46 CFR § 154.701
Cargo pressure and temperature control: General
April 15, 2021
Except as allowed under §154.703, cargo tanks must:
(a) Have their safety relief valves set at a pressure equal to or greater than the vapor pressure of the cargo at 45 °C (113 °F) but not greater than the MARVS under §154.405; or
(b) Be refrigerated by a system meeting §154.702, and each refrigerated incompatible cargo refrigerated by a separate system.