This study used water mist to cool temperatures in a bench scale flashover fire simulator. Results show that a high-pressure system producing smaller droplet of water mist provides better flame cooling, up to 150℃, in flashover scenarios when the nozzle is located in the center of the opening. The temperature contour provides a clear picture of the cooling effectiveness of water mist in all of the flashover scenario tests. Water mist has better cooling, up to 200℃, when it is applied from left side of the opening. The left side has better air entrainment because it is windier during the fire test. Nozzle B with a pressure of 10 Mpa and a flow rate of 1 Lpm provides better flame cooling, up to 175℃, than nozzle A with a pressure of 4.9 Mpa and a flow rate of 4 Lpm because nozzle B produces smaller droplets during the tests. Water mist proved to be an effective tool for flame cooling in a flashover scenario given that the water mist can be entrained by air from the sides of the fire rather than on the fire base directly.