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Subpart A—Introduction, Approvals and Reports8

Subpart B—General Design Requirements11

Subpart C—Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120)31

Subpart D—Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW, 115AW, and 117AW)69

Subpart E—Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW)20

Subpart F—Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A)44

Regulationcurrent

49 CFR 179.400-21

-21 Test of pressure relief valves.

Current as of 2026-08-18 Government source

eCFR editorial compilationAuthoritative but unofficial

Each valve must be tested with air or gas for compliance with § 179.401-1 before being put into service.#