Pre-action fire sprinklers are a dry sprinkler system, water is not contained in the pipes but is held back by a pre-action valve. Pre-action valves are electrically operated valve that is activated by heat, smoke or flame. … The sprinkler head must be activated to release water onto the affected area.
What are the three basic categories of preaction sprinkler systems?
Fire suppression systems fall into three fundamental categories: wet pipe, dry pipe, and deluge. Pre-action fire sprinklers fall right in between all of these. Pre-action pipes start out as dry pipes; they hold water back using an electronic “pre-action” valve.
What is a dry pipe sprinkler system?
A dry pipe sprinkler system is one in which pipes are filled with pressurized air or nitrogen, rather than water. This air holds a remote valve, known as a dry pipe valve, in a closed position. … Water then enters the pipe, flowing through open sprinklers onto the fire.
What happens when the sprinkler head in a preaction system accidentally opens?
However, anything else that opens a sprinkler head or breaks the pipe can also release water and cause needless and expensive water damage. These include: Damage from freezing. Accidental physical damage of the pipe or fittings.
What are the types of sprinkler system?
Sprinkler system types
- Wet pipe systems. Wet pipe sprinkler systems are the most common system. …
- Dry pipe systems. Dry pipe systems are installed in spaces where the ambient temperature may be cold enough to freeze the water in a wet pipe system, making a wet pipe system inoperable. …
- Deluge systems. …
- Pre-action systems.
Is a preaction system a dry system?
Preaction systems may take the place of dry systems. Preaction systems utilize closed sprinklers, compressed nitrogen or air in the system piping, and water under pressure held below the clapper of the valve. Preaction systems require a detection and release system.