CFR › Title 46 › Part 153 › §153.96646 CFR §153.966Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkThe person in charge of cargo transfer may not authorize cargo discharge by liquid displacement unless the liquid supply line to the tank has:(a)A safety relief or pressure reducing valve set to operate at no more than 80 percent of the tank's relief valve setting; and(b)A manual control valve between the tank and the supply line's safety relief valve or pressure reducing valve.