The Arpco valve comes in a flanged and threaded version. Both versions come in a standard 2” 3000 WP build. The design uses pneumatic actuator coupled with a reverse acting gate to produce a fail-closed operation. When there is an abnormal condition in the system, the actuator will bleed down and, utilizing spring tension, force the valve into the closed position. Under normal operating conditions of the system, the valve is in the open position.