46 CFR 154.450: General.

Independent tanks type C and process pressure vessels must be designed to meet the requirements under Part 54 of this chapter, except § 54.01-40(b), and:

(a) The calculation under § 54.01-18 (b)(1) must also include the design loads determined under § 154.406;

(b) The calculated tank plating thickness, including any corrosion allowance, must be the minimum thickness without a negative plate tolerance; and

(c) The minimum tank plating thickness must not be less than:

(1) 5mm ( 3/16 in.) for carbon-manganese steel and nickel steel;

(2) 3mm ( 1/8 in.) for austenitic steels; or

(3) 7mm ( 9/32 in.) for aluminum alloys.