed, a tell-tale pipe may be provided. Telltale pipeshall be capable of determining that re-quired outage is provided. Pipe shall beequipped with 1⁄4 inch minimum NPTcontrol valve mounted outside tankand enclosed within a housing. Otherapproved devices may be used in lieu ofoutage scale or telltale pipe.

(e) Bottom of tank shell may beequipped with a sump or siphon bowl,or both, welded or pressed into theshell. Such sumps or siphon bowls, ifapplied are not limited in size andmust be made of cast, forged, or fab-ricated metal. Each sump or siphonbowl must be of good welding qualityin conjunction with the metal of thetank shell. When sump or siphon bowlis pressed in the bottom of the tankshell, the wall thickness of the pressedsection must not be less than thatspecified for the shell. The section of acircular cross section tank to which asump or siphon bowl is attached neednot comply with the out-of-roundnessrequirement specified in appendix W,W14.06, of the AAR Specifications forTank Cars. Any portion of a sump or si-phon bowl not forming a part of a cyl-inder of revolution must have walls ofsuch thickness and be so reinforcedthat the stresses in the walls caused bya given internal pressure are not great-er than the circumferential stresswhich would exist under the same in-ternal pressure in the wall of a tank ofcircular cross section designed in ac-cordance with § 179.200–6 (a) and (d). Inno case shall the wall thickness be lessthan that specified in § 179.201–1(a).

(f) When top loading and dischargedevices, or venting and air inlet de-vices are installed with exposed pipingto a removed location, shutoff valvesmust be applied directly to reinforcingpads or nozzles at their communicationthrough the tank shell, and must beenclosed in a protective housing withprovision for a seal. The piping must

include breakage grooves, and suitablebracing. Relief valves must be appliedto liquid lines for protection in caselading is trapped. Provision must bemade to insure closure of the valveswhile the car is in transit.

(g) Protective housing, when re-quired, must be fabricated of approvedmaterial and have cover and sidewallsnot less than 0.119 inch in thickness.


§ 179.200–17 Bottom outlets.(a) If indicated in § 179.201–1, tank

may be equipped with bottom outlet.Bottom outlet, if applied, must complywith the following requirements:

(1) The extreme projection of the bot-tom outlet equipment may not be morethan that allowed by appendix E of theAAR Specifications for Tank Cars. Allbottom outlet reducers and closuresand their attachments shall be securedto the car by at least 3⁄8-inch chain, orits equivalent, except that the bottomoutlet closure plugs may be attachedby 1⁄4-inch chain. When the bottom out-let closure is of the combination capand valve type, the pipe connection tothe valve shall be closed by a plug, cap,or approved quick coupling device. Thebottom outlet equipment should in-clude only the valve, reducers and clo-sures that are necessary for the attach-ment of unloading fixtures. The perma-nent attachment of supplementary ex-terior fittings shall be approved by theAAR Committee on Tank Cars.

(2) Bottom outlet must be of ap-proved construction, and be providedwith a liquid-tight closure at its lowerend.

(3) On cars with center sills, a ballvalve may be welded to the outside bot-tom of the tank or mounted on a pad ornozzle with a tongue and groove ormale and female flange attachment. Inno case shall the breakage groove orequivalent extend below the bottomflange of the center sill. On cars with-out continuous center sills, a ball valvemay be welded to the outside bottom ofthe tank or mounted with a tongue andgroove or male and female flange at-tachment on a pad attached to the out-side bottom of the tank. The mounting


924

49 CFR Ch. I (10–1–98 Edition)§ 179.200–17

pad must have a maximum thickness of21⁄2 inches measured on the longitu-dinal centerline of the tank. The valveoperating mechanism must be providedwith a suitable locking arrangement toinsure positive closure during transit.

(4) The valve operating mechanismfor valves applied to the interior of thetank, and outlet nozzle construction,must insure against the unseating ofthe valve due to stresses or shocks in-cident to transportation.

(5) Bottom outlet nozzle of interiorvalves and the valve body of exteriorvalves, must be of cast, fabricated, orforged metal. If welded to tank, theymust be of good weldable quality inconjunction with metal of tank.

(6) To provide for the attachment ofunloading connections, the dischargeend of the bottom outlet nozzle or re-ducer, the valve body of the exteriorvalve, or some fixed attachment there-to, shall be provided with one of thefollowing arrangements or an approvedmodification thereof. (See appendix E.Fig. E17 of the AAR Specifications forTank Cars for illustrations of some ofthe possible arrangements.)

(i) A bolted flange closure arrange-ment including a minimum 1-inch NPTpipe plug (see Fig. E17.1) or includingan auxiliary valve with a threaded clo-sure.

(ii) A threaded cap closure arrange-ment including a minimum 1-inch NPTpipe plug (see Fig. E17.2) or includingan auxiliary valve with a threaded clo-sure.

(iii) A quick-coupling device using athreaded plug closure of at least 1-inchNPT or having a threaded cap closurewith a minimum 1-inch NPT pipe plug(see Fig. E17.3 through E17.5). A mini-mum 1-inch auxiliary test valve with athreaded closure may be substitutedfor the 1-inch pipe plug (see Fig. E17.6).If the threaded cap closure does nothave a pipe plug or integral auxiliarytest valve, a minimum 1-inch NPT pipeplug shall be installed in the outletnozzle above the closure (see Fig.E17.7).

(iv) A two-piece quick-coupling de-vice using a clamped dust cap must in-clude an in-line auxiliary valve, eitherintegral with the quick-coupling deviceor located between the primary bottomoutlet valve and the quick-coupling de-

vice. The quick-coupling device closuredust cap or outlet nozzle shall be fittedwith a minimum 1-inch NPT closure(see Fig. E17.8 and E17.9).

(7) If the outlet nozzle extends 6inches or more from the shell of thetank, a V-shaped breakage groove shallbe cut (not cast) in the upper part ofthe outlet nozzle at a point imme-diately below the lowest part of valveclosest to the tank. In no case may thenozzle wall thickness at the root of the‘‘V’’ be more than 1⁄4 inch. The outletnozzle on interior valves or the valvebody on exterior valves may be steamjacketed, in which case the breakagegroove or its equivalent must be belowthe steam chamber but above the bot-tom of center sill construction. If theoutlet nozzle is not a single piece, or ifexterior valves are applied, provisionsshall be made for the equivalent of thebreakage groove. On cars without con-tinuous center sills, the breakagegroove or its equivalent must be nomore than 15 inches below the tankshell. On cars with continuous centersills, the breakage groove or its equiva-lent must be above the bottom of thecenter sill construction.

(8) The flange on the outlet nozzle orthe valve body of exterior valves mustbe of a thickness which will preventdistortion of the valve seat or valve byany change in contour of the shell re-sulting from expansion of lading, orother causes, and which will insurethat accidental breakage of the outletnozzle will occur at or below the ‘‘V’’groove, or its equivalent.

(9) The valve must have no wings orstem projecting below the ‘‘V’’ grooveor its equivalent. The valve and seatmust be readily accessible or remov-able for repairs, including grinding.

(10) The valve operating mechanismon interior valves must have means forcompensating for variation in the ver-tical diameter of the tank produced byexpansion, weight of the liquid con-tents, or other causes, and may operatefrom the interior of the tank, but inthe event the rod is carried throughthe dome, or tank shell, leakage mustbe prevented by packing in stuffing boxor other suitable seals and a cap.

(b) If indicated in § 179.201–1, tankmay be equipped with bottom washoutof approved construction. If applied,


925


bottom washout shall be in accordancewith the following requirements:


(2) Bottom washout shall be of cast,forged or fabricated metal. If welded totank, they shall be of good weldablequality in conjunction with metal oftank.

(3) If the washout nozzle extends 6inches or more from the shell of thetank, a V-shaped breakage groove shallbe cut (not cast) in the upper part ofthe nozzle at a point immediatelybelow the lowest part of the inside clo-sure seat or plug. In no case may thenozzle wall thickness at the root of the‘‘V’’ be more than 1⁄4 inch. Where thenozzle is not a single piece, provisionsshall be made for the equivalent of thebreakage groove. The nozzle must be ofa thickness to insure that accidentalbreakage will occur at or below the‘‘V’’ groove or its equivalent. On carswithout continuous center sills, thebreakage groove or its equivalent maynot be more than 15 inches below theouter shell. On cars with continuouscenter sills, the breakage groove or itsequivalent must be above the bottomof the center sill construction.

(4) The closure plug and seat must bereadily accessible or removable for re-pairs, including grinding.




§ 179.200–19 Reinforcements, whenused, and appurtenances not other-wise specified.

(a) All attachments to tank anddome shall be applied by approvedmeans. Rivets if used shall be caulkedinside and outside.

(b) Reinforcing pads must be used be-tween external brackets and shells ifthe attachment welds exceed 6 lineal

inches of 1⁄4-inch fillet or equivalentweld per bracket or bracket leg. Whenreinforcing pads are used, they mustnot be less than one-fourth inch inthickness, have each corner rounded toa 1 inch minimum radius, and be at-tached to the tank by continuous filletwelds except for venting provisions.The ultimate shear strength of thebracket to reinforcing pad weld mustnot exceed 85 percent of the ultimateshear strength of the reinforcing pad totank weld.


§ 179.200–21 Closures for openings.

(a) All plugs shall be solid, with NPTthreads, and shall be of a length whichwill screw at least 6 threads inside theface of fitting or tank. Plugs, when in-serted from the outside of tank heads,shall have the letter ‘‘S’’ at least 3⁄8inch in size stamped with steel stampor cast on the outside surface to indi-cate the plug is solid.

(b) [Reserved]

§ 179.200–22 Test of tanks.

(a) Each tank shall be tested by com-pletely filling the tank and dome ornozzles with water, or other liquid hav-ing similar viscosity, of a temperaturewhich shall not exceed 100 °F. duringthe test; and applying the pressure pre-scribed in § 179.201–1. Tank shall holdthe prescribed pressure for at least 10minutes without leakage or evidence ofdistress. All rivets and closures, exceptsafety relief valves or safety vents,shall be in place when test is made.

(b) Insulated tanks shall be tested be-fore insulation is applied.

(c) Rubber-lined tanks shall be testedbefore rubber lining is applied.

(d) Caulking of welded joints to stopleaks developed during the foregoingtests is prohibited. Repairs in weldedjoints shall be made as prescribed inAAR Specifications for Tank Cars, ap-pendix W.


(a) Each valve shall be tested by airor gas for compliance with § 179.15 be-fore being put into service.


926

49 CFR Ch. I (10–1–98 Edition)§ 179.200–24

(b) [Reserved]

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, as amended at 62 FR51561, Oct. 1, 1997]

§ 179.200–24 Stamping.(a) To certify that the tank complies

with all specification requirements,each tank shall be plainly and perma-nently stamped in letters and figuresat least 3⁄8 inch high into the metalnear the center of both outside headsas follows:

Example of requiredstamping

Specification .................................. DOT–103–WMaterial ......................................... ASTM A 516–GR 70Cladding material (if any) ............. ASTM A240–304 CladTank builder’s initials .................... ABCDate of original test ...................... 00–0000Car assembler (if other than tank

builder).DEF

(b) On Class DOT–111 tank cars, thelast numeral of the specification num-ber may be omitted from the stamping;for example, DOT–111A100W.


§ 179.201 Individual specification re-quirements applicable to non-pres-sure tank car tanks.



DOT Specifica-tion 1 Insulation

Burstingpressure

(psi)

Minimumplate

thickness(inches)

Testpressure

(psi)

Bottomoutlet

Bottomwashout

References(179.201 - ***)

103A–ALW ...... Optional .......... 240 1⁄2 60 No ................... Optional.103AW ............. Optional .......... 240 179.201–2 60 No ................... Optional.103ALW ........... Optional .......... 240 1⁄2 60 Optional .......... Optional .......... 6(a).103ANW .......... Optional .......... 240 179.201–2 60 No ................... Optional .......... 6(d).103BW ............. Optional .......... 240 179.201–2 60 No ................... No ................... 6(b), 3.103CW ............ Optional .......... 240 179.201–2 60 No ................... No ................... 6(c), 4,5.103DW ............ Optional .......... 240 179.201–2 60 Optional .......... Optional .......... 6(a), 6(c), 4, 5.103EW ............. Optional .......... 240 179.201–2 60 No ................... Optional .......... 6(c), 4, 5.103W ............... Optional .......... 240 179.201–2 60 Optional .......... Optional .......... 6(a).104W ............... Yes .................. 240 179.201–2 60 Optional .......... Optional .......... 6(a).111A60ALW1 .. Optional .......... 240 1⁄2 60 Optional .......... Optional .......... 6(a).111A60ALW2 .. Optional .......... 240 1⁄2 60 No ................... Optional.111A60W1 ....... Optional .......... 240 7⁄16 60 Optional .......... Optional .......... 6(a).111A60W2 ....... Optional .......... 240 7⁄16 60 No ................... Optional.111A60W5 ....... Optional .......... 240 7⁄16 60 No ................... No ................... 3, 6(b).111A60W6 ....... Optional .......... 240 7⁄16 60 Optional .......... Optional .......... 4, 5, 6(a), 6(c).111A60W7 ....... Optional .......... 240 7⁄16 60 No ................... No ................... 4, 5, 6(a).111A100ALW1 Optional .......... 500 5⁄8 100 Optional .......... Optional .......... 6(a).111A100ALW2 Optional .......... 500 5⁄8 100 No ................... Optional.111A100W1 ..... Optional .......... 500 7⁄16 100 Optional .......... Optional .......... 6(a).111A100W2 ..... Optional .......... 500 7⁄16 100 No ................... Optional.111A100W3 ..... Yes .................. 500 7⁄16 100 Optional .......... Optional .......... 6(a).111A100W4 ..... Yes (see

179.201–11).500 7⁄16 100 No ................... No ................... 6(a), 8, 10.

111A100W5 ..... Optional .......... 500 7⁄16 100 No ................... No ................... 3.111A100W6 ..... Optional .......... 500 7⁄16 100 Optional .......... Optional .......... 4, 5, 6(a) and 6(c).111A100W7 ..... Optional .......... 500 7⁄16 100 No ................... No ................... 4, 5, 6(c).

1 Tanks marked ‘‘ALW’’ are constructed from aluminum alloy plate; ‘‘AN’’ nickel plate; ‘‘CW,’’ ‘‘DW,’’ ‘‘EW,’’ ‘‘W6,’’ and ‘‘W7’’high alloy steel or manganese-molybdenum steel plate; and those marked ‘‘BW’’ or ‘‘W5’’ must have an interior lining that con-forms to § 179.201–3.

