Which automatic sprinkler system can't be used where temperatures are below freezing?

Which automatic sprinkler system can't be used where temperatures are below freezing?

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

Answer: (A)

Wet pipe systems have water-filled piping that runs to every sprinkler head. When temperatures drop below freezing, that water can freeze inside the pipes, causing expansion that can crack or burst the piping and block water flow to the heads. Because of that vulnerability, a wet pipe system isn’t suitable for spaces where the temperature may stay below freezing unless the area is heated or the system is modified to prevent freezing. Dry pipe systems avoid this issue by keeping the main piping charged with air or nitrogen and holding water in a separate supply until a sprinkler head is released, so freezing in the main lines is less of a concern. Deluge and foam-water systems also carry water in the pipes, but many cold-area installations rely on dry pipe or heated/insulated solutions to manage freezing risk.

Wet pipe systems have water-filled piping that runs to every sprinkler head. When temperatures drop below freezing, that water can freeze inside the pipes, causing expansion that can crack or burst the piping and block water flow to the heads. Because of that vulnerability, a wet pipe system isn’t suitable for spaces where the temperature may stay below freezing unless the area is heated or the system is modified to prevent freezing.

Dry pipe systems avoid this issue by keeping the main piping charged with air or nitrogen and holding water in a separate supply until a sprinkler head is released, so freezing in the main lines is less of a concern. Deluge and foam-water systems also carry water in the pipes, but many cold-area installations rely on dry pipe or heated/insulated solutions to manage freezing risk.