178.245 49 cfr ch. i (101 01 edition) - gpo · pdf filerately at the other location or in the...

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49 CFR Ch. I (10–1–01 Edition)§ 178.245

latter specimens fails to meet require-ments, the entire lot represented mustbe rejected.

(2) Guided bend test. A bend test speci-men must be cut from the cylinderused for the physical tests specified inparagraph (j) of this section. Specimenmust be taken across the seam, mustbe 11⁄2 inches wide, edges must be par-allel and rounded with a file, and back-up strip, if used, must be removed bymachining. The specimen must be bentto refusal in the guided bend test jig il-lustrated in paragraph 6.10 of CGAPamphlet C–3. The root of the weld (in-side surface of the cylinder) must be lo-cated away from the ram of the jig. Nospecimen must show a crack or otheropen defect exceeding 1⁄8 inch in any di-rection upon completion of the test.Should this specimen fail to meet therequirements, specimens may be takenfrom each of 2 additional cylindersfrom the same lot and tested. If eitherof the latter specimens fail to meet re-quirements, the entire lot representedmust be rejected.

(m) Rejected cylinders. Repair of weld-ed seams is authorized. Acceptable cyl-inders must pass all prescribed tests.

(n) Inspector’s report. In addition tothe information required by § 178.35, therecord of chemical analyses must alsoinclude applicable information on iron,titanium, zinc, and magnesium used inthe construction of the cylinder.

[Amdt. 178–114, 61 FR 25942, May 23, 1996, asamended at 62 FR 51561, Oct. 1, 1997; 66 FR45386, Aug. 28, 2001]

Subparts D–G [Reserved]

Subpart H—Specifications forPortable Tanks

SOURCE: 29 FR 18972, Dec. 29, 1964, unlessotherwise noted. Redesignated at 32 FR 5606,Apr. 5, 1967.

§ 178.245 Specification 51; steel port-able tanks.

§ 178.245–1 Requirements for designand construction.

(a) Tanks must be seamless or weldedsteel construction or combination ofboth and have a water capacity in ex-cess of 454 kg (1,000 pounds). Tanksmust be designed, constructed, cer-

tified and stamped in accordance withthe ASME Code.

(b) Tanks must be postweld heattreated and radiographed as prescribedin the ASME Code except that eachtank constructed in accordance withpart UHT of the ASME Code must bepostweld heat treated. Where postweldheat treatment is required, the tankmust be treated as a unit after comple-tion of all the welds in and/or to theshell and heads. The method must be asprescribed in the ASME Code. Weldedattachments to pads may be made afterpostweld heat treatment is made. Atank used for anhydrous ammoniamust be postweld heat treated. Thepostweld heat treatment must be asprescribed in the ASME Code, but in noevent at less than 1050 °F tank metaltemperature. Additionally, tanks con-structed in accordance with part UHTof the ASME Code must conform to thefollowing requirements:

(1) Welding procedure and welder per-formance tests must be made annuallyin accordance with section IX of theASME Code. In addition to the essen-tial variables named therein, the fol-lowing must be considered to be essen-tial variables: number of passes, thick-ness of plate, heat input per pass, andmanufacturer’s identification of rodand flux. The number of passes, thick-ness of plate and heat input per passmay not vary more than 25 percentfrom the procedure qualification.Records of the qualification must beretained for at least 5 years by thetank manufacturer and made availableto duly identified representatives ofthe Department of Transportation orthe owner of the tank.

(2) Impact tests must be made on alot basis. A lot is defined as 100 tons orless of the same heat and having athickness variation no greater thanplus or minus 25 percent. The minimumimpact required for full-sized speci-mens shall be 20 foot-pounds (or 10foot-pounds for half-sized specimens) at0 °F Charpy V-Notch in both the longi-tudinal and transverse direction. If thelot test does not pass this requirement,individual plates may be accepted ifthey individually meet this impact re-quirement.

(c) Except as provided in paragraph(d) of this section, all openings in the

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Research and Special Programs Admin., DOT § 178.245–4

tank shall be grouped in one location,either at the top of the tank or at oneend of the tank.

(d) The following openings may be in-stalled at locations other than on thetop or end of the tank:

(1) The openings for liquid level gaug-ing devices, pressure gauges, or forsafety devices, may be installed sepa-rately at the other location or in theside of the shell;

(2) One plugged opening of 2-inch Na-tional Pipe Thread or less provided formaintenance purposes may be locatedelsewhere;

(3) An opening of 3-inch NationalPipe Size or less may be provided atanother location, when necessary, tofacilitate installation of condensingcoils; or

(4) Filling and discharge connectionsmay be installed below the normal liq-uid level of the tank if the tank designconforms to the following require-ments:

(i) The tank must be permanentlymounted in a full framework for con-tainerized transport. For each tank de-sign, a prototype tank, must fulfill therequirements of parts 450 through 453of this title for compliance with the re-quirements of Annex II of the Inter-national Convention for Safe Con-tainers.

(ii) Each filling and discharge con-nection must be equipped with an in-ternal self-closing stop-valve capable ofclosing within 30 seconds of actuation.Each internal self-closing stop-valvemust be protected by a shear section orsacrificial device located outboard ofthe valve. The shear section or sacrifi-cial device must break at no more than70 percent of the load that would causefailure of the internal self-closing stop-valve.

(iii) Each internal self-closing stop-valve must be provided with remotemeans of automatic closure, both ther-mal and mechanical. The thermalmeans of automatic closure must actu-ate at a temperature of not over 250 °F.

(e) Each uninsulated tank used forthe transportation of compressed gas,as defined in § 173.300 of this sub-chapter, must have an exterior surfacefinish that is significantly reflective,such as a light reflecting color if paint-

ed, or a bright reflective metal or othermaterial if unpainted.

[Amdt. 178–117, 61 FR 50627, Sept. 26, 1996]

§ 178.245–2 Material.(a) All material used for the con-

struction of the tank and appur-tenances shall be suitable for use withthe commodity to be transportedtherein.

(b) A material of thickness less than3⁄16 inch shall not be used for the shellsand heads.

§ 178.245–3 Design pressure.(a) The design pressure of a tank au-

thorized under this specification shallbe not less than the vapor pressure ofthe commodity contained therein at115 °F., or as prescribed for a particularcommodity by part 173 of this chapter,except that in no case shall the designpressure of any container be less than100 psig or more than 500 psig. Whencorrosion factor is prescribed by theseregulations, the wall thickness of thetank calculated in accordance with the‘‘Code’’ (see § 178.245–1(a)) shall be in-creased by 20 percent or 0.10 inch,whichever is less.

NOTE 1: The term design pressure as used inthis specification is identical to the termMAWP as used in the ‘‘Code’’ (see § 178.245–1(a)).

(b) [Reserved]

[29 FR 18972, Dec. 29, 1964; Redesignated at 32FR 5606, Apr. 5, 1967, as amended by 66 FR45387, Aug. 28, 2001]

§ 178.245–4 Tank mountings.(a) Tanks shall be designed and fab-

ricated with mountings to provide a se-cure base in transit. ‘‘Skids’’ or similardevices shall be deemed to comply withthis requirement.

(b) All tank mountings such as skids,fastenings, brackets, cradles, liftinglugs, etc., intended to carry loadingsshall be permanently secured to tanksin accordance with the requirements ofthe Code under which the tanks werefabricated and shall be designed towithstand static loadings in any direc-tion equal to twice the weight of thetank and attachments when filled withthe lading using a safety factor of notless than four, based on the ultimatestrength of the material to be used.


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49 CFR Ch. I (10–1–01 Edition)§ 178.245–5

The specific gravity used in deter-mining the static loadings shall beshown on the marking required by§ 178.245–6(a) and on the report requiredby § 178.245–7(a).

(c) Lifting lugs or hold-down lugsmay be added to either the tank ortank mountings. If lifting lugs andhold-down lugs are added directly tothe tank, they shall be secured to dou-bling plates welded to the tank and lo-cated at points of support, except thatlifting lugs or hold-down lugs with in-tegral bases serving as doubling platesmay be welded directly to the tank.Each lifting lug and hold-down lugshall be designed to withstand staticloadings in any direction equal totwice the weight of the tank and at-tachments when filled with the ladingusing a safety factor of not less thanfour, based on the ultimate strength ofthe material to be used.

(d) All tank mountings shall be de-signed so as to prevent the concentra-tion of excessive loads on the tankshell.

(e) A DOT 51 portable tank thatmeets the definition of ‘‘container’’ in§ 450.3(a)(2) of this title must meet therequirements of parts 450 through 453of this title, in addition to the require-ments of this subchapter.

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, as amended by Amdt.178–117, 61 FR 50628, Sept. 26, 1996; 64 FR51919, Sept. 27, 1999]

§ 178.245–5 Protection of valves andaccessories.

(a) All valves, fittings, accessories,safety devices, gaging devices, and thelike shall be adequately protectedagainst mechanical damage.

(b) The protective device or housingshall conform to the requirementsunder which the tanks are fabricatedwith respect to design and construc-tion, and shall be designed to with-stand static loadings in any directionequal to twice the weight of the tankand attachments when filled with thelading using a safety factor of not lessthan four, based on the ultimatestrength of the material to be used.

(c) Requirements concerning types ofvalves, retesting, and qualification ofportable tanks contained in §§ 173.32

and 173.315 of this chapter must be ob-served.

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, as amended by Amdt.178–104, 59 FR 49135, Sept. 26, 1994]

§ 178.245–6 Name plate.

(a) In addition to the markings re-quired by the Code (see § 178.245–1(a))under which tanks were constructed,they shall have permanently affixed, inclose proximity to the ASME ‘‘U’’stamp certification, a metal plate. Thisplate shall be permanently affixed bymeans of soldering, brazing, or weldingaround its complete perimeter. Neitherthe plate itself nor the means of at-tachment to the tank shall be subjectto destructive attack by the contentsof tank. Upon such plate shall be plain-ly marked by stamping, embossing, orother means of forming letters into oronto the metal plate itself the fol-lowing information in characters atleast 1⁄8-inch high:

Manufacturer’s name llllllllllll

Serial No. ——— Owner’s serial No. lllll

D.O.T. Specification No. llllllllll

Water capacity (pounds) llllllllll

Tare weight (pounds) llllllllllll

Design pressure (psig) llllllllllll

Design specific gravity lllllllllll

Original test date llllllllllllll

Tank retested at ——— (psig) on: llllll

(b) All tank outlets and inlets, exceptsafety relief valves, shall be marked todesignate whether they communicatewith vapor or liquid when the tank isfilled to the maximum permitted fill-ing density.

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.178–67, 46 FR 49906, Oct. 8, 1981; Amdt. 178–117,61 FR 50628, Sept. 26, 1996]

§ 178.245–7 Report.

(a) A copy of the manufacturer’s datareport required by the Code (See§ 178.245–1(a)) under which the tank isfabricated shall be furnished to theowner for each new tank.

(b) [Reserved]

[Amdt. 178–76, 48 FR 28102, June 20, 1983]


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§§ 178.251—178.253–5 [Reserved]

§ 178.255 Specification 60; steel port-able tanks.

§ 178.255–1 General requirements.(a) Tanks must be of fusion welded

construction, cylindrical in shape withseamless heads concave to the pres-sure. Tank shells may be of seamlessconstruction.

(b) Tanks must be designed and con-structed in accordance with and fulfillall the requirements of the ASMECode.

(c) Tanks including all permanent at-tachments must be postweld heattreated as a unit.

(d) Requirements concerning types ofvalves, retesting, and qualification ofportable tanks contained in §§ 173.32and 173.315 of this chapter must be ob-served.

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.178–7, 34 FR 18250, Nov. 14, 1969]

§ 178.255–2 Material.(a) Material used in the tank must be

steel of good weldable quality and con-form with the requirements of theASME Code.

(b) The minimum thickness of metal,exclusive of lining material, for shelland heads of tanks shall be as follows:

Tank capacityMinimumthickness

(inch)

Not more than 1,200 gallons ............................... 1⁄4Over 1,200 to 1,800 gallons ................................ 5⁄16

Over 1,800 gallons .............................................. 3⁄8

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.178–7, 34 FR 18250, Nov. 14, 1969]

§ 178.255–3 Expansion domes.(a) Expansion domes, if applied, must

have a minimum capacity of one per-cent of the combined capacity of thetank and dome.

(b) [Reserved]

§ 178.255–4 Closures for manholes anddomes.

(a) The manhole cover shall be de-signed to provide a secure closure ofthe manhole. All covers, not hinged tothe tanks, shall be attached to the out-

side of the dome by at least 1⁄8 inchchain or its equivalent. Closures shallbe made tight against leakage of vaporand liquid by use of gaskets of suitablematerial.

(b) [Reserved]

§ 178.255–5 Bottom discharge outlets.(a) Bottom discharge outlets prohib-

ited, except on tanks used for ship-ments of sludge acid and alkaline cor-rosive liquids.

(b) If installed, bottom outlets orbottom washout chambers shall be ofmetal not subject to rapid deteriora-tion by the lading, and each shall beprovided with a valve or plug at itsupper end and liquid-tight closure at itlower end. Each valve or plug shall bedesigned to insure against unseatingdue to stresses or shocks incident totransportation. Bottom outlets shall beadequately protected against handlingdamage and outlet equipment must notextend to within less than one inch ofthe bottom bearing surface of the skidsor tank mounting.


§ 178.255–6 Loading and unloading ac-cessories.

(a) When installed, gauging, loadingand air inlet devices, including theirvalves, shall be provided with adequatemeans for their secure closure; andmeans shall also be provided for theclosing of pipe connections of valves.

(b) Interior heater coils, if installed,must be of extra heavy pipe and so con-structed that breaking off of exteriorconnections will not cause leakage oftanks.


(a) All valves, fittings, accessories,safety devices, gauging devices, and thelike shall be adequately protectedagainst mechanical damage by a hous-ing closed with a cover plate.

(b) Protective housing shall complywith the requirements under which thetanks are fabricated with respect to de-sign and construction, and shall be de-signed with a minimum factor of safetyof four to withstand loadings in any di-rection equal to two times the weight


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49 CFR Ch. I (10–1–01 Edition)§ 178.255–8

of the tank and attachments whenfilled with water.

§ 178.255–8 Safety devices.(a) See § 173.315(i) of this subchapter.(b) [Reserved]

[Amdt. 178–83, 50 FR 11066, Mar. 19, 1985]

§ 178.255–9 Compartments.(a) When the interior of the tank is

divided into compartments, each com-partment shall be designed, con-structed and tested as a separate tank.Thickness of shell and compartmentheads shall be determined on the basisof total tank capacity.

(b) [Reserved]

§ 178.255–10 Lining.(a) If a lining is required, the mate-

rial used for lining the tank shall behomogeneous, nonporous, imperforatewhen applied, not less elastic than themetal of the tank proper. It shall be ofsubstantially uniform thickness, notless than 1⁄32 inch thick if metallic, andnot less than 1⁄16 inch thick if non-metallic, and shall be directly bondedor attached by other equally satisfac-tory means. Rubber lining shall be notless than 3⁄16 inch thick. Joints andseams in the lining shall be made byfusing the material together or byother equally satisfactory means. Theinterior of the tank shall be free fromscale, oxidation, moisture and all for-eign matter during the lining oper-ation.

(b) [Reserved]

§ 178.255–11 Tank mountings.(a) Tanks shall be designed and fab-

ricated with mountings to provide a se-cure base in transit. ‘‘Skids’’ or similardevices shall be deemed to comply withthis requirement.

(b) All tank mountings such as skids,fastenings, brackets, cradles, liftinglugs, etc., intended to carry loadingsshall be permanently secured to tanksin accordance with the requirementsunder which the tanks are fabricated,and shall be designed with a factor ofsafety of four, and built to withstandloadings in any direction equal to twotimes the weight of the tanks and at-tachments when filled to the maximumpermissible loaded weight.

(c) Lifting lugs or side hold-downlugs shall be provided on the tankmountings in a manner suitable for at-taching lifting gear and hold-down de-vices. Lifting lugs and hold-down lugswelded directly to the tank shall be ofthe pad-eye type. Doubling plates weld-ed to the tank and located at thepoints of support shall be deemed tocomply with this requirement.

