Abstract: Based on the standard oil-pan fire extinguishing test model, a high-temperature oil layer with a thickness of approximately 1 cm and a wide temperature range of 300~500 ℃ was constructed, and a repeatable test and evaluation method for extinguishing boiling-over oil pool fires was established. Fire extinguishing tests were conducted using four types of foam extinguishing agents. The results indicate that both I A-grade 6%AFFF and 3%AFFF/AR can achieve rapid fire suppression within 1 min. The ranking of fire extinguishing effectiveness is I A-grade 6%AFFF and 3%AFFF/AR > II B-grade 3%FP > III B-grade 3%S, which is consistent with the performance grade ranking of the foam agents. This confirms that the established evaluation method can effectively distinguish the fire-extinguishing performance differences of different grades of foam agents on boiling-over oil pool fires. Furthermore, the time corresponding to the maximum cooling rate of the oil surface temperature is in close agreement with the 90% fire-control time of the foam agents. The underlying mechanism is that the effective foam coverage on the oil surface eliminates the radiant heat feedback from the flame, thereby demonstrating that foam coverage effectiveness is the dominant factor influencing the extinguishing performance of boiling-over oil pool fires.

Key words: boiling-over oil, foam fire extinguishing, evaluation methodology