Mathematical modelling of LPG tanks subjected to full and partial fire engulfment

This paper describes the use of field and zone modelling techniques in studying the behaviour of LPG tanks when subjected to accidental fire conditions. The field modelling approach is used to determine the free convective flows and heat transfer in both the vapour and the liquid regions, and also the heat transfer through the tank wall. Zone modelling techniques are employed to calculate the fire heat flux and the radiation heat transfer from the vapour wetted wall to the liquid/vapour interface. The model is verified by comparing predicted results with full scale experimental data obtained by the Health and Safety Executive, U.K.1 The comparisons indicate that the model can accurately predict the tank pressure and time to first valve opening. The model is used to investigate the effect of fire exposure level on the tank behaviour.