(d) All tank mountings shall be so de-signed as to prevent the concentrationof excessive loads on the tank shell.

§ 178.255–12 Pressure test.(a) Each completed portable tank

prior to application of lining shall betested before being put into transpor-tation service by completely filling thetank with water or other liquid havinga similar viscosity, the temperature ofwhich shall not exceed 100 °F duringthe test, and applying a pressure of 60psig. The tank shall be capable of hold-ing the prescribed pressure for at least10 minutes without leakage, evidenceof impending failure, or failure. All clo-sures shall be in place while the test ismade and the pressure shall be gaugedat the top of the tank. Safety devicesand/or vents shall be plugged duringthis test.

(b) [Reserved]


§ 178.255–13 Repair of tanks.(a) Tanks failing to meet the test

may be repaired and retested, providedthat repairs are made in complete com-pliance with the requirements of thisspecification.

(b) [Reserved]

§ 178.255–14 Marking.(a) In addition to marking required

by the American Society of MechanicalEngineers Code, every tank shall bearpermanent marks at least 1⁄8-inch highstamped into the metal near the centerof one of the tank heads or stampedinto a plate permanently attached tothe tank by means of brazing or weld-ing or other suitable means as follows:

Manufacturer’s name —— Serial No. llll

DOT specification llllllllllllll

Nominal capacity ——————— (gallons)Tare weight ——————— (pounds)


825


Date of manufacture llllllllllll

(b) [Reserved]

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.178–67, 46 FR 49906, Oct. 8, 1981]

§ 178.255–15 Report.(a) A copy of the manufacturer’s data

report required by the Code (See§ 178.245–1(a)) under which the tank isfabricated must be furnished to theowner for each new tank.

Place ———————————————Date ————————————————

Portable tankManufactured for ——————— CompanyLocation llllllllllllllllll

Manufactured by ——————— CompanyLocation llllllllllllllllll

Consigned to ————————— CompanyLocation llllllllllllllllll

Size ——— feet outside diameter by———long.

Marks on tank as prescribed by § 178.255–14 ofthis specification are as follows:

Manufacturer’s name llllllllllll

Serial number llllllllllllllll

Owner’s serial number lllllllllll

DOT specification llllllllllllll

ASME Code Symbol (par U–201) lllllll

Date of manufacture llllllllllll

Nominal capacity ——————— gallons.It is hereby certified that this tank is in

complete compliance with the requirementsof DOT specification No. 60.

(Signed) ———————————————Manufacturer or owner

(b) [Reserved]

[29 FR 18972, Dec. 29, 1964. Redesignated at 32FR 5606, Apr. 5, 1967, and amended by Amdt.178–83, 50 FR 11066, Mar. 19, 1985]

§ 178.270 Specification IM 101 and IM102 steel portable tanks; general de-sign and construction require-ments.

§ 178.270–1 Specification requirementsfor IM 101 and IM 102 steel portabletanks.

(a) Each IM portable tank must meetthe requirements of this section in ad-dition to the requirements of § 178.271(IM 101) or § 178.272 (IM 102). These re-quirements apply to IM portable tanksof diameters no greater than 2438 mm(96 inches) that are designed to carryliquids having a vapor pressure of lessthan 2.97 bar-absolute (43 psia) at atemperature of 50 °C (122 °F).

(b) [Reserved]

[Amdt. 178–65, 46 FR 9895, Jan. 29, 1981]

§ 178.270–2 General.(a) Each tank, including attachments

and service and structural equipment,must be designed to withstand, withoutloss of contents, the maximum internalpressure that can be anticipated to re-sult from the contents and the staticand dynamic stresses incurred in nor-mal handling and transportation.

(b) For the purpose of this subchapterMAWP is the maximum pressure thatan IM portable tank may experienceduring any normal operation (includingloading and unloading). The only ex-ception to this limitation is hydro-static testing.

(c) Each portable tank must have across-sectional design that is capableof being stress analyzed either mathe-matically or by the experimentalmethod contained in UG–101 of theASME Code, or other method accept-able to the Associate Administrator.

(d) Each portable tank must be de-signed so that the center of gravity ofthe filled tank is approximately cen-tered within the points of attachmentfor lifting devices.

(e) When credit is taken for insula-tion to reduce the required emergencyventing capacity of safety relief de-vices, the insulation must be jacketedor otherwise protected from the accu-mulation of moisture or foreign matterthat would decrease its efficiency orcorrode the tank.

(f) Each portable tank that has a lin-ing must have a lining material thatmeets the following requirements:

(1) The material used to line the tankmust be—

(i) Substantially immune to attackby the hazardous material transported;

(ii) Homogeneous;(iii) Nonporous;(iv) Imperforated when applied;(v) At least as elastic as the material

of the tank shell; and(vi) Have thermal-expansion charac-

teristics compatible with the tankshell.

(2) The lining of the tank, tank fit-ting and piping must be—

(i) Attached by bonding or other sat-isfactory means;

(ii) Continuous; and


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49 CFR Ch. I (10–1–01 Edition)§ 178.270–3

(iii) Extended around the face of anyflange.

(3) Joints and seams in the liningmust be made by fusing the materialtogether or by other equally effectivemeans.

[Amdt. 178–65, 46 FR 9895, Jan. 29, 1981, asamended by Amdt. 178–65, 46 FR 24184, Apr.30, 1981; Amdt. 178–97, 56 FR 66284 and 66287,Dec. 20, 1991; 66 FR 45386, 45389, Aug. 28, 2001]

§ 178.270–3 Materials of construction.(a) Each portable tank must be con-

structed of carbon or alloy steels. Ma-terials included in part UHT of theASME Code or equivalent materialsare not authorized. Any materials usedin the tank shell must conform to arecognized national standard and mustbe suitable for the external environ-ments in which the tank will be car-ried. The minimum elongation for anymaterial must be 20 percent or greater.

(b) The maximum stress allowed for amaterial shall be determined using oneof the following methods:

(1) 1.5 times the specified values forthe material at 93 °C (200 °F) in SectionVIII, Division 1 of the ASME Code;

(2) Derived by test for the actualyield and tensile strengths at 93 °C (200°F) for the actual group of plates usedto fabricate the tank using the meth-ods described in §178.270–3(d); or

(3) Derived from the minimum yieldand tensile strengths at 93 °C (200 °F)specified by the national standard towhich the material is manufacturedusing the methods described in§ 178.270–3(d).

(c) Maximum allowable stress values,derived for an actual group of plates,that are based on actual tensile andyield strengths of the material at 93 °C(200 °F) shall not be greater than 120percent of the specified minimum yieldand tensile strength specified in thenational standard to which the mate-rial is manufactured.

(d) The maximum allowable stressvalues must be derived from the fol-lowing criteria:

(1) For austenitic steels;(i) When the yield strength is deter-

mined using the 0.2 percent offset, 93.75percent of the yield strength.

(ii) When the yield strength is deter-mined using the 1.0 percent offset, 75percent of the yield strength.

(2) For carbon and low alloy steels,the yield strength is determined usingthe 0.2 percent offset. The maximumallowable stress value is the lower of93.75 percent of the yield strength or37.5 percent of the tensile strength.

(e) For purposes of these specifica-tions, tensile strength, yield strengthand elongation must be determinedusing a specimen having a gaugelength:

L0 = 5.65(S0)1/2

where:

L0 = the gauge length of the specimen—milli-meters (inches); and

S0 = the cross sectional area of the speci-men—square millimeters (square inches).

Tensile tests and analysis of resultsmust be in accordance with ‘‘ISO 82Steels-Tensile Testing.’’ The yieldstrength in tension shall be the stresscorresponding to a permanent strain of0.2 percent of the gauge length, exceptthat for high alloy austenitic steels theyield strength shall be the stress cor-responding to a permanent strain of 0.2or 1.0 percent of the gauge length asappropriate. The elongation must be atleast 20 percent.

(f) If maximum allowable stress val-ues or minimum tank wall thicknessesare based on the actual yield strength,the actual tensile strength, or the ac-tual elongation for the material usedto fabricate the tank, the test recordsor certification of test results by thematerial producer or tank manufac-turer must be approved by the approvalagency, retained by the tank manufac-turer for a period not less than 15years, and made available to any dulyidentified representative of the Depart-ment or the owner of the tank.

[Amdt. 178–65, 46 FR 9895, Jan. 29, 1981, asamended at 64 FR 10782, Mar. 5, 1999]

§ 178.270–4 Structural integrity.(a) Maximum stress values. The max-

imum calculated stress value in a tankat the Test Pressure must be less thanor equal to that specified for the mate-rial of construction at 93 °C. (200 °F.) in§ 178.270–3 of this part.

(b) Tank shell loadings. Tank shells,heads, and their fastenings shall be de-signed to prevent stresses in excess oftwo thirds those specified in § 178.270–3


827


of this part. The design calculationsmust include the forces imposed byeach of the following loads:

(1) An internal pressure equal to theMAWP less 1 bar (14.5 psig) in combina-tion with the simultaneously appliedloadings of 3W vertically downward, 2Wlongitudinally, and 1W laterally actingthrough the center of the tank (W isthe maximum permissible weight ofthe loaded tank and its attachments),and the requirements of paragraphs (b)(4), (5) and (6) of this section;

(2) An internal pressure equal to theMAWP less 1 bar (14.5 psig), in com-bination with the simultaneously ap-plied loadings of 1W vertically upward,2W longitudinally, and 1W laterallyacting through the center of the tank(W is the maximum permissible weightof the loaded tank and its attachment),and the requirements of paragraphs (b)(4), (5) and (6) of this section;

(3) The load on the tank head result-ing from an internal pressure equal tothe MAWP, less 1 bar (14.5 psig), incombination with the dynamic pres-sure resulting from a longitudinal de-celeration of 2 ‘‘g’’, and the require-ments of paragraphs (b) (4), (5) and (6)of this section;

(4) Loads resulting from any dis-continuities between tank shell andheads;

(5) Superimposed loads such as oper-ating equipment, insulation, liningsand piping; and

(6) Reactions of supporting lugs andsaddles or other supports.

(c) The shell thickness used in calcu-lating the resulting stress levels in atank shall be exclusive of any corro-sion allowance.

[Amdt. 178–65, 46 FR 9895, Jan. 29, 1981, asamended at 66 FR 45387, Aug. 28, 2001]

§ 178.270–5 Minimum thickness ofshells and heads.

(a) For the purposes of this section,mild steel is steel with a guaranteedminimum tensile strength of 37decanewtons per square millimeter(53,650 p.s.i.) and a guaranteed elon-gation of 27 percent or greater.

(b) Except as otherwise provided inthis subchapter, the shell and heads ofeach portable tank constructed of ref-erence mild steel:

(1) With a maximum cross-sectionaldimension of 1.8 m (5.9 feet) or less,shall be at least 5 mm (0.197 inches)thick; or,

(2) With a maximum cross-sectionaldimension exceeding 1.8 m (5.9 feet),shall be at least 6.35 mm (0.250 inches)thick.

(c) The minimum thickness of theshell and heads of each portable tankconstructed of a steel other than thereference mild steel, shall be obtainedfrom the following formula:

Formula for metric units

e1 = (10e0) / (Rm1 A1)1/3

Formula for nonmetric units

e1 = (112.3e0) / (Rm1 A1)1/3

where:

e0 = Required thickness of the reference steelfrom § 178.270–5(b)—millimeters (inches);

e1 = Equivalent thickness of the steel used—millimeters (inches);

Rm1 = Specified minimum tensile strength ofthe steel used—decanewtons per squaremillimeter (p.s.i.); and

A1 = Specified minimum percentage elon-gation of the steel used—percent times 100(i.e., if 20% use 20.0).

(d) When other than the standardminimum thickness for the referencemild steel is specified for a tank in thissubchapter, the specified minimumshell and head thickness must be atleast equal to the larger of thethicknesses calculated from the for-mula given in § 178.270–5(c) and the fol-lowing formula:


e1 = (10e0 d1) / 1.8(Rm1 A1)1/3


e1 = (112.3e0 d1) / 5.9(Rm1 A1)1/3

where:

e1 = Equivalent thickness of the steel used—millimeters (inches);

e0 = The specified minimum shell and headthickness of the reference mild steel speci-fied in the IM Tank Table—millimeters(inches);

d1 = Actual outside diameter of the tank—m(feet);

Rm1 = Specified minimum tensile strength ofthe steel used—decanewtons per squaremillimeter (p.s.i.); and


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49 CFR Ch. I (10–1–01 Edition)§ 178.270–6

A1 = Specified minimum percentage elon-gation of the steel used—percent times 100(i.e., if 20% use 20.0).

NOTE: For paragraphs (c) and (d) of thissection the actual values for the tensilestrength and percent elongation for thesteel, as determined through tests on speci-mens from the group of plates to be used inthe fabrication of the tank, may be sub-stituted for the specified minimum values inthe calculation prescribed in this paragraph(See § 178.270–3 of this part). Test records orcertification of test results by the materialproducer or tank manufacturer must be re-tained by the tank manufacturer for a periodnot less than 15 years and must be madeavailable to the Department or the owner ofthe tank.

[Amdt. 178–65, 46 FR 9896, Jan. 29, 1981, asamended by Amdt. 178–97, 56 FR 66284, Dec.20, 1991; 57 FR 45465, Oct. 1, 1992; Amdt. 178–99, 58 FR 51534, Oct. 1, 1993; 66 FR 45387, 45389,Aug. 28, 2001]

§ 178.270–6 Tank supports, frameworksand lifting attachments.

(a) Each portable tank must be con-structed with a permanent supportstructure that provides a secure base intransport. Skids, frameworks, cradles,or similar devices are acceptable. Thecalculated stress in tank supports,frameworks, and lifting attachmentsmust not exceed 80 percent of the speci-fied minimum yield strength of thematerial of construction under the ap-plicable loading conditions specified in§ 178.270–4(b).

(b) An IM portable tank that meetsthe definition of ‘‘container’’ in§ 450.3(a)(3) must meet the require-ments of parts 450 through 453 of thistitle, in addition to the requirementsof this subchapter.

[Amdt. 178–65, 46 FR 9896, Jan. 29, 1981]

§ 178.270–7 Joints in tank shells.Joints in tank shells must be made

by fusion welding. Such joints andtheir efficiencies must be as requiredby the ASME Code. Weld proceduresand welder performance must be ASMECode qualified or must be qualified bythe approval agency in accordance withthe procedures in the ASME Code, Sec-tion IX, Welding and Brazing Qualifica-tions. A record of each qualificationmust be retained by the manufacturerfor the period prescribed in ASMECode, Section VIII, Pressure Vessels,

and must be made available to anyduly identified representative of theDepartment and the owner of the tank.

[Amdt. 178–65, 46 FR 9896, Jan. 29, 1981; 46 FR24184, Apr. 30, 1981]


Each valve, fitting, accessory, safetydevice, gauging device, and other ap-purtenance shall be adequately pro-tected against mechanical damage.

[Amdt. 178–65, 46 FR 9896, Jan. 29, 1981]

§ 178.270–9 Inspection openings.Each portable tank must be fitted

with a manhole or other inspectionopening sited above the maximum liq-uid level to allow for complete internalinspection and adequate access formaintenance and repair of the interior.Each portable tank with a capacity ofmore than 1894 L (500 gallons) must befitted with an elliptical or round man-hole at least 279 × 381 mm (11 × 15inches), or 254 × 405 mm (10 × 16 inches),or with a circular manhole at least 381mm (15 inches) in diameter. Any in-spection opening and closure must bedesigned and reinforced as required bythe ASME Code.

[Amdt. 178–65, 46 FR 9896, Jan. 29, 1981, asamended by Amdt. 178–104, 59 FR 49135, Sept.26, 1994; 66 FR 45387, Aug. 28, 2001]

§ 178.270–10 External design pressure.(a) Each portable tank not fitted

with vacuum relief devices must be de-signed to withstand a positive externalpressure differential of at least 0.4 bar(6 psig).

(b) Each portable tank fitted withvacuum relief devices must be designedto withstand a positive external pres-sure differential not less than the setpressure of the vacuum relief deviceand in any case at least 0.21 bar (3psig).


