A deluge system is a water mist system using open spray heads attached to a piping system that is connected to a water supply through a valve that is opened by means of a detection system installed in the same area as the spray heads.

Deluge systems are used in high hazard areas such as power plants, aircraft hangars, and chemical plants. These systems are very effective in hazardous areas because they release water or another fire suppressant to all the open sprinkler heads simultaneously