Preaction Fire Sprinkler Systems

Traditional “wet pipe” sprinkler systems offers protection against fires, but can result in water damage if unnecessarily activated in sensitive areas, such as; computer rooms, museums, libraries or refrigerated areas. Single or double interlock preaction systems can be configured to allow time for alternative fire extinguishment before the Water Deluge Systems are activated.

According to your specific requirements, fire hazard and fuel load, Wormald can design a system that is activated by wet or dry pilot sprinklers or electric detectors and can be automatic or manually operated. Having designed and installed hundreds of systems for applications large and small, Wormald can work with you to deliver a solution to meet your needs and budget.

Single Interlock Preaction Systems

Single interlock preaction systems protect areas where there is danger of serious water damage that might result from damaged automatic sprinklers or piping. Typically, such areas include computer rooms, storage areas for valuable artifacts, libraries and archives. Preaction systems are effectively used to protect properties where a prealarm of a possible fire condition may allow time for fire extinguishment by alternate suppression means, prior to a sprinkler discharge. In the event the fire cannot otherwise be extinguished, the preaction sprinkler system will then perform as the primary fire protection system.

Double Interlock Preaction Systems

Double interlock preaction systems are designed for applications such as refrigerated areas that require the maximum degree of protection against an inadvertent operation that could result in unnecessary flooding of the sprinkler system piping.

In order to actuate the double interlock preaction system, two independent events, caused by a fire condition, must occur. The sprinkler system piping must lose air or nitrogen pressure due to the operation of one or more sprinklers, and the deluge releasing panel must energize and open the solenoid valve upon the operation of a fire detection device. The double interlock system will operate only when both the dry pilot actuator and the solenoid valve are open at the same time. Opening of the dry pilot actuator only (for example: a forklift truck accidentally dislodges a sprinkler) or of the solenoid valve only (for example: accidental operation of an electric manual pull station) will cause an alarm, and will not trip the system or flood the sprinkler system piping.