[Amdt. 179–52, 61 FR 28680, June 5, 1996]

§ 179.201–2 Minimum plate thickness.(a) The minimum plate thickness,

after forming, must be as follows:


927


Inside diameter of tanks Bottomsheets

Shellsheets

Expan-sion

domesheets

2:1 ellip-soidalheads

3:1 ellip-soidaland

dishedtank

heads

Expan-sion

domeheads

Interiorcom-part-mentheads

Inches

60 inches or under .................................................... 7⁄16 1⁄4 5⁄16 7⁄16 1⁄2 5⁄16 5⁄16

Over 60 to 78 inches ................................................ 7⁄16 5⁄16 5⁄16 7⁄16 1⁄2 5⁄16 5⁄16

Over 78 to 96 inches ................................................ 11⁄2 3⁄8 5⁄16 7⁄16 1⁄2 5⁄16 3⁄8Over 96 to 112 inches .............................................. 11⁄2 7⁄16 5⁄16 7⁄16 9⁄16 5⁄16 7⁄16

Over 112 to 122 inches ............................................ 1⁄2 1⁄2 5⁄16 1⁄2 5⁄8 5⁄16 1⁄2

1 May be reduced to 7⁄16 inch when approved steels having tensile strength of 65,000 psi or higher are used.

(b) [Reserved][29 FR 18995, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967, and amended by Amdt.179–10, 36 FR 21352, Nov. 6, 1971]

§ 179.201–3 Lined tanks.

(a) Rubber-lined tanks. (1) Each tankor each compartment thereof must belined with acid-resistant rubber orother approved rubber compound vul-canized or bonded directly to the metaltank, to provide a nonporous laminatedlining, at least 5⁄32-inch thick, exceptoverall rivets and seams formed by riv-eted attachments in the lining must bedouble thickness. The rubber liningmust overlap at least 11⁄2 inches at alledges which must be straight and bebeveled to an angle of approximately45, or butted edges of lining must besealed with a 3-inch minimum strip oflining having 45 beveled edges.

(2) As an alternate method, the liningmay be joined with a skived butt seamthen capped with a separate strip oflining 3 inches wide having 45 bevelededges. An additional rubber reinforcingpad at least 41⁄2 feet square and at least1⁄2-inch thick must be applied by vul-canizing to the lining on bottom oftank directly under the manway open-ing. The edges of the rubber pad mustbe beveled to an angle of approxi-mately 45. An opening in this pad forsump is permitted. No lining must beunder tension when applied except dueto conformation over rivet heads. Inte-rior of tank must be free from scale,oxidation, moisture, and all foreignmatter during the lining operation.

(3) Other approved lining materialsmay be used provided the material isresistant to the corrosive or solvent ac-tion of the lading in the liquid or gasphase and is suitable for the servicetemperatures.

(b) Before a tank car tank is linedwith rubber, or other rubber compound,a report certifying that the tank andits equipment have been brought intocompliance with spec. DOT–103B,103BW, 111A60W5, or 111A100W5 must befurnished by car owner to the partywho is to apply the lining. A copy ofthis report in approved form, certifyingthat tank has been lined in compliancewith all requirements of one of theabove specifications, must be furnishedby party lining tank to car owner. Re-ports of the latest lining applicationmust be retained by the car owneruntil the next relining has been accom-plished and recorded.

(c) All rivet heads on inside of tankmust be buttonhead, or similar shape,and of uniform size. The under surfaceof heads must be driven tight againstthe plate. All plates, castings and rivetheads on the inside of the tank must becalked. All projecting edges of plates,castings and rivet heads on the insideof the tank must be rounded and freefrom fins and other irregular projec-tions. Castings must be free from po-rosity.

(d) All surfaces of attachments or fit-tings and their closures exposed to thelading must be covered with at least 1⁄8-inch acid resistant material. Attach-ments made of metal not affected bythe lading need not be covered withrubber or other acid resistant material.

(e) Hard rubber or polyvinyl chloridemay be used for pressure retainingparts of safety vents provided the ma-terial is resistant to the corrosive or


928

49 CFR Ch. I (10–1–98 Edition)§ 179.201–4

solvent action of the lading in the liq-uid or gas phase and is suitable for theservice temperatures.

(f) Polyvinyl chloride lined tanks.Tank car tanks or each compartmentthereof may be lined with elastomericpolyvinyl chloride having a minimumlining thickness of three thirty-secondsinch.

(g) Polyurethane lined tanks. Tankcar tanks or each compartment thereofmay be lined with elastomeric poly-urethane having a minimum liningthickness of one-sixteenth inch.

[Amdt. 179–10, 36 FR 21352, Nov. 6, 1971]

§ 179.201–4 Material.

All fittings, tubes, and castings andall projections and their closures, ex-cept for protective housing, must alsomeet the requirements specified inASTM specification A 262, except thatwhen preparing the specimen for test-ing the carburized surface may be fin-ished by grinding or machining.

[Amdt. 179–10, 36 FR 21353, Nov. 6, 1971, asamended by Amdt. 179–52, 61 FR 28681, June5, 1996; Amdt. 179–52, 61 FR 50255, Sept. 25,1996]

§ 179.201–5 Postweld heat treatmentand corrosion resistance.

(a) Tanks and attachments welded di-rectly thereto must be postweld heattreated as a unit at the proper tem-perature except as indicated below.Tanks and attachments welded directlythereto fabricated from ASTM Speci-fication A 240 Type 430A, Type 304 andType 316 materials must be postweldheat treated as a unit and must betested to demonstrate that they pos-sess the corrosion resistance specifiedin § 179.200–7(d), Footnote 2. Tanks andattachments welded directly thereto,fabricated from ASTM Specification A240 Type 304L or Type 316L materialsare not required to be postweld heattreated.

(b) Tanks and attachments welded di-rectly thereto, fabricated from ASTMSpecification A 240 Type 304L and Type316 materials must be tested to dem-onstrate that they possess the corro-

sion resistance specified in § 179.200–7(d), Footnote 2.

[Amdt. 179–10, 36 FR 21353, Nov. 6, 1971, asamended by Amdt. 179–52, 61 FR 28681, June5, 1996]

§ 179.201–6 Manways and manway clo-sures.

(a) The manway cover for spec. DOT103ALW, 103DW, 103W, 104W, 111A60–ALW1, 111A60W1, 111A100ALW1, 111A–100W1, 111A100W3, or 111A100W6 must bedesigned to make it impossible to re-move the cover while the interior ofthe tank is subjected to pressure.

(b) The manway cover for spec. DOT103BW, 11A60W5, or 111A100W5 must bemade of a suitable metal. The top, bot-tom and edge of manway cover must beacid resistant material covered as pre-scribed in § 179.201–3. Through-boltholes must be lined with acid resistantmaterial at least one-eighth inch inthickness. Cover made of metal not af-fected by the lading need not be acidresistant material covered.

(c) The manway ring and cover forspec. DOT–103CW, 103DW, 103EW,111360W7, or 11A100W6 must be made ofthe metal and have the same inspec-tion procedures specified in AAR Speci-fications for Tanks Cars Appendix M,M3.03.

(d) The manway ring for DOT 103ANW must be made of cast, forged orfabricated nickel and be a goodweldable quality in conjunction withthe metal of the dome. Manway covermust be made of nickel.

[Amdt. 179–10, 36 FR 21353, Nov. 6, 1971]

§ 179.201–8 Sampling device and ther-mometer well.

(a) Sampling valve and thermometerwell are not specification require-ments. When used, they must be of ap-proved design, made of metal not sub-ject to rapid deterioration by lading,and must withstand a pressure of 100pounds per square inch without leak-age. Interior pipes of the samplingvalve must be equipped with excessflow valves of an approved design. Inte-rior pipe of thermometer well must beclosed by an approved valve attachedclose to fitting where it passes throughthe tank and closed by a screw plug.


929


Other approved arrangements that per-mit testing thermometer well for leakswithout complete removal of the clo-sure may be used.

(b) [Reserved]

§ 179.201–9 Gauging device.

A gauging device of an approved de-sign must be applied to permit deter-mining the liquid level of the lading.The gauging device must be made ofmaterials not subject to rapid deterio-ration by the lading. When the interiorpipe of the gauging device provides ameans for passage of the lading fromthe interior to the exterior of the tank,it must be equipped with an excess flowvalve of an approved design. If theopening for passage of lading throughthe gauging device is not more than0.060 inch diameter an excess flow valveis not required. The gauging devicemust be provided with a protectivehousing.

[Amdt. 179–10, 36 FR 21353, Nov. 6, 1971]

§ 179.201–10 Water capacity marking.

(a) Water capacity of the tank inpounds stamped plainly and perma-nently in letters and figures at least 3⁄8inch high into the metal of the tankimmediately below the stamped marksspecified in § 179.200–24(a). This markshall also be stenciled on the jacketimmediately below the dome platformand directly behind or within 3 feet ofthe right or left side of the ladder, orladders, if there is a ladder on each sideof the tank, in letters and figures atleast 11⁄2 inches high as follows:

WATER CAPACITY

000000 Pounds

(b) [Reserved]

§ 179.201–11 Insulation.

(a) Insulation shall be of sufficientthickness so that the thermal conduct-ance at 60 °F. is not more than 0.075Btu per hour, per square foot, per de-gree F. temperature differential.

(b) [Reserved]

§ 179.220 General specifications appli-cable to nonpressure tank car tanksconsisting of an inner containersupported within an outer shell(class DOT–115).

§ 179.220–1 Tanks built under thesespecifications must meet the re-quirements of §§ 179.220, 179.221,and 179.222.

§ 179.220–3 Type.(a) Tanks built under these specifica-

tions must consist of an inner con-tainer, a support system for the innercontainer, and an outer shell.

(b) The inner container must be a fu-sion welded tank of circular cross sec-tion with formed heads designed con-vex outward and must have a manwayon top of the tank as prescribed herein.When the inner container is dividedinto compartments, each compartmentmust be considered a separate con-tainer.

(c) The outer shell must be a fusionwelded tank with formed heads de-signed convex outward.

[Amdt. 179–9, 36 FR 21340, Nov. 6, 1971]

§ 179.220–4 Insulation.The annular space between the inner

container and the outer shell must con-tain an approved insulation material.

[Amdt. 179–9, 36 FR 21340, Nov. 6, 1971]

§ 179.220–6 Thickness of plates.(a) The wall thickness, after forming

of the inner container shell and 2:1 el-lipsoidal heads must be not less thanspecified in § 179.221–1, or not less thanthat calculated by the following for-mula:

t =Pd

SE2where:

d = Inside diameter in inches;E = 0.9 welded joint efficiency; except E=1.0



rial in p.s.i. as prescribed in AAR Speci-fications for Tank Cars, appendix M, TableM1;


930

49 CFR Ch. I (10–1–98 Edition)§ 179.220–7


(b) The wall thickness after formingof the inner container heads, if flangedand dished, must be not less than speci-fied in § 179.221–1, or not less than thatcalculated by the following formula:

t =PL

SE

5

6where:

E = 0.9 welded joint efficiency; except E=1.0for seamless heads;

L = Main inside radius to which head isdished, measured on concave side in inches;

P = Minimum required bursting pressure inp.s.i.;

S = Minimum tensile strength of plate mate-rial in p.s.i. as prescribed in AAR Speci-fications for Tank Cars, appendix M., TableM1;


(c) The wall thickness after formingof the cylindrical section and heads ofthe outer shell must be not less thanseven-sixteenths of an inch.

(d) See § 179.220–9 for plate thicknessrequirements for inner container whendivided into compartments.

[Amdt. 179–9, 36 FR 21340, Nov. 6, 1971]


(a) The plate material used to fab-ricate the inner container and nozzlesmust meet one of the following speci-fications and with the indicated mini-mum tensile strength and elongationin the welded condition.

(b) Carbon steel plate: The maximumallowable carbon content must be 0.31percent when the individual specifica-tion allows carbon content greaterthan this amount. The plates may beclad with other approved materials.

Specifications

Mini-mum

tensilestrength(p.s.i.)weldedcondi-tion 1

Mini-mumelon-

gation in2 inches

(per-cent)weldmetal

(longitu-dinal)

AAR TC 128, Gr. B ................................ 81,000 19ASTM A 516, Gr. 70 .............................. 70,000 20


(c) Aluminum alloy plate: Aluminumalloy plate must be suitable for weld-ing and comply with one of the follow-ing specifications:

Specifications

Minimumtensile

strength(p.s.i.)weldedcondi-tion3 6


weld metal(longitu-

dinal)

ASTM B 209, Alloy 50521 ............. 25,000 18ASTM B 209, Alloy 50832 ............. 38,000 16ASTM B 209, Alloy 50861 ............. 35,000 14ASTM B 209, Alloy 51541 ............. 30,000 18ASTM B 209, Alloy 52541 ............. 30,000 18ASTM B 209, Alloy 54541 ............. 31,000 18ASTM B 209, Alloy 56521 ............. 25,000 18

1 For fabrication, the parent plate material may be 0 H112,or H32 temper, but design calculations must be based on theminimum tensile strength shown.

2 0 temper only.3 Weld filler metal 5556 must not be used.4 Not authorized for tank shells, manways or domes.5 T6 temper only.6 Maximum stresses to be used in calculations.

(d) High alloy steel plate: High alloysteel plate must comply with one ofthe following specifications:

Specifications

Minimumtensile


condition1


weld metal(longitu-

dinal)

ASTM A 240, Type 304 ................. 75,000 30ASTM A 240, Type 304L ............... 70,000 30ASTM A 240, Type 316 ................. 74,000 30ASTM A 240, Type 316L ............... 70,000 30


(e) Manganese-molybdenum steelplate: Manganese-molybdenum steelplate must be suitable for fusion weld-ing and must comply with the follow-ing specification:

Specifications

Minimumtensile


condition 1


weld metal(longitu-

dinal)

ASTM A 302, Gr. B ........................ 80,000 20


(f) Plate materials used to fabricatethe outer shell and heads must be thoselisted in paragraphs (b), (c), (d), or (e)of this section. The maximum allow-able carbon content must be 0.31 per-cent when the individual specificationallows carbon content greater thanthis amount. The plates may be cladwith other approved materials.


931


(g) All appurtenances on the innercontainer in contact with the ladingmust be made of approved materialcompatible with the plate material ofthe inner container. These appur-tenances must not be subject to rapiddeterioration by the lading, or must becoated or lined with suitable corrosionresistant material. See AAR Specifica-tions for Tank Cars, appendix M, M4.05for approved material specifications forcastings for fittings.

[Amdt. 179–9, 36 FR 21340, Nov. 6, 1971, asamended by Amdt. 179–28, 46 FR 49906, Oct. 8,1981; Amdt. 179–40, 52 FR 13048, Apr. 20, 1987;Amdt. 179–52, 61 FR 28681, June 5, 1996]

§ 179.220–8 Tank heads.(a) Tank heads of the inner con-

tainer, inner container compartmentsand outer shell must be of approvedcontour, and may be flanged and dishedor ellipsoidal for pressure on concaveside.

