Code of Federal Regulations Title 49. Transportation § 49.178.338–1 General requirements

(1) Design pressure means the “MAWP” as used in Section VIII of the ASME Code (IBR, see § 171.7 of this subchapter), and is the gauge pressure at the top of the tank.

(2) Design service temperature means the coldest temperature for which the tank is suitable (see §§ 173.318(a)(1) and (f) of this subchapter).

(1) Each cargo tank must have an insulation system that will prevent the tank pressure from exceeding the pressure relief valve set pressure within the specified holding time when the tank is loaded with the specific cryogenic liquid at the design conditions of—

(2) For a cargo tank used to transport oxygen, the insulation may not sustain combustion in a 99.5 percent oxygen atmosphere at atmospheric pressure when contacted with a continuously heated glowing platinum wire. The cargo tank must be marked in accordance with § 178.338–18(b)(7).

(3) Each vacuum-insulated cargo tank must be provided with a connection for a vacuum gauge to indicate the absolute pressure within the insulation space.

(1) The jacket must be designed to sustain a minimum critical collapsing pressure of 30 psig.

(2) If the jacket also supports additional loads, such as the weight of the tank and lading, the combined stress, computed according to the formula in § 178.338–3(b), may not exceed 25 percent of the minimum specified tensile strength.