Pre – Action System is a unique water-based fire protection system that will sense and respond to a fire condition in locations where accidental activation is undesired, delivering fire suppression when needed, there are several types of Pre – Action systems, but all of them are closed automatic sprinklers in the sprinkler piping.

A detection network i.e. compressed air is used in parallel with the automatic sprinkler system and is designed to operate before a sprinkler head fuses. This network may be hydraulic, pneumatic or electric and actuated by manual, fixed temperature, rate of rise temperature, smoke or other means.

The detection system operates before the sprinkler fuses. It gives an alarm because the Pre-action system is often used in server rooms, critical areas, labs, and museums with rare artworks, manuscripts, or books.

The system consists of a deluge valve, air compressor, panel, solenoid valve, actuator, sprinklers & other accessories.

Pre-action systems are hybrids of wet, dry, and deluge systems, depending on the exact system goal.

There are two main sub-types of pre-action systems: single interlock, and double interlock.