§ 178.270–11 Pressure and vacuum re-lief devices.

(a) Relief devices required. Each port-able tank, or each independent com-partment of a portable tank, must befitted with pressure relief devices inaccordance with the following:


829


(1) Each portable tank, or each inde-pendent compartment of a portabletank, with a capacity of more than 1893L (500 gallons), must be provided with aprimary spring-loaded pressure reliefdevice, and, in addition, may have oneor more emergency pressure relief de-vices that may be a spring-loaded pres-sure relief valve, a rupture disc or fusi-ble element in parallel with the pri-mary pressure relief device.

(2) Each portable tank, or each inde-pendent compartment of a portabletank, with a capacity of 1893 L (500 gal-lons) or less, must be fitted with a pri-mary pressure relief device that mayeither be a non-reclosing device or aspring-loaded pressure relief valve.

(3) If a non-reclosing device is in-serted in series with a required pres-sure relief valve, the space betweenthem must have a suitable tell-tale in-dicator to permit detection, prior toand during shipment, of disc rupture,pinholing, or leakage which couldcause a malfunction of the pressure re-lief system. The frangible disc mustrupture at a tank pressure within therange specified in paragraph (c)(1) ofthis section.

(b) Location and construction of reliefdevices. (1) Pressure relief devices mustbe spring-loaded valves, rupture discs,or fusible elements. Vacuum relief de-vices must be capable of reclosing inany attitude. Each pressure relief de-vice inlet must be situated in the vaporspace of the tank. The discharge fromany device must be unrestricted and di-rected to prevent impingement uponthe tank shell or structural frame-work. Protective devices which deflectthe flow of vapor are permissible pro-vided the required vent capacity ismaintained. Pressure and vacuum re-lief devices including their inlets mustbe sited on the top of the tank in a po-sition as near as possible to the longi-tudinal and transversal center of thetank within the following limitation:

(i) Longitudinally on the tank within107 cm (31⁄2 feet) or 1⁄6 the tank length,whichever is less, from the top centerof the tank; and

(ii) Transversally within 12 degrees ofthe tank top.

(2) Except for a relief device installedin a piping system, each relief devicemust provide unrestricted venting

under all conditions. Each pressure re-lief system, including any piping, mustprovide a venting capacity at leastequal to the venting capacity specifiedin § 178.270–11(d) for the tank on whichthe system is installed.

(3) Fusible elements, when installed,must not be protected from direct com-munication with external heat sources.

(4) Spring-loaded pressure reliefvalves must be constructed in a man-ner to prevent unauthorized adjust-ment of the relief setting.

(c) Pressure settings of relief devices—(1) Primary pressure relief devices. Theprimary relief device required by para-graph (a) of this section must be set tofunction in the range of—

(i) No less than 67 percent and nogreater than 83 percent of test pressurefor tanks hydrostatically tested under§ 178.270–13(a) of this subpart at a gaugepressure below 455 kPa (66 psig).Spring-loaded pressure relief valvesmust close after discharge at a pres-sure not less than 80 percent of start-to-discharge pressure.

(ii) No less than 67 percent and nogreater than 74 percent of test pressurefor tanks hydrostatically tested under§ 178.270–13(a) of this subpart at a gaugepressure of 455 kPa (66 psig) or higher.Spring-loaded pressure relief valvesmust close after discharge at a pres-sure not less than 90 percent of start-to-discharge pressure.

(2) Emergency pressure relief devices.Each rupture disc, other than one usedas a primary relief device in accord-ance with paragraph (b)(2) of this sec-tion, must be designed to burst at apressure greater than 83 percent of andless than or equal to tank hydrostatictest pressure. Each spring-loaded pres-sure relief device must be set to oper-ate at no less than 83 percent of hydro-static test pressure and be fully openat test pressure.

(3) Fusible elements. Fusible elementsmust have a nominal yield temperaturegreater than the highest tank oper-ating temperature and less than orequal to 121 °C (250 °F). The pressuredeveloped in the tank at the fusibleelement yield temperature must bebelow the test pressure of the tank.

(4) Vacuum relief devices. Vacuum re-lief devices, when used, must be de-signed to provide total containment of


830

49 CFR Ch. I (10–1–01 Edition)§ 178.270–11

product under normal and accidentconditions and must be set to open at anominal external overpressure of notless than 0.21 bar (3 psig) but not great-er than the external pressure for whichthe tank is designed. Each vacuum re-lief device must have a minimum crosssectional flow area of 2.84 cm 2 (0.44square inches).

(d) Venting capacity of pressure reliefdevices—(1) Pressure relief valves(spring-loaded). Each pressure reliefvalve must have a minimum vent ca-pacity of at least 170 standard cubicmeters per hour (SCMH) (6,000 standardcubic feet per hour (SCFH)). The min-imum total pressure relief valve ventcapacity for each tank shall be 340SCMH (12,000 SCFH) per 32.5m2 (350square feet) of exposed tank area, butin any case at least 340 SCMH (12,000SCFH).

(2) Total tank vent capacity. The totalvent capacity of all pressure relief de-vices installed on each portable tankmust be sufficient with all devices op-erating to limit the pressure in thetank to less than or equal to the testpressure. Except as provided in para-graph (d)(3) or (d)(4) of this section, thetotal vent capacity must be at leastequal to that shown in the followingtable:

TABLE I—MINIMUM TOTAL VENT CAPACITY[Metric units table in cubic meters of air per hour at

atmospheric pressure and 15 °C]

Exposed areasquare meters

Cubic me-ters freeair perhour

Exposedarea square

meters

Cubic me-ters freeair perhour

2 ............................. 841 37.5 9.3063 ............................. 1,172 40 9,8104 ............................. 1,485 42.5 10,3085 ............................. 1,783 45 10,8066 ............................. 2,069 47.5 11,3927 ............................. 2,348 50 11,7788 ............................. 2,621 52.5 12,2589 ............................. 2,821 55 12,73210 ........................... 3,146 57.5 13,20612 ........................... 3,655 60 13,67414 ........................... 4,146 62.5 14,14216 ........................... 4,625 65 14,60418 ........................... 5,092 67.5 15,06620 ........................... 5,556 70 15,51622.5 ........................ 6,120 75 16,42225 ........................... 6,672 80 17,31627.5 ........................ 7,212 85 18,19830 ........................... 7,746 90 19,07432.5 ........................ 8,268 95 19,93835 ........................... 8,790 100 20,790

[Nonmetric units in cubic feet of air per hour at atmosphericpressure and 59 °F]

Exposed areasquare feet

Cubic feetfree air per

hour

Exposedarea

square feet

Cubic feetfree air per

hour

20. ............................ 27,600 275 237,00030 ............................. 38,500 300 256,00040 ............................. 48,600 350 289,50050 ............................. 58,600 400 322,10060 ............................. 67,700 450 355,90070 ............................. 77,000 500 391,00080 ............................. 85,500 550 417,50090 ............................. 94,800 600 450,000100 ........................... 104,000 650 479,000120 ........................... 121,000 700 512,000140 ........................... 136,200 750 540,000160 ........................... 152,100 800 569,000180 ........................... 168,200 850 597,000200 ........................... 184,000 900 621,000225 ........................... 199,000 950 656,000250 ........................... 219,500 1,000 686,000

Note: Interpolate for intermediate sizes.

(3) Notwithstanding the minimumtotal vent capacity shown in table I, ofparagraph (d)(2), a tank in dedicatedservice may have a lesser total vent ca-pacity provided the approval certifi-cate required by § 173.32a of this sub-chapter specifies the hazardous mate-rials for which the tank is suitable.The lesser total vent capacity must bedetermined in accordance with the fol-lowing formula:


Q = 5,660,000 A 0.82 (ZT) 0.5 / (LC)(M 0.5)


Q = 37,980,000 A 0.82 (ZT) 0.5 / (LC)(M 0.5)

where:

Q = The total required venting capacity, incubic meters of air per hour at standardconditions of 15.6 °C and 1 atm (cubic feetof air per hour at standard conditions of 60°F and 14.7 psia);

T = The absolute temperature of the vapor atthe venting conditions—degrees Kelvin (°C+273) [degrees Rankine ( °F+460)];

A = The exposed surface area of tank shell—square meters (square feet);

L = The latent heat of vaporization of thelading—calories per gram (BTU/lb);

Z = The compressibiliy factor for the vapor(if this factor is unknown, let Z equal 1.0);

M = The molecular weight of vapor;C = A constant derived from (K), the ratio of

specific heats of the vapor. If (K) is un-known, let C = 315.

C = 520[K(2/(K+1)) [(K+1) / (K¥1)]]1⁄2

where:

K = Cp / Cv


831


Cp = The specific heat at constant pressure,in -calories per gram degree centigrade(BTU/lb °F.); and

Cv = The specific heat at constant volume, in-calories per gram degree centigrade (BTU/lb °F.).

(4) The required total venting capac-ity determined by using table I or para-graph (d)(3) of this section may be re-duced for insulated tanks to Qt by thefollowing formula:

Qt = FQ1

where:

Qt = The total required venting capacity ofthe insulated tank;

Q1 = The total venting capacity requiredfor an uninsulated tank according to table Ior paragraph (d)(3) of this section;

F = A coefficient with a value greater thanor equal to 0.25 according to the followingformula:


F = 8U(649–t) / 93.5 × 106


F = 8U(1200–t) / 34,500

where:

U = The thermal conductance of the insula-tion system taken at 38 °C (100 °F), in gramcalories per hour square meter °C (BTU perhour square feet °F); and

t = The actual temperature of the substanceat loading, in °C (°F).

(5) Insulation systems, used for thepurpose of reducing the venting capac-ity, must be approved by the approvalagency. In all cases, insulation systemsapproved for this purpose must:

(i) Remain effective at all tempera-tures up to 649 °C (1200 °F); and

(ii) Be jacketed with a material hav-ing a melting point of 649 °C (1200 °F) orgreater.

(6) The flow capacity rating of anypressure relief device must be certifiedby the manufacturer to be in accord-ance with the applicable provisions ofthe ASME Code with the following ex-ceptions:

(i) The ASME Code stamp is not re-quired; and

(ii) The flow capacity certificationtest for spring loaded pressure reliefvalves may be conducted at a pressurenot to exceed 120% of the set pressureprovided the stamped flow capacityrating is not greater than 83% of theaverage capacity of the valves tested.

(e) Markings on pressure and vacuumrelief devices. The following informationshall be plainly displayed on each pres-sure relief device:

(1) The pressure or, when appro-priate, the temperature at which thedevice is set to function;

(2) Except for vacuum relief devices,the rated flow capacity of air dis-charged per minute at 15 °C (59 °F) andatmospheric pressure, at:

(i) The set pressure for rupture discs;(ii) No greater than 20% above the

start-to-discharge pressure for spring-loaded relief devices; or

(iii) The fusing temperature for fusi-ble elements.

(3) The manufacturer’s name andcatalog number; and

(4) The allowable tolerances at thestart-to-discharge pressure and the al-lowable tolerances at the dischargetemperature.

[Amdt. 178–65, 46 FR 9897, Jan. 29, 1981; 46 FR24184, Apr. 30, 1981, as amended by Amdt. 178–97, 55 FR 52716, Dec. 21, 1990; Amdt. 178–99, 58FR 51534, Oct. 1, 1993; Amdt. 178–104, 59 FR49135, Sept. 26, 1994; 66 FR 45386, 45389, Aug.28, 2001]

§ 178.270–12 Valves, nozzles, piping,and gauging devices.

(a) All tank nozzles, except those pro-vided for filling and discharge connec-tions below the normal liquid level ofthe tank, relief devices, thermometerwells, and inspection openings, must befitted with manually operated stopvalves located as near the shell as prac-ticable either internal or external tothe shell. Each filling and dischargeconnection located below the normalliquid level of the tank must beequipped with an internal dischargevalve. A tank nozzle installed in thevapor space to provide a filling orcleaning opening, which is closed by ablank flange or other suitable means,need not be provided with a manuallyoperated stop valve. A tank nozzle in-stalled for a thermometer well or in-spection opening need not be providedwith a manually operated stop valve.

(b) Each valve must be designed andconstructed to a rated pressure not lessthan the MAWP of the tank. Each stopvalve with a screwed spindle must beclosed by a clockwise motion of the


832

49 CFR Ch. I (10–1–01 Edition)§ 178.270–13

handwheel. All valves must be con-structed to prevent unintentionalopening.

(c) Each internal discharge valveshall be self-closing, located inside thetank, within the welded flange or with-in its companion flange.

(d) A shear section must be locatedoutboard of each internal dischargevalve seat and within 10.2 cm (4 inches)of the vessel. The shear section mustbreak under strain without affectingthe product retention capabilities ofthe tank and any attachments.

(e) All piping must be of suitable ma-terial. Welded joints must be usedwherever practicable. The burstingstrength of all piping and pipe fittingsmust be at least 4 times the MAWP ofthe tank. Piping must be supported insuch a manner as to prevent damagedue to thermal stresses, jarring or vi-bration.

(f) All nozzles and tank shell penetra-tions for nozzles shall be designed andconstructed in accordance with theASME Code.

(g) Glass liquid level gauges, orgauges of other easily destructible ma-terial, which are in direct communica-tion with the contents of the tank areprohibited.

[Amdt. 178–65, 46 FR 9898, Jan. 29, 1981; 46 FR24184, Apr. 30, 1981, as amended by Amdt. 178–117, 61 FR 50628, Sept. 26, 1996; 66 FR 45386,Aug. 28, 2001]

§ 178.270–13 Testing.(a) Hydrostatic test. Each portable

tank and all piping, valves, and otherattachments which are subject to thepressure of the contents of the tank,except pressure relief devices, must behydrostatically tested by completelyfilling the tank (including domes, ifany) with water or other liquid havinga similar density and viscosity and ap-plying a pressure of at least 150 percentof the MAWP. The pressure shall bemaintained for at least 10 minutes.While under pressure, the tank shall beinspected for leakage, undue distor-tion, or other conditions which indi-cate weakness or which might renderthe tank unsafe for transportationservice. Failure to successfully meetthe test criteria shall be deemed evi-dence of failure to meet the require-ments of this specification. Tanks fail-

ing to pass the test shall be suitablyrepaired and must successfully pass theprescribed tests prior to use for trans-porting any hazardous material.

(b) Testing of internal coils. Internalcoils, if installed, must behydrostatically tested to an internalpressure of 13.8 bar (200 psig) or 150 per-cent of the rated pressure of the coils,whichever is greater.

(c) Tank container qualification test.For each tank design, a prototypetank, using a framework for container-ized transport, must fulfill the require-ments of parts 450–453 of this title forcompliance with the requirements ofAnnex II of the International Conven-tion for Safe Containers. In addition,the following tests must be completedwithout leakage or deformation thatwould render the tank unsuitable foruse:

(1) Longitudinal inertia. The tankloaded to its maximum gross weightmust be positioned with its longitu-dinal axis vertical. It shall be held inthis position for five minutes by sup-port at the lower end of the base struc-ture providing vertical and lateral re-straint and by support at the upper endof the base structure providing lateralrestraint only.

(2) Lateral inertia. The tank loaded toits maximum gross weight must be po-sitioned for five minutes with its trans-verse axis vertical. It shall be held inthis position for five minutes by sup-port at the lower side of the base struc-ture providing vertical and lateral re-straint and by support at the upperside of the base structure providing lat-eral restraint only.

(d) Approval of smaller tanks of thesame design. Design approval must in-clude the prototype testing of at leastone tank of each design and each size;however, a set of tests made on a tankof one size may serve for the approvalof smaller tanks with equal or lesserdiameter and length) made of the samematerial and thickness by the samefabrication technique and with iden-tical supports and equivalent closuresand other appurtenances.

(e) Pressure and vacuum relief devices.Each spring loaded relief device mustbe tested for the accuracy of the set-ting prior to installation on a tank and


833


must be effectively sealed to maintainthe required setting.

