46 CFR §32.65-40

1. (a)All cargo tanks to be vented at gage pressures of 4 pounds per square inch or less shall be constructed and tested as required by the requirements of the American Bureau of Shipping or other recognized classification society.
2. (b)All cargo tanks to be vented at gage pressures above 4 pounds per square inch shall be considered as pressure vessels and shall meet the requirements for such vessels as to construction and testing, as set forth in subchapter F (Marine Engineering) of this chapter.
3. (c)Gastight bulkheads shall be subjected to a thorough hose test.