The Fire pump discharge control valve is for isolation purposes. This valve, combined with the pump suction control valve, provides the ability to isolate the fire pump, fire pump discharge check valve, and pump test header piping and components for repair, replacement, and testing, while keeping the pump suction and bypass piping in service.

Isolation valves on the discharge side of the fire pump do not affect the operation of the pump, so approved indicating valves that are not outside screw and yoke (OS&Y) type are permitted.

4.17.8* A listed indicating gate or butterfly valve shall be installed on the fire protection system side of the pump discharge check valve.