(b) Flanged and dished heads musthave main inside radius not exceeding10 feet and inside knuckle radius mustbe not less than 33⁄4 inches for steel andalloy steel tanks nor less than 5 inchesfor aluminum alloy tanks.

(c) Ellipsoidal heads must be an ellip-soid of revolution in which the majoraxis must equal the diameter of theshell and the minor axis must be one-half the major axis.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–9 Compartment tanks.(a) The inner container may be di-

vided into compartments by insertinginterior heads, or by fabricating eachcompartment as a separate containerand joining with a cylinder, or by fab-ricating each compartment as a sepa-rate tank without a joining cylinder.Each compartment must be capable ofwithstanding, without evidence ofyielding or leakage, the required testpressure applied in each compartmentseparately, or in any combination ofcompartments.

(b) When the inner container is di-vided into compartments by fabricat-ing each compartment as a separatecontainer and joining with a cylinder,the cylinder must have a plate thick-ness not less than that required for theinner container shell and must be ap-

plied to the outside surface of thestraight flange portion of the containerhead. The cylinder must fit thestraight flange tightly for a distance ofat least two times the plate thickness,or 1 inch, whichever is greater andmust be joined to the straight flangeby a full fillet weld. Distance from fil-let weld seam to container head seammust be not less than 11⁄2 inches orthree times the plate thickness, which-ever is greater.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–10 Welding.(a) All joints must be fusion-welded

in compliance with AAR Specificationsfor Tank Cars, appendix W. Weldingprocedures, welders, and fabricatorsshall be approved.

(b) Radioscopy of the outer shell isnot a specification requirement.

(c) Welding is not permitted on or toductile iron or malleable iron fittings.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–11 Postweld heat treatment.(a) Postweld heat treatment of the

inner container is not a specificationrequirement.

(b) Postweld heat treatment of thecylindrical portions of the outer shellto which the anchorage or draft sillsare attached must comply with AARSpecifications for Tank Cars, appendixW.

(c) When cold formed heads are usedon the outer shell they must be heattreated before welding to shell ifpostweld heat treatment is not prac-ticable due to assembly procedures.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–13 Inner container manwaynozzle and cover.

(a) Inner container manway nozzlemust be of approved design with accessopening at least 18 inches inside diame-ter, or at least 14 inches by 18 inchesobround or oval.

(b) Manway covers must be of ap-proved type. Design must provide a se-cure closure of the manway and mustmake it impossible to remove the coverwhile the tank interior is under pres-sure.

(c) All joints between manway coversand their seats must be made tight


932

49 CFR Ch. I (10–1–98 Edition)§ 179.220–14

against leakage of vapor and liquid byuse of suitable gaskets.

(d) Manway covers must be cast,forged, or fabricated metal complyingwith subsection § 179.220–7(g) of thissection.

(e) A seal must be provided betweenthe inner container manway nozzle andthe opening in the outer shell.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–14 Openings in the tanks.

Openings in the inner container andthe outer shell must be reinforced incompliance with AAR Specificationsfor Tank Cars, appendix E. In deter-mining the required reinforcementarea for openings in the outer shell, tshall be one-fourth inch.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–15 Support system for innercontainer.

(a) The inner container must be sup-ported within the outer shell by a sup-port system of adequate strength andductility at its operating temperatureto support the inner container whenfilled with liquid lading to any level.The support system must be designedto support, without yielding, impactloads producing accelerations of thefollowing magnitudes and directionswhen the inner container is loaded sothat the car is at its rail load limit,and the car is equipped with a conven-tional AAR Specification M–901 draftgear.Longitudinal...............................................7GTransverse ..................................................3GVertical ......................................................3G

(b) The longitudinal accelerationmay be reduced to 3G where a cushion-ing device of approved design, whichhas been tested to demonstrate its abil-ity to limit body forces to 400,000pounds maximum at a 10 miles perhour impact, is used between the cou-pler and the tank structure. The sup-port system must be of approved designand the inner container must be ther-mally isolated from the outer shell tothe best practical extent. The innercontainer and outer shell must be per-manently bonded to each other elec-trically either by the support system

used, piping, or by a separate electricalconnection of approved design.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971, asamended by Amdt. 179–28, 46 FR 49906, Oct. 8,1981]

§ 179.220–16 Expansion capacity.Expansion capacity must be provided

in the shell of the inner container asprescribed in § 179.221–1.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–17 Gauging devices, top load-ing and unloading devices, ventingand air inlet devices.

(a) When installed, each device mustbe of approved design which will pre-vent interchange with any other fix-ture and must be tightly closed. Eachunloading pipe must be securely an-chored within the inner container.Each inner container or compartmentthereof may be equipped with one sepa-rate air connection.

(b) When the characteristics of thecommodity for which the car is author-ized require these devices to beequipped with valves or fittings to per-mit the loading and unloading of thecontents, these devices includingvalves, shall be provided with a protec-tive housing except when plug or ball-type valves with operating handles re-moved are used. Provision must bemade for closing pipe connections ofvalves.

(c) Inner container may be equippedwith a vacuum relief valve of approveddesign. Protective housing is not re-quired.

(d) When a gauging device is requiredin § 179.221–1, an outage scale visiblethrough the manway opening must beprovided. If loading devices are appliedto permit tank loading with coverclosed, a telltale pipe may be provided.The telltail pipe must be capable of de-termining that required outage is pro-vided. The pipe must be equipped with1⁄4-inch maximum, NPT control valvemounted outside tank and enclosedwithin a protective housing. Other ap-proved devices may be used in place ofan outage scale or a telltale pipe.

(e) The bottom of the tank shell maybe equipped with a sump or siphonbowl, or both, welded or pressed intothe shell. These sumps or siphon bowls,if applied, are not limited in size and


933


must be made of cast, forged, or fab-ricated metal. Each sump or siphonbowl must be of good welding qualityin conjunction with the metal of thetank shell. When the sump or siphonbowl is pressed in the bottom of thetank shell, the wall thickness of thepressed section must not be less thanthat specified for the shell. The sectionof a circular cross section tank towhich a sump or siphon bowl is at-tached need not comply with the out-of-roundness requirement specified inappendix W, W14.06 of the AAR Speci-fications for Tank Cars. Any portion ofa sump or siphon bowl not forming apart of a cylinder of revolution musthave walls of such thickness and mustbe so reinforced that the stresses in thewalls caused by a given internal pres-sure are not greater than the circum-ferential stress which would existunder the same internal pressure in thewall of a tank of circular cross sectiondesigned in accordance with §§ 179.220–6(a) and 179.220–9. In no case shall thewall thickness be less than that speci-fied in § 179.221–1(a).

(f) Protective housing, when re-quired, must be of approved materialand must have cover and sidewalls notless than 0.119 inch in thickness.

[Amdt. 179–9, 36 FR 21341, Nov. 6, 1971]

§ 179.220–18 Bottom outlets.(a) The inner container may be

equipped with a bottom outlet of ap-proved design and an opening providedin the outer shell of its access. If ap-plied, the bottom outlet must complywith the following requirements:

(1) The extreme projection of the bot-tom outlet equipment may not be morethan that allowed by appendix E of theAAR Specifications for Tank Cars. Allbottom outlet reducers and closuresand their attachments shall be securedto car by at at least 3⁄8-inch chain, orits equivalent, except that bottom out-let closure plugs may be attached by1⁄4-inch chain. When the bottom outletclosure is of the combination cap andvalve type, the pipe connection to thevalve shall be closed by a plug, or cap.The bottom outlet equipment shouldinclude only the valve, reducers andclosures that are necessary for the at-tachment of unloading fixtures. Thepermanent attachment of supple-

mentary exterior fittings shall be ap-proved by the AAR Committee on TankCars.

(2) Each bottom outlet must be pro-vided with a liquid tight closure at itslower end.

(3) The valve and its operating mech-anism must be applied to the outsidebottom of the inner container. Thevalve operating mechanism must beprovided with a suitable locking ar-rangement to insure positive closureduring transportation.

(4) Valve outlet nozzle and valve bodymust be of cast, fabricated or forgedmetal. If welded to inner container,they must be of good weldable qualityin conjunction with metal of tank.

(5) To provide for the attachment ofunloading connections, the bottom ofthe main portion of the outlet nozzle orvalve body, or some fixed attachmentthereto, must be provided with thread-ed cap closure arrangement or boltedflange closure arrangement havingminimum 1-inch threaded pipe plug.

(6) If outlet nozzle and its closure ex-tends below the bottom of the outershell, a V-shaped breakage groove shallbe cut (not cast) in the upper part ofthe outlet nozzle at a point imme-diately below the lowest part of thevalve closest to the tank. In no casemay the nozzle wall thickness at theroot of the ‘‘V’’ be more than 1⁄4-inch.The outlet nozzle or the valve bodymay be steam jacketed, in which casethe breakage groove or its equivalentmust be below the steam chamber butabove the bottom of the center sill con-struction. If the outlet nozzle is not asingle piece or its exterior valves areapplied, provision shall be made for theequivalent of the breakage groove. Oncars without continuous center sills,the breakage groove or its equivalentmay not be more than 15 inches belowthe outer shell. On cars with continu-ous center sills, the breakage groove orits equivalent must be above the bot-tom of the center sill construction.

(7) The valve body must be of a thick-ness which will prevent distortion ofthe valve seat or valve by any changein contour of the shell resulting fromexpansion of lading, or other causes,and which will insure that accidentalbreakage of the outlet nozzle will occur


934

49 CFR Ch. I (10–1–98 Edition)§ 179.220–20

at or below the ‘‘V’’ groove, or itsequivalent.

(8) The valve must have no wings orstem projection below the ‘‘V’’ grooveor its equivalent. The valve and seatmust be readily accessible or remov-able for repairs, including grinding.

(b) Inner container may be equippedwith bottom washout of approved de-sign. If applied, bottom washout mustcomply with the following require-ments:


(2) Bottom washout must be of cast,forged or fabricated metals. If it iswelded to the inner container, it mustbe of good weldable quality in conjunc-tion with metal of tank.

(3) If washout nozzle extends belowthe bottom of the outer shell, a V-shaped breakage groove shall be cut(not cast) in the upper part of the noz-zle at a point immediately below thelowest part of the inside closure seat orplug. In no case may the nozzle wallthickness at the root of the ‘‘V’’ bemore than 1⁄4-inch. Where the nozzle isnot a single piece, provisions shall bemade for the equivalent of the break-age groove. The nozzle must be of athickness to insure that accidentalbreakage will occur at or below the‘‘V’’ groove or its equivalent. On carswithout a continuous center sill, thebreakage groove or its equivalent maynot be more than 15 inches below theouter shell. On cars with continuouscenter sills, the breakage groove or itsequivalent must be above the bottomof the center sill construction.

(4) The closure plug and seat must bereadily accessible or removable for re-pairs.



[Amdt. 179–9, 36 FR 21342, Nov. 6, 1971, asamended by Amdt. 179–40, 52 FR 13048, Apr.20, 1987]

§ 179.220–20 Reinforcements, whenused, and appurtenances not other-wise specified.

All attachments to inner containerand outer shell must be applied by ap-proved means.

[Amdt. 179–9, 36 FR 21342, Nov. 6, 1971]

§ 179.220–22 Closure for openings.

(a) All plugs must be solid, with NPTthreads, and must be of a length whichwill screw at least six threads insidethe face of fitting or tank. Plugs, wheninserted from the outside of the outershell tank heads, must have the letter‘‘S’’ at least three-eighths inch in sizestamped with steel stamp or cast onthe outside surface to indicate the plugis solid.

(b) Openings in the outer shell usedduring construction for installationmust be closed in an approved manner.

[Amdt. 179–9, 36 FR 21343, Nov. 6, 1971]

§ 179.220–23 Test of tanks.

(a) Each inner container or compart-ment must be tested hydrostatically tothe pressure specified in § 179.221–1. Thetemperature of the pressurizing me-dium must not exceed 100 °F. duringthe test. The container must hold theprescribed pressure for at least 10 min-utes without leakage or evidence ofdistress. Safety relief devices must notbe in place when the test is made.

(b) The inner container must be pres-sure tested before installation withinthe outer shell. Items which, because ofassembly sequence, must be welded toinner container after its installationwithin outer shell must have their at-tachment welds thoroughly inspectedby a nondestructive dye penetrantmethod or its equivalent.

(c) Pressure testing of outer shell isnot a specification requirement.

[Amdt. 179–9, 36 FR 21343, Nov. 6, 1971]


Each safety relief valve must be test-ed by air or gas for compliance with§ 179.15 before being put into service.

[Amdt. 179–9, 36 FR 21343, Nov. 6, 1971, asamended at 62 FR 51561, Oct. 1, 1997]


935


§ 179.220–25 Stamping.

To certify that the tank complieswith all specification requirements,each outer shell must be plainly andpermanently stamped in letters andfigures at least 3⁄8-inch high into themetal near the center of both outsideheads as follows:

Examples of requiredstamping

Specifications ................................ DOT–115A60W6.Inner container:

Material .................................. ASTM A240–316L.Shell thickness ....................... Shell 0.167 in.Head thickness ...................... Head 0.150 in.Tank builders initials .............. ABC.Date of original test ............... 00–0000.

Outer shell:Material .................................. ASTM A285–C.Tank builders initials .............. WYZ.

Car assembler (if other than innercontainer or outer shell build-ers).

DEF.

[Amdt. 179–9, 36 FR 21343, Nov. 6, 1971]

§ 179.220–26 Stenciling.(a) The outer shell, or the jacket if

the outer shell is insulated, must bestenciled in compliance with AARSpecifications for Tank Cars, appendixC.

(b) Stenciling must be applied onboth sides of the outer shell or jacketnear the center in letters and figures atleast 11⁄2 inches high to indicate thesafe upper temperature limit, if appli-cable, for the inner tank, insulation,and the support system.

[Amdt. 179–9, 36 FR 21343, Nov. 6, 1971]

§ 179.221 Individual specification re-quirements applicable to tank cartanks consisting of an inner con-tainer supported within an outershell.



DOT specification InsulationBurstingpressure

(psi)

Minimumplate

thickness(inches)

Testpressure

(psi)

Bottomoutlet

Bottomwashout

Reference(179.221–***)

115A60ALW ............ Yes ................. 240 3⁄16 60 Optional. Optional ..........115A60W1 ............... Yes ................. 240 1⁄8 60 Optional .......... Optional .......... 1115A60W6 ............... Yes ................. 240 1⁄8 60 Optional .......... Optional .......... 1

[Amdt. 170–52, 61 FR 28681, June 5, 1996, as amended at 62 FR 51561, Oct. 1, 1997]

Subpart E—Specifications forMulti-Unit Tank Car Tanks(Classes DOT–106A and110AW)

§ 179.300 General specifications appli-cable to multi-unit tank car tanksdesigned to be removed from carstructure for filling and emptying(Classes DOT–106A and 110AW).

