Abstract: In order to investigate the effect of high-pressure fine water mist on the suppression of ancient building fires, this paper simulates and builds an experimental platform through Pyrosim software to determine the the self starting time of fire water mist under fire linkage alarm,temperature of the smoke layer of ancient building flashover under different spray intensities, the rate of heat release from the fire, combined with a comprehensive fire prediction method to analyse the occurrence of flashover in ancient buildings when the fine water mist is turned on. The results show that the fine water mist turned on 103 s after the fire occurred; the high-pressure water mist with a spray intensity of 1.3 L/（min·m2） can suppress the ancient building flashover, and the high-pressure water mist with a spray intensity of 2.0 L/（min·m2） can extinguish the ancient building flashover. High-pressure fine water mist can effectively inhibit the ancient building flashover, the study can provide reference for high-pressure fine water mist fire extinguishing system applied to the ancient building fire design.

Key words: historic building, flashover, high-pressure fine water mist fire extinguishing system, Pyrosim software simulation, physical fire experiment