Continuing our series of short articles on the elements of fire prevention and fire safety. Last month we looked at fire extinguishers and their suitability on different classes of fire. This month we look at the different types of sprinkler systems.
There are essentially four types of system, wet pipe, pre-action, dry pipe and deluge. These different systems are selected according to the needs of the building and the processes taking place.
Wet Pipe Fire Sprinkler Systems
Wet pipe fire sprinklers, as the name suggests, constantly have water in them. This gives a quick reaction to fire and is the most common type of sprinkler installed in buildings. Usually, they are used in high rise offices or buildings with a few floors. This fire protection sprinkler system is cost efficient and low maintenance.
Pre-action fire sprinkler systems are filled with air and only activate when the smoke alarm or detector goes off. This type of system requires two triggers to start water flow. For example, a heat sensor and a smoke alarm. It can be set to prevent water from spraying in case of a false alarm or a mechanical failure.
The pre-action system is used in buildings where the sprinklers are only necessary where there is an actual fire so other items in the building do not get water damaged or from an accidental activation. They are used in such buildings as libraries and data centres where items of high value are stored like electronics and goods damageable by water such as books.
Dry Pipe Systems
Dry pipe sprinklers are similar to pre-action systems having pressurized air in the pipe which escapes before the water flows. This does cause a slight delay in water discharge but is ideal for buildings with low temperatures so the pipes do not freeze. Warehouses located where temperatures fall substantially below zero degrees are an example of where dry pipe sprinklers are utilised.
These fire sprinkler systems also need a smoke or heat detector much like the pre-action system. A deluge system has open nozzles that can be used when a hazard is present. These are used in industrial buildings where flammable liquids could spread across a floor. They are also used where there are tanks of flammable materials.
Need a sprinkler system fitted or inspected? For any queries, contact Firebrand.