It is used in places where water would damage stored objects, such as archives, galleries, and museums. There is no water in the piping, as there is in the dry system. Water is sent to the system when it is triggered. The system is activated via a separate detection line. This could be a secondary pilot sprinkler line (dry or wet type) or a detector line.

There are two different types single locking and double locking. In a single locking system, it is sufficient to send a signal from the sensing line for the water to pass into the system. After that, water is sent to the system. The water is discharged by the explosion of the sprinkler. In a double-locking system, both the sensing line and the sprinkler head must be activated for water to pass through the system. Thus, the possibility of the sprinkler being activated accidentally and discharging water to the objects in the space is prevented.

Varieties

Wet Pilot Activated

Dry Pilot Activated

Electrically Activated

PRE-ACTION ALARM VALVE