Pre-action sprinkler system overview
A pre-action sprinkler system helps protect property that is easily damaged by water. It uses double trigger system to help prevent water release by mistake. Pre-action systems are like deluge systems, except that the sprinklers are closed. An initial “action”—such as a heat or smoke alarm—causes the system to fill with water. Like wet-pipe systems, the sprinkler heads are sealed. The water spray is not released until a sprinkler head is opened by the flames. The system requires both “triggers”: and alarm and an open sprinkler head. If one is missing, there is no water spray from the sprinkler system.
The technology
A pre-action system is like a cross between wet- and dry-pipe systems. It remains dry until tripped by an alarm system, such as a fire or smoke alarm. However, like wet pipe systems, pre-action sprinkler heads are sealed with a heat-sensitive plug. They do not deliver water until the heat of the fire opens a sprinkler head. With their two-level trigger system, pre-action systems are much less likely to spray water accidentally. They are often chosen for areas where water damage would be very harmful, such as museums or computer labs. Pre-action systems deliver water to the fire more quickly than dry pipe systems.
Water is held back by a pre-action valve. When an alarm triggers the valve, it may be opened electrically, pneumatically, or hydraulically. Because a pre-action sprinkler system is so complex, the design and construction can also be quite costly. They are used only when an extra level of protection against water damage is needed. Upkeep may also be much more costly than wet- or dry-pipe systems. They also must be tested each year.
Applications
A pre-action sprinkler system is designed for special uses, such as an environment where water damage presents a major threat to the facility:
- Museums
- Aircraft hangars
- Computer rooms
- Libraries
- Flammable liquid handling
- Archives
- Telecommunications rooms
Call Global Fire Prevention today at (845) 781-0117 to learn how we can help protect your building.