Dry Pipe Systems
A Dry Pipe Sprinkler System is a system which employs automatic and closed-type sprinkler heads, which are connected to a piping system containing compressed air or nitrogen, rather than water. This type of system is used where the area being protected is not maintained at a constant, year-round temperature of at least 40F. Water would freeze in the piping, rendering the system inoperable, even causing severe damage should the system components crack or break.
The water supply for the system is held back by the dry-pipe valve, which will only release the water after the evacuation of the air pressure from the system (such as the operation of a sprinkler head). The water will then flow into the piping system, and out of the opened sprinklers to the fire.
Dry Pipe Systems are frequently installed in areas subject to freezing temperatures, such as unheated storage areas, attics, coolers and freezers, unheated parking garages, and loading docks.