Preaction
Preaction fire sprinkler systems replace water in sprinkler lines with compressed air or gas. The result is a system with the reliability of sprinkler protection coupled with a greatly reduced risk of accidental water damage. There are two widely used versions; single interlock and double interlock.
Single Interlock preaction systems use a detection and release system to control a deluge valve. The deluge valve is maintained closed in normal conditions. Piping between the deluge valve and the automatic sprinkler heads is filled with compressed air or nitrogen. In the event of a fire, the detection system will cause the deluge valve to open, admitting water into the pipes, At this point, the single interlock system performs in the same way as a standard wet pipe sprinkler system; water will discharge from automatic sprinkler heads that have actuated. Integrated packaged systems are far preferred for these systems which rely on the interconnection of mechanical, hydraulic, and electrical subsystems. These UL listed and FM approved packaged systems are assembled and tested in factory facilitating the specification of the equipment and enhancing system reliability.
Double Interlock preaction systems use a detection and release system to control a deluge valve. The deluge valve is maintained closed in normal conditions. Piping between the deluge valve and the automatic sprinkler heads is filled with compressed air or nitrogen. Double interlock systems require a detection of fire and the loss of air or nitrogen from the pipes to open the deluge valve. Integrated packaged systems are far preferred for these systems which rely on the interconnection of mechanical, hydraulic, and electrical subsystems. These UL listed and FM approved packaged systems are assembled and tested in factory facilitating the specification of the equipment and enhancing system reliability.