(a) The longitudinal 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.
(b) The longitudinal contiguous hull structure of a vessel having cargo containment systems with secondary barriers must be designed for a temperature that is:
(1) Colder than the calculated temperature of this hull structure when:
(i) The temperature of the secondary barrier is the design temperature; and
(ii) For any waters in the world except Alaskan waters, the ambient cold condition of:
(A) Five knots air at -18 [deg]C (0 [deg]F); and
(B) Still sea water at 0 [deg]C (32 [deg]F); or
(iii) For Alaskan waters the ambient cold condition of:
(A) Five knots air at -29 [deg]C (-20 [deg]F); and
(B) Still sea water at -2 [deg]C (28 [deg]F); or
(2) Maintained by the heating system under Sec. 154.178, if, without heat, the contiguous hull structure is designed for a temperature that is colder than the calculated temperature of the hull structure assuming the:
(i) Temperature of the secondary barrier is the design temperature; and
(ii) Ambient cold conditions of still air at 5 [deg]C (41 [deg]F) and still sea water at 0 [deg]C (32 [deg]F). [CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]