Application of fault tree analysis in LNG fire risk assessment of LNG fueled ships

Assess the risk of LNG fire of LNG fueled ships navigating in the middle reaches of Yangtze River of China according to the acceptable risk criteria so that support technically to design, building and shipping safety management of LNG fueled ships and also to marine safety administration. “Fault tree analysis” was used to analyze the contribution of factors for LNG fire of LNG fueled ships. Statistical analysis base on the Normal distribution was carried out to reveal the confidence intervals of the probability of ships collision, touch and general fire. Quantitative assessment showed that LNG fuel is not suitable for passenger ships and chemical cargo carriers. It was found that ship length is the key to people onboard evacuating in case of LNG fire, so that LNG valid volume above 20M3 was unsuitable for a ship with length less than 80 m as well as that more than 10M3 was very dangerous for crew onboard a ship with length less than 45 m. Factors of bridges over river, berths along banks and anchorages in river, which would aggravate the consequences of LNG fire, were taken into consideration during risk assessment. In view of navigation condition in the middle reaches of Yangtze River, measures were suggested for LNG fire risk control of LNG fueled ships.