Which sprinkler system type is most common in residential occupancies?

• A. Wet-pipe
• B. Dry-pipe
• C. Deluge
• D. Foam-water

Answer: (A)

Wet-pipe systems are most common in residential occupancies because they are simple and cost-effective for typical heated homes. Since the pipes are filled with water, a single sprinkler head being triggered releases water immediately, providing rapid control of the fire with minimal delay. Dry-pipe systems, which use air or nitrogen in the pipes and require filling with water after activation, add complexity, potential delay, and higher cost, making them less suited for standard residences. Deluge systems involve all heads being open and would flood a home with water, which isn’t practical for typical living spaces. Foam-water systems are specialized for particular hazards and are not used in ordinary residential settings.