![]() ![]() There are as small as 1 to 2 micrometers. ![]() The aerosol cools the flame by engulfing it with a cloud with large concentrations of microparticles with a mass median aerodynamic diameter (MMAD). Disrupting the reactions necessary to sustain the flame's combustion, the cycle continues until the combustion's chain reactions are terminated and the flame is extinguished.Ĭondensed aerosol agents also have secondary extinguishing mechanisms implicating the other three elements of the fire tetrahedron described above. The potassium radicals are propagated since they are both consumed and produced by reaction with the fire radicals. The potassium radicals bond with the hydroxide (OH+), hydrogen (H+) and oxygen (O+) free radicals that sustain combustion, producing harmless by-product molecules like potassium hydroxide (KOH) and water (H 2O). As the aerosol particles surround and come into contact with the flame, the particulates absorb the flame heat energy, breaking down and releasing large concentrations of potassium radicals (K+) (ions with an unpaired electron). Typically, condensed aerosol particulates consist of potassium carbonate (K 2CO 3)) that are produced from the thermal decomposition of