[Amdt. 178–65, 46 FR 9898, Jan. 29, 1981; 46 FR24184, Apr. 30, 1981, as amended by 66 FR45387, Aug. 28, 2001]

§ 178.270–14 Marking of tanks.(a) General. Each tank must bear a

corrosion resistant metal identifica-tion plate that is permanently at-tached to the portable tank and readilyaccessible for inspection. The informa-tion required in paragraph (b), and,when appropriate, paragraph (c) of thissection must be stamped, embossed orotherwise marked by an equally dura-ble method on the plate in charactersat least 3 mm (0.118 inches) high. Theplate must not be painted.

(b) Required information. At least thefollowing information must appear onthe metal identification plate for eachtank:

(1) US DOT Specification number.(2) Country of manufacture.(3) Manufacturer’s name.(4) Date of manufacture.(5) Manufacturer’s serial number.(6) Identification of USA/DOT ap-

proval agency and approval number.(7) MAWP, in bar or psig.(8) Test pressure, in bar or psig.(9) Total measured water capacity at

20 °C (68 °F), in liters or gallons.(10) Maximum allowable gross

weight, in kg or lbs.(11) Equivalent minimum shell thick-

ness in mild steel, in mm or inches.(12) Tank material and specification

number.(13) Metallurgical design temperature

range, in °C or °F.(c) Additional information. The fol-

lowing additional information must ap-pear on the metal identification platewhen applicable:

(1) Lining material.(2) Heating coil MAWP in bar and

psig.(3) Corrosion allowance, in mm or in.(d) In addition to the markings re-

quired above, each tank used in inter-national transport must have a SafetyApproval Plate containing the informa-tion required in §§ 451.21 through 451.25of this title.

(e) Nothing in this section shall bedeemed to preclude the display of other

pertinent information on the requiredmetal identification plate.

[Amdt. 178–65, 46 FR 9899, Jan. 29, 1981, asamended at 62 FR 51561, Oct. 1, 1997; 66 FR45387, Aug. 28, 2001]

§ 178.271 Specification IM 101 steelportable tanks.

§ 178.271–1 General requirements.(a) Specification IM 101 portable

tanks must conform to the general de-sign and construction requirements in§ 178.270 of this subpart in addition tothe specific design requirements con-tained in this section.

(b) The MAWP of each tank shall beequal to or greater than 1.75 bar (25.4psig) and less than 6.8 bar (100 psig).

(c) Each tank shall be designed andconstructed in accordance with the re-quirements of Section VIII, Division 1,of the ASME Code except as limited ormodified in this section or in § 178.270 ofthis subpart. ASME certification orstamp is not required.


§ 178.272 Specification IM 102 steelportable tanks.

§ 178.272–1 General requirements.(a) Specification IM 102 portable

tanks must conform to the general de-sign and construction requirements in§ 178.270 of this subpart in addition tothe specific design requirements con-tained in this section.

(b) The MAWP of each tank shall beless than 1.75 bar (25.4 psig) but at least1.0 bar (14.5 psig).

(c) Each tank shall be designed andconstructed in accordance with the re-quirements of Section VIII, Division 1,of the ASME Code except as limited ormodified in this section or in § 178.270 ofthis subpart. ASME certification orstamp is not required.


§ 178.272–2 Minimum thickness ofshells and heads.

(a) The approval agency may author-ize a minimum thickness less than thatrequired by § 178.270–5 of this subpart


834

49 CFR Ch. I (10–1–01 Edition)§ 178.273

where additional protection againsttank puncture provides equal integrity.

(b) The shell and head thickness of atank must be at least:

(1) 3.18 mm (0.125 inches) for a tankwith a maximum cross-sectional di-mension of 1.8 m (5.9 feet) or less; or

(2) 4 mm (0.157 inches) for a tank con-structed of the reference mild steelhaving a maximum cross-sectional di-mension exceeding 1.8 m (5.9 feet). Fortanks having a maximum cross-sec-tional dimension exceeding 1.8 m (5.9feet) constructed of other steels, anequivalent head and shell thicknesscalculated in accordance with § 178.270–5(c) of this subpart may be used, sub-ject to an absolute minimum of 3.18mm (0.125 inches).

(c) The following additional punctureprotection systems are authorized:

(1) An overall external structuralprotection, such as a jacket, which isrigidly secured to the tank with a layerof cushioning material installed be-tween the external structural protec-tion and the tank; or

(2) A complete framework sur-rounding the tank including both lon-gitudinal and transverse structuralmembers.


§ 178.273 Approval of Specification IMportable tanks and UN portabletanks.

(a) Application for approval. (1) Anowner or manufacturer of a portabletank shall apply for approval to a des-ignated approval agency authorized toapprove the portable tank in accord-ance with the procedures in subpart E,part 107 of this subchapter.

(2) Each application for approvalmust contain the following informa-tion:

(i) Two complete copies of all engi-neering drawings, calculations, andtest data necessary to ensure that thedesign meets the relevant specifica-tion.

(ii) The manufacturer’s serial numberthat will be assigned to each portabletank.

(iii) A statement as to whether thedesign type has been examined by anyapproval agency previously and judgedunacceptable. Affirmative statements

must be documented with the name ofthe approval agency, reason for non-acceptance, and the nature of modifica-tions made to the design type.

(b) Action by approval agency. The ap-proval agency must perform the fol-lowing activities:

(1) Review the application for ap-proval to determine whether it is com-plete and conforms with the require-ments of paragraph (a) of this section.If an application is incomplete, it willbe returned to the applicant with anexplanation as to why the applicationis incomplete.

(2) Review all drawings and calcula-tions to ensure that the design is incompliance with all requirements ofthe relevant specification. If the appli-cation is approved, one set of the ap-proved drawings, calculations, and testdata shall be returned to the applicant.The second (inspector’s copy) set of ap-proved drawings, calculations, and testdata shall be retained by the approvalagency. Maintain drawings and ap-proval records for as long as the port-able tank remains in service. The draw-ings and records must be provided tothe Department of Transportation(DOT) upon request.

(3) Witness all tests required for theapproval of the portable tank specifiedin this section and part 180, subpart Gof this subchapter.

(4) Ensure, through appropriate in-spection that each portable tank is fab-ricated in all respects in conformancewith the approved drawings, calcula-tions, and test data.

(5) Determine and ensure that theportable tank is suitable for its in-tended use and that it conforms to therequirements of this subchapter.

(6) For UN portable tanks intendedfor non-refrigerated and refrigeratedliquefied gases and Division 6.1 liquidswhich meet the inhalation toxicity cri-teria (Zone A or B) as defined in§ 173.132 of this subchapter, or that aredesignated as toxic by inhalation mate-rials in the § 172.101 Table of this sub-chapter, the approval agency must en-sure that:

(i) The portable tank has been con-structed in accordance with the ASMECode, Section VIII, Division 1 (see§ 171.7 of this subchapter). ASME Code,Section VIII, Division 2 (see § 171.7 of


835

Research and Special Programs Admin., DOT § 178.273

this subchapter) or other design codesmay be used if approved by the Asso-ciate Administrator (see § 178.274(b)(1));

(ii) All applicable provisions of thedesign and construction have been metto the satisfaction of the designatedapproval agency in accordance with therules established in the ASME Codeand that the portable tank meets therequirements of the ASME Code and allthe applicable requirements specifiedin this subchapter;

(iii) The inspector has carried out allthe inspections specified by the rulesestablished in the ASME Code; and

(iv) The portable tank is markedwith a U stamp code symbol under theauthority of the authorized inde-pendent inspector.

(7) Upon successful completion of allrequirements of this subpart, the ap-proval agency must:

(i) Apply its name, identifying markor identifying number, and the dateupon which the approval was issued, tothe metal identification marking plateattached to the portable tank. Any ap-provals for UN portable tanks author-izing design or construction alter-natives (Alternate Arrangements) ap-proved by the Associate Administrator(see § 178.274(a)(2)) must be indicated onthe plate as specified in § 178.274(i).

(ii) Issue an approval certificate foreach portable tank or, in the case of aseries of identical portable tanks man-ufactured to a single design type, foreach series of portable tanks. The ap-proval certificate must include all theinformation required to be displayed onthe required metal identification platerequired by § 178.270–14 of this sub-chapter for IM portable tanks, § 178.245–6 for Specification 51 steel portabletanks, or § 178.274(i) for UN portabletanks. The approval certificate mustcertify that the approval agency des-ignated to approve the portable tankhas approved the portable tank in ac-cordance with the procedures in sub-part E of part 107 of this subchapterand that the portable tank is suitablefor its intended purpose and meets therequirements of this subchapter. Whena series of portable tanks is manufac-tured without change in the designtype, the certificate may be valid forthe entire series of portable tanks rep-resenting a single design type. For UN

portable tanks, the certificate mustrefer to the prototype test report, thehazardous material or group of haz-ardous materials allowed to be trans-ported, the materials of construction ofthe shell and lining (when applicable)and an approval number. The approvalnumber must consist of the distin-guishing sign or mark of the country(‘‘USA’’ for the United States of Amer-ica) where the approval was grantedand a registration number.

(iii) Retain a copy of each approvalcertificate.

(8) For UN portable tanks, the ap-proval certificate must also include thefollowing:

(i) The results of the applicableframework and rail impact test speci-fied in part 180, subpart G, of this sub-chapter; and

(ii) The results of the initial inspec-tion and test in § 180.605 of this sub-chapter.

(9) The approval agency shall be inde-pendent from the manufacturer. Theapproval agency and the authorized in-spector may be the same entity.

(c) Manufacturers’ responsibilities. Themanufacturer is responsible for compli-ance with the applicable specificationsfor the design and construction of port-able tanks. In addition to responsi-bility for compliance, manufacturersare responsible for ensuring that thecontracted approval agency and au-thorized inspector, if applicable, arequalified, reputable and competent.The manufacturer of a portable tankshall—

(1) Comply with all the applicable re-quirements of the ASME Code (see§ 171.7 of this subchapter) and of thissubpart including, but not limited to,ensuring that the quality control, de-sign calculations and required tests areperformed and that all aspects of theportable tank meet the applicable re-quirements.

(2) Obtain and use a designated ap-proval agency, if applicable, and obtainand use a DOT-designated approvalagency to approve the design, construc-tion and certification of the portabletank.

(3) Provide a statement in the manu-facturers’ data report certifying that


836

49 CFR Ch. I (10–1–01 Edition)§ 178.273

each portable tank that is manufac-tured complies with the relevant speci-fication and all the applicable require-ments of this subchapter.

(4) Maintain records of the qualifica-tion of portable tanks for at least 5years and provide copies to the ap-proval agency, the owner or lessee ofthe tank. Upon request, provide theserecords to a representative of DOT.

(d) Denial of application for approval.If an approval agency finds that a port-able tank cannot be approved for anyreason, it shall notify the applicant inwriting and shall provide the applicantwith the reasons for which the ap-proval is denied. A copy of the notifica-tion letter shall be provided to the As-sociate Administrator. An applicantaggrieved by a decision of an approvalagency may appeal the decision inwriting, within 90 days of receipt, tothe Associate Administrator.

(e) Modifications to approved portabletanks. (1) Prior to modification of anyapproved portable tank which may af-fect conformance and the safe use of anIM or UN portable tank, which may in-volve a change to the design type orwhich may affect its ability to retainthe hazardous material in transpor-tation, the person desiring to makesuch modification shall inform the ap-proval agency that issued the initialapproval of the portable tank (or if un-available another approval agency) ofthe nature of the modification and re-quest approval of the modification. Theperson desiring to modify the tankmust supply the approval agency withthree sets of all revised drawings, cal-culations, and test data relative to theintended modification.

(2) A statement as to whether the in-tended modification has been examinedand determined to be unacceptable byany approval agency. The writtenstatement must include the name ofthe approving agency, the reason fornonacceptance, and the nature ofchanges made to the modification sinceits original rejection.

(3) The approval agency shall reviewthe request for modification, and if itis determined that the proposed modi-fication is in full compliance with therelevant DOT specification, including aUN portable tank, the request shall be

approved and the approval agency shallperform the following activities:

(i) Return one set of the approved re-vised drawings, calculations, and testdata to the applicant. The second andthird sets of the approved revised draw-ings, calculations, and data shall be re-tained by the approval agency as re-quired in § 107.404(a)(3) of this sub-chapter.

(ii) Ensure through appropriate in-spection that all modifications con-form to the revised drawings, calcula-tions, and test data.

(iii) Determine the extent to whichretesting of the modified tank is nec-essary based on the nature of the pro-posed modification, and ensure that allrequired retests are satisfactorily per-formed.

(iv) If modification to an approvedtank alters any information on the ap-proval certificate, issue a new approvalcertificate for the modified tank andensure that any necessary changes aremade to the metal identification plate.A copy of each newly issued approvalcertificate shall be retained by the ap-proval agency and by the owner of eachportable tank.

(4) If the approval agency determinesthat the proposed modification is notin compliance with the relevant DOTspecification, the approval agencyshall deny the request in accordancewith paragraph (d) of this section.

(f) Termination of Approval Certificate.(1) The Associate Administrator mayterminate an approval issued underthis section if he determines that—

(i) Information upon which the ap-proval was based is fraudulent or sub-stantially erroneous; or

(ii) Termination of the approval isnecessary to adequately protectagainst risks to life and property; or

(iii) The approval was not issued bythe approval agency in good faith; or

(iv) The portable tank does not meetthe specification.

(2) Before an approval is terminated,the Associate Administrator gives theinterested party(ies):

(i) Written notice of the facts or con-duct believed to warrant the termi-nation;

(ii) Opportunity to submit oral andwritten evidence; and


837


(iii) Opportunity to demonstrate orachieve compliance with the applicablerequirements.

(3) If the Associate Administrator de-termines that a certificate of approvalmust be terminated to preclude a sig-nificant and imminent adverse affecton public safety, he may terminate thecertificate immediately. In such cir-cumstances, the opportunities of para-graphs (f)(2) (ii) and (iii) of this sectionneed not be provided prior to termi-nation of the approval, but shall beprovided as soon as practicable there-after.

[66 FR 33439, June 21, 2001]

§ 178.274 Specifications for UN port-able tanks.

(a) General. (1) Each UN portabletank must meet the requirements ofthis section. In addition to the require-ments of this section, requirementsspecific to UN portable tanks used forliquid and solid hazardous materials,non-refrigerated liquefied gases and re-frigerated liquefied gases are providedin §§ 178.275, 178.276 and 178.277, respec-tively. Requirements for approval,maintenance, inspection, testing anduse are provided in § 178.273 and part180, subpart G, of this subchapter. Anyportable tank which meets the defini-tion of a ‘‘container’’ within the termsof the International Convention forSafe Containers (CSC) must meet therequirements of the CSC as amendedand 49 CFR parts 450 through 453 andmust have a CSC safety approval plate.

(2) In recognition of scientific andtechnological advances, the technicalrequirements applicable to UN portabletanks may be varied if approved by theAssociate Administrator and the port-able tank is shown to provide a level ofsafety equal to or exceeding the re-quirements of this subchapter. Port-able tanks approved to alternativetechnical requirements must bemarked ‘‘Alternative Arrangement’’ asspecified in paragraph (i) of this sec-tion.

(3) Definitions. The following defini-tions apply for the purposes of designand construction of UN portable tanksunder this subpart:

Alternate Arrangement portable tankmeans a UN portable tank that hasbeen approved to alternative technical

requirements or testing methods otherthan those specified for UN portabletanks in part 178 or part 180 of this sub-chapter.

Approval agency means the des-ignated approval agency authorized toapprove the portable tank in accord-ance with the procedures in subpart Eof part 107 of this subchapter.

Design pressure is defined accordingto the hazardous materials intended tobe transported in the portable tank.See §§ 178.275, 178.276 and 178.277, as ap-plicable.

Design type means a portable tank orseries of portable tanks made of mate-rials of the same material specifica-tions and thicknesses, manufacturedby a single manufacturer, using thesame fabrication techniques (for exam-ple, welding procedures) and made withequivalent structural equipment, clo-sures, and service equipment.

Fine grain steel means steel which hasa ferritic grain size of 6 or finer whendetermined in accordance with ASTME 112–96 (see § 171.7 of this subchapter).

Fusible element means a non-reclosingpressure relief device that is thermallyactivated and that provides protectionagainst excessive pressure buildup inthe portable tank developed by expo-sure to heat, such as from a fire (see§ 178.275(g)).

