Preaction systems utilize closed sprinklers, compressed nitrogen or air in the system piping, and water under pressure held below the clapper of the valve. Preaction systems require a detection and release system. When activated by a detector, the valve opens, allowing water to flow into the system pipe and sounding an alarm. When the heat source activates a sprinkler, water flows through only the open sprinklers.
Passive Fire Protection (PFP) systems are important ‘buildt-in’components of structural fire protection and fire safety in a building. They compartmentalise a building through the use of fire-resistance rated walls and floors, keeping the fire from spreading quickly and providing time to for people to escape from the building.