Fire protection – Fog systems in fire protection
Fog systems, as fire protection, are used wherever traditional sprinkler systems are not suitable. Also extremely dangerous for humans gas systems displacing oxygen, i.e. filling rooms with gas. The most common applications: churches, museums, printing houses, factories, wood processing plants, control rooms, electrical switchboards.
Construction and components
The heart of the fog system is a high-pressure pump unit with a buffer extinguishing water tank. Fogging nozzles and fire detectors (electronic or pneumatic) are installed in the protected rooms. The power supply of the system is guaranteed by an appropriate UNINTERRUPTIBLE POWER SUPPLY.
If a fire is detected, the pump unit immediately pumps water under high pressure into the nozzles by applying water mist directly into the fire zone. Furthermore, acoustic signaling is activated and automatically (by phone, radio or VIA GSM) the appropriate persons. And the fire brigade unit are notified.
The system can be started manually at any time to check the correctness of operation or preventively in the event of a fire hazard.
A high degree of water fragmentation is the basis for the extinguishing capacity of fog systems. Traditional sprinkler systems generate droplets with a diameter of about 1 mm. While fog systems generate a diameter of only 10 μm. The evaporation area of 1 liter of water composed of droplets as above is respectively 2 m2 and up to 600 m2 of evaporation surface for fog systems!
Displacement of oxygen from the combustion zone
Evaporation of water mist droplets occurs primarily in the zone of elevated temperature in the immediate vicinity of the flame. After evaporation, the volume of water increases 1720 times. As a result, oxygen is displaced from the fire zone, in the same way as in the case of inert gas extinguishing systems. It is important that oxygen is displaced only from the zones directly occupied by the fire, the remaining rooms and escape routes are still usable. There is no risk of suffocation as in the case of gas systems.
Cooling due to rapid evaporation
The huge evaporation surface of water in fog systems causes very effective cooling of the zone affected by the fire. Evaporation of 1 liter of water draws up to 2500 kJ of thermal energy from the environment. Thanks to this, we effectively fight fire, and at the same time protect people and material goods from heat. Additional protection is obtained thanks to the barrier of water mist for thermal radiation.