Which sprinkler system releases water through all sprinkler heads simultaneously when activated?

• A. Wet-pipe
• B. Dry-pipe
• C. Pre-action
• D. Deluge

Answer: (D)

Deluge sprinkler systems are built so every sprinkler head is connected to an open piping network. When the system is activated, the deluge valve releases water into the entire network, and because all heads are open, water exits from every head at once. This provides rapid, full-area coverage for quick suppression in high-hazard environments. In contrast, wet-pipe systems keep water in the pipes and release water through the head that heats, dry-pipe systems fill the pipes with pressurized air and only admit water to the heads as they’re activated, and pre-action systems require a two-step event before water enters the pipes, preventing all-head discharge on a single activation.