2020 年 55 巻 3 号 p. 355-359
Amid growing energy consumption backed by world economic growth, global demand of liquefied petroleum gas (LPG) and the number of LPG carriers are increasing. For a stable supply of LPG, the safety of LPG carriers is important. Risk analyses using risk models, such as Event Tree, are one of the effective ways to assess the safety. However, risks estimated by these models have large uncertainty due to limits to the availability of data. Therefore, it is essential to validate the value of estimated risks through such means as comparing it with figures obtained from statistical analyses of accidents in the past.
This paper presents the results of a statistical analysis that covered accidents of LPG carriers of 100 GT or greater in the period between 1990 and 2016. To take application of the International Gas Carrier Code (IGC Code) into consideration, the authors conducted the analysis by developing three categories: ships built in or after July 1986 (IGC ships), those built before July 1986 (old ships) and the combination of the two categories.
The results have showed that in the case of IGC ships, the Potential Loss of Life (PLL) was estimated at 1.4×10-3 (fatalities/ship year). The PLL of IGC ships was clearly lower than that of old ships. In addition, the authors calculated PLLs and confidence intervals of each casualty category. We believe that these results will help verify the validity of PLLs calculated from risk models for LPG carriers.