- Automatic Fire Sprinkler (pre-action) System
A pre-action fire sprinkler system is a type of automatic fire sprinkler system designed to provide fire suppression while minimising false alarms and unwarranted water damage.
Unlike traditional wet pipe systems, the pipes in a pre-action system do not contain water; instead, they contain air or other gas such as nitrogen in the sprinkler pipe network. The extinguishing agent (water) is held back by a pre-action valve.
The pre-action valve is electrically operated by a combination of a fire detection and alarm system signal from a heat detector, smoke detector, or flame detector and a low pressure caused by the activation of a sprinkler head.
Pre-action systems typically include a pressure maintenance pump (compressor) or other arrangement to incorporate other inert gasses such as nitrogen to maintain the system pressure.
The activation process of a pre-action sprinkler system involves several steps:
- Fire Detection: Upon detecting a fire, the pre-action valve is triggered and opens. This action allows water to flow into the otherwise dry sprinkler pipes, effectively converting the system into a wet pipe system at this stage.
- Individual Sprinkler Activation: Despite water filling the pipes, it is not immediately released. Each fire sprinkler head must be individually activated by the heat from the fire. Water is discharged only from the sprinkler heads that detect sufficient heat, targeting the affected area precisely.
This operation method ensures that water is released only when a fire is genuinely present, thereby offering a high level of protection against accidental water discharge. The pre-action fire sprinkler system is ideal for use in environments where water damage needs to be strictly avoided, such as data centres, archives, and museums.