Pre-action Sprinkler Systems

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.

Common Applications:

  • 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.