Jacket means the outer insulationcover or cladding which may be part ofthe insulation system.

Leakage test means a test using gas tosubject the shell and its service equip-ment to an internal pressure.

Maximum allowable working pressure(MAWP) is defined according to thehazardous materials intended to betransported in the portable tank. See§§ 178.275, 178.276 and 178.277, as applica-ble.

Maximum permissible gross mass(MPGM) means the sum of the taremass of the portable tank and theheaviest hazardous material authorizedfor transportation.

Mild steel means a steel with a guar-anteed minimum tensile strength of 360N/mm2 to 440 N/mm2 and a guaranteedminimum elongation at fracture asspecified in paragraph (c)(10) of thissection.


838

49 CFR Ch. I (10–1–01 Edition)§ 178.274

Offshore portable tank means a port-able tank specially designed for re-peated use in the transportation of haz-ardous materials to, from and betweenoffshore facilities. An offshore portabletank is designed and constructed in ac-cordance with the Guidelines for theApproval of Containers Handled inOpen Seas specified in the IMDG Code(see § 171.7 of this subchapter).

Reference steel means a steel with atensile strength of 370 N/mm2 and anelongation at fracture of 27%.

Service equipment means measuringinstruments and filling, discharge,venting, safety, heating, cooling andinsulating devices.

Shell means the part of the portabletank which retains the hazardous ma-terials intended for transportation, in-cluding openings and closures, but doesnot include service equipment or exter-nal structural equipment.

Structural equipment means the rein-forcing, fastening, protective and stabi-lizing members external to the shell.

Test pressure means the maximumgauge pressure at the top of the shellduring the hydraulic pressure testequal to not less than 1.5 times the de-sign pressure for liquids and 1.3 for liq-uefied compressed gases. In some in-stances a pneumatic test is authorizedas an alternative to the hydraulic test.The minimum test pressures for port-able tanks intended for specific liquidand solid hazardous materials are spec-ified in the applicable portable tank Tcodes (such as T1–T23) assigned tothese hazardous materials in the§ 172.101 Table of this subchapter.

(b) General design and construction re-quirements. (1) The design temperaturerange for the shell must be ¥40 °C to 50°C (¥40 °F to 122 °F) for hazardous ma-terials transported under normal con-ditions of transportation, except forportable tanks used for refrigeratedliquefied gases where the minimum de-sign temperature must not be higherthan the lowest (coldest) temperature(for example, service temperature) ofthe contents during filling, dischargeor transportation. For hazardous mate-rials handled under elevated tempera-ture conditions, the design tempera-ture must not be less than the max-imum temperature of the hazardousmaterial during filling, discharge or

transportation. More severe designtemperatures must be considered forportable tanks subjected to severe cli-matic conditions (for example, portabletanks transported in arctic regions).Shells must be designed and con-structed in accordance with the re-quirements of the ASME Code, SectionVIII, Division 1 (see § 171.7 of this sub-chapter), except as limited or modifiedin this subchapter. For portable tanksused for liquid or solid hazardous mate-rials, a design code other than theASME Code may be used if approved bythe Associate Administrator. Portabletanks used for non-refrigerated and re-frigerated liquified compressed gasesrequire an ASME certification and Ustamp. Shells must be made of metallicmaterials suitable for forming. Non-metallic materials may be used for theattachments and supports between theshell and jacket, provided their mate-rial properties at the minimum andmaximum design temperatures areproven to be sufficient. For weldedshells, only a material whoseweldability has been fully dem-onstrated may be used. Welds must beof high quality and conform to a levelof integrity at least equivalent to thewelding requirements specified in Sec-tion VIII of the ASME Code for thewelding of pressure vessels. When themanufacturing process or the materialsmake it necessary, the shells must besuitably heat-treated to guarantee ade-quate toughness in the weld and in theheat-affected zones. In choosing thematerial, the design temperature rangemust be taken into account with re-spect to risk of brittle fracture, stresscorrosion cracking, resistance to im-pact, and suitability for the hazardousmaterials intended for transportationin the portable tank. When fine grainsteel is used, the guaranteed value ofthe yield strength must be not morethan 460 N/mm2 and the guaranteedvalue of the upper limit of the tensilestrength must be not more than 725 N/mm2 according to the material speci-fication. Aluminum may not be used asa construction material for the shellsof portable tanks intended for thetransport of non-refrigerated liquefiedgases. For portable tanks intended forthe transport of liquid or solid haz-ardous materials, aluminum may only


839


be used as a construction material forportable tank shells if approved by theAssociate Administrator. Portabletank materials must be suitable for theexternal environment where they willbe transported, taking into account thedetermined design temperature range.Portable tanks shall be designed towithstand, without loss of contents, atleast the internal pressure due to thecontents and the static, dynamic andthermal loads during normal condi-tions of handling and transportation.The design must take into account theeffects of fatigue, caused by repeatedapplication of these loads through theexpected life of the portable tank.

(2) Portable tank shells, fittings, andpipework shall be constructed frommaterials that are:

(i) Compatible with the hazardousmaterials intended to be transported;or

(ii) Properly passivated or neutral-ized by chemical reaction, if applica-ble; or

(iii) For portable tanks used for liq-uid and solid materials, lined with cor-rosion-resistant material directlybonded to the shell or attached byequivalent means.

(3) Gaskets and seals shall be made ofmaterials that are compatible with thehazardous materials intended to betransported.

(4) When shells are lined, the liningmust be compatible with the hazardousmaterials intended to be transported,homogeneous, non-porous, free fromperforations, sufficiently elastic andcompatible with the thermal expansioncharacteristics of the shell. The liningof every shell, shell fittings and pipingmust be continuous and must extendaround the face of any flange. Whereexternal fittings are welded to thetank, the lining must be continuousthrough the fitting and around the faceof external flanges. Joints and seams inthe lining must be made by fusing thematerial together or by other equallyeffective means.

(5) Contact between dissimilar met-als which could result in damage bygalvanic action must be prevented byappropriate measures.

(6) The construction materials of theportable tank, including any devices,gaskets, linings and accessories, must

not adversely affect or react with thehazardous materials intended to betransported in the portable tank.

(7) Portable tanks must be designedand constructed with supports thatprovide a secure base during transpor-tation and with suitable lifting and tie-down attachments.

(c) Design criteria. (1) Portable tanksand their fastenings must, under themaximum permissible loads and max-imum permissible working pressures,be capable of absorbing the followingseparately applied static forces (forcalculation purposes, acceleration dueto gravity (g) =9.81m/s2):

(i) In the direction of travel: 2g(twice the MPGM multiplied by the ac-celeration due to gravity);

(ii) Horizontally at right angles tothe direction of travel: 1g (the MPGMmultiplied by the acceleration due togravity);

(iii) Vertically upwards: 1g (theMPGM multiplied by the accelerationdue to gravity); and

(iv) Vertically downwards: 2g (twicethe MPGM multiplied by the accelera-tion due to gravity).

(2) Under each of the forces specifiedin paragraph (c)(1) of this section, thesafety factor must be as follows:

(i) For metals having a clearly de-fined yield point, a design margin of 1.5in relation to the guaranteed yieldstrength; or

(ii) For metals with no clearly de-fined yield point, a design margin of 1.5in relation to the guaranteed 0.2%proof strength and, for austeniticsteels, the 1% proof strength.

(3) The values of yield strength orproof strength must be the values ac-cording to recognized material stand-ards. When austenitic steels are used,the specified minimum values of yieldstrength or proof strength according tothe material standards may be in-creased by up to 15% for portable tanksused for liquid and solid hazardous ma-terials, other than toxic by inhalationliquids meeting the criteria of HazardZone A or Hazard Zone B (see § 173.133of this subchapter), when these greatervalues are attested in the material in-spection certificate.

(4) Portable tanks must be capable ofbeing electrically grounded to preventdangerous electrostatic discharge when


840

49 CFR Ch. I (10–1–01 Edition)§ 178.274

they are used for Class 2 flammablegases or Class 3 flammable liquids, in-cluding elevated temperature mate-rials transported at or above theirflash point.

(5) For shells of portable tanks usedfor liquefied compressed gases, theshell must consist of a circular crosssection. Shells must be of a design ca-pable of being stress-analysed mathe-matically or experimentally by resist-ance strain gauges as specified in UG–101, Section VIII of the ASME Code (see§ 171.7 of this subchapter), or othermethods approved by the Associate Ad-ministrator.

(6) Shells must be designed and con-structed to withstand a hydraulic testpressure of not less than 1.5 times thedesign pressure for portable tanks usedfor liquids and 1.3 times the designpressure for portable tanks used for liq-uefied compressed gases. Specific re-quirements are provided for each haz-ardous material in the applicable TCode or portable tank special provisionspecified in the § 172.101 Table of thissubchapter. The minimum shell thick-ness requirements must also be takeninto account.

(7) For metals exhibiting a clearlydefined yield point or characterized bya guaranteed proof strength (0.2% proofstrength, generally, or 1% proofstrength for austenitic steels), the pri-mary membrane stress σ (sigma) in theshell must not exceed 0.75 Re or 0.50Rm, whichever is lower, at the testpressure, where:Re = yield strength in N/mm2, or 0.2%

proof strength or, for austeniticsteels, 1% proof strength;

Rm = minimum tensile strength in N/mm2.

(8) The values of Re and Rm to beused must be the specified minimumvalues according to recognized mate-rial standards. When austenitic steelsare used, the specified minimum valuesfor Re and Rm according to the mate-rial standards may be increased by upto 15% when greater values are at-tested in the material inspection cer-tificate.

(9) Steels which have a Re/Rm ratioof more than 0.85 are not allowed forthe construction of welded shells. Thevalues of Re and Rm to be used in de-termining this ratio must be the values

specified in the material inspectioncertificate.

(10) Steels used in the construction ofshells must have an elongation at frac-ture, in percentage, of not less than10,000/Rm with an absolute minimum of16% for fine grain steels and 20% forother steels.

(11) For the purpose of determiningactual values for materials for sheetmetal, the axis of the tensile test speci-men must be at right angles (trans-versely) to the direction of rolling. Thepermanent elongation at fracture mustbe measured on test specimens of rec-tangular cross sections in accordancewith ISO 6892 (see § 171.7 of this sub-chapter), using a 50 mm gauge length.

(d) Minimum shell thickness. (1) Theminimum shell thickness must be thegreatest thickness of the following:

(i) the minimum thickness deter-mined in accordance with the require-ments of paragraphs (d)(2) through(d)(10) of this section;

(ii) the minimum thickness deter-mined in accordance with Section VIIIof the ASME Code (see § 171.7 of thissubchapter) or other approved pressurevessel code; or

(iii) the minimum thickness specifiedin the applicable T code or portabletank special provision indicated foreach hazardous material in the § 172.101Table of this subchapter.

(2) Shells (cylindrical portions, headsand manhole covers) not more than 1.80m in diameter may not be less than 5mm thick in the reference steel or ofequivalent thickness in the metal to beused. Shells more than 1.80 m in diame-ter may not be less than 6 mm (0.2inches) thick in the reference steel orof equivalent thickness in the metal tobe used. For portable tanks used onlyfor the transportation of powdered orgranular solid hazardous materials ofPacking Group II or III, the minimumthickness requirement may be reducedto 5 mm in the reference steel or ofequivalent thickness in the metal to beused regardless of the shell diameter.For vacuum-insulated tanks, the ag-gregate thickness of the jacket and theshell must correspond to the minimumthickness prescribed in this paragraph,with the thickness of the shell itselfnot less than the minimum thickness


841


prescribed in paragraph (d)(3) of thissection.

(3) When additional protectionagainst shell damage is provided in thecase of portable tanks used for liquidand solid hazardous materials requir-ing test pressures less than 2.65 bar(265.0 kPa), subject to certain limita-tions specified in the UN Recommenda-tions (see § 171.7 of this subchapter), theAssociate Administrator may approvea reduced minimum shell thickness.

(4) The cylindrical portions, headsand manhole covers of all shells mustnot be less than 3 mm (0.1 inch) thickregardless of the material of construc-tion, except for portable tanks used forliquefied compressed gases where thecylindrical portions, ends (heads) andmanhole covers of all shells must notbe less than 4 mm (0.2 inch) thick re-gardless of the material of construc-tion.

(5) When steel is used, that has char-acteristics other than that of referencesteel, the equivalent thickness of theshell and heads must be determined ac-cording to the following formula:

ee d

m Rm A1

0 1

1 13

21

18=

×.4

.Where:

e1 = required equivalent thickness (in mm) ofthe metal to be used;

e0 = minimum thickness (in mm) of the ref-erence steel specified in the applicable Tcode or portable tank special provisionindicated for each material in the§ 172.101 Table of this subchapter;

d1 = 1.8m, unless the formula is used to de-termine the equivalent minimum thick-ness for a portable tank shell that is re-quired to have a minimum thickness of8mm or 10mm according to the applica-ble T code indicated in the § 172.101 Tableof this subchapter. When reference steelthicknesses of 8mm or 10mm are speci-fied, d1 is equal to the actual diameter ofthe shell but not less than 1.8m;

Rm1 = guaranteed minimum tensile strength(in N/mm 2) of the metal to be used;

A1 = guaranteed minimum elongation atfracture (in %) of the metal to be usedaccording to recognized material stand-ards.

(6) The wall and all parts of the shellmay not have a thickness less thanthat prescribed in paragraphs (d)(2),(d)(3) and (d)(4) of this section. This

thickness must be exclusive of any cor-rosion allowance.

(7) There must be no sudden changeof plate thickness at the attachment ofthe heads to the cylindrical portion ofthe shell.

(e) Service equipment. (1) Serviceequipment must be arranged so that itis protected against the risk of me-chanical damage by external forcesduring handling and transportation.When the connections between theframe and the shell allow relativemovement between the sub-assemblies,the equipment must be fastened toallow such movement without risk ofdamage to any working part. The ex-ternal discharge fittings (pipe sockets,shut-off devices) and the internal stop-valve and its seating must be protectedagainst mechanical damage by exter-nal forces (for example, by using shearsections). Each internal self-closingstop-valve must be protected by ashear section or sacrificial device lo-cated outboard of the valve. The shearsection or sacrificial device must breakat no more than 70% of the load thatwould cause failure of the internal self-closing stop valve. The filling and dis-charge devices (including flanges orthreaded plugs) and any protectivecaps must be capable of being securedagainst unintended opening.

(2) Each filling or discharge openingof a portable tank must be clearlymarked to indicate its function.

(3) Each stop-valve or other means ofclosure must be designed and con-structed to a rated pressure not lessthan the MAWP of the shell takinginto account the temperatures ex-pected during transport. All stop-valves with screwed spindles mustclose by a clockwise motion of thehandwheel. For other stop-valves, theposition (open and closed) and direc-tion of closure must be clearly indi-cated. All stop-valves must be designedto prevent unintentional opening.

(4) Piping must be designed, con-structed and installed to avoid the riskof damage due to thermal expansionand contraction, mechanical shock andvibration. All piping must be of a suit-able metallic material. Welded pipejoints must be used wherever possible.

(5) Joints in copper tubing must bebrazed or have an equally strong metal


842

49 CFR Ch. I (10–1–01 Edition)§ 178.274

union. The melting point of brazingmaterials must be no lower than 525 °C(977 °F). The joints must not decreasethe strength of the tubing, such as mayhappen when cutting threads. Brazedjoints are not authorized for portabletanks intended for refrigerated lique-fied gases.

(6) The burst pressure of all pipingand pipe fittings must be greater thanthe highest of four times the MAWP ofthe shell or four times the pressure towhich it may be subjected in service bythe action of a pump or other device(except pressure relief devices).

(7) Ductile metals must be used inthe construction of valves and acces-sories.

(f) Pressure relief devices.—(1) Markingof pressure relief devices. Every pressurerelief device must be clearly and per-manently marked with the following:

(i) the pressure (in bar or kPa) ortemperature for fusible elements (in°C) at which it is set to discharge;

(ii) the allowable tolerance at thedischarge pressure for reclosing de-vices;

(iii) the reference temperature cor-responding to the rated pressure forfrangible discs;

(iv) the allowable temperature toler-ance for fusible elements;

(v) the rated flow capacity of the de-vice in standard cubic meters of air persecond (m3/s)determined according toISO 4126–1 (see § 171.7 of this sub-chapter); and

(vi) when practicable, the devicemust show the manufacturer’s nameand product number.

