Dry-pipe systems are the sprinkler system of choice when the piping will be exposed to temperatures below 40 degrees F. Dry sprinkler system piping does not contain any water and is charged with pressurized air, or sometimes nitrogen. When a fire occurs and generates enough heat to release the sprinklers, the air in the pipes escapes, resulting in a drop in system air pressure, which allows the dry valve to open and water to flow to the open sprinklers.
Dry-Pipe Fire Sprinkler Systems: For Cold Environments with Temperatures Below 40°F
Although wet sprinkler systems are extremely effective against a spreading fire, they can present challenges in cold climates. When the weather is cold, the water stored inside the pipes of a wet pipe sprinkler system is susceptible to freezing, which can block the flow of water in an emergency. Furthermore, cold weather can damage the pipes that make up a wet pipe sprinkler system. As water freezes and turns to ice, it expands, causing so much pressure that the pipes can become warped or even burst.
It’s in these situations that a dry pipe sprinkler has the edge. Instead of water, the pipes in these systems are filled with pressurized air, such as nitrogen. When the sprinkler system is triggered, the air is released, lowering air pressure inside the piping. That decrease in air pressure allows water to flow into the pipe system and through the sprinkler heads. While this results in a slight delay from when the fire starts and when the water is released, with dry pipe sprinkler systems, you can be sure that you will always have a properly functioning and undamaged fire sprinkler system in cold temperatures.
Keystone Has the Special Expertise Demanded by Dry Sprinkler Systems
Dry-pipe sprinkler systems can be more complex than wet-pipe systems. Keystone has in-depth experience with the special requirements of dry systems. Because of the delayed dispersal of water from the dry-pipe valve to the open sprinklers, dry systems place limits on the system design and require a reliable air supply source.
These limitations may require restricting the system size; including components, such as accelerators and exhausters; and adjusting the number of operating sprinklers. Additionally, dry-pipe systems could operate as a subsystem of a larger wet-pipe system as in attic spaces, warehouses or refrigerated areas, for example.
Pre-Action Sprinkler Systems: Ideal for Water Sensitive Environments
Pre-action sprinkler systems are specialized for use in locations where accidental activation could damage high value physical assets as in archival vaults, museums, libraries or data centers. Similar to a dry-pipe system, a pre-action sprinkler system uses piping charged with air or nitrogen under pressure. The pre-action system holds back the water with an electrically operated valve, known as a pre-action valve. Water will not flow into the system until the supplemental fire detection system operates, signaling the pre-action valve to open.
This system can allow assessment of the incipient fire prior to water release, potentially saving valuable assets from water damage.
Deluge Systems: For High Hazard Occupancies Needing Rapid Suppression
Like a pre-action sprinkler system, a deluge system holds back water via an electrically operated deluge valve. However, unlike pre-action systems, the sprinkler heads are always open and the piping is not pressurized with air.
When the automatic detection system activates, the valve is opened and water releases through all the heads simultaneously. This massive release of water is needed in areas such as aircraft hangars, fuel loading facilities, power plants, and chemical and hydrocarbon storage or processing facilities.
Deluge systems often include foam mixed with water, which creates a protective blanket to control and cool a rapidly developing fire. Learn more about AFFF and FFFP foams.
Dry Fire Sprinkler Systems Require the Special Expertise of Keystone
Don’t leave the design and installation of critical systems like these to just anyone – choose the fire protection specialists at Keystone with over 60 years of special hazard fire protection experience.