What Are Foam Water Systems?
Foam-water sprinkler systems can provide prevention, extinguishment, control and/or exposure protection, depending on how they are implemented.
Foam-water sprinkler systems are installed to protect structures and facilities where a potential hazard for two-dimensional flammable liquid fire exists. They are used in locations where putting out a fire could be extra challenging. Typically, foam-water sprinkler systems are installed in aircraft hangars, petrochemical plants, tank farms, fuel-loading facilities and power plants.
How Does A Foam Water Sprinkler System Work?
Once the fire detection system is activated (either automatically or manually), the installation control valve opens. Foam concentrate is stored in a bladder tank and water is mixed together with this foam using a proportioning device located next to the installation control valve. The foam-water mixture is discharged through the sprinkler system over the protected area to help extinguish the fire.
Foam is essential for putting out highly flammable solvent fires – such as alcohol and gas – because it suppresses the fire by suffocating any combustible fumes and eliminating the possibility of a re-flash and the fire spreading once again.
4 Types Of Foam Water Spray Systems
Each of these systems is based on the same concept as normal sprinkler systems. The main difference is that they are also equipped with a bladder tank containing foam. Foam-water sprinkler systems are divided into four categories:
1. Wet pipe spray system
This type of sprinkler system employs automatic sprinklers or nozzles that are directly connected with a water-based piping system.
2. Dry pipe
Dry pipe sprinkler systems employ automatic sprinklers or nozzles that are connected to air or nitrogen. The release of this allows the water pressure to open valves.
Pre-action spray systems are similar to dry pipe spray systems. However,
they have an additional supplemental detection system installed in the sprinkler compartment. These systems are commonly used in areas where inadvertent damage to the operation of spray systems must be avoided.
Pre-action systems are typically divided into two groups, these are:
- Single interlock pre-action systems
This system requires one single preceding fire detection event to occur. Once this is triggered, the pre-action valve allows water to enter the piping system.
- Double interlock pre-action systems
These systems require two independent events in order to activate. Firstly, the sprinkler system loses air or nitrogen pressure due to the activation of one or more sprinklers. The second event is the triggering of the valve by the operation of a fire protection device.
A deluge sprinkler system is similar to the wet pipe spray system, with the exception of employing open discharge devices. These sprinkler heads always remain open and contain no water or pressurised air.