46 CFR § 154.450
General
April 15, 2021
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.