Determination of safety exclusion zone for LNG bunkering at fuel-supplying point

With strong environmental and economic driving forces for using LNG as a marine fuel over the last decade, an increasing number of local/international ports, mainly in Europe, have initiated LNG fuel providing service to LNG-fuelled ships. This trend is now spreading throughout the world. The LNG bunkering methods currently in use are truck-to-ship (TTS), ship-to-ship (STS) and pipeline-to-ship (PTS). This paper describes a study conducted to identify potential risks associated with LNG bunkering with particular emphasis on the fuel-supplying side. A series of parametric analyses were also carried out to identify the sensitivity to some parameters with the aid of a purpose-built computer program, Integrated Quantitative Risk Assessment (IQRA). Through the parametric analyses, general relationships between the risk and various parameters could be established from which the importance of the selected parameters might be evaluated. This paper also proposes a new approach of establishing realistic safety exclusion zones in LNG bunkering process. Research findings demonstrate that the implied hypothesis that the current practice of the probabilistic risk assessment focused on the population-independent analysis only is somewhat inadequate when applied to determining the safety exclusion zones as showing that the extent of safety exclusion zones tends to be set up unpractically wide. Instead, the proposed approach designed with the combination of population-dependant and independent analyses is proven to be useful in determining the zones more realistically. It may form a basis on which more useful safety-related standards and regulations on LNG bunkering can be built