§ 179.300–1 Tanks built under thesespecifications shall meet the re-quirements of § 179.300, § 179.301and when applicable, § 179.302.

§ 179.300–3 Type and general require-ments.

(a) Tanks built under this specifica-tion shall be cylindrical, circular incross section, and shall have heads ofapproved design. All openings shall belocated in the heads.

(b) Each tank shall have a water ca-pacity of at least 1500 pounds and notmore than 2600 pounds.

(c) For tanks made in foreign coun-tries, a chemical analysis of materialsand all tests as specified shall be car-ried out within the limits of the UnitedStates under the supervision of a com-petent and impartial inspector.

§ 179.300–4 Insulation.

(a) Tanks shall not be insulated.(b) [Reserved]

§ 179.300–6 Thickness of plates.

(a) For class DOT–110A tanks, thewall thickness after forming of the cy-lindrical portion of the tank must notbe less than that specified in § 179.301nor that calculated by the followingformula:


936

49 CFR Ch. I (10–1–98 Edition)§ 179.300–7

t =Pd

SE2where:

d = inside diameter in inches;E = 1.0 welded joint efficiency;P = minimum required bursting pressure in

p.s.i.;S = minimum tensile strength of plate mate-

rial in p.s.i. as prescribed § 179.300–7;t = minimum thickness of plate material in

inches after forming.

(b) For class DOT–106A tanks, thewall thickness of the cylindrical por-tion of the tank shall not be less thanthat specified in § 179.301 and shall besuch that at the tank test pressure themaximum fiber stress in the wall of thetank will not exceed 15,750 p.s.i. as cal-culated by the following formula:s = [p(1.3D 2 + 0.4d 2)] / (D 2 ¥ d 2)where:

d = inside diameter in inches;D = outside diameter in inches;p = tank test pressure in p.s.i.;s = wall stress in p.s.i.

(c) If plates are clad with materialhaving tensile strength at least equalto the base plate, the cladding may beconsidered a part of the base platewhen determining the thickness. Ifcladding material does not have tensilestrength at least equal to the baseplate, the base plate alone shall meetthe thickness requirements.

[29 FR 18995, Dec. 29, 1964, as amended byOrder 71, 31 FR 9083, July 1, 1966. Redesig-nated at 32 FR 5606, Apr. 5, 1967]

EDITORIAL NOTE: For FEDERAL REGISTER ci-tations to § 179.300–6, see the List of CFR Sec-tions Affected in the Finding Aids section ofthis volume.


(a) Steel plate material used to fab-ricate tanks must conform with thefollowing specifications with the indi-cated minimum tensile strength andelongation in the welded condition.However, the maximum allowable car-bon content for carbon steel must notexceed 0.31 percent, although the indi-vidual ASTM specification may allowfor a greater amount of carbon. Theplates may be clad with other approvedmaterials:

Specifications

Tensilestrength

(psi) weldedcondition 1

(minimum)

Elongationin 2 inches(percent)

welded con-dition 1 (lon-

gitudinal)(minimum)

ASTM A 240 type 304 ............... 75,000 25ASTM A 240 type 304L ............. 70,000 25ASTM A 240 type 316 ............... 75,000 25ASTM A 240 type 316L ............. 70,000 25ASTM A 240 type 321 ............... 75,000 25ASTM A285 Gr. A ...................... 45,000 29ASTM A285 Gr. B ...................... 50,000 20ASTM A285 Gr. C ...................... 55,000 20ASTM A515 Gr. 65 .................... 65,000 20ASTM A515 Gr. 70 .................... 70,000 20ASTM A516 Gr. 70 .................... 70,000 20


(b) [Reserved](c) All plates must have their heat

number and the name or brand of themanufacturer legibly stamped on themat the rolling mill.

[Amdt. 179–10, 36 FR 21355, Nov. 6, 1971, asamended by Amdt. 179–42, 54 FR 38798, Sept.20, 1989; Amdt. 179–43, 55 FR 27642, July 5,1990; Amdt. 179–52, 61 FR 28682, June 5, 1996;Amdt. 179–52, 61 FR 50255, Sept. 25, 1996;Amdt. 179–53, 61 FR 51342, Oct. 1, 1996]

§ 179.300–8 Tank heads.

(a) Class DOT–110A tanks shall havefusion-welded heads formed concave topressure. Heads for fusion welding shallbe an ellipsoid of revolution 2:1 ratio ofmajor to minor axis. They shall be onepiece, hot formed in one heat so as toprovide a straight flange at least 11⁄2inches long. The thickness shall not beless than that calculated by the follow-ing formula:

t =Pd

SE2

where symbols are as defined in§ 179.300–6(a).

(b) Class DOT–106A tanks must haveforged-welded heads, formed convex topressure. Heads for forge welding mustbe torispherical with an inside radiusnot greater than the inside diameter ofthe shell. They must be one piece, hotformed in one heat so as to provide astraight flange at least 4 inches long.They must have snug drive fit into theshell for forge welding. The wall thick-ness after forming must be sufficient tomeet the test requirements of § 179.300–


937


16 and to provide for adequate thread-ing of openings.


§ 179.300–9 Welding.(a) Longitudinal joints must be fu-

sion welded. Head-to-shell joints mustbe forge welded on class DOT–106Atanks and fusion welded on class DOT–110A tanks. Welding procedures, weld-ers and fabricators must be approved inaccordance with AAR Specificationsfor Tank Cars, appendix W.

(b) Fusion-welded joints must be incompliance with the requirements ofAAR Specifications for Tank Cars, ap-pendix W, except that circumferentialwelds in tanks less than 36 inches in-side diameter need not be radiotaped.

(c) Forge-welded joints shall be thor-oughly hammered or rolled to insuresound welds. The flanges of the headsshall be forge lapwelded to the shelland then crimped inwardly toward thecenter line at least one inch on the ra-dius. Welding and crimping must be ac-complished in one heat.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and as amended byAmdt. 179–10, 36 FR 21355, Nov. 6, 1971]

§ 179.300–10 Postweld heat treatment.After welding is complete, steel

tanks and all attachments weldedthereto, must be postweld heat treatedas a unit in compliance with the re-quirements of AAR Specifications forTank Cars, appendix W.

[Amdt. 179–10, 36 FR 21355, Nov. 6, 1971]

§ 179.300–12 Protection of fittings.(a) Tanks shall be of such design as

will afford maximum protection to anyfittings or attachment to the head in-cluding the housing referred to in§ 179.300–12(b). Tank ends shall slope orcurve inward toward the axis so thatthe diameter at each end is at least 2inches less than the maximum diame-ter.

(b) Loading and unloading valvesshall be protected by a detachable pro-tective housing of approved designwhich shall not project beyond the endof the tank and shall be securely fas-tened to the tank head. Safety relief

devices shall not be covered by thehousing.

§ 179.300–13 Venting, loading and un-loading valves.

(a) Valves shall be of approved type,made of metal not subject to rapid de-terioration by lading, and shall with-stand tank test pressure without leak-age. The valves shall be screwed di-rectly into or attached by other ap-proved methods to one tank head. Pro-vision shall be made for closing outletconnections of the valves.

(b) Threads for openings shall be Na-tional Gas Taper Threads (NGT) tappedto gage, clean cut, even and withoutchecks.

§ 179.300–14 Attachments not other-wise specified.

Siphon pipes and their couplings onthe inside of the tank head and lugs onthe outside of the tank head for attach-ing the valve protective housing mustbe fusion-welded in place prior topostweld heat treatment. All other fix-tures and appurtenances, except as spe-cifically provided for, are prohibited.

[Amdt. 179–10, 36 FR 21355, Nov. 6, 1971]

§ 179.300–15 Safety relief devices.

(a) Unless prohibited in § 179.302, or inpart 173 of this chapter, tanks shall beequipped with one or more safety reliefdevices of approved type, made ofmetal not subject to rapid deteriora-tion by the lading and screwed directlyinto tank heads or attached to tankheads by other approved methods. Thetotal discharge capacity shall be suffi-cient to prevent building up pressure intank in excess of 82.5 percent of thetank test pressure. When safety reliefdevices of the fusible plug type areused, the required discharge capacityshall be available in each head. SeeAAR Specifications for Tank Cars, ap-pendix A, for formula for calculatingdischarge capacity.

(b) Threads for openings shall be Na-tional Gas Taper Threads (NGT) tappedto gage, clean cut, even and withoutchecks.

(c) Safety relief valves shall be setfor start-to-discharge and frangiblediscs shall burst at a pressure not ex-ceeding that specified in § 179.301.


938

49 CFR Ch. I (10–1–98 Edition)§ 179.300–16

(d) Fusible plugs shall function at atemperature not exceeding 175 °F. andshall be vapor-tight at a temperatureof not less than 130 °F.

§ 179.300–16 Tests of tanks.

(a) After postweld heat treatment,tanks shall be subjected to hydrostaticexpansion test in a water jacket, or byother approved methods. No tank shallhave been subjected previously to in-ternal pressure within 100 pounds ofthe test pressure. Each tank shall betested to the pressure prescribed in§ 179.301. Pressure shall be maintainedfor 30 seconds and sufficiently longer toinsure complete expansion of tank.Pressure gage shall permit reading toaccuracy of one percent. Expansiongage shall permit reading of total ex-pansion to accuracy of one percent. Ex-pansion shall be recorded in cubic cen-timeters.

(1) No leaks shall appear and perma-nent volumetric expansion shall notexceed 10 percent of total volumetricexpansion at test pressure.

(2) [Reserved](b) After all fittings have been in-

stalled, each tank shall be subjected tointerior air pressure test of at least 100p.s.i. under conditions favorable to de-tection of any leakage. No leaks shallappear.

(c) Repairs of leaks detected in man-ufacture or in foregoing tests shall bemade by the same process as employedin manufacture of tank. Caulking, sol-dering, or similar repairing is prohib-ited.


§ 179.300–17 Tests of safety relief de-vices.

(a) Each valve shall be tested by airor gas before being put into service.The valve shall open and be vapor-tightat the pressure prescribed in § 179.301.

(b) Frangible discs of safety ventsmust be tested as prescribed in AARSpecifications for Tank Cars, appendixA, A5.03.

(c) For safety relief devices of the fu-sible plug type, a sample of the plugused shall function at the temperaturesprescribed in § 179.300–15.

(d) The start-to-discharge and vapor-tight pressures shall not be affected byany auxiliary closure or other com-bination.


§ 179.300–18 Stamping.

(a) To certify that the tank complieswith all specification requirements,each tank shall be plainly and perma-nently stamped in letters and figures 3⁄8inch high into the metal of valve endchime as follows:

(1) DOT Specification number.(2) Material and cladding material if

any (immediately below the specifica-tion number).

(3) Owner’s or builder’s identifyingsymbol and serial number (imme-diately below the material identifica-tion). The symbol shall be registeredwith the Bureau of Explosives, duplica-tions are not authorized.

(4) Inspector’s official mark (imme-diately below the owner’s or builder’ssymbol).

(5) Date of original tank test (monthand year, such as 1–64 for January1964). This should be so placed thatdates of subsequent tests may easily beadded thereto.

(6) Water capacity—0000 pounds.(b) A copy of the above stamping in

letters and figures of the prescribedsize stamped on a brass plate securedto one of the tank heads is authorized.

§ 179.300–19 Inspection.(a) Tank shall be inspected within

the United States and Canada by acompetent and impartial inspector ac-ceptable to the Bureau of Explosives.For tanks made outside the UnitedStates and Canada, the specified in-spection shall be made within theUnited States.

(b) The inspector shall carefully in-spect all plates from which tanks areto be made and secure records certify-ing that plates comply with the speci-fication. Plates which do not complywith § 179.300–7 shall be rejected.

(c) The inspector shall make such in-spection as may be necessary to seethat all the requirements of this speci-fication, including markings, are fully


939


complied with; shall see that the fin-ished tanks are properly stress relievedand tested.

(d) The inspector shall stamp his offi-cial mark on each accepted tank as re-quired in § 179.300–18, and render the re-port required in § 179.300–20.

§ 179.300–20 Reports.(a) Before a tank is placed in service,

the inspector shall furnish to the build-er, tank owner, Bureau of Explosivesand the Secretary, Mechanical Divi-sion, Association of American Rail-roads, a report in approved form cer-

tifying that the tank and its equip-ment comply with all the requirementsof this specification.

(b) For builder’s Certificate of Con-struction, see § 179.5 (b), (c), and (d).


§ 179.301 Individual specification re-quirements for multi-unit tank cartanks.

(a) In addition to § 179.300 the individ-ual specification requirements are asfollows:

DOT specification 106A500–X 106A800–X 110A500–W 110A600–W 110A800–W 110A1000–W

Bursting pressure, p.s.i. (see§ 179.300–5) ................................... (1) (1) 1250 1500 2000 2500

Minimum thickness shell, inches ........ 13⁄32 11⁄16 11⁄32 3⁄8 15⁄32 19⁄32

Test pressure, p.s.i. (see § 179.300–16) ................................................... 500 800 500 600 800 1000

Safety relief devices, p.s.i. (see§ 179.300–15) ................................. .................... .................... .................... .................... .................... ........................

Start-to-discharge, or burst maximum,p.s.i. ................................................. 375 600 375 450 600 700

Vapor-tight, minimum p.s.i .................. 300 480 300 360 480 650

1 None specified.

(b) [Reserved]


§ 179.302 [Reserved]

Subpart F—Specification for Cryo-genic Liquid Tank Car Tanksand Seamless Steel Tanks(Classes DOT–113 and 107A)

SOURCE: Sections 179.400 through 179.401–1appear at 48 FR 27708, June 16, 1983 (Amdt.179–32), unless otherwise noted.

Sections 179.500 through 179.500–18 appearat 29 FR 18995, Dec. 29, 1964, unless otherwisenoted. Redesignated at 32 FR 5606, Apr. 5,1967.

§ 179.400 General specification appli-cable to cryogenic liquid tank cartanks.

§ 179.400–1 General.

A tank built to this specificationmust comply with §§ 179.400 and 179.401.

§ 179.400–3 Type.(a) A tank built to this specification

must—(1) Consist of an inner tank of cir-

cular cross section supported essen-tially concentric within an outer jack-et of circular cross section, with theout of roundness of both the inner tankand outer jacket limited in accordancewith Section VIII, Division I, Para-graph UG–80 of the ASME Code;

(2) Have the annular space evacuatedafter filling the annular space with anapproved insulating material;

(3) Have the inner tank heads de-signed concave to pressure; and

(4) Have the outer jacket heads de-signed convex to pressure.

(b) The tank must be equipped withpiping systems for vapor venting andtransfer of lading, and with pressurerelief devices, controls, gages andvalves, as prescribed herein.

