– Developed by Canadian National Research Council Institute for Research in Construction (NRC-IRC)
Suppressing fire by throwing water onto it has been used since ancient times. Fire suppression systems for the protection of buildings have evolved in response to new requirements, environmental pressures and advances in technology.
Sprinkler systems were developed in the late 19th century. Since then, automatic sprinklers have become the most common fixed fire suppression system for providing fire safety in buildings.
Fire suppression systems for liquid fuels typically use foam or dry chemicals, which cover the fuel surface, hence limiting thermal feedback to the liquid fuel surface and fuel vaporization.
Fires in electrical and electronic facilities call for special solutions for suppression. Carbon dioxide (CO2) systems were used early on.
They deliver large amounts of CO2 to the fire area to reduce the oxygen concentration to below the level required for combustion.
For total flooding systems, in which pressurized cylinders are connected to a fixed piping and nozzle system to discharge the gas into an enclosed space, the oxygen concentration can be reduced to below the level required by occupants. As a result, CO2 systems are typically limited to unoccupied spaces.
For decades, foam systems have been used to provide fire protection in the chemical and petroleum industries and in military installations.
The overall effectiveness of current fixed-pipe foam systems, is limited since they are unable to provide foams with high injection velocities.
As well, the foam produced using traditional systems is not as stable and consistent, and expansion ratios are not as high as desired for some applications, because the air to generate foam at the nozzle, which comes from the fire environment, may be contaminated.
However, if compressed air is used for foam generation, the foam possesses superior quality and substantial injection velocity, as well as requiring a much smaller quantity of water and foam concentrates.
Source : National Research Council of Canada
(this article written for 1BINA.my)