(2) Connections to pressure relief de-vices. Connections to pressure relief de-vices must be of sufficient size to en-able the required discharge to pass un-restricted to the safety device. No stop-valve may be installed between theshell and the pressure relief devices ex-cept where duplicate devices are pro-vided for maintenance or other reasonsand the stop-valves serving the devicesactually in use are locked open or thestop-valves are interlocked so that atleast one of the devices is always inuse. There must be no obstruction inan opening leading to a vent or pres-sure relief device which might restrictor cut-off the flow from the shell tothat device. Vents or pipes from the

pressure relief device outlets, whenused, must deliver the relieved vapor orliquid to the atmosphere in conditionsof minimum back-pressure on the re-lieving devices.

(3) Location of pressure relief devices.(i) Each pressure relief device inletmust be situated on top of the shell ina position as near the longitudinal andtransverse center of the shell as rea-sonably practicable. All pressure reliefdevice inlets must, under maximumfilling conditions, be situated in thevapor space of the shell and the devicesmust be so arranged as to ensure thatany escaping vapor is not restricted inany manner. For flammable hazardousmaterials, the escaping vapor must bedirected away from the shell in such amanner that it cannot impinge uponthe shell. For refrigerated liquefiedgases, the escaping vapor must be di-rected away from the tank and in sucha manner that it cannot impinge uponthe tank. Protective devices which de-flect the flow of vapor are permissibleprovided the required relief-device ca-pacity is not reduced.

(ii) Provisions must be implementedto prevent unauthorized persons fromaccess to the pressure relief devicesand to protect the devices from damagecaused by the portable tank over-turning.

(g) Gauging devices. Unless a portabletank is intended to be filled by weight,it must be equipped with one or moregauging devices. Glass level-gauges andgauges made of other fragile material,which are in direct communicationwith the contents of the tank are pro-hibited. A connection for a vacuumgauge must be provided in the jacket ofa vacuum-insulated portable tank.

(h) Portable tank supports, frameworks,lifting and tie-down attachments. (1)Portable tanks must be designed andconstructed with a support structure toprovide a secure base during transport.The forces and safety factors specifiedin paragraphs (c)(1) and (c)(2) of thissection, respectively, must be takeninto account in this aspect of the de-sign. Skids, frameworks, cradles orother similar structures are accept-able.

(2) The combined stresses caused byportable tank mountings (for example,cradles, framework, etc.) and portable


843


tank lifting and tie-down attachmentsmust not cause stress that would dam-age the shell in a manner that wouldcompromise its lading retention capa-bility. Permanent lifting and tie-downattachments must be fitted to all port-able tanks. Preferably they should befitted to the portable tank supportsbut may be secured to reinforcingplates located on the shell at thepoints of support. Each portable tankmust be designed so that the center ofgravity of the filled tank is approxi-mately centered within the points ofattachment for lifting devices.

(3) In the design of supports andframeworks, the effects of environ-mental corrosion must be taken intoaccount.

(4) Forklift pockets must be capableof being closed off. The means of clos-ing forklift pockets must be a perma-nent part of the framework or perma-nently attached to the framework. Sin-gle compartment portable tanks with alength less than 3.65 m (12 ft.) need nothave forklift pockets that are capableof being closed off provided that:

(i) The shell, including all the fit-tings, are well protected from being hitby the forklift blades; and

(ii) The distance between forkliftpockets (measured from the center ofeach pocket) is at least half of themaximum length of the portable tank.

(5) During transport, portable tanksmust be adequately protected againstdamage to the shell, and service equip-ment resulting from lateral and longi-tudinal impact and overturning, or theshell and service equipment must beconstructed to withstand the forces re-sulting from impact or overturning.External fittings must be protected soas to preclude the release of the shellcontents upon impact or overturning ofthe portable tank on its fittings. Ex-amples of protection include:

(i) Protection against lateral impactwhich may consist of longitudinal barsprotecting the shell on both sides atthe level of the median line;

(ii) Protection of the portable tankagainst overturning which may consistof reinforcement rings or bars fixedacross the frame;

(iii) Protection against rear impactwhich may consist of a bumper orframe;

(iv) Protection of the shell againstdamage from impact or overturning byuse of an ISO frame in accordance withISO 1496–3 (see § 171.7 of this sub-chapter); and

(v) Protection of the portable tankfrom impact or damage that may re-sult from overturning by an insulationjacket.

(i) Marking. (1) Every portable tankmust be fitted with a corrosion resist-ant metal plate permanently attachedto the portable tank in a conspicuousplace and readily accessible for inspec-tion. When the plate cannot be perma-nently attached to the shell, the shellmust be marked with at least the infor-mation required by Section VIII of theASME Code (see § 171.7 of this sub-chapter). At a minimum, the followinginformation must be marked on theplate by stamping or by any otherequivalent method:

Country of manufactureU NApproval CountryApproval NumberAlternative Arrangements (see § 178.247(a)(2))

‘‘AA’’Manufacturer’s name or markManufacturer’s serial numberApproval Agency (Authorized body for the

design approval)Owner’s registration numberYear of manufacturePressure vessel code to which the shell is de-

signedTest pressurellllbar gauge.MAWPllllbar gauge.External design pressure (not required for

portable tanks used for refrigerated liq-uefied gases)llllbar gauge.

Design temperature rangellll °Ctollll °C. (For portable tanks usedfor refrigerated liquefied gases, the min-imum design temperature must bemarked.)

Water capacity at 20 °C/llllliters.Water capacity of each compartment at 20

°Cllllliters.Initial pressure test date and witness identi-

fication.MAWP for heating/cooling systemllllbar

gauge.Shell material(s) and material standard ref-

erence(s).Equivalent thickness in reference

steelllllmm.Lining material (when applicable).Date and type of most recent periodic test(s).MonthllllYearllllTest pres-

surellllbar gauge.Stamp of approval agency that performed or

witnessed the most recent test.


844

49 CFR Ch. I (10–1–01 Edition)§ 178.274

For portable tanks used for refrigeratedliquefied gases:Either ‘‘thermally insulated’’ or ‘‘vacuum in-

sulated’’llll.Effectiveness of the insulation system (heat

influx)llllWatts (W).Reference holding timelllldays or hours

and initial pressurellllbar/kPa gaugeand degree of fillingllllin kg for eachrefrigerated liquefied gas permitted fortransportation.

(2) The following information mustbe marked either on the portable tankitself or on a metal plate firmly se-cured to the portable tank:

Name of the operator.Name of hazardous materials being trans-

ported and maximum mean bulk tem-perature (except for refrigerated lique-fied gases, the name and temperature areonly required when the maximum meanbulk temperature is higher than 50 °C).

Maximum permissible gross mass(MPGM)llllkg.

Unladen (tare) massllllkg.NOTE TO PARAGRAPH (I)(2): For the identi-

fication of the hazardous materials beingtransported refer to part 172 of this sub-chapter.

(3) If a portable tank is designed andapproved for open seas operations, suchas offshore oil exploration, in accord-ance with the IMDG Code, the words‘‘OFFSHORE PORTABLE TANK’’ mustbe marked on the identification plate.

(j) Initial inspection and test. The ini-tial inspection and test of a portabletank must include the following:

(1) A check of the design characteris-tics.

(2) An internal and external examina-tion of the portable tank and its fit-tings, taking into account the haz-ardous materials to be transported. ForUN portable tanks used for refrigeratedliquefied gases, a pressure test using aninert gas may be conducted instead ofa hydrostatic test. An internal inspec-tion is not required for a portable tankused for the dedicated transportationof refrigerated liquefied gases that arenot filled with an inspection opening.

(3) A pressure test as specified inparagraph (i) of this section.

(4) A leakage test.(5) A test of the satisfactory oper-

ation of all service equipment includ-ing pressure relief devices must also beperformed. When the shell and its fit-tings have been pressure-tested sepa-rately, they must be subjected to a

leakage test after reassembly. Allwelds, subject to full stress level in theshell, must be inspected during the ini-tial test by radiographic, ultrasonic, oranother suitable non-destructive testmethod. This does not apply to thejacket.

(6) A UN portable tank that meetsthe definition of ‘‘container’’ in theCSC (see 49 CFR 450.3(a)(2)) must besubjected to an impact test using aprototype representing each designtype. The prototype portable tankmust be shown to be capable of absorb-ing the forces resulting from an impactnot less than 4 times (4 g) the max-imum permissable gross mass of thefully loaded portable tank at a dura-tion typical of the mechanical shocksexperienced in rail transportation. Alisting of standards describing methodsacceptable for performing the impacttest are provided in the UN Rec-ommendations (see § 171.7 of this sub-chapter). UN portable tanks used forthe dedicated transportation of ‘‘He-lium, refrigerated liquid,’’ UN1963 and‘‘Hydrogen, refrigerated liquid,’’UN1966 that are marked ‘‘NOT FORRAIL TRANSPORT’’ in letters of aminimum height of 20 cm (8 inches) onat least two sides of the portable tankare excepted from the 4 g impact test.

(7) The following tests must be com-pleted on a portable tank or a series ofportable tanks designed and con-structed to a single design type that isalso a CSC container without leakageor deformation that would render theportable tank unsafe for transportationand use:

(i) Longitudinal inertia. The portabletank loaded to its maximum grossweight must be positioned with its lon-gitudinal axis vertical. It shall be heldin this position for five minutes by sup-port at the lower end of the base struc-ture providing vertical and lateral re-straint and by support at the upper endof the base structure providing lateralrestraint only.

(ii) Lateral inertia. The portable tankloaded to its maximum gross weightmust be positioned for five minuteswith its transverse axis vertical. Itshall be held in this position for fiveminutes by support at the lower side ofthe base structure providing verticaland lateral restraint and by support at


845


the upper side of the base structureproviding lateral restraint only.

[66 FR 33440, June 21, 2001]

§ 178.275 Specification for UN PortableTanks intended for the transpor-tation of liquid and solid hazardousmaterials.

(a) In addition to the requirements of§ 178.274, this section sets forth defini-tions and requirements that apply toUN portable tanks intended for thetransportation of liquid and solid haz-ardous materials.

(b) Definitions and requirements—(1)Design pressure means the pressure tobe used in calculations required by therecognized pressure vessel code. Thedesign pressure must not be less thanthe highest of the following pressures:

(i) The maximum effective gaugepressure allowed in the shell duringfilling or discharge; or

(ii) The sum of—(A) The absolute vapor pressure (in

bar) of the hazardous material at 65 °C,minus 1 bar (149 °F, minus 100 kPa);

(B) The partial pressure (in bar) ofair or other gases in the ullage space,resulting from their compression dur-ing filling without pressure relief by amaximum ullage temperature of 65 °C(149 °F) and a liquid expansion due toan increase in mean bulk temperatureof 35 °C (95 °F); and

(C) A head pressure determined onthe basis of the forces specified in§ 178.274(c) of this subchapter, but notless than 0.35 bar (35 kPa).

(2) Maximum allowable working pres-sure (MAWP) means a pressure thatmust not be less than the highest ofthe following pressures measured atthe top of the shell while in operatingposition:


(ii) The maximum effective gaugepressure to which the shell is designedwhich must be not less than the designpressure.

(c) Service equipment. (1) In additionto the requirements specified in§ 178.274, for service equipment, allopenings in the shell, intended for fill-ing or discharging the portable tankmust be fitted with a manually oper-ated stop-valve located as close to the

shell as reasonably practicable. Otheropenings, except for openings leadingto venting or pressure relief devices,must be equipped with either a stop-valve or another suitable means of clo-sure located as close to the shell asreasonably practicable.

(2) All portable tanks must be fittedwith a manhole or other inspectionopenings of a suitable size to allow forinternal inspection and adequate ac-cess for maintenance and repair of theinterior. Compartmented portabletanks must have a manhole or otherinspection openings for each compart-ment.

(3) For insulated portable tanks, topfittings must be surrounded by a spillcollection reservoir with suitabledrains.

(4) Piping must be designed, con-structed and installed to avoid the riskof damage due to thermal expansionand contraction, mechanical shock andvibration. All piping must be of a suit-able metallic material. Welded pipejoints must be used wherever possible.

(d) Bottom openings. (1) Certain haz-ardous materials may not be trans-ported in portable tanks with bottomopenings. When the applicable T codeor portable tank special provision, asreferenced for materials in the § 172.101Table of this subchapter, specifies thatbottom openings are prohibited, theremust be no openings below the liquidlevel of the shell when it is filled to itsmaximum permissible filling limit.When an existing opening is closed, itmust be accomplished by internallyand externally welding one plate to theshell.

(2) Bottom discharge outlets for port-able tanks carrying certain solid, crys-tallizable or highly viscous hazardousmaterials must be equipped with atleast two serially fitted and mutuallyindependent shut-off devices. Use ofonly two shut-off devices is only au-thorized when this paragraph is ref-erenced in the applicable T Code indi-cated for each hazardous material inthe § 172.101 Table of this subchapter.The design of the equipment must be tothe satisfaction of the approval agencyand must include:

(i) An external stop-valve fitted asclose to the shell as reasonably prac-ticable; and


846

49 CFR Ch. I (10–1–01 Edition)§ 178.275

(ii) A liquid tight closure at the endof the discharge pipe, which may be abolted blank flange or a screw cap.

(3) Except as provided in paragraph(c)(2) of this section, every bottom dis-charge outlet must be equipped withthree serially fitted and mutually inde-pendent shut-off devices. The design ofthe equipment must include:

(i) A self-closing internal stop-valve,which is a stop-valve within the shellor within a welded flange or its com-panion flange, such that:

(A) The control devices for the oper-ation of the valve are designed to pre-vent any unintended opening throughimpact or other inadvertent act;

(B) The valve is operable from aboveor below;

(C) If possible, the setting of thevalve (open or closed) must be capableof being verified from the ground;

(D) Except for portable tanks havinga capacity less than 1,000 liters (264.2gallons), it must be possible to closethe valve from an accessible positionon the portable tank that is remotefrom the valve itself within 30 secondsof actuation; and

(E) The valve must continue to be ef-fective in the event of damage to theexternal device for controlling the op-eration of the valve;

(ii) An external stop-valve fitted asclose to the shell as reasonably prac-ticable;

(iii) A liquid tight closure at the endof the discharge pipe, which may be abolted blank flange or a screw cap; and

(iv) For portable tanks used for thetransportation of liquid materials thatare flammable, pyrophoric, oxidizing ortoxic, the remote means of closuremust be capable of thermal activation.The thermal means of activation mustactivate at a temperature of not morethan 121 °C (250 °F).

(e) Pressure relief devices. All portabletanks must be fitted with at least onepressure relief device. All relief devicesmust be designed, constructed andmarked in accordance with the require-ments of this subchapter.

(f) Vacuum-relief devices. (1) A shellwhich is to be equipped with a vacuum-relief device must be designed to with-stand, without permanent deformation,an external pressure of not less than0.21 bar (21.0 kPa). The vacuum-relief

device must be set to relieve at a vacu-um setting not greater than –0.21 bar (–21.0 kPa) unless the shell is designedfor a higher external over pressure, inwhich case the vacuum-relief pressureof the device to be fitted must not begreater than the tank design vacuumpressure. A shell that is not fitted witha vacuum-relief device must be de-signed to withstand, without perma-nent deformation, an external pressureof not less than 0.4 bar (40.0 kPa).

(2) Vacuum-relief devices used onportable tanks intended for the trans-portation of hazardous materials meet-ing the criteria of Class 3, includingelevated temperature hazardous mate-rials transported at or above theirflash point, must prevent the imme-diate passage of flame into the shell orthe portable tank must have a shell ca-pable of withstanding, without leak-age, an internal explosion resultingfrom the passage of flame into theshell.

