(a) An aluminum cargo tank and its dome must be enclosed by the vessel's hull structure or a separate steel cover.
(b) The steel cover for the aluminum cargo tank must meet the steel structural standards of the American Bureau of Shipping published in ``Rules for Building and Classing Steel Vessels'', 1981.
(c) The steel cover for the aluminum tank dome must be:
(1) At least 3.2 mm (\1/8\ in.) thick;
(2) Separated from the tank dome, except at the support points; and
(3) Thermally isolated from the dome. [CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
Ship Survival Capability and Cargo Tank Location