In a foam-water deluge system, the discharge devices are opened by what mechanism?

• A. Manual valve only
• B. An automatic valve opened by a detection system
• C. A timer
• D. A handle release

Answer: (B)

Foam-water deluge systems are designed so that all discharge devices vent water (and foam) to the protected area as soon as the system is activated. The key mechanism is a master or deluge valve that is normally held closed and is automatically opened by signals from the fire-detection system. When detection detects a fire and sends an alarm, it trips that automatic valve, pressurizing the piping and releasing water to every discharge device simultaneously. This automatic valve opening ensures immediate, full coverage without requiring manual intervention, which is essential for rapid control of a fire. Manual releases or timers don’t meet the same need for instant, system-wide discharge in response to detection, and a manual handle release would only actuate locally rather than the entire system.