(g) Pressure relief devices. (1) Eachportable tank with a capacity not lessthan 1,900 liters (501.9 gallons) andevery independent compartment of aportable tank with a similar capacity,must be provided with one or morepressure relief devices of the reclosingtype. Such portable tanks may, in ad-dition, have a frangible disc or fusibleelement in parallel with the reclosingdevices, except when the applicable Tcode assigned to a hazardous materialrequires that the frangible disc precedethe pressure relief device, according toparagraph (g)(3) of this section, orwhen no bottom openings are allowed.The pressure relief devices must havesufficient capacity to prevent ruptureof the shell due to over pressurizationor vacuum resulting from filling, dis-charging, heating of the contents orfire.

(2) Pressure relief devices must be de-signed to prevent the entry of foreignmatter, the leakage of liquid and thedevelopment of any dangerous excesspressure.

(3) When required for certain haz-ardous materials by the applicable Tcode or portable tank special provisionspecified for a hazardous material inthe § 172.101 Table of this subchapter,portable tanks must have a pressure


847


relief device consistent with the re-quirements of this subchapter. Exceptfor a portable tank in dedicated servicethat is fitted with an approved reliefdevice constructed of materials com-patible with the hazardous material,the relief device system must include afrangible disc preceding (such as, be-tween the lading and the reclosingpressure relief device) a reclosing pres-sure relief device. A pressure gauge orsuitable tell-tale indicator for the de-tection of disc rupture, pin-holing orleakage must be provided in the spacebetween the frangible disc and thepressure relief device to allow the port-able tank operator to check to deter-mine if the disc is leak free. The fran-gible disc must rupture at a nominalpressure 10% above the start-to-dis-charge pressure of the reclosable pres-sure relief device.

(4) Every portable tank with a capac-ity less than 1,900 liters (501.9 gallons)must be fitted with a pressure relief de-vice which, except as provided in para-graph (g)(3) of this section, may be afrangible disc when this disc is set torupture at a nominal pressure equal tothe test pressure at any temperaturewithin the design temperature range.

(5) When the shell is fitted for pres-sure discharge, a suitable pressure re-lief device must provide the inlet lineto the portable tank and set to operateat a pressure not higher than theMAWP of the shell, and a stop-valvemust be fitted as close to the shell aspracticable to minimize the potentialfor damage.

(6) Setting of pressure relief devices. (i)Pressure relief devices must operateonly in conditions of excessive rise intemperature. The shell must not besubject to undue fluctuations of pres-sure during normal conditions of trans-portation.

(ii) The required pressure relief de-vice must be set to start to dischargeat a nominal pressure of five-sixths ofthe test pressure for shells having atest pressure of not more than 4.5 bar(450 kPa) and 110% of two-thirds of thetest pressure for shells having a testpressure of more than 4.5 bar (450 kPa).A self-closing relief device must closeat a pressure not more than 10% belowthe pressure at which the dischargestarts. The device must remain closed

at all lower pressures. This require-ment does not prevent the use of vacu-um-relief or combination pressure re-lief and vacuum-relief devices.

(h) Fusible elements. Fusible elementsmust operate at a temperature between110 °C (230 °F) and 149 °C (300.2 °F) pro-vided that the pressure in the shell atthe fusing temperature will not exceedthe test pressure. They must be placedat the top of the shell with their inletsin the vapor space and in no case maythey be shielded from external heat.Fusible elements must not be utilizedon portable tanks with a test pressurewhich exceeds 2.65 bar (265.0 kPa). Fusi-ble elements used on portable tanks in-tended for the transport of elevatedtemperature hazardous materials mustbe designed to operate at a tempera-ture higher than the maximum tem-perature that will be experienced dur-ing transport and must be designed tothe satisfaction of the approval agency.

(i) Capacity of pressure relief devices.(1) The reclosing pressure relief devicerequired by paragraph (g)(1) of this sec-tion must have a minimum cross sec-tional flow area equivalent to an ori-fice of 31.75 mm (1.3 inches) diameter.Vacuum-relief devices, when used,must have a cross sectional flow areanot less than 284 mm 2 (11.2 inches 2).

(2) Under conditions of complete fireengulfment of the portable tank, thecombined delivery capacity of the re-lief devices must be sufficient to limitthe pressure in the shell to 20% abovethe start-to-discharge pressure speci-fied in paragraph (g)(6) of this section.Emergency pressure relief devices maybe used to achieve the full relief capac-ity prescribed. The total required ca-pacity of the relief devices may be de-termined using the formula in para-graph (i)(2)(i)(A) of this section or thetable in paragraph (i)(2)(iii) of this sec-tion.

(i)(A) To determine the total re-quired capacity of the relief devices,which must be regarded as being thesum of the individual capacities of allthe contributing devices, the followingformula must be used:

QFA

LC

ZT

M= 12

0 82

.4.

Where:


848

49 CFR Ch. I (10–1–01 Edition)§ 178.275

Q = minimum required rate of discharge incubic meters of air per second (m 3/s) atstandard conditions: 1 bar and 0 °C (273K);

F = for uninsulated shells: 1; for insulatedshells: U(649-t)/13.6 but in no case is lessthan 0.25 where: U = thermal conduct-ance of the insulation, in kW·m¥2 K¥1, at38 °C; and t = actual temperature of thehazardous material during filling (in °C)or when this temperature is unknown, lett = 15 °C. The value of F given in thisparagraph (i)(2)(i)(A) for insulated shellsmay only be used if the insulation is inconformance with paragraph (i)(2)(iv) ofthis section;

A = total external surface area of shell insquare meters;

Z = the gas compressibility factor in the ac-cumulating condition (when this factoris unknown, let Z equal 1.0);

T = absolute temperature in Kelvin ( °C +273) above the pressure relief devices inthe accumulating condition;

L = the latent heat of vaporization of the liq-uid, in kJ/kg, in the accumulating condi-tion;

M = molecular weight of the hazardous mate-rial.

(B) The constant C, as shown in theformula in paragraph (i)(2)(i)(A) of thissection, is derived from one of the fol-lowing formula as a function of theratio k of specific heats:

kc

cp

v

=

Where:

cp is the specific heat at constant pressure;and

cv is the specific heat at constant volume.

(C) When k >1:

C kk

k

k=+

+−2

1

1

1

(D) When k = 1 or k is unknown, avalue of 0.607 may be used for the con-stant C. C may also be taken from thefollowing table:

C CONSTANT VALUE TABLE

k C k C k C

1.00 0.607 1.26 0.660 1.52 0.7041.02 0.611 1.28 0.664 1.54 0.7071.04 0.615 1.30 0.667 1.56 0.7101.06 0.620 1.32 0.671 1.58 0.7131.08 0.624 1.34 0.674 1.60 0.7161.10 0.628 1.36 0.678 1.62 0.7191.12 0.633 1.38 0.681 1.64 0.7221.14 0.637 1.40 0.685 1.66 0.7251.16 0.641 1.42 0.688 1.68 0.7281.18 0.645 1.44 0.691 1.70 0.7311.20 0.649 1.46 0.695 2.00 0.7701.22 0.652 1.48 0.698 2.20 0.7931.24 0.656 1.50 0.701

(ii) As an alternative to the formulain paragraph (i)(2)(i)(A) of this section,relief devices for shells used for trans-porting liquids may be sized in accord-ance with the table in paragraph(i)(2)(iii) of this section. The table inparagraph (i)(2)(iii) of this section as-sumes an insulation value of F = 1 andmust be adjusted accordingly when the

shell is insulated. Other values used indetermining the table in paragraph(i)(2)(iii) of this section are: L = 334.94kJ/kg; M = 86.7; T = 394 K; Z = 1; and C= 0.607.

(iii) Minimum emergency vent capac-ity, Q, in cubic meters per air per sec-ond at 1 bar and 0 °C (273 K) shown inthe following table:

MINIMUM EMERGENCY VENT CAPACITY[Q Values]

AExposed area

(square meters)

Q(Cubic meters of air per sec-

ond)

AExposed area

(square meters)


ond)

2 0.230 37.5 2.5393 0.320 40 2.677


849


MINIMUM EMERGENCY VENT CAPACITY—Continued[Q Values]

AExposed area

(square meters)


ond)

AExposed area

(square meters)


ond)

4 0.405 42.5 2.8145 0.487 45 2.9496 0.565 47.5 3.0827 0.641 50 3.2158 0.715 52.5 3.3469 0.788 55 3.47610 0.859 57.5 3.60512 0.998 60 3.73314 1.132 62.5 3.86016 1.263 65 3.98718 1.391 67.5 4.11220 1.517 70 4.236

22.5 1.670 75 4.48325 1.821 80 4.726

27.5 1.969 85 4.96730 2.115 90 5.206

32.5 2.258 95 5.44235 2.400 100 5.676

(iv) Insulation systems, used for thepurpose of reducing venting capacity,must be specifically approved by theapproval agency. In all cases, insula-tion systems approved for this purposemust—

(A) Remain effective at all tempera-tures up to 649 °C (1200.2 °F); and

(B) Be jacketed with a material hav-ing a melting point of 700 °C (1292 °F) orgreater.

(j) Approval, inspection and testing.Approval procedures for UN portabletanks are specified in § 178.273. Inspec-tion and testing requirements are spec-ified in § 180.605 of this subchapter.

[66 FR 33445, June 21, 2001]

§ 178.276 Requirements for the design,construction, inspection and testingof portable tanks intended for thetransportation of non-refrigeratedliquefied compressed gases.

(a) In addition to the requirements of§ 178.274 applicable to UN portabletanks, the following requirementsapply to UN portable tanks used fornon-refrigerated liquefied compressedgases. In addition to the definitions in§ 178.274, the following definitionsapply:

(1) Design pressure means the pressureto be used in calculations required bythe ASME Code, Section VIII (see§ 171.7 of this subchapter). The designpressure must be not less than thehighest of the following pressures:


(ii) The sum of:(A) The maximum effective gauge

pressure to which the shell is designedas defined in this paragraph under‘‘MAWP’’; and

(B) A head pressure determined onthe basis of the dynamic forces speci-fied in paragraph (h) of this section,but not less than 0.35 bar (35 kPa).

(2) Design reference temperature meansthe temperature at which the vaporpressure of the contents is determinedfor the purpose of calculating theMAWP. The value for each portabletank type is as follows:

(i) Shell with a diameter of 1.5 meters(4.9 ft.) or less: 65 °C (149 °F); or

(ii) Shell with a diameter of morethan 1.5 meters (4.9 ft.):

(A) Without insulation or sun shield:60 °C (140 °F);

(B) With sun shield: 55 °C (131 °F); and(C) With insulation: 50 °C (122 °F).(3) Filling density means the average

mass of liquefied compressed gas perliter of shell capacity (kg/l).

(4) Maximum allowable working pres-sure (MAWP) means a pressure thatmust be not less than the highest ofthe following pressures measured atthe top of the shell while in operatingposition, but in no case less than 7 bar(700 kPa):


850

49 CFR Ch. I (10–1–01 Edition)§ 178.276


(ii) The maximum effective gaugepressure to which the shell is designed,which must be:

(A) Not less than the pressure speci-fied for each liquefied compressed gaslisted in portable tank special provi-sion T50; and

(B) Not less than the sum of:(1) The absolute vapor pressure (in

bar) of the liquefied compressed gas atthe design reference temperatureminus 1 bar; and

(2) The partial pressure (in bar) of airor other gases in the ullage spacewhich is determined by the design ref-erence temperature and the liquidphase expansion due to the increase ofthe mean bulk temperature of tr-tf (tf =filling temperature, usually 15 °C, tr =50 °C maximum mean bulk tempera-ture).

(b) General design and construction re-quirements. (1) Shells must be of seam-less or welded steel construction, orcombination of both, and have a watercapacity greater than 450 liters (118.9gallons). Shells must be designed, con-structed, certified and stamped in ac-cordance with the ASME Code, SectionVIII (see § 171.7 of this subchapter).

(2) Portable tanks must be postweldheat-treated and radiographed as pre-scribed in Section VIII of the ASMECode, except that each portable tankconstructed in accordance with partUHT of the ASME Code must bepostweld heat-treated. Where postweldheat treatment is required, the port-able tank must be treated as a unitafter completion of all the welds inand/or to the shell and heads. Themethod must be as prescribed in theASME Code. Welded attachments topads may be made after postweld heattreatment is made. A portable tankused for anhydrous ammonia must bepostweld heat-treated. The postweldheat treatment must be as prescribedin the ASME Code, but in no event atless than 1050 °F tank metal tempera-ture. Additionally, portable tanks con-structed in accordance with part UHTof the ASME Code must conform to thefollowing requirements:

(i) Welding procedure and welder per-formance tests must be made annually

in accordance with Section IX of theASME Code (see § 171.7 of this sub-chapter). In addition to the essentialvariables named therein, the followingmust be considered to be essential vari-ables: number of passes, thickness ofplate, heat input per pass, and manu-facturer’s identification of rod andflux. The number of passes, thicknessof plate and heat input per pass maynot vary more than 25 percent from thequalified procedure. Records of thequalification must be retained for atleast 5 years by the portable tank man-ufacturer or his designated agent and,upon request, made available to a rep-resentative of the Department ofTransportation or the owner of thetank.

(ii) Impact tests must be made on alot basis. A lot is defined as 100 tons orless of the same heat and having athickness variation no greater thanplus or minus 25 percent. The minimumimpact required for full-sized speci-mens shall be 20 foot-pounds (or 10foot-pounds for half-sized specimens) at0 °F (¥17.8 °F) Charpy V–Notch in boththe longitudinal and transverse direc-tion. If the lot test does not pass thisrequirement, individual plates may beaccepted if they individually meet thisimpact requirement.

(3) When the shells intended for thetransportation of non-refrigerated liq-uefied compressed gases are equippedwith thermal insulation, a device mustbe provided to prevent any dangerouspressure from developing in the insu-lating layer in the event of a leak,when the protective covering is closedit must be gas tight. The thermal insu-lation must not inhibit access to thefittings and discharge devices. In addi-tion, the thermal insulation systemsmust satisfy the following require-ments:

(i) consist of a shield covering notless than the upper third, but not morethan the upper half of the surface ofthe shell, and separated from the shellby an air space of approximately 40 mm(1.7 inches) across; or

(ii) consist of a complete cladding ofinsulating materials. The insulationmust be of adequate thickness and con-structed to prevent the ingress of mois-ture and damage to the insulation. Theinsulation and cladding must have a


851


thermal conductance of not more than0.67 (W·m¥2·K¥1) under normal condi-tions of transportation.

(c) Service equipment. (1) Each openingwith a diameter of more than 1.5 mm(0.1 inch) in the shell of a portabletank, except openings for pressure-re-lief devices, inspection openings andclosed bleed holes, must be fitted withat least three mutually independentshut-off devices in series: the firstbeing an internal stop-valve, excessflow valve, integral excess flow valve,or excess flow feature (see § 178.337–1(g)), the second being an externalstop-valve and the third being a blankflange, thread cap, plug or equivalenttight liquid closure device.

(2) When a portable tank is fittedwith an excess flow valve, the excessflow valve must be so fitted that itsseating is inside the shell or inside awelded flange or, when fitted exter-nally, its mountings must be designedso that in the event of impact it main-tains its effectiveness. The excess flowvalves must be selected and fitted so asto close automatically when the ratedflow, specified by the manufacturer, isreached. Connections and accessoriesleading to or from such a valve musthave a capacity for a flow more thanthe excess flow valve’s rated flow.

(3) For filling and discharge openingsthat are located below the liquid level,the first shut-off device must be an in-ternal stop-valve and the second mustbe a stop-valve placed in an accessibleposition on each discharge and fillingpipe.

(4) For filling and discharge openingslocated below the liquid level of port-able tanks intended for the transpor-tation of flammable and/or toxic lique-fied compressed gases, the internalstop-valve must be a self-closing safetydevice that fully closes automaticallyduring filling or discharge in the eventof fire engulfment. The device shallfully close within 30 seconds of actu-ation and the thermal means of closuremust actuate at a temperature of notmore than 121 °C (250 °F). Except forportable tanks having a capacity lessthan 1,000 liters (264.2 gallons), this de-vice must be operable by remote con-trol.

(5) In addition to filling, dischargeand gas pressure equalizing orifices,

shells may have openings in whichgauges, thermometers and manometerscan be fitted. Connections for such in-struments must be made by suitablewelded nozzles or pockets and may notbe connected by screwed connectionsthrough the shell.

