Abstract: A fire suppression system in which fire suppressant material is contained in a reservoir, the reservoir having an outlet and a system containing one or more nozzles from which the suppressant is delivered for fire suppresant purposes.The system incorporates a valve between the reservoir outlet and the nozzle(s) the valve including a movable valve member and a valve seat which cooperates with the movable member. The valve member is movable from a closed position with respect to the valve seat preventing communication of suppressant between the reservoir and the nozzle(s) to an open position permitting flow of the suppressant from the reservoir to the nozzle(s).An actuator is provided to selectively open and close the aforesaid valve member. The actuator maintains a fluid (preferably nitrogen) under pressure to maintain the valve member in the closed position and is operable to vent the fluid to lower the pressure in the valve, thus permitting the valve member to open.