§ 179.400–4 Insulation system and per-formance standard.

(a) For the purposes of this specifica-tion—

(1) Standard Heat Transfer Rate(SHTR), expressed in Btu/day/lb of


940

49 CFR Ch. I (10–1–98 Edition)§ 179.400–5

water capacity, means the rate of heattransfer used for determining the satis-factory performance of the insulationsystem of a cryogenic tank car tank incryogenic liquid service (see § 179.401–1table).

(2) Test cryogenic liquid means thecryogenic liquid, which may be dif-ferent from the lading intended to beshipped in the tank, being used duringthe performance tests of the insulationsystem.

(3) Normal evaporation rate (NER), ex-pressed in lbs. (of the cryogenic liquid)/day, means the rate of evaporation, de-termined by test of a test cryogenicliquid in a tank maintained at a pres-sure of approximately one atmosphere,absolute. This determination of theNER is the NER test.

(4) Stabilization period means theelapsed time after a tank car tank isfilled with the test cryogenic liquiduntil the NER has stabilized, or 24hours has passed, whichever is greater.

(5) Calculated heat transfer rate. Thecalculated heat transfer rate (CHTR) isdetermined by the use of test data ob-tained during the NER test in the for-mula:

q = [N(∆ h)(90-tl)] / [V(8.32828)(ts-tf)]

Where:

q = CHTR, in Btu/day/lb., of water capacity;N = NER, determined by NER test, in lbs./

day;∆h = latent heat of vaporization of the test

cryogenic liquid at the NER test pressureof approximately one atmosphere, abso-lute, in Btu/lb.;

90 = ambient temperature at 90 °F.V = gross water volume at 60 °F. of the inner

tank, in gallons;tl = equilibrium temperature of intended lad-

ing at maximum shipping pressure, in ° F.;8.32828 = constant for converting gallons of

water at 60 °F. to lbs. of water at 60 °F., inlbs./gallon;

ts = average temperature of outer jacket, de-termined by averaging jacket tempera-tures at various locations on the jacket atregular intervals during the NER test, in°F.

tf = equilibrium temperature of the testcryogenic liquid at the NER test pressureof approximately, one atmosphere, abso-lute, in °F.

(b) DOT–113A60W tank cars must—(1) Be filled with hydrogen, cryogenic

liquid to the maximum permitted filldensity specified in § 173.319(d)(2) table

of this subchapter prior to performingthe NER test; and

(2) Have a CHTR equal to or less thanthe SHTR specified in § 179.401–1 tablefor a DOT–113A60W tank car.

(c) DOT–113C120W tank cars must—(1) Be filled with ethylene, cryogenic

liquid to the maximum permitted filldensity specified in § 173.319(d)(2) tableof this subchapter prior to performingthe NER test, or be filled with nitro-gen, cryogenic liquid to 90 percent ofthe volumetric capacity of the innertank prior to performing the NER test;and

(2) Have a CHTR equal to or less than75 percent of the SHTR specified in§ 179.401–1 table for a DOT–113C120Wtank car.

(d) Insulating materials must be ap-proved.

(e) If the insulation consists of a pow-der having a tendency to settle, the en-tire top of the cylindrical portion ofthe inner tank must be insulated witha layer of glass fiber insulation at leastone-inch nominal thickness, or equiva-lent, suitably held in position and cov-ering an area extending 25 degrees toeach side of the top center line of theinner tank.

(f) The outer jacket must be providedwith fittings to permit effective evacu-ation of the annular space between theouter jacket and the inner tank.

(g) A device to measure the absolutepressure in the annular space must beprovided. The device must be portablewith an easily accessible connection orpermanently positioned where it isreadily visible to the operator.

[Amdt. 179–32, 48 FR 27708, June 16, 1983, asamended at 49 FR 24318, June 12, 1984]

§ 179.400–5 Materials.(a) Stainless steel of ASTM Speci-

fication A240, Type 304 or 304L must beused for the inner tank and its appur-tenances, as specified in AAR Speci-fications for Tank Cars, appendix M,and must be—

(1) In the annealed condition prior tofabrication, forming and fusion weld-ing;

(2) Suitable for use at the tempera-ture of the lading; and

(3) Compatible with the lading.(b) Any steel casting, steel forging,

steel structural shape or carbon steel


941


plate used to fabricate the outer jacketor heads must be as specified in AARSpecifications for Tank Cars, appendixM.

(c) Impact tests must be—(1) Conducted in accordance with

AAR Specifications for Tank Cars, ap-pendix W, W9.01;

(2) Performed on longitudinal speci-mens of the material;

(3) Conducted at the tank designservice temperature or colder; and

(4) Performed on test plate welds andmaterials used for inner tanks and ap-purtenances and which will be sub-jected to cryogenic temperatures.

(d) Impact test values must be equalto or greater than those specified inAAR Specifications for Tank Cars, ap-pendix W. The report of impact testsmust include the test values and lat-eral expansion data.

§ 179.400–6 Bursting and bucklingpressure.

(a) [Reserved](b) The outer jacket of the required

evacuated insulation system must bedesigned in accordance with § 179.400–7(d) and in addition must comply withthe design loads specified in Section 6.2of the AAR Specifications for TankCars. The designs and calculationsmust provide for the loadings trans-ferred to the outer jacket through thesupport system.

[Amdt. 179–32, 48 FR 27708, June 16, 1983, asamended by Amdt. 179–51, 61 FR 18934, Apr.29, 1996]

§ 179.400–7 Tank heads.(a) Tank heads of the inner tank and

outer jacket must be flanged anddished, or ellipsoidal.

(b) Flanged and dished heads musthave—

(1) A main inside dish radius notgreater than the outside diameter ofthe straight flange;

(2) An inside knuckle radius of notless than 6 percent of the outside diam-eter of the straight flange; and

(3) An inside knuckle radius of atleast three times the head thickness.

§ 179.400–8 Thickness of plates.(a) The minimum wall thickness,

after forming, of the inner shell andany 2:1 ellipsoidal head for the inner

tank must be that specified in § 179.401–1, or that calculated by the followingformula, whichever is greater:

t = Pd / 2SE

Where:

t = minimum thickness of plate, after form-ing, in inches;

P = minimum required bursting pressure, inpsi;

d = inside diameter, in inches;S = minimum tensile strength of the plate

material, as prescribed in AAR Specifica-tions for Tank Cars, appendix M, table M1,in psi;

E = 0.9, a factor representing the efficiencyof welded joints, except that for seamlessheads, E = 1.0.

(b) The minimum wall thickness,after forming, of any 3:1 ellipsoidalhead for the inner tank must be thatspecified in § 179.401–1, or that cal-culated by the following formula,whichever is greater:

t = 1.83 Pd / 2SE

Where:



d = inside diameter, in inches;S = minimum tensile strength of the plate

material, as prescribed in AAR Specifica-tions for Tank Cars, Appendix M, TableM1, in psi;

E = 0.9, a factor representing the efficiencyof welded joints, except that for seamlessheads, E=1.0.

(c) The minimum wall thickness,after forming, of a flanged and dishedhead for the inner tank must be thatspecified in § 179.401–1, or that cal-culated by the following formula,whichever is greater:

t = [PL(3 + √(L/r))] / (8SE)

Where:



L = main inside radius of dished head, ininches;

r = inside knuckle radius, in inches;S = minimum tensile strength of plate mate-

rial, as prescribed in AAR Specificationsfor Tank Cars, appendix M, table M1, inpsi;

E = 0.9, a factor representing the efficiencyof welded joints, except that for seamlessheads, E = 1.0.


942

49 CFR Ch. I (10–1–98 Edition)§ 179.400–9

(d) The minimum wall thickness,after forming, of the outer jacket shellmay not be less than 7⁄16 inch. The min-imum wall thickness, after forming, ofthe outer jacket heads may not be lessthan 1⁄2 inch and they must be madefrom steel specified in § 179.100–23(a)(1).The annular space is to be evacuated,and the cylindrical portion of the outerjacket between heads, or between stiff-ening rings if used, must be designed towithstand an external pressure of 37.5psi (critical collapsing pressure), as de-termined by the following formula:

Pc = [2.6E(t/D)2.5] / [(L/D) ¥ 0.45(t/D)0.5]

Where:

Pc = Critical collapsing pressure (37.5 psiminimum), in psi;

E = modulus of elasticity of jacket material,in psi;

t = minimum thickness of jacket material,after forming, in inches;

D = outside diameter of jacket, in inches;L = distance between stiffening ring centers

in inches. (The heads may be considered asstiffening rings located 1⁄3 of the headdepth from the head tangent line.)

[Amdt. 179–32, 48 FR 27708, June 16, 1983; 49FR 42736, Oct. 24, 1984]

§ 179.400–9 Stiffening rings.(a) If stiffening rings are used in de-

signing the cylindrical portion of theouter jacket for external pressure, theymust be attached to the jacket bymeans of fillet welds. Outside stiffen-ing ring attachment welds must becontinuous on each side of the ring. In-side stiffening ring attachment weldsmay be intermittent welds on each sideof the ring with the total length ofweld on each side not less than one-third of the circumference of the tank.The maximum space between weldsmay not exceed eight times the outerjacket wall thickness.

(b) A portion of the outer jacket maybe included when calculating the mo-ment of inertia of the ring. The effec-tive width of jacket plate on each sideof the attachment of the stiffening ringis given by the following formula:

W = 0.78(Rt)0.5

Where:

W = width of jacket effective on each side ofthe stiffening ring, in inches;

R = outside radius of the outer jacket, ininches;

t = plate thickness of the outer jacket, afterforming, in inches.

(c) Where a stiffening ring is usedthat consists of a closed section havingtwo webs attached to the outer jacket,the jacket plate between the webs maybe included up to the limit of twice thevalue of ‘‘W’’, as defined in paragraph(b) of this section. The outer flange ofthe closed section, if not a steel struc-tural shape, is subject to the same lim-itations with ‘‘W’’ based on the ‘‘R’’and ‘‘t’’ values of the flange. Where twoseparate members such as two angles,are located less than ‘‘2W’’ apart theymay be treated as a single stiffeningring member. (The maximum length ofplate which may be considered effec-tive is 4W.) The closed section betweenan external ring and the outer jacketmust be provided with a drain opening.

(d) The stiffening ring must have amoment of inertia large enough to sup-port the critical collapsing pressure, asdetermined by either of the followingformulas:

I = [0.035D3 LPc] / E,

or

I′ = [0.046D3 LPc] / E

Where:

I = required moment of inertia of stiffeningring about the centroidal axis parallel tothe vessel axis, in inches to the fourthpower;

I′ = required moment of inertia of combinedsection of stiffening ring and effectivewidth of jacket plate about the centroidalaxis parallel to the vessel axis, in inches tothe fourth power;

D = outside diameter of the outer jacket, ininches;

L = one-half of the distance from the center-line of the stiffening ring to the next lineof support on one side, plus one-half of thedistance from the centerline to the nextline of support on the other side of stiffen-ing ring. Both distances are measured par-allel to the axis of the vessel, in inches. (Aline of support is:

(1) A stiffening ring which meets the re-quirements of this paragraph, or

(2) A circumferential line of a head atone-third the depth of the head fromthe tangent line);

Pc = critical collapsing pressure (37.5 psiminimum), in psi;

E = modulus of elasticity of stiffening ringmaterial, in psi.


943


(e) Where loads are applied to theouter jacket or to stiffening rings fromthe system used to support the innertank within the outer jacket, addi-tional stiffening rings, or an increasedmoment of inertia of the stiffeningrings designed for the external pres-sure, must be provided to carry thesupport loads.

§ 179.400–10 Sump or siphon bowl.

A sump or siphon bowl may be in thebottom of the inner tank shell if—

(a) It is formed directly into theinner tank shell, or is formed and weld-ed to the inner tank shell and is ofweldable quality metal that is compat-ible with the inner tank shell;

(b) The stress in any orientationunder any condition does not exceedthe circumferential stress in the innertank shell; and

(c) The wall thickness is not lessthan that specified in § 179.401–1.

§ 179.400–11 Welding.(a) Except for closure of openings and

a maximum of two circumferentialclosing joints in the cylindrical portionof the outer jacket, each joint of aninner tank and the outer jacket mustbe a fusion double welded butt joint.

(b) The closure for openings and thecircumferential closing joints in thecylindrical portion of the outer jacket,including head to shell joints, may be asingle welded butt joint using a back-ing strip on the inside of the joint.

(c) Each joint must be welded in ac-cordance with the requirements ofAAR Specifications for Tank Cars, ap-pendix W.

(d) Each welding procedure, welder,and fabricator must be approved.

§ 179.400–12 Postweld heat treatment.(a) Postweld heat treatment of the

inner tank is not required.(b) The cylindrical portion of the

outer jacket, with the exception of thecircumferential closing seams, must bepostweld heat treated as prescribed inAAR Specifications for Tank Cars, ap-pendix W. Any item to be welded tothis portion of the outer jacket mustbe attached before postweld heat treat-ment. Welds securing the followingneed not be postweld heat treated when

it is not practical due to final assemblyprocedures:

(1) the inner tank support system tothe outer jacket,

(2) connections at piping penetra-tions,

(3) closures for access openings, and(4) circumferential closing joints of

head to shell joints.(c) When cold formed heads are used

on the outer jacket they must be heattreated before welding to the jacketshell if postweld heat treatment is notpractical due to assembly procedures.

§ 179.400–13 Support system for innertank.

(a) The inner tank must be supportedwithin the outer jacket by a supportsystem of approved design. The systemand its areas of attachment to theouter jacket must have adequatestrength and ductility at operatingtemperatures to support the inner tankwhen filled with the lading to any levelincident to transportation.

(b) The support system must be de-signed to support, without yielding,impact loads producing accelerationsof the following magnitudes and direc-tions when the inner tank is fully load-ed and the car is equipped with a con-ventional draft gear:Longitudinal ...........................................7‘‘g’’Transverse...............................................3‘‘g’’Vertical ...................................................3‘‘g’’

The longitudinal acceleration may bereduced to 3‘‘g’’ where a cushioning de-vice of approved design, which has beentested to demonstrate its ability tolimit body forces to 400,000 poundsmaximum at 10 miles per hour, is usedbetween the coupler and the tankstructure.

(c) The inner tank and outer jacketmust be permanently bonded to eachother electrically, by either the sup-port system, piping, or a separate elec-trical connection of approved design.

§ 179.400–14 Cleaning of inner tank.

The interior of the inner tank and allconnecting lines must be thoroughlycleaned and dried prior to use. Properprecautions must be taken to avoidcontamination of the system aftercleaning.


944

49 CFR Ch. I (10–1–98 Edition)§ 179.400–15

§ 179.400–15 Radioscopy.

