The vessel which failed was a heat exchanger, GP905. It was also known as a demethaniser re boiler because it operated to heat rich oil at the bottom of a piece of equipment known as a Rich Oil Demethaniser (ROD). Near GP905 was another heat exchanger, GP922, which preheated rich oil flowing from the ROD on its way to the Rich Oil Fractionator (ROF). GP922 had developed leaks at its flanges some time before the accident and attempts were being made to repair them at the time GP905 failed. t.s Immediately before its failure, the temperature of GP905 was well below its normal operating temperature and may have been as low as -48°C. The normal operating temperature was in the vicinity of 100°C. The low temperature of GP905 was due to the loss oflean oil flow in GPl. Hot lean oil flowing through GP905 was the means by which it was heated to its normal operating temperature. 11