Which option is NOT a standpipe system type?

• A. Dry system
• B. Wet system
• C. Dry/Wet Combination
• D. Fog suppression system

Answer: (D)

A standpipe system is a built-in water distribution method for firefighters to connect hoses and deliver water to upper floors or remote areas of a building. The common standpipe types are wet, dry, and a dry/wet combination.

A wet standpipe is kept charged with water in the piping, so hose connections deliver water immediately when opened. A dry standpipe, on the other hand, has its piping filled with pressurized air or another gas until a hose hose line is opened, at which point water is released into the system from a remote location. A dry/wet combination mixes these approaches, with some sections always filled with water and others pressurized but not water-filled, used to fit varying climate or architectural needs.

Fog suppression systems are not standpipes. They are a separate type of suppression system that uses a fine water spray or mist to control heat and smoke or protect occupants, rather than providing a ready-for-use water supply through standpipe hose outlets for firefighters.