Dry Pipe System

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 will be unable to maintain a constant, year-round temperature of at least 40 degrees Fahrenheit. 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). The water will then flow into the piping system, and out of the opened sprinklers.

Dry Pipe Systems are frequently installed in areas subject to freezing temperatures, such as unheated storage areas, coolers and freezers, unheated parking garages, and loading docks

GEM 

Dry Pipe Sprinkler Systems

Dry pipe sprinkler systems are installed in hazards where the piping and sprinklers can be subjected to freezing temperatures. Valving for the system, however, must be installed in areas that are not subject to freezing, as this portion of the system does contain water. In most dry pipe systems, pipe lines to the sprinklers are pressurized with air, but nitrogen is used at times. When pressure in the system is lost through the actuation of a sprinkler head, the dry pipe valve trips and releases water into the system and activates alarms. The system may be equipped with automatic or manual air supply controls and air supervisory devices with appropriate trouble alarms. Accessory items, such as dry pipe valve accelerators which increase the speed of system operation, and pressure switches which are used to activate electric alarms, may be used to enhance the system. Typical applications for dry pipe sprinkler systems include unheated warehouses, parking garages, store windows, attic spaces, loading docks, and other areas exposed to freezing temperatures.