Sprinkler systems are important in fire protection strategies in a variety of buildings. Although they have common functions to keep fire in control until relevant authorities attend the scene, sprinkler systems operate differently. In general, there are four types, viz. deluge, wet-pipe, pre-action and dry-pipe system. We will elaborate more on the differences below. Our main focus is on one of the popular sprinkler systems: pre-action fire sprinkler system.
The pre-action sprinkler system is predominantly used in water-sensitive environments such as data centers and museums which can be damaged by water should an inadvertent discharge occur due to false alarms. Other sprinkler systems are prone to discharge accidentally and such discharges could cause massive damages to delicate items.
What is a pre-action sprinkler system?
A pre-action sprinkler system is basically a hybrid between different sprinkler systems, particularly wet and dry-pipe systems. But, predominantly, it uses the concept of a dry-pipe sprinkler system in that water is not readily available in the piping system until triggered by smoke or heat sensors. What distinguishes the pre-action system from the dry-pipe system is the supplemental detection of the electrically-controlled pre-action valve. In short, the pre-action system has the additional security against the inadvertent discharge whereas the dry-pipe can be prone to an accidental discharge.
This system is ideally available in two versions: double interlock and single interlock. With the single interlock system, the valve should be activated to release water into the pipes and then the sprinkler heads have to be activated by heat as well to release the water. The double interlock system, on the other hand, makes use of air or nitrogen filled into the piping system to help monitor for possible leaks and to help hold water intact should the valve fail so that there is no an accidental discharge. It’s apparent that the double interlock offers extra security and as such it’s preferred even though the installation becomes challenging.
Advantages of the pre-action fire sprinkler system
- Best-suited to water-sensitive environments such as data centers, archival vaults, and laboratories
- Dual action to discharge water thus making sure that there is no accidental releases of water
- Prevents water damages and fire damages
- Ideal for extremely cold areas because water will not freeze in the pipes as it is not readily held in the piping system unless the valve is activated.
Drawbacks of the pre-action fire sprinkler system
- It’s challenging and costly to install pre-action sprinkler systems because they need many components such as supplemental detection devices
- Regular maintenance required
- Difficult to modify the system as is the case with the dry-pipe systems due to size limitations
- There is a lag time before the water is discharged
Pre-action sprinkler system versus other sprinklers
As highlighted in the beginning, pre-action sprinklers are part of a family of sprinklers which include wet-pipe, deluge and dry-pipe systems. All these sprinklers have a common function which is to extinguish flames before a fire gets out of control in buildings. The choice of a specific sprinkler is dependent on various purposes such as the type of items stored and the urgency of response. For instance, the heads of deluge sprinklers are always open so it reacts as fast as a wet-pipe system. On the other hand, pre-action and dry-pipe sprinkler systems have a lag time. Let’s elaborate more about their differences below:
Wet pipe fire sprinkler systems: water is stored directly in the pipes ready for a discharge should the sprinkler head be activated when the fire breaks out. There is no lag time with this system; it discharges water instantly thus minimizing the likelihood of fire damage.
Dry-pipe sprinkler systems: in environments notorious of extreme cold temperatures, wet-pipe systems would possibly freeze and therefore rendering the system useless in fire emergencies. The dry-pipe sprinkler system works best in cold climates as the water is not directly stored in the pipes until activated. The pipe could be filled with air or nitrogen gas which gets released when the heat-activated sprinkler head opens. The pressure in the pipe will decrease and thus causing the valve to open to discharge water.
Deluge sprinkler systems: these ones are not popular, or rather applicable, in residential properties due to the nature of their operation. The sprinkler head is always open and it is not activated by heat sensors. There is a valve controlled by a specialized alarm to open and discharge water in large volumes until the valve is turned off manually. The deluge sprinkler systems are best suited for environments where fire emergencies could be frequent. Unlike residential sprinklers, these ones need manual operation to turn off the valve after a discharge.
Pre-action sprinkler systems: there’s not much to say about these systems as we have already highlighted them above. The main advantage of these systems is that they are not prone to false alarms and inadvertent discharges, and so they prevent possible water damages due to accidental discharges with no fire.
Installing pre-action fire sprinkler systems in buildings
To install these systems, you need a network of pipes with a reliable supply of water to your setup. The whole setup can be complex as this system is demanding compared to others. The installation requires advanced sprinkler engineering expertise. New York Engineers have extensive experience and the expertise to design, install and maintain pre-action fire sprinkler systems.
Building codes reinforce the importance of having sprinkler systems in buildings as the best measures to manage possible fire emergencies. The installation of pre-action fire sprinklers in water-sensitive areas is rather mandatory than optional as other sprinkler systems are prone to accidental discharges.
For your water-sensitive areas, pre-action sprinkler systems are a must-have due to the extended security and dual-function they have. Common areas for these systems are museums, archive vaults, data centers and any other area where water damage could be catastrophic. Pre-action sprinklers are also best-applied in cold climates where wet-pipe systems would freeze because water is readily and directly stored in pipes.