A mathematical model for simulating the pressure and relief valve response of a liquefied petroleum gas tank in fire environment was proposed.The model was used to predict the variation of the pressure,total tank mass relief mass flow rate,and wall temperature,in a horizontal cylindrical tank with 41% propane exposed to non-uniform heating.The calculation results agree well with the experimental results.The results show that the pressure increase during the process of opening the relief valve and the high temperature experienced by the wall are two main factors that lead to the rapture of the tank.