(6) All portable tanks must be fittedwith manholes or other inspectionopenings of suitable size to allow forinternal inspection and adequate ac-cess for maintenance and repair of theinterior.

(7) Inlets and discharge outlets on chlo-rine portable tanks. The inlet and dis-charge outlets on portable tanks usedto transport chlorine must meet the re-quirements of § 178.337–1(c)(2) and mustbe fitted with an internal excess flowvalve. In addition to the internal ex-cess flow valve, the inlet and dischargeoutlets must be equipped with an ex-ternal stop valve (angle valve). Excessflow valves must conform to the stand-ards of The Chlorine Institute, Inc. (see§ 171.7 of this subchapter) as follows:

(i) A valve conforming to Drawing101–7, dated July 1993, must be installedunder each liquid angle valve.

(ii) A valve conforming to Drawing106–6, dated July 1993, must be installedunder each gas angle valve. For port-able tanks used to transport non-re-frigerated liquefied gases.

(8) External fittings must be groupedtogether as close as reasonably prac-ticable. The following openings may beinstalled at locations other than on thetop or end of the tank:

(i) The openings for liquid level gaug-ing devices, pressure gauges, or forsafety devices, may be installed sepa-rately at the other location or in theside of the shell;

(ii) One plugged opening of 2-inch Na-tional Pipe Thread or less provided formaintenance purposes may be locatedelsewhere;

(iii) An opening of 3-inch NationalPipe Size or less may be provided atanother location, when necessary, tofacilitate installation of condensingcoils.

(9) Filling and discharge connectionsare not required to be grouped and maybe installed below the normal liquidlevel of the tank if:


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49 CFR Ch. I (10–1–01 Edition)§ 178.277

(i) The portable tank is permanentlymounted in a full framework for con-tainerized transport;

(ii) For each portable tank design, aprototype portable tank, meets the re-quirements of parts 450 through 453 ofthis title for compliance with the re-quirements of Annex II of the Inter-national Convention for Safe Con-tainers; and

(iii) Each filling and discharge outletmeets the requirements of paragraph(c)(4) of this section.

(d) Bottom openings. Bottom openingsare prohibited on portable tanks whenthe portable tank special provision T50in § 172.102(c)(7) of this subchapter indi-cates that bottom openings are not al-lowed. In this case, there may be noopenings located below the liquid levelof the shell when it is filled to its max-imum permissible filling limit.

(e) Pressure relief devices. (1) Portabletanks must be provided with one ormore reclosing pressure relief devices.The pressure relief devices must openautomatically at a pressure not lessthan the MAWP and be fully open at apressure equal to 110% of the MAWP.These devices must, after discharge,close at a pressure not less than 10%below the pressure at which dischargestarts and must remain closed at alllower pressures. The pressure relief de-vices must be of a type that will resistdynamic forces including liquid surge.A frangible disc may only be used in se-ries with a reclosing pressure relief de-vice.

(2) Pressure relief devices must be de-signed to prevent the entry of foreignmatter, the leakage of gas and the de-velopment of any dangerous excesspressure.

(3) A portable tank intended for thetransportation of certain liquefiedcompressed gases identified in portabletank special provision T50 in § 172.102 ofthis subchapter must have a pressurerelief device which conforms to the re-quirements of this subchapter. Unless aportable tank, in dedicated service, isfitted with a relief device constructedof materials compatible with the haz-ardous material, the relief device mustbe comprised of a frangible disc pre-ceded by a reclosing device. The spacebetween the frangible disc and the de-vice must be provided with a pressure

gauge or a suitable tell-tale indicator.This arrangement must facilitate thedetection of disc rupture, pinholing orleakage which could cause a malfunc-tion of the pressure relief device. Thefrangible disc must rupture at a nomi-nal pressure 10% above the start-to-dis-charge pressure of the relief device.

(4) In the case of portable tanks usedfor more than one gas, the pressure re-lief devices must open at a pressure in-dicated in paragraph (e)(1) of this sec-tion for the gas having the highestmaximum allowable pressure of thegases allowed to be transported in theportable tank.

(f) Capacity of relief devices. The com-bined delivery capacity of the relief de-vices must be sufficient so that, in theevent of total fire engulfment, thepressure inside the shell cannot exceed120% of the MAWP. Reclosing relief de-vices must be used to achieve the fullrelief capacity prescribed. In the caseof portable tanks used for more thangas, the combined delivery capacity ofthe pressure relief devices must betaken for the liquefied compressed gaswhich requires the highest delivery ca-pacity of the liquefied compressedgases allowed to be transported in theportable tank. The total required ca-pacity of the relief devices must be de-termined according to the require-ments in § 178.275(h). These require-ments apply only to liquefied com-pressed gases which have critical tem-peratures well above the temperatureat the accumulating condition. Forgases which have critical temperaturesnear or below the temperature at theaccumulating condition, the calcula-tion of the pressure relief device deliv-ery capacity must consider the addi-tional thermodynamic properties of thegas (for example, CGA S–1.2–1980 (see§ 171.7 of this subchapter).

[66 FR 33448, June 21, 2001]

§ 178.277 Requirements for the design,construction, inspection and testingof portable tanks intended for thetransportation of refrigerated lique-fied gases.

(a) In addition to the requirements of§ 178.274 applicable to UN portabletanks, the following requirements anddefinitions apply to UN portable tanksused for refrigerated liquefied gases:


853


Design pressure For the purpose ofthis section the term ‘‘design pressure’’is consistent with the definition for de-sign pressure in the ASME Code, Sec-tion VIII (see § 171.7 of this subchapter).

Holding time is the time, as deter-mined by testing, that will elapse fromloading until the pressure of the con-tents, under equilibrium conditions,reaches the lowest set pressure of thepressure limiting device(s) (for exam-ple, pressure control valve or pressurerelief device). Holding time must be de-termined as specified in § 178.338–9.

Maximum allowable working pressure(MAWP) means the maximum effectivegauge pressure permissible at the topof the shell of a loaded portable tank inits operating position including thehighest effective pressure during fillingand discharge;

Minimum design temperature meansthe temperature which is used for thedesign and construction of the shellnot higher than the lowest (coldest)service temperature of the contentsduring normal conditions of filling, dis-charge and transportation.

Shell means the part of the portabletank which retains the refrigerated liq-uefied gas intended for transport, in-cluding openings and their closures,but does not include service equipmentor external structural equipment.

Tank means a construction whichnormally consists of either:

(1) A jacket and one or more innershells where the space between theshell(s) and the jacket is exhausted ofair (vacuum insulation) and may incor-porate a thermal insulation system; or

(2) A jacket and an inner shell withan intermediate layer of solid ther-mally insulating material (for exam-ple, solid foam).

(b) General design and construction re-quirements. (1) Portable tanks must beof seamless or welded steel construc-tion and have a water capacity of morethan 450 liters (118.9 gallons). Portabletanks must be designed, constructed,certified and stamped in accordancewith Section VIII of the ASME Code(see § 171.7 of this subchapter).

(2 ) Portable tanks must be postweldheat treated and radiographed as pre-scribed in the ASME Code except thateach tank constructed in accordancewith part UHT of the ASME Code must

be postweld heat treated. Wherepostweld heat treatment is required,the tank must be treated as a unitafter completion of all the welds to theshell and heads. The method must be asprescribed in the ASME Code. Weldedattachments to pads may be made afterpostweld heat treatment is made. Thepostweld heat treatment must be asprescribed in Section VIII of the ASMECode, but in no event at less than 1050°F tank metal temperature.

(3) Welding procedure and welder per-formance tests must be made annuallyin accordance with Section IX of theASME Code (see § 171.7 of this sub-chapter). In addition to the essentialvariables named in the ASME Code, thefollowing must be considered as essen-tial variables: number of passes, thick-ness of plate, heat input per pass, andthe specified rod and flux. The numberof passes, thickness of plate and heatinput per pass may not vary more than25% from the procedure qualification.Records of the qualification must beretained for at least 5 years by theportable tank manufacturer and madeavailable to the approval agency andthe owner of the portable tank as spec-ified in § 178.273.

(4) Shells and jackets must be madeof metallic materials suitable for form-ing. Jackets must be made of steel.Non-metallic materials may be usedfor the attachments and supports be-tween the shell and jacket, providedtheir material properties at the min-imum design temperature are provento be sufficient. In choosing the mate-rial, the minimum design temperaturemust be taken into account with re-spect to risk of brittle fracture, to hy-drogen embrittlement, to stress corro-sion cracking and to resistance to im-pact.

(5) Any part of a portable tank, in-cluding fittings, gaskets and pipe-work, which can be expected normallyto come into contact with the refrig-erated liquefied gas transported mustbe compatible with that refrigeratedliquefied gas.

(6) The thermal insulation systemmust include a complete covering ofthe shell with effective insulating ma-terials. External insulation must beprotected by a jacket so as to prevent


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49 CFR Ch. I (10–1–01 Edition)§ 178.277

the ingress of moisture and other dam-age under normal transport conditions.

(7) When a jacket is so closed as to begas-tight, a device must be provided toprevent any dangerous pressure fromdeveloping in the insulation space.

(8) Materials which may react withoxygen or oxygen enrichedatmospheres in a dangerous mannermay not be used in portable tanks in-tended for the transport of refrigeratedliquefied gases having a boiling pointbelow minus 182 °C at atmosphericpressure in locations with the thermalinsulation where there is a risk of con-tact with oxygen or with oxygen en-riched fluid.

(9) Insulating materials must not de-teriorate to an extent that the effec-tiveness of the insulation system, asdetermined in accordance with para-graph (b)(11) of this section, would bereduced in service.

(10) A reference holding time must bedetermined for each refrigerated lique-fied gas intended for transport in aportable tank. The reference holdingtime must be determined by testing inaccordance with the requirements of§ 178.338–9, considering the followingfactors:

(i) The effectiveness of the insulationsystem, determined in accordance withparagraph (b)(11) of this section;

(ii) The lowest set pressure of thepressure limiting device;

(iii) The initial filling conditions;(iv) An assumed ambient tempera-

ture of 30 °C (86 °F);(v) The physical properties of the in-

dividual refrigerated liquefied gas in-tended to be transported.

(11) The effectiveness of the insula-tion system (heat influx in watts) maybe determined by type testing the port-able tank in accordance with a proce-dure specified in § 178.338–9(c) or byusing the holding time test in § 178.338–9(b). This test must consist of either:

(i) A constant pressure test (for ex-ample, at atmospheric pressure) whenthe loss of refrigerated liquefied gas ismeasured over a period of time; or

(ii) A closed system test when therise in pressure in the shell is measuredover a period of time.

(12) When performing the constantpressure test, variations in atmos-pheric pressure must be taken into ac-

count. When performing either test,corrections must be made for any vari-ation of the ambient temperature fromthe assumed ambient temperature ref-erence value of 30 °C (86 °F).

(13) The jacket of a vacuum-insulateddouble-wall tank must have either anexternal design pressure not less than100 kPa (1 bar) gauge pressure cal-culated in accordance with the ASMECode or a calculated critical collapsingpressure of not less than 200 kPa (2 bar)gauge pressure. Internal and externalreinforcements may be included in cal-culating the ability of the jacket to re-sist the external pressure.

NOTE TO PARAGRAPH (B): For the deter-mination of the actual holding time, as indi-cated by paragraphs (b)(10), (11), (12), and(13), before each journey, refer to § 178.338–9(b).

(c) Design criteria. For shells withvacuum insulation, the test pressuremust not be less than 1.3 times the sumof the MAWP and 100 kPa (1 bar). In nocase may the test pressure be less than300 kPa (3 bar) gauge pressure.

(d) Service equipment. (1) Each fillingand discharge opening in portabletanks used for the transport of flam-mable refrigerated liquefied gases mustbe fitted with at least three mutuallyindependent shut-off devices in series:the first being a stop-valve situated asclose as reasonably practicable to thejacket, the second being a stop-valveand the third being a blank flange orequivalent device. The shut-off deviceclosest to the jacket must be a self-closing device, which is capable ofbeing closed from an accessible posi-tion on the portable tank that is re-mote from the valve within 30 secondsof actuation. This device must actuateat a temperature of not more than 121°C (250 °F).

(2) Each filling and discharge openingin portable tanks used for the trans-port of non-flammable refrigerated liq-uefied gases must be fitted with atleast two mutually independent shut-off devices in series: the first being astop-valve situated as close as reason-ably practicable to the jacket and thesecond a blank flange or equivalent de-vice.

(3) For sections of piping which canbe closed at both ends and where liquidproduct can be trapped, a method of


855


automatic pressure relief must be pro-vided to prevent excess pressure build-up within the piping.

(4) Each filling and discharge openingon a portable tank must be clearlymarked to indicate its function.

(5) When pressure-building units areused, the liquid and vapor connectionsto that unit must be provided with avalve as close to the jacket as reason-ably practicable to prevent the loss ofcontents in case of damage to the pres-sure-building unit. A check valve maybe used for this purpose if it is locatedon the vapor side of the pressure build-up coil.

(6) The materials of construction ofvalves and accessories must have satis-factory properties at the lowest oper-ating temperature of the portabletank.

(7) Vacuum insulated portable tanksare not required to have an inspectionopening.

(e) Pressure relief devices. (1) Everyshell must be provided with not lessthan two independent reclosing pres-sure relief devices. The pressure reliefdevices must open automatically at apressure not less than the MAWP andbe fully open at a pressure equal to110% of the MAWP. These devicesmust, after discharge, close at a pres-sure not lower than 10% below the pres-sure at which discharge starts andmust remain closed at all lower pres-sures. The pressure relief devices mustbe of the type that will resist dynamicforces including surge.

(2) Except for portable tanks used foroxygen, portable tanks for non-flam-mable refrigerated liquefied gases (ex-cept oxygen) and hydrogen may in ad-dition have frangible discs in parallelwith the reclosing devices as specifiedin paragraphs (e)(4)(ii) and (e)(4)(iii) ofthis section.

(3) Pressure relief devices must be de-signed to prevent the entry of foreignmatter, the leakage of gas and the de-velopment of any dangerous excesspressure.

(4) Capacity and setting of pressure re-lief devices. (i) In the case of the loss ofvacuum in a vacuum-insulated tank orof loss of 20% of the insulation of aportable tank insulated with solid ma-terials, the combined capacity of allpressure relief devices installed must

be sufficient so that the pressure (in-cluding accumulation) inside the shelldoes not exceed 120% of the MAWP.

(ii) For non-flammable refrigeratedliquefied gases (except oxygen) and hy-drogen, this capacity may be achievedby the use of frangible discs in parallelwith the required safety-relief devices.Frangible discs must rupture at nomi-nal pressure equal to the test pressureof the shell.

(iii) Under the circumstances de-scribed in paragraphs (e)(4)(i) and(e)(4)(ii) of this section, together withcomplete fire engulfment, the com-bined capacity of all pressure relief de-vices installed must be sufficient tolimit the pressure in the shell to thetest pressure.

(iv) The required capacity of the re-lief devices must be calculated in ac-cordance with CGA Pamphlet S–1.2 (see§ 171.7 of this subchapter).

[66 FR 33450, June 21, 2001]

Subpart I [Reserved]

Subpart J—Specifications for Con-tainers for Motor VehicleTransportation

SOURCE: 29 FR 18975, Dec. 29, 1964, unlessotherwise noted. Redesignated at 32 FR 5606,Apr. 5, 1967.

§ 178.318 Specification MC 201; con-tainer for detonators and percus-sion caps.

§ 178.318–1 Scope.

(a) This specification pertains to acontainer to be used for the transpor-tation of detonators and percussioncaps in connection with the transpor-tation of liquid nitroglycerin, desen-sitized liquid nitroglycerin ordiethylene glycol dinitrate, where anyor all of such types of caps may be usedfor the detonation of liquid nitroglyc-erin, desentitized liquid nitroglycerinor diethylene glycol dinitrate in blast-ing operations. This specification isnot intended to take the place of anyshipping or packing requirements ofthis Department where the caps inquestion are themselves articles ofcommerce.


178.245 49 cfr ch. i (101 01 edition) - gpo · pdf filerately at the other location or in the...

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