Comparative Analysis of Danger Zone Ranges Determined for LNG in the Coastal Area

The analysis of danger zone ranges for LNG in the coastal area is an important task on account of, inter alia, the safety of human life. It is not an easy process, which is why we consider an danger situation for various weather conditions in the function of constant wind speeds and for various wind speeds in constant weather stability. Pasquill weather stability scale and Beaufort scale with regard to terrain roughness were adopted for the analysis. Both scenarios were considered in the example of Q-flex type vessels in the Świnoujście terminal for two methods of LNG release, i.e. related to a sudden explosion and slow release caused by a leak. The analysis was conducted and considered for the values in the top and bottom flammability limit. Modelling of the danger zone range was analysed with DNV PHAST software, version 7.11. In the process of comparison of the situation related to the risk of explosion in the function of various weather stabilities according to Pasquill scale and constant wind speeds, the values of 1.5 m/s and 5 m/s were adopted, corresponding to 1 and 3 wind force on the Beaufort scale. Those speeds correspond to the water conditions featuring tiny ripples and small waves, the crests of which start to break. The adopted weather stabilities analysed for wind speed equal to 1.5 m/s are A, B, D. A-type stability signifies the least stable atmospheric conditions, and D-type means neutral conditions. In turn, for the wind speed of 5 m/s B, D and F parameters in Pasquill scale were selected. Furthermore, ranges for variable wind speed values were analysed for the selected Pasquill stability.