Each longitudinal and circumferen-tial joint of the inner tank, and eachlongitudinal and circumferential dou-ble welded butt joint of the outer jack-et, must be examined along its entirelength in accordance with the require-ments of AAR Specifications for TankCars, appendix W.

§ 179.400–16 Access to inner tank.

(a) The inner tank must be providedwith a means of access having a mini-mum inside diameter of 16 inches. Re-inforcement of the access opening mustbe made of the same material used inthe inner tank. The access closuremust be of an approved material anddesign.

(b) If a welded closure is used, itmust be designed to allow it to be re-opened by grinding or chipping and tobe closed again by rewelding, pref-erably without a need for new parts. Acutting torch may not be used.

§ 179.400–17 Inner tank piping.

(a) Product lines. The piping systemfor vapor and liquid phase transfer andventing must be made for materialcompatible with the product and hav-ing satisfactory properties at the lad-ing temperature. The outlets of allvapor phase and liquid phase linesmust be located so that accidental dis-charge from these lines will not im-pinge on any metal of the outer jacket,car structures, trucks or safety appli-ances. Suitable provison must be madeto allow for thermal expansion andcontraction.

(1) Loading and unloading line. A liq-uid phase transfer line must be pro-vided and it must have a manually op-erated shut-off valve located as closeas practicable to the outer jacket, plusa secondary closure that is liquid andgas tight. This secondary closure mustpermit any trapped pressure to bleedoff before the closure can be removedcompletely. A vapor trap must be in-corporated in the line and located asclose as practicable to the inner tank.On a DOT–113A60W tank car, any load-ing and unloading line must be vacuumjacketed between the outer jacket andthe shut-off valve and the shut-offvalve must also be vacuum jacketed

(2) Vapor phase line. A vapor phaseline must connect to the inner tankand must be of sufficient size to permitthe pressure relief devices specified in§ 179.400–20 and connected to this line tooperate at their design capacity with-out excessive pressure build-up in thetank. The vapor phase line must have amanually operated shut-off valve lo-cated as close as practicable to theouter jacket, plus a secondary closurethat is liquid and gas tight. This sec-ondary closure must permit anytrapped pressure to bleed off before theclosure can be removed completely.

(3) Vapor phase blowdown line. A blow-down line must be provided. It must beattached to the vapor phase line speci-fied in paragraph (a)(2) of this section,upstream of the shut-off valve in thatline. A by-pass line with a manuallyoperated shut-off valve must be pro-vided to permit reduction of the innertank pressure when the vapor phaseline is connected to a closed system.The discharge from this line must beoutside the housing and must be di-rected upward and away from operat-ing personnel.

(b) Any pressure building system pro-vided for the purpose of pressurizingthe vapor space of the inner tank to fa-cilitate unloading the liquid ladingmust be approved.

§ 179.400–18 Test of inner tank.

(a) After all items to be welded to theinner tank have been welded in place,the inner tank must be pressure testedat the test pressure prescribed in§ 179.401–1. The temperature of the pres-surizing medium may not exceed 100°F. during the test. The inner tankmust hold the prescribed pressure for aperiod of not less than ten minuteswithout leakage or distortion. In apneumatic test, due regard for the pro-tection of all personnel should be takenbecause of the potential hazard in-volved. After a hydrostatic test thecontainer and piping must be emptiedof all water and purged of all watervapor.

(b) Caulking of welded joints to stopleaks developed during the test is pro-hibited. Repairs to welded joints mustbe made as prescribed in AAR Speci-fications for Tank Cars, appendix W.


945


§ 179.400–19 Valves and gages.(a) Valves. Manually operated shut-

off valves and control valves must beprovided wherever needed for control ofvapor phase pressure, vapor phase vent-ing, liquid transfer and liquid flowrates. All valves must be made fromapproved materials compatible withthe lading and having satisfactoryproperties at the lading temperature.

(1) Liquid control valves must be ofextended stem design.

(2) Packing, if used, must be satisfac-tory for use in contact with the ladingand of approved materials that will ef-fectively seal the valve stem withoutcausing difficulty of operation.

(3) Each control valve and shut-offvalve must be readily operable. Thesevalves must be mounted so that theiroperation will not transmit excessiveforces to the piping system.

(b) Gages. Gages, except portableunits, must be securely mounted with-in suitable protective housings. A liq-uid level gage and a vapor phase pres-sure gage must be provided as follows:

(1) Liquid level gage. (i) A gage of ap-proved design to indicate the quantityof liquefied lading within the innertank, mounted where it will be readilyvisible to an operator during transferoperations or storage, or a portablegage with a readily accessible connec-tion, or

(ii) A fixed length dip tube, with amanually operated shut-off valve lo-cated as close as practicable to theouter jacket. The dip tube must indi-cate the maximum liquid level for theallowable filling density. The inner endof the dip tube must be located on thelongitudinal centerline of the innertank and within four feet of the trans-verse centerline of the inner tank.

(2) Vapor phase pressure gage. A vaporphase pressure gage of approved design,with a manually operated shut-offvalve located as close as practicable tothe outer jacket. The gage must indi-cate the vapor pressure within theinner tank and must be mounted whereit will be readily visible to an operator.An additional fitting for use of a testgage must be provided.

§ 179.400–20 Pressure relief devices.(a) The tank must be provided with

pressure relief devices for the protec-

tion of the tank assembly and pipingsystem. The discharge from these de-vices must be directed away from oper-ating personnel, principal load bearingmembers of the outer jacket, car struc-ture, trucks and safety appliances.Vent or weep holes in pressure reliefdevices are prohibited. All main pres-sure relief devices must discharge tothe outside of the protective housingsin which they are located, except thatthis requirement does not apply topressure relief valves installed to pro-tect isolated sections of lines betweenthe final valve and end closure.

(b) Materials. Materials used in pres-sure relief devices must be suitable foruse at the temperature of the ladingand otherwise compatible with the lad-ing in both the liquid and vapor phases.

(c) Inner tank. Pressure relief devicesfor the inner tank must be attached tovapor phase piping and mounted so asto remain at ambient temperatureprior to operation. The inner tankmust be equipped with one or morepressure relief valves and one or moresafety vents (except as noted in para-graph (c)(3)(iv) of this section), and in-stalled without an intervening shut-offvalve (except as noted in paragraph(c)(3)(iii) of this section). Additional re-quirements are as follows:

(1) Safety vent. The safety vent shallfunction at the pressure specified in§ 179.401–1. The safety vent must be flowrated in accordance with the applicableprovisions of AAR Specifications forTank Cars, appendix A, and providesufficient capacity to meet the require-ments of AAR Specifications for TanksCars, appendix A, A8.07(a).

(2) Pressure relief valve. The pressurerelief valve must:

(i) be set to start-to-discharge at thepressure specified in § 179.401–1, and

(ii) meet the requirements of AARSpecifications for Tank Cars, appendixA, A8.07(b).

(3) Installation of safety vent and pres-sure relief valve.—(i) Inlet piping. (A)The opening through all piping and fit-tings between the inner tank and itspressure relief devices must have across-sectional area at least equal tothat of the pressure relief device inlet,and the flow characteristics of this up-stream system must be such that thepressure drop will not adversely affect


946

49 CFR Ch. I (10–1–98 Edition)§ 179.400–20

the relieving capacity or the proper op-eration of the pressure relief device.

(B) When the required relief capacityis met by the use of multiple pressurerelief device placed on one connection,the inlet internal cross-sectional areaof this connection must be sufficient toprovide the required flow capacity forthe proper operation of the pressure re-lief device system.

(ii) Outlet piping. (A) The openingthrough the discharge lines must havea cross-sectional area at least equal tothat of the pressure relief device outletand may not reduce the relieving ca-pacity below that required to properlyprotect the inner tank.

(B) When the required relieving ca-pacity is met by use of multiple pres-sure relief devices placed on a commondischarge manifold, the manifold out-let internal cross-sectional area mustbe at least equal to the combined out-let areas of the pressure relief devices.

(iii) Duplicate pressure relief devicesmay be used when an approved 3-wayselector valve is installed to providefor relief through either duplicate pres-sure relief device. The 3-way valvemust be included in the mounting pre-scribed by AAR Specifications for TankCars, appendix A, A6.02(g), when con-ducting the flow capacity test on thesafety vent prescribed by AAR Speci-fications for Tank Cars, appendix A,A6.01. Flow capacity tests must be per-formed with the 3-way valve at both ofthe extreme positions as well as at themid-position and the flow capacitymust be in accordance with AAR Speci-fications for Tank Cars, appendix A,A8.07(a).

(iv) An alternate pressure reliefvalve, set as required in § 179.401–1, maybe used in lieu of the safety vent, pro-vided it meets the flow capacity pre-scribed in AAR Specifications for TankCars, appendix A at a flow rating pres-sure of 110 percent of its start-to-dis-charge pressure. Installation must—

(A) Prevent moisture accumulationat the seat by providing drainage awayfrom that area,

(B) Permit periodic drainage of thevent piping, and

(C) Prevent accumulation of foreignmaterial in the vent system.

(4) Evaporation control. The routinerelease of vaporized lading may be con-

trolled with a pressure controlling andmixing device, except that a pressurecontrolling and mixing device is re-quired on each DOT–113A60W car. Anypressure controlling and mixing devicemust—

(i) Be set to start-to-discharge at apressure not greater than that speci-fied in § 179.401–1;

(ii) Have sufficient capacity to limitthe pressure within the inner tank tothat pressure specified in § 179.401–1,when the discharge is equal to twicethe normal venting rate during trans-portation, with normal vacuum and theouter shell at 130 °F; and

(iii) Prevent the discharge of a gasmixture exceeding 50% of the lowerflammability limit to the atmosphereunder normal conditions of storage ortransportation.

(5) Safety interlock. If a safety inter-lock is provided for the purpose of al-lowing transfer of lading at a pressurehigher than the pressure control valvesetting but less than the pressure reliefvalve setting, the design must be suchthat the safety interlock will not affectthe discharge path of the pressure re-lief value or safety vent at any time.The safety interlock must automati-cally provide an unrestricted dischargepath for the pressure control device atall times when the tank car is in trans-port service.

(d) Outer jacket. The outer jacketmust be provided with a suitable sys-tem to prevent buildup of annularspace pressure in excess of 16 psig orthe external pressure for which theinner tank was designed, whichever isless. The total relief area provided bythe system must be a minimum of 25square inches, and means must be pro-vided to prevent clogging of any sys-tem opening, as well as to ensure ade-quate communication to all areas ofthe insulation space. If a safety vent isa part of the system, it must be de-signed to prevent distortion of thefrangible disc when the annular spaceis evacuated.

(e) Piping system. Where a piping cir-cuit can be isolated by closing a valve,means for pressure relief must be pro-vided.


947


§ 179.400–21 Test of pressure reliefvalves.

Each valve must be tested with air orgas for compliance with § 179.401–1 be-fore being put into service.

§ 179.400–22 Protective housings.Each valve, gage, closure and pres-

sure relief device, with the exception ofsecondary relief valves for the protec-tion of isolated piping, must be en-closed within a protective housing. Theprotective housing must be adequate toprotect the enclosed components fromdirect solar radiation, mud, sand, ad-verse environmental exposure and me-chanical damage incident to normaloperation of the tank car. It must bedesigned to provide reasonable accessto the enclosed components for oper-ation, inspection and maintenance andso that vapor concentrations cannotbuild up to a dangerous level inside thehousing in the event of valve leakageor pressure relief valve operation. Allequipment within the protective hous-ing must be operable by personnelwearing heavy gloves and must incor-porate provisions for locks or seals. Aprotective housing and its cover mustbe constructed of metal not less than0.119 inch thick.

§ 179.400–23 Operating instructions.All valves and gages must be clearly

identified with corrosion-resistantnameplates. A plate of corrosion-resist-ant material bearing precautionary in-structions for the safe operation of theequipment during storage and transferoperations must be securely mountedso as to be readily visible to an opera-tor. The instruction plate must bemounted in each housing containingoperating equipment and controls forproduct handling. These instructionsmust include a diagram of the tank andits piping system with the variousgages, control valves and pressure re-lief devices clearly identified and lo-cated.

§ 179.400–24 Stamping.(a) A tank that complies with all

specification requirements must havethe following information plainly andpermanently stamped into the metalnear the center of the head of the outerjacket at the ‘‘B’’ end of the car, in let-

ters and figures at least 3⁄8-inch high, inthe following order:

Example of re-quired stamping

Specification ............................................. DOT–113A60W.Design service temperature ..................... Minus 423° F.Inner tank ................................................. Inner Tank.

Material ............................................. ASTM A240–304.Shell thickness .................................. Shell 3⁄16 inch.Head thickness ................................. Head 3⁄16 inch.Inside diameter ................................. ID 107 inch.Inner tank builder’s initials ................ ABC.Date of original test (month and

year) and initials of person con-ducting original test.

00–0000GHK.

Water capacity .................................. 00000 lbs.Outer jacket ............................................. Outer jacket.

Material ............................................. ASTM A515–70.Outer jacket builder’s initials ............ DEF.

Car assembler’s initials (if other thaninner tank or outer jacket builder).

XYZ.

(b) Any stamping on the shell orheads of the inner tank is prohibited.

(c) In lieu of the stamping requiredby paragraph (a) of this section, thespecified markings may be incor-porated on a data plate of corrosion-re-sistant metal, fillet welded in place onthe head of the outer jacket at the ‘‘B’’end of the car.

§ 179.400–25 Stenciling.Each tank car must be stenciled in

compliance with the provisions of theAAR Specifications for Tank Cars, ap-pendix C. The stenciling must also in-clude the following:

(a) The date on which the frangibledisc was last replaced and the initialsof the person making the replacement,on the outer jacket in letters and fig-ures at least 11⁄2 inches high.

(b) The design service temperatureand maximum lading weight, in lettersand figures at least 11⁄2 inches high ad-jacent to the hazardous material sten-cil.

(c) The water capacity, in pounds netat 60 °F., with the tank at its coldestoperating temperature, after deductionfor the volume above the inlet to thepressure relief device or pressure con-trol valve, structural members, baffles,piping, and other appurtenances insidethe tank, in letters and figures at least11⁄2 inches high.

(d) Both sides of the tank car, in let-ters at least 11⁄2 inches high, with thestatement ‘‘Do Not Hump or Cut OffWhile in Motion.’’


948

49 CFR Ch. I (10–1–98 Edition)§ 179.401

(e) The outer jacket, below the tankclassification stencil, in letters at least11⁄2 inches high, with the statement,‘‘vacuum jacketed.’’

§ 179.401 Individual specification re-quirements applicable to innertanks for cryogenic liquid tank cartanks.


In addition to § 179.400, the individualspecification requirements for theinner tank and its appurtenances areas follows:

DOT specification 113A60W 113C120W

Design service tem-perature, °F.

¥423 ................ ¥260.

