Model for estimating the maximum water content that would maintain the flammability of an aqueous−organic mixture

Abstract

Adding water to liquid fuels can make them nonflammable; substantial amounts of water are required to do so for highly volatile fuels. A limited amount of water being required to eliminate the flammability of low-volatility fuels would enable adjustments to be made to fire and explosion (F&E) hazard assessments for such fuels and the requirements for preventing F&E hazards of various regulations. This study developed a novel generic model for determining two critical parameters used to assess F&E hazards and that can be leveraged to eliminate these hazards: (1) the maximum water composition in the liquid phase for which the aqueous solution remains flammable and (2) the maximum flash point (FP). The model was verified using experimental data on nine low-volatility aqueous−organic mixtures and published data on eight high-volatility aqueous−organic mixtures. The model made acceptable predictions for ignitable chemicals with an FP range of −19 to 145 °C. Both the simulations and measurements revealed that only a small amount of water is required to render low-volatility fuels nonflammable, whereas substantial amounts of water are required for highly volatile fuels. The proposed model and present results can be employed to reduce the cost of F&E protection.