Similar to dry pipe sprinkler systems, pre-action systems do not contain water within the pipes. Water is held from the piping by an electrical valve called a “pre-action valve.” The valve is triggered to open by heat, flame or smoke detection. Therefore, in order for the system to discharge, it must detect a fire or impending fire and then open the valve. This effectively creates a wet pipe sprinkler system where individual sprinkler heads will release and water will discharge.
- Computer systems
- Fine art displays
- Historic document storage areas
- Rare book vaults
Why use pre-action systems?
- Reliability – These systems are preferred when you need to avoid inadvertent discharge, particularly in water-sensitive environments.
- Independence – Individual sprinkler heads only open if activated by heat.
Limitations of pre-action systems:
- Installation and maintenance costs are higher due to the complexity of the system.
- Size limitations may inhibit the ability to modify systems.
- Reliability is decreased due to increased complexity of the systems.