Material ....................... § 179.400–5 ...... § 179.400–5.Impact test (weld and

plate material).§ 179.400–5(c) .. § 179.400–5(c).

Impact test values ....... § 179.400–5(d) .. § 179.400–5(d).Standard heat transfer

rate.(Btu per day per lb.

of water capacity,max.) (see§ 179.400–4).

0.097 ................. 0.4121.

Bursting pressure, min.psi.

240 .................... 300.

Minimum plate thick-ness shell, inches(see § 179.400–7(a)).

3⁄16 ..................... 3⁄16.

Minimum head thick-ness, inches (see§ 179.400–7 (a), (b),and (c)).

3⁄16 ..................... 3⁄16.

Test pressure, psi (see§ 179.400–16).

60 ...................... 120.

Safety vent burstingpressure, max. psi.

60 ...................... 120.

Pressure relief valvestart-to-dischargepressure, psi (± 3psi).

30 ...................... 75.

Pressure relief valvevapor tight pressure,min. psi.

24 ...................... 60.

Pressure relief valveflow rating pressure,max. psi.

40 ...................... 85.

Alternate pressure re-lief valve start to-dis-charge pressure, psi(± 3 psi).

........................... 90.

Alternate pressure re-lief valve vapor tightpressure, min. psi.

........................... 72.

Alternate pressure re-lief valve flow ratingpressure, max. psi.

........................... 100.

Pressure control valveStart-to-vent, max.psi (see § 179.400–20(c)(4)).

17 ...................... Not required.

Relief device dischargerestrictions.

§ 179.400–20 .... 179.400–20.

Transfer line insulation § 179.400–17 .... Not required.

[Amdt. 179–32, 48 FR 27708, June 16, 1983, asamended at 49 FR 24318, June 12, 1984]

§ 179.500 Specification DOT–107A * * ** seamless steel tank car tanks.

§ 179.500–1 Tanks built under thesespecifications shall meet the re-quirements of § 179.500.

§ 179.500–3 Type and general require-ments.

(a) Tanks built under this specifica-tion shall be hollow forged or drawn inone piece. Forged tanks shall be ma-chined inside and outside before endsare necked-down and, after necking-down, the ends shall be machined tosize on the ends and outside diameter.Machining not necessary on inside oroutside of seamless steel tubing, butrequired on ends after necking-down.

(b) For tanks made in foreign coun-tries, chemical analysis of materialand all tests as specified must be car-ried out within the limits of the UnitedStates under supervision of a com-petent and disinterested inspector; inaddition to which, provisions in§ 179.500–18 (b) and (c) shall be carriedout at the point of manufacture by arecognized inspection bureau with prin-cipal office in the United States.

(c) The term ‘‘marked end’’ and‘‘marked test pressure’’ used through-out this specification are defined asfollows:

(1) ‘‘Marked end’’ is that end of thetank on which marks prescribed in§ 179.500–17 are stamped.

(2) ‘‘Marked test pressure’’ is thatpressure in pounds per square inchwhich is indicated by the figures sub-stituted for the **** in the markingDOT–107A **** stamped on the markedend of tank.

(d) The gas pressure at 130 F in thetank shall not exceed 7⁄10 of the markedtest pressure of the tank.

§ 179.500–4 Thickness of wall.(a) Minimum thickness of wall of

each finished tank shall be such that ata pressure equal to 7⁄10 of the markedtest pressure of the tank, the cal-culated fiber stress in pounds persquare inch at inner wall of tank mul-tiplied by 3.0 will not exceed the tensilestrength of any specimen taken fromthe tank and tested as prescribed in


949


§ 179.500–7(b). Minimum wall thicknessshall be 1⁄4 inch.

(b) Calculations to determine themaximum marked test pressure per-mitted to be marked on the tank shallbe made by the formula:

P = [10S(D 2 ¥ d 2)] / [7(D 2+d 2)]where:

P = Maximum marked test pressure per-mitted;

S = U / 3.0

where:

U = Tensile strength of that specimen whichshows the lower tensile strength of the twospecimens taken from the tank and testedas prescribed in § 179.500–7(b).

3 = Factor of safety.

(D 2 ¥ d 2/(D 2 + d 2) = The smaller value ob-tained for this factor by the operationsspecified in § 179.500–4(c).

(c) Measure at one end, in a planeperpendicular to the longitudinal axisof the tank and at least 18 inches fromthat end before necking-down:

d = Maximum inside diameter (inches) forthe location under consideration; to be de-termined by direct measurement to an ac-curacy of 0.05 inch.

t = Minimum thickness of wall for the loca-tion under consideration; to be determinedby direct measurement to an accuracy of0.001 inch.

Take D = d + 2t.Calculate the value of (D 2¥d 2)/(D 2 + d 2)

(1) Make similar measurements andcalculation for a corresponding loca-tion at the other end of the tank.

(2) Use the smaller result obtained,from the foregoing, in making calcula-tions prescribed in paragraph (b) of thissection.


§ 179.500–5 Material.

(a) Tanks shall be made from open-hearth or electric steel of uniformquality. Material shall be free fromseams, cracks, laminations, or otherdefects injurious to finished tank. Ifnot free from such defects, the surfacemay be machined or ground to elimi-nate these defects. Forgings and seam-less tubing for bodies of tanks shall bestamped with heat numbers.

(b) Steel (see Note 1) must conformto the following requirements as tochemical composition:

Designation Class I(percent)

Class II(percent)

Class III(percent)

Carbon, maximum .......... 0.50 0.50 0.53Manganese, maximum ... 1.65 1.65 1.85Phosphorus, maximum .. .05 .05 .05Sulphur, maximum ......... .06 .05 .05Silicon, maximum ........... .35 .30 .37Molybdenum, maximum ................ .25 .30Chromium, maximum ..... ................ .30 .30Sum of manganese and

carbon not over .......... 2.10 2.10 ................

NOTE 1: Alternate steel containing other alloying elementsmay be used if approved.

(1) For instructions as to the obtain-ing and checking of chemical analysis,see § 179.500–18(b)(3).

(2) [Reserved]

§ 179.500–6 Heat treatment.(a) Each necked-down tank shall be

uniformly heat treated. Heat treat-ment shall consist of annealing or nor-malizing and tempering for Class I,Class II and Class III steel or oilquenching and tempering for Class IIIsteel. Tempering temperatures shallnot be less than 1000 °F. Heat treat-ment of alternate steels shall be ap-proved. All scale shall be removed fromoutside of tank to an extent sufficientto allow proper inspection.

(b) To check uniformity of heattreatment, Brinnel hardness tests shallbe made at 18 inch intervals on the en-tire longitudinal axis. The hardnessshall not vary more than 35 points inthe length of the tank. No hardnesstests need be taken within 12 inchesfrom point of head to shell tangency.

(c) A magnetic particle inspectionshall be performed after heat treat-ment on all tanks subjected to aquench and temper treatment to detectthe presence of quenching cracks.Cracks shall be removed to soundmetal by grinding and the surface ex-posed shall be blended smoothly intothe surrounding area. A wall thicknesscheck shall then be made of the af-fected area by ultrasonic equipment orother suitable means acceptable to theinspector and if the remaining wallthickness is less than the minimum re-corded thickness as determined by§ 179.500–4(b) it shall be used for makingthe calculation prescribed in paragraph(b) of this section.


950

49 CFR Ch. I (10–1–98 Edition)§ 179.500–7

§ 179.500–7 Physical tests.

(a) Physical tests shall be made ontwo test specimens 0.505 inch in diame-ter within 2-inch gauge length, taken180 degrees apart, one from each ringsection cut from each end of eachforged or drawn tube before necking-down, or one from each prolongation ateach end of each necked-down tank.These test specimen ring sections orprolongations shall be heat treated,with the necked-down tank which theyrepresent. The width of the test speci-men ring section must be at least itswall thickness. Only when diametersand wall thickness will not permit re-moval of 0.505 by 2-inch tensile testbar, laid in the transverse direction,may test bar cut in the longitudinal di-rection be substituted. When the thick-ness will not permit obtaining a 0.505specimen, then the largest diameterspecimen obtainable in the longitu-dinal direction shall be used. Speci-mens shall have bright surface and areduced section. When 0.505 specimen isnot used the gauge length shall be aratio of 4 to 1 length to diameter.

(b) Elastic limit as determined by ex-tensometer, shall not exceed 70 percentof tensile strength for class I steel or 85percent of tensile strength for class IIand class III steel. Determination shallbe made at cross head speed of notmore than 0.125 inch per minute withan extensometer reading to 0.0002 inch.The extensometer shall be read at in-crements of stress not exceeding 5,000pounds per square inch. The stress atwhich the strain first exceeds

stress (pounds per square inch)/30,000,000(pounds per square inch) +0.005 (inches perinch)

shall be recorded as the elastic limit.(1) Elongation shall be at least 18 per-

cent and reduction of area at least 35percent.

NOTE 1: Upon approval, the ratio of elasticlimit to ultimate strength may be raised topermit use of special alloy steels of definitecomposition that will give equal or betterphysical properties than steels herein speci-fied.

(2) [Reserved]

[Amdt. 179–8, 36 FR 18470, Sept. 15, 1971]

§ 179.500–8 Openings in tanks.

(a) Each end shall be closed by acover made of forged steel. Covers shallbe secured to ends of tank by throughbolts or studs not entering interior oftank. Covers shall be of a thicknesssufficient to meet test requirements of§ 179.500–12 and to compensate for theopenings closed by attachments pre-scribed herein.

(1) It is also provided that each endmay be closed by internal threading toaccommodate an approved fitting. Theinternal threads as well as the threadson fittings for these openings shall beclean cut, even, without checks, andtapped to gauge. Taper threads are re-quired and shall be of a length not lessthan as specified for American Stand-ard taper pipe threads. Externalthreading of an approved type shall bepermissible on the internal threadedends.

(b) Joints between covers and endsand between cover and attachmentsshall be of approved form and madetight against vapor or liquid leakageby means of a confined gasket of suit-able material.

§ 179.500–10 Protective housing.

(a) Safety devices, and loading andunloading valves on tanks shall be pro-tected from accidental injury by ap-proved metal housing, arranged so itmay be readily opened to permit in-spection and adjustment of safety re-lief devices and valves, and securelylocked in closed position. Housing shallbe provided with opening having anopening equal to twice the total dis-charge area of safety relief device en-closed.

(b) [Reserved]

§ 179.500–11 Loading and unloadingvalves.

(a) Loading and unloading valve orvalves shall be mounted on the cover orthreaded into the marked end of tank.These valves shall be of approved type,made of metal not subject to rapid de-terioration by lading or in service, andshall withstand without leakage a pres-sure equal to the marked test pressureof tank. Provision shall be made forclosing service outlet of valves.

(b) [Reserved]


951


§ 179.500–12 Safety relief devices.

(a) Tank shall be equipped with oneor more safety relief devices of ap-proved type and discharge area, mount-ed on the cover or threaded into thenon-marked end of the tank. If fittingsare mounted on a cover, they shall beof the flanged type, made of metal notsubject to rapid deterioration by ladingor in service. Total flow capacity shallbe such that, with tank filled with airat pressure equal to 70 percent of themarked test pressure of tank, flow ca-pacity will be sufficient to reduce airpressure to 30 percent of the markedtest pressure within 3 minutes aftersafety relief device opens.

(b) Safety relief devices shall open atpressure not exceeding the marked testpressure of tank and not less than 7⁄10 ofmarked test pressure. (For tolerancefor safety relief valves, see § 179.500–16(a).)

(c) Cars used for the transportationof flammable gases shall have the safe-ty devices equipped with an approvedignition device.

§ 179.500–13 Fixtures.(a) Attachments, other than those

mounted on tank covers or serving asthreaded closures for the ends of thetank, are prohibited.

(b) [Reserved]

§ 179.500–14 Test of tanks.(a) After heat-treatment, tanks shall

be subjected to hydrostatic tests in awater jacket, or by other accuratemethod, operated so as to obtain reli-able data. No tank shall have been sub-jected previously to internal pressuregreater than 90 percent of the markedtest pressure. Each tank shall be testedto a pressure at least equal to themarked test pressure of the tank. Pres-sure shall be maintained for 30 seconds,and sufficiently longer to insure com-plete expansion of tank. Pressuregauge shall permit reading to accuracyof one percent. Expansion gauge shallpermit reading of total expansion toaccuracy of one percent. Expansionshall be recorded in cubic centimeters.

(b) No leaks shall appear and perma-nent volumetric expansion shall notexceed 10 percent of the total volu-metric expansion at test pressure.

§ 179.500–15 Handling of tanks failingin tests.

(a) Tanks rejected for failure in anyof the tests prescribed may be reheat-treated, and will be acceptable if subse-quent to reheat-treatment they aresubjected to and pass all of the tests.

(b) [Reserved]

§ 179.500–16 Tests of safety relief de-vices.

(a) Safety relief valves shall be testedby air or gas before being put into serv-ice. Valve shall open at pressure notexceeding the marked test pressure oftank and shall be vapor-tight at 80 per-cent of the marked test pressure. Theselimiting pressures shall not be affectedby any auxiliary closure or other com-bination.

(b) For safety relief devices of fran-gible disc type, samples of discs usedshall burst at a pressure not exceedingthe marked test pressure of tank andnot less than 7⁄10 of marked test pres-sure.

§ 179.500–17 Marking.

(a) Each tank shall be plainly andpermanently marked, thus certifyingthat tank complies with all require-ments of this specification. Thesemarks shall be stamped into the metalof necked-down section of tank atmarked end, in letters and figures atleast 1⁄4 inch high, as follows:

(1) Spec. DOT–107A * * * *, the * * * *to be replaced by figures indicatingmarked test pressure of the tank. Thispressure shall not exceed the cal-culated maximum marked test pres-sure permitted, as determined by theformula in § 179.500–4(b).

(2) Serial number immediately belowthe stamped mark specified in para-graph (a)(1) of this section.

(3) Inspector’s official mark imme-diately below the stamped mark speci-fied in paragraph (a)(1) of this section.

(4) Name, mark (other than trade-mark), or initials of company or personfor whose use tank is being made,which shall be recorded with the Bu-reau of Explosives.

(5) Date (such as 1–62, for January1962) of tank test, so placed that datesof subsequent tests may easily beadded thereto.


952

49 CFR Ch. I (10–1–98 Edition)§ 179.500–18

(6) Date (such as 1–62, for January1962) of latest test of safety relief valveor of frangible disc, required only whentank is used for transportation of flam-mable gases.

(b) [Reserved]

[29 FR 18995, Dec. 29, 1964, as amended byAmdt. 179–52, 61 FR 28682, June 5, 1996]

§ 179.500–18 Inspection and reports.(a) Before a tank car is placed in

service, the party assembling the com-pleted car shall furnish to car owner,Bureau of Explosives, and the Sec-retary, Mechanical Division, Associa-tion of American Railroads, a report inproper form certifying that tanks andtheir equipment comply with all therequirements of this specification andincluding information as to serial num-bers, dates of tests, and ownershipmarks on tanks mounted on car struc-ture.

