Which sprinkler system type maintains air under pressure in the piping?

Which sprinkler system type maintains air under pressure in the piping?

• A. Wet pipe
• B. Deluge
• C. Dry pipe
• D. Deluge with dry pipe

Answer: (C)

Dry pipe sprinkler systems keep the piping charged with compressed air (or nitrogen) rather than water. This air pressure acts as a barrier to water, holding it back from the piping until a sprinkler head is activated. When a head releases due to heat, the dry pipe valve releases, water from the building supply rushes into the piping, and water reaches the activated head. This design helps protect against freezing and reduces the risk of water damage before a head is opened, while still delivering water quickly once a head is triggered. Wet pipe systems have water-filled piping, and deluge systems have all piping filled with water with all heads open, so neither maintains air under pressure in the piping. A hybrid like deluge with dry pipe isn’t a standard configuration for this purpose.

Dry pipe sprinkler systems keep the piping charged with compressed air (or nitrogen) rather than water. This air pressure acts as a barrier to water, holding it back from the piping until a sprinkler head is activated. When a head releases due to heat, the dry pipe valve releases, water from the building supply rushes into the piping, and water reaches the activated head. This design helps protect against freezing and reduces the risk of water damage before a head is opened, while still delivering water quickly once a head is triggered. Wet pipe systems have water-filled piping, and deluge systems have all piping filled with water with all heads open, so neither maintains air under pressure in the piping. A hybrid like deluge with dry pipe isn’t a standard configuration for this purpose.