Deluge systems are systems where all sprinklers connected are open. These sprinklers have no sensing element (glass bulb). Deluge systems are used in areas where there is a concern for a rapid fire spread. The open sprinklers will distribute water over the entire area.
The piping is filled with atmospheric pressure and a mechanical activated deluge valve, will open in case of fire, enabling the water to fill the sprinkler pipe. The deluge valve is activated by a signal from a fire alarm system, and remains open once it has been activated.