Which sprinkler system uses water-filled piping that releases water immediately upon sprinkler activation?

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

Answer: (A)

Water-filled piping with immediate release at the activated head describes a wet-pipe system. In wet-pipe setups, the piping is charged with water, so when a sprinkler head is triggered by heat, water flows out of that specific head right away, providing a rapid response to the fire.

Dry-pipe systems keep pipes filled with pressurized air and only fill with water after the valve is opened, causing a short delay. Pre-action systems require a separate trigger before water enters the pipes, also delaying discharge. Deluge systems have all heads open and filled with water, so water is released through all heads as soon as the system is activated, which is a different behavior from the single-head release of a wet-pipe system.