How Does a Pre-Action Sprinkler System Work?
A pre-action sprinkler system prepares to act when a fire detection system identifies a developing fire inside a facility and electrically opens the pre-action valve through the use of a solenoid switch, which allows water to flow into the piping system. (Note that in freezer warehouses and other below-freezing situations where the pipes must be kept dry unless fire suppression is definitively called for, a specific type of system known as a double interlocked pre-action system is typically employed to mitigate against accidental tripping of the fire detection system, as detailed in the Types of Pre-Action Sprinkler Systems section of this article.) The types of fire detection systems that trigger the pre-action valve include: • Thermal detectors, which react to temperature increases • Smoke detectors, which react to combustion products or flaming/smoldering fire conditions • Flame detectors, which react to a fires infrared radiation and/or ultraviolet light Once the pre-action valve h
