Abstract: Hexafluoropropylene(HFP) meets the environmental friendly requirements of Halon alternative fire extinguishing agent due to the existence of the C=C double bond. However, there are few studies focus on its fire extinguishing performance, and the interaction with flame is still unclear. In this paper, the fire extinguishing performance of HFP on methane and propane flames is studied by cup burner, and it was compared with saturated fluoroalkane, hexafluoropropane(HFC-236fa) and heptafluoropropane(HFC-227ea). The results indicated that HFP has an earlier trend of decreasing flame height and brightness than HFC-236fa and HFC-227ea, and has a more obvious effect on the increase or decrease of flame temperature.The C=C double bond structure of HFP makes it easier for fluorine-containing groups to react with free radicals in the flame, resulting in a sharp rise in the flame temperature, and then consume a lot of free radicals in the flame, resulting in a sudden drop in the temperature.

Key words: HFP, minimum extinguishing volume fraction, flame height, flame shape