What is Pre-Action System in Fire Fighting?

A fire can cause a great deal of property damage which is why it is imperative to have a fire fighting annual maintenance contract. However, extinguishing water can occasionally cause just as much harm to protected things as the fire itself. Computer rooms, film archives, museums, and other moisture-sensitive spaces fall under this category. A preaction fire protection system can be useful in situations where a false alert could be disastrous and water deployment should be limited to the fire location alone, rather than the entire building or room.

What is a pre-action system?

In this, automatic sprinklers are connected to a pipe system that includes air that may or may not be under pressure, and a supplemental detection system is installed in the same locations as the sprinklers.

There will usually be supplemental detecting sensors and closed automatic heat sensitive sprinklers fixed to the air or nitrogen filled system pipes in the protected region in a pre-action sprinkler system. Closed automatic heat sensitive sprinklers used in pre-action systems have the advantage of just letting water into the area where the fire is when activated by a localised heat source. This avoids soaking broad parts of the protected area, as a deluge system can, and the water damage is usually limited to the fire area alone.

The pipework in the covered area is kept dry by pre-action sprinkler systems. The sprinkler piping is filled with air or nitrogen instead of water. As a result, some pre-action systems are the preferred method of protecting freezing zones such as refrigeration systems.

The activation of the main valve and the flow of water into the protected area through the sprinklers differs between pre-action systems. The pre-action system used is determined by the designer's priorities in terms of the level or type of protection required.

Types of pre-action systems

Double interlock pre-action - Before water is released into the sprinkler piping in a double interlock system, the electric detecting device must be actuated in conjunction with a drop in the maintained air pressure in the closed automatic sprinkler pipeline, as at least one sprinkler is activated by a heat source. The plumbing contractor can help to maintain the line of water smooth.

Single interlock pre-action - The single interlock pre-action system is designed to decrease the time it takes to administer extinguishing water while still protecting the protected area from inadvertent water deployment. A supplemental electric detecting device and automated sprinklers are used in the single interlock valve, just as they are in the double interlock system.

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