Extinguishing & Isolation
Extinguishing is as important as detection...
Different applications and problems of fire require totally different types of water extinguishing methods. Large water droplets with powerful full cone water spray is needed to penetrate material flows in chutes or pneumatic conveying systems. For extinguishing of flames in enclosed volumes or open areas, smaller droplet sizes are an advantage due to their high evaporation rate, efficient heat absorption and its ability to displace oxygen. Designing a superior extinguishing system is a well-defined science.
Extinguishing of sparks and hot bodies
Momentum of the extinguishing water is the key factor for a successful, reliable and effective extinguishing in conveying systems.
The momentum or force depends on two factors, water pressure and water droplet size. A small droplet has less momentum compared to a larger droplet at a given pressure. This in turn means poorer extinguishing effect in conveying systems, as the droplets cannot penetrate the material flow.
Low pressure at the water nozzle reduces the chances of saturating the ignition source. A large droplet size in combination with 7-9 bar pressure that ensures the material flow can be penetrated and the ignition source extinguished.
It is important to consider the dimensions of the chute or duct that will be acting as the extinguishing zone as well as the material flow rate. Large physical dimensions and flow rates needs to be considered while designing the extinguishing zone as the water droplets run the risk of being absorbed in the outer layers of the material, leaving a partially extinguished ignition source.
Extinguishing of flames
Water mist as fire extinguishing medium is gaining ground and has proven to be very effective in fighting and controlling fires. It has a remarkable potential for suppressing fires and is causing minimal residual damage. It can be used for extinguishing of flames in a number of different applications such as panel presses, hot oil pumps, silos, planers, mills and in sensitive machines etc. Water mist has even been found to be usable in applications that are normally not considered suitable for water based systems e.g. oil fires etc.
Water mist systems work by spraying microscopic water droplets onto a fire. This results in efficient extinguishment using nothing more than water. The water removes heat from the fire that in turn creates steam, which displaces the oxygen and ensures that the combustion cannot be sustained.