Model to predict pressure effect on the flash point of liquid fuels at sub-atmospheric pressures

The fuel in the fuel tanks of the aircraft in flight and the fuel storage and transportation at high altitude plateau are all under sub-atmospheric pressures conditions. Additionally, chemical processes are often operated at non-atmospheric pressures. The flash point measured at sub-atmospheric pressures is lower than that at standard atmospheric pressure, 101.3 kPa, which means that ignitable liquids at sub-atmospheric pressures are more hazardous than those at 101.3 kPa. A simple model for predicting the influence of pressure on the flash point only requiring basic thermodynamics data was derived, and was validated with experimental data from the literature for three single-component liquid fuels at sub-atmospheric pressures. The derived model predicts the closed-cup flash point data well. Because the test condition is far from the assumption of vapor-liquid equilibrium, there are deviations between the predicted and measured open-cup flash point data, although the predicted trends are consistent with the experimental data.