Code of Federal Regulations Title 46. Shipping § 46.153.515 Special requirements for extremely flammable cargoes

(a) An enclosed space containing a cargo tank must have an inerting system that meets the requirements in § 153.500 applying to the inert gas system of a containment system;

(b) Cargo discharge pumps must be of a type that does not subject the shaft gland to the cargo under pressure or that is submerged;  and

(c) The cargo tank's relief valve setting must be no less than 21 kPa gauge (approx. 3 psig).