Dry pipe sprinkler systems are filled with pressurized air or nitrogen rather than water. This is necessary in areas where freezing temperatures are present. Dry systems have automatic, closed sprinkler heads. When the sprinklers are activated by fire, the compressed air is released and, as the pressure decreases, water flows and discharges. The sprinkler heads operate independently, so water will only flow from heads that have been activated by heat.
- Unheated warehouses
- Exposed loading docks
- Commercial freezers
Why use dry pipe systems?
- Reliability in freezing temperatures – Water is kept from the pipes until the system is activated ensuring they will not freeze up in cold temperatures.
- Independence – Sprinkler heads will only be activated by heat, allowing only necessary heads to activate.
Limitations of dry pipe systems:
- Dry systems are more complex requiring air pressure components and more frequent maintenance.
- Dry systems are more expensive than wet systems to install and maintain.
- There are limitations on the allowable size of a system.There are delayed response times due to air having to decompress before water can flow. This can add up to 60 seconds to response time.
- There is a delay in getting the system operational after discharge because it must be completely drained and dried before recharging.