Deluge (Sprinkler System)

A deluge fire sprinkler system is a specialised suppression system designed for high-risk environments. In this configuration, all connected discharge devices (sprinklers or nozzles) are permanently open; they do not contain the heat-sensitive glass bulbs or fusible links found in standard sprinkler heads. Consequently, the distribution piping remains empty and contains only atmospheric air during normal conditions.

Unlike standard automatic systems that rely on individual head activation, the flow of water in a deluge system is managed by a central deluge valve. This valve is held in its normally closed position by a "priming" mechanism—typically using inert gas, compressed air, or liquid pressure. On the reduction of pressure, the deluge valve is opened by the upstream water pressure.

When a separate manual operation or fire detection system (such as heat, smoke, or flame detectors) is triggered, the deluge valve opens, allowing water to discharge simultaneously through every head in the protected area.