By OGJ editors
HOUSTON, Aug. 17 -- The Society of International Gas Tanker & Terminal Operators (SIGTTO) has issued a safety alert about the commingling of propane and butane on LPG tankers.
SIGTTO says the practice, often initiated at the instruction of charterers, raises a number of safety concerns, especially when the commingling is performed on fully refrigerated gas carriers.
Mixing refrigerated propane and butane can create large amounts of flash gas, which must be controlled by a ship's reliquefaction plant. If uncontrolled, the gas can lift cargo tank relief valves and escape to form large clouds of heavier-than-air, flammable vapor.
SIGTTO offers a guidance document for download at www.sigtto.org.