Risk assessment of liquefied natural gas carriers using fuzzy TOPSIS

An approach for the risk assessment of liquefied natural gas (LNG) carriers is proposed in this study. The approach is based on the use of the fuzzy technique of order preference by similarity to the ideal solution or fuzzy TOPSIS. In the proposed approach, probabilities and consequences of hazardous scenarios are represented by fuzzy sets to take into account imprecision associated with the subjective assignment of their values by experts. A case study for an LNG ship during loading and offloading at terminals is presented to illustrate the capability and effectiveness of the proposed fuzzy TOPSIS method and its difference from other qualitative techniques. Results show that the proposed approach is effective for handling imprecision often associated with subjective expert assessment of risk data. It gives more reasonable and robust risk ranking of the different hazardous scenarios. The proposed methodology is also applicable to other ship-operating modes such as transit in open sea and/or entering/leaving port.