DRY PIPE SYSTEM

Where the room temperature is cold enough to freeze the water in a wet pipe system, dry pipe systems are the solution. Dry pipe systems are often installed in unheated buildings, parking garages, outside canopies, and refrigerated coolers. Considering NFPA regulations, wet pipe systems are not suggested to be installed at a room temperature above 40 °F (4 °C).
The piping system is filled with air at a pressure below the water supply pressure to prevent the water supply pressure from prematurely forcing water to flow into the piping system.
When the automatic sprinkler is triggered, it opens, allowing the air in the piping to flow from that sprinkler. Each sprinkler operates independently based on each triggering threshold. As the air pressure drops, the pressure differential across the dry pipe valve changes, allowing water to flow through the built piping system. Until the air is fully vented from the sprinklers, the water flow from sprinklers is delayed. In regions using NFPA 13 regulations, there is a “Maximum Time of Water Delivery,” where the time for water to reach the hydraulically remote sprinkler from the time the sprinkler is activated is limited to a maximum of 60 seconds. The maximum time of water delivery may be reduced, depending on the hazard classification of the protected area by the sprinkler system.
All in all, the system is advantageous for the protection of valuable collections and other water-sensitive areas.