FPS-DIC0
The Pre-action system is a fire protection (FP) combined system, consisting of a controlled FDV deluge valve and a riser check valve installed downstream. The pressurized automatic sprinkler pipeline keeps the riser check valve closed. The section between the downstream side of the closed deluge valve and the check valve clapper serves as the “intermediate chamber,” where the water pressure switch and acoustic alarm are connected.
In double-interlock pre-action systems, such as the one described, full system activation is dependent on two independent fire-related events: one resulting from heat exposure, and the other from fire detection. The operation of the FPS-DIC0 system requires both pneumatic and electrical triggering.
In the event of fire, heat causes one or more automatic sprinklers to open, leading to depressurization of the sprinkler pipeline. The resulting pressure drop triggers the air pressure switch, which sends a signal to the main control board. This constitutes the first actuation event. In parallel, the pressure drop opens a pneumatic actuator located on the deluge valve control chamber drain line, which is installed in series with a normally closed solenoid valve. At this stage, the solenoid valve remains closed.
When one or more smoke detectors are activated, they send an electrical signal to the main control board. This constitutes the second actuation event. Only when both actuation events occur does the control board open the solenoid valve, which in turn causes the FDV deluge valve to open, allowing water to flow into the sprinkler pipeline.
