Fire-extinguishing performance and mechanism of aqueous film-forming foam in diesel pool fire

Abstract

A laboratory fire-extinguishing system was applied to investigate the effect of gas-liquid ratio on the fire-extinguishing performance of aqueous film-forming foam (AFFF) in diesel pool fire, and the proposed fire-extinguishing mechanism of AFFF is carefully analyzed. The results show that the AFFF foam possesses the shortest extinguishing time of 42s and lowest foam liquid consumption of 210 g at a gas-liquid ratio of 16, exhibiting the best fire-extinguishing performance. Chemical analysis of AFFF indicates that a proper gas-liquid ratio is beneficial to enhance the expansion ratio and drainage rate of AFFF that affect the cooling and covering effects of foam, thus achieving the optimum fire-extinguishing efficiency. Infrared thermal imaging analysis indicates that the main fire-extinguishing mechanism of AFFF is mainly ascribed to the superior cooling, covering and suffocating effects of foam against the transfer of heat and oxygen, thus effectively preventing the underlying fuel from further combustion.