(a) Toughness tests for the materials listed in UHA-51(a) in section VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 54.01-1) for service temperatures below −425 °F., UHA-51(b)(1) through (5) for service temperatures below 0 °F., and UHA-51(c) for all service temperatures, shall be performed in accordance with the requirements of subpart 54.05. These requirements are also applicable to nonpressure vessel type, low temperature tanks and associated secondary barriers, as defined in §38.05-4 in subchapter D (Tank Vessels) of this chapter. Such tests are required regardless of the vessel's design stress. Service temperature is defined in §54.25-10(a)(2).

(b) Materials for pressure vessels with service temperatures below −320 °F. shall be of the stabilized or low carbon (less than 0.10 percent) austenitic stainless steel type, produced according to the applicable specifications of table UHA-23 of section VIII of the ASME Boiler and Pressure Vessel Code. These materials and their weldments shall be tested for toughness according to the requirements of subpart 54.05 except that the Charpy V-notch testing acceptance criteria will be in accordance with UHT-6(a)(4) and (5) of section VIII of the ASME Boiler and Pressure Vessel Code.”

(c) Except as permitted by §54.05-30, the allowable stress values used in the design of low temperature pressure vessels may not exceed those given in table UHA-23 of section VIII of the ASME Boiler and Pressure Vessel Code for temperatures of −20 °F. to 100 °F.

[CGFR 68-82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 73-133R, 39 FR 9178, Mar. 8, 1974; CGD 73-254, 40 FR 40164, Sept. 2, 1975; USCG-2003-16630, 73 FR 65171, Oct. 31, 2008]