46 CFR §154.174

1. (a)The transverse contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the standards of the American Bureau of Shipping published in “Rules for Building and Classing Steel Vessels”, 1981.
2. (b)The transverse contiguous hull structure of a vessel having cargo containment systems with secondary barriers must be designed for a temperature that is:
   1. (1)Colder than the calculated temperature of this hull structure when:
      1. (i)The temperature of the secondary barrier is the design temperature, and
      2. (ii)The ambient cold condition under § 154.176(b)(1)(ii) and (iii) are assumed; or
   2. (2)Maintained by the heating system under § 154.178.