Abstract: A controlled pressure release valve includes a valve body having a gas inlet for connection to a gas container and a gas outlet for delivering gas to a protected area. The controlled valve comprises a slidable spool housed in the valve body that is slidable between a first position and a second position. The slidable spool has a first end and a second end. A primary flow passage connects the gas inlet and the gas outlet and increases with lineal movement of the slidable spool. The sliding spool is biased towards the first position by a gas pressure applied by the second chamber and a spring.