(b) Purchaser of tanks shall providefor inspection by a competent inspec-tor as follows:

(1) Inspector shall carefully inspectall material and reject that not com-plying with § 179.500–5.

(2) Inspector shall stamp his officialmark on each forging or seamless tubeaccepted by him for use in makingtanks, and shall verify proper applica-tion of heat number to such materialby occasional inspections at steel man-ufacturer’s plant.

(3) Inspector shall obtain certifiedchemical analysis of each heat of mate-rial.

(4) Inspector shall make inspection ofinside surface of tanks before necking-down, to insure that no seams, cracks,laminations, or other defects exist.

(5) Inspector shall fully verify com-pliance with specification, verify heattreatment of tank as proper; obtainsamples for all tests and check chemi-cal analyses; witness all tests; and re-port minimum thickness of tank wall,maximum inside diameter, and cal-culated value of D, for each end of eachtank as prescribed in § 179.500–4(c).

(6) Inspector shall stamp his officialmark on each accepted tank imme-diately below serial number, and makecertified report (see paragraph (c) ofthis section) to builder, to company orperson for whose use tanks are beingmade, to builder of car structure on

which tanks are to be mounted, to theBureau of Explosives, and to the Sec-retary, Mechanical Division, Associa-tion of American Railroads.

(c) Inspector’s report required hereinshall be in the following form:

(Place) ——————————————(Date) ———————————————

STEEL TANKS

It is hereby certified that drawings weresubmitted for these tanks under AAR Appli-cation for Approval llllll and approvedby the AAR Committee on Tank Cars underdate of llllll.Built for llllllllllll CompanyLocation at lllllllllllllllllBuilt by llllllllllll CompanyLocation at lllllllllllllllllConsigned to lllllllll CompanyLocation at lllllllllllllllllQuantity llllllllllllllllllLength (inches) lllllllllllllllOutside diameter (inches) llllllllllMarks stamped into tank as required in

§ 179.500–17 are:

DOT–107A* * * *

NOTE 1: The marked test pressure sub-stituted for the * * * * on each tank is shownon Record of General Data on Tanks at-tached hereto.

Serial numbers ll to ll inclusiveInspector’s mark llllllllllllllOwner’s mark llllllllllllllllTest date llllllllllllllllllWater capacity (see Record of Hydrostatic

Tests).Tare weights (yes or no) (see Record of Hy-

drostatic Tests).These tanks were made by process of llll

Steel used was identified as indicated bythe attached list showing the serial numberof each tank, followed by the heat number.

Steel used was verified as to chemicalanalysis and record thereof is attached here-to. Heat numbers were stamped into metal.All material was inspected and each tankwas inspected both before and after closingin ends; all material accepted was found freefrom seams, cracks, laminations, and otherdefects which might prove injurious tostrength of tank. Processes of manufactureand heat-treatment of tanks were witnessedand found to be efficient and satisfactory.

Before necking-down ends, each tank wasmeasured at each location prescribed in§ 179.500–4(c) and minimum wall thickness ininches at each location was recorded; maxi-mum inside diameter in inches at each loca-tion was recorded; value of D in inches ateach location was calculated and recorded;maximum fiber stress in wall at locationshowing larger value for


953


(D 2+d 2)/(D 2¥d 2)

was calculated for 7⁄10 the marked test pres-sure and recorded. Calculations were madeby the formula:

S=[0.7P(D 2¥d 2)/(D 2+d 2)]

Hydrostatic tests, tensile test of material,and other tests as prescribed in this speci-fication, were made in the presence of the in-spector, and all material and tanks acceptedwere found to be in compliance with the re-quirements of this specification. Recordsthereof are attached hereto.

I hereby certify that all of these tanksproved satisfactory in every way and complywith the requirements of Department ofTransportation Specification No.107A* * * *.

(Signed) ——————————————(Inspector)

(Place) ——————————————(Date) ———————————————

RECORD OF CHEMICAL ANALYSIS OF STEEL FORTANKS

Numbered llll to llll inclusiveSize l inches outside diameter by l inches

longBuilt by llllllllllll Company

For lllllllllllllll Company

Heat No.Tanks rep-resented

(serial Nos.)

Chemical analysis

C Mn P S Si Ni Cr Mo

These analyses were made by(Signed) ——————————————(Place) ——————————————(Date) ———————————————

RECORD OF CHEMICAL ANALYSIS OF STEEL INTANKS

Numbered llll to llll inclusiveSize ll inches outside by ll inches longBuilt by llllllllllll CompanyFor lllllllllllllll Company

HeatNo.

Tanksrep-

resent-ed bytest

(serialNos.)

Elasticlimit

(poundsper

squareinch)

Tensilestrength(pounds

persquareinch)

Elon-gation

(percentin 2

inches)

Re-duc-

tion ofarea(per-cent)

(Signed) ——————————————

(Place) ......................................(Date) .....................................

RECORD OF HYDROSTATIC TESTS ON TANKS

Numbered ............................................................ to ......................................................................... inclusiveSize ...................................................................... inches outside by ................................................ ................ inches longBuilt by ...................................................................................................................................................................... CompanyFor ............................................................................................................................................................................ Company

Serial Nos. oftanks

Actual test pres-sure (pounds

per square inch)

Total expansion(cubic centi-

meters)

Permanent ex-pansion (cubiccentimeters)

Percent ratio ofpermanent ex-pansion to total

expansion1

Tare weight(pounds)2

Capacity inpounds of water

at 60 °F

1 If tests are made by method involving measurement of amount of liquid forced into tank by test pressure, then the basic dataon which calculations are made, such as pump factors, temperature of liquid, coefficient of compressibility of liquid, etc., mustalso be given.

2 Do not include protective housing, but state whether with or without valves.

(Signed) .......................................(Place) ......................................

(Date) .....................................

RECORD OF GENERAL DATA ON TANKS

Numbered ............................................................ to ......................................................................... inclusiveBuilt by ...................................................................................................................................................................... CompanyFor ............................................................................................................................................................................ Company


954

49 CFR Ch. I (10–1–98 Edition)Pt. 179, App. A

Data obtained as prescribed in § 179.500–4(c)

Largervalue ofthe fac-

torD 2+d 2/D 2¥d 2

(S) Cal-culated

fiberstress inpounds

persquare

inchat|0jA

markedtest

pressure

Markedtest pres-

sure inpounds

persquare

inchstampedin tank

Minimumtensile

strengthof mate-

rial inpounds

persquareinch re-corded

Marked end of tank Other end of tank

SerialNo. oftank

(t) Min.thick-

ness ofwall ininches

(d)Max.insidediame-ter in

inches

(D) Calculatedvalue of D ininches=d+2t

(t) Mini-mumthick-

ness ofwall ininches

(d)Maxi-muminsidediame-ter in

inches

(D) calculatedvalue of D ininches=d+2t

(Signed) .......................................

APPENDIX A TO PART 179—PROCEDURESFOR TANK-HEAD PUNCTURE-RESIST-ANCE TEST

1. This test procedure is designed to verifythe integrity of new or untried tank-headpuncture-resistance systems and to test forsystem survivability after coupler-to-tank-head impacts at relative speeds of 29 km/hour (18 mph). Tank-head puncture-resist-ance is a function of one or more of the fol-lowing: Head thickness, jacket thickness, in-sulation thickness, and material of construc-tion.

2. Tank-head puncture-resistance test. Atank-head puncture-resistance system mustbe tested under the following conditions:

a. The ram car used must weigh at least119,295 kg (263,000 pounds), be equipped with acoupler, and duplicate the condition of a con-ventional draft sill including the draft yokeand draft gear. The coupler must protrudefrom the end of the ram car so that it is theleading location of perpendicular contactwith the impacted test car.

b. The impacted test car must be loadedwith water at six percent outage with inter-nal pressure of at least 6.9 Bar (100 psi) andcoupled to one or more ‘‘backup’’ cars whichhave a total weight of 217,724 kg (480,000pounds) with hand brakes applied on the last‘‘backup’’ car.

c. At least two separate tests must be con-ducted with the coupler on the vertical cen-terline of the ram car. One test must be con-ducted with the coupler at a height of 53.3cm (21 inches), plus-or-minus 2.5 cm (1 inch),above the top of the sill; the other test mustbe conducted with the coupler height at 79cm (31 inches), plus-or-minus 2.5 cm (1 inch),above the top of the sill. If the combinedthickness of the tank head and any addi-tional shielding material is less than thecombined thickness on the vertical center-line of the car, a third test must be con-ducted with the coupler positioned so as tostrike the thinnest point of the tank head.

3. One of the following test conditionsmust be applied:

Minimum weight ofattached ram cars in

kg (pounds)

Minimum ve-locity of im-pact in km/hour (mph)

Restrictions

119,295 (263,000) ... 29 (18) ........... One ram car only.155,582 (343,000) ... 25.5 (16) ........ One ram car or one

car plus one rigidlyattached car.

311,164 (686,000) ... 22.5 (14) ........ One ram car plusone or more rigidlyattached cars.

4. A test is successful if there is no visibleleak from the standing tank car for at leastone hour after impact.


APPENDIX B TO PART 179—PROCEDURESFOR SIMULATED POOL AND TORCH-FIRE TESTING

1. This test procedure is designed to meas-ure the thermal effects of new or untriedthermal protection systems and to test forsystem survivability when exposed to a 100-minute pool fire and a 30-minute torch fire.

2. Simulated pool fire test.a. A pool-fire environment must be simu-

lated in the following manner:(1) The source of the simulated pool fire

must be hydrocarbon fuel with a flame tem-perature of 871 °C (1,600 °F), plus-or-minus37.8 °C (100 °F), throughout the duration ofthe test.

(2) A square bare plate with thermal prop-erties equivalent to the material of construc-tion of the tank car must be used. The platedimensions must be not less than one foot byone foot by nominal 1.6 cm (0.625 inch) thick.The bare plate must be instrumented withnot less than nine thermocouples to recordthe thermal response of the bare plate. Thethermocouples must be attached to the sur-face not exposed to the simulated pool fireand must be divided into nine equal squareswith a thermocouple placed in the center ofeach square.

(3) The pool-fire simulator must be con-structed in a manner that results in total


955

Research and Special Programs Administration, DOT Pt. 180

flame engulfment of the front surface of thebare plate. The apex of the flame must be di-rected at the center of the plate.

(4) The bare plate holder must be con-structed in such a manner that the only heattransfer to the back side of the bare plate isby heat conduction through the plate andnot by other heat paths.

(5) Before the bare plate is exposed to thesimulated pool fire, none of the temperaturerecording devices may indicate a plate tem-perature in excess of 37.8 °C (100 °F) nor lessthan 0 °C (32 °F).

(6) A minimum of two thermocouple de-vices must indicate 427 °C (800 °F) after 13minutes, plus-or-minus one minute, of simu-lated pool-fire exposure.

b. A thermal protection system must betested in the simulated pool-fire environ-ment described in paragraph 2a of this ap-pendix in the following manner:

(1) The thermal protection system mustcover one side of a bare plate as described inparagraph 2a(2) of this appendix.

(2) The non-protected side of the bare platemust be instrumented with not less thannine thermocouples placed as described inparagraph 2a(2) of this appendix to recordthe thermal response of the plate.

(3) Before exposure to the pool-fire simula-tion, none of the thermocouples on the ther-mal protection system configuration may in-dicate a plate temperature in excess of 37.8°C (100 °F) nor less than 0 °C (32 °F).

(4) The entire surface of the thermal pro-tection system must be exposed to the simu-lated pool fire.

(5) A pool-fire simulation test must run fora minimum of 100 minutes. The thermal pro-tection system must retard the heat flow tothe plate so that none of the thermocoupleson the non-protected side of the plate indi-cate a plate temperature in excess of 427 °C(800 °F).

(6) A minimum of three consecutive suc-cessful simulation fire tests must be per-formed for each thermal protection system.

3. Simulated torch fire test.a. A torch-fire environment must be simu-

lated in the following manner:(1) The source of the simulated torch must

be a hydrocarbon fuel with a flame tempera-ture of 1,204 °C (2,200 °F), plus-or-minus 37.8°C (100 °F), throughout the duration of thetest. Furthermore, torch velocities must be64.4 km/h ± 16 km/h (40 mph ± 10 mph)throughout the duration of the test.

(2) A square bare plate with thermal prop-erties equivalent to the material of construc-tion of the tank car must be used. The platedimensions must be at least four feet by fourfeet by nominal 1.6 cm (0.625 inch) thick. Thebare plate must be instrumented with notless than nine thermocouples to record thethermal response of the plate. Thethermocouples must be attached to the sur-face not exposed to the simulated torch and

must be divided into nine equal squares witha thermocouple placed in the center of eachsquare.

(3) The bare plate holder must be con-structed in such a manner that the only heattransfer to the back side of the plate is byheat conduction through the plate and notby other heat paths. The apex of the flamemust be directed at the center of the plate.

(4) Before exposure to the simulated torch,none of the temperature recording devicesmay indicate a plate temperature in excessof 37.8 °C (100 °F) or less than 0 °C (32 °F).

(5) A minimum of two thermocouples mustindicate 427 °C (800 °F) in four minutes, plus-or-minus 30 seconds, of torch simulation ex-posure.

b. A thermal protection system must betested in the simulated torch-fire environ-ment described in paragraph 3a of this ap-pendix in the following manner:

(1) The thermal protection system mustcover one side of the bare plate identical tothat used to simulate a torch fire underparagraph 3a(2) of this appendix.

(2) The back of the bare plate must be in-strumented with not less than ninethermocouples placed as described in para-graph 3a(2) of this appendix to record thethermal response of the material.

(3) Before exposure to the simulated torch,none of the thermocouples on the back sideof the thermal protection system configura-tion may indicate a plate temperature in ex-cess of 37.8 °C (100 °F) nor less than 0 °C (32°F).

(4) The entire outside surface of the ther-mal protection system must be exposed tothe simulated torch-fire environment.

(5) A torch-simulation test must be run fora minimum of 30 minutes. The thermal pro-tection system must retard the heat flow tothe plate so that none of the thermocoupleson the backside of the bare plate indicate aplate temperature in excess of 427 °C (800 °F).

(6) A minimum of two consecutive success-ful torch-simulation tests must be performedfor each thermal protection system.

[Amdt. 179–50, 60 FR 49078, Sept. 21, 1995]

PART 180—CONTINUING QUALI-FICATION AND MAINTENANCEOF PACKAGINGS

Subpart A—General

Sec.180.1 Purpose and scope.180.2 Applicability.180.3 General requirements.


pt. 178, app. c 49 cfr ch. i (10–1–98 edition)

Documents