Experimental Research on the Effectiveness of Different Types of Foam of Extinguishing Methanol / Diesel Pool Fires

Storage tank fire can pose great threats to life and environment as it can cause strong radiant heat, fast-spreading flame, and destructive explosion. In this research, a 1.5 m-diameter circular steel pan is used to simulate the full surface fire of a storage tank in an industrial park. A self-built fire-extinguishing system gently releasing foam at the rate of 11.4 L/min was applied for the evaluation of the effectiveness of different types of foam of extinguishing diesel/methanol pool fires. Experiments were conducted to analyze the temperature increases of fires after releasing different types of foam. In this research, the nondimensional average temperature 0.85 and 0.71 regard as the fire extinguishing temperatures of methanol and diesel fuel, respectively. Over the spreading process, the increase in foam spreading length over time still follows the power law. The fastest flow velocity of 6% FP/AR in methanol pool fire and 6% Synthetic foams in diesel pool fire was 0.0136 m s (-1)and 0.044 m s (-1), respectively, with a foam application rate of 11.4 L/min. The results show that, in the methanol pool fire, the cooling effect of the foam is ranked as FP/AR > AFFF > AFFF/AR > S > FP > S/AR. And the cooling effect of foam for diesel is ranked as S > S/AR > AFFF > AFFF/AR > FP > FP/AR. Foam's cooling impact is especially notable in diesel pool fires. As for methanol pool fires, the foam extinguishing mechanism is mainly based on the "anti-soluble film" effect, which quickly forms a covering layer on the surface of the flammable liquid, seperating the flame from heat feedback and inhibiting the generation of flammable vapors, insulating itself against the air and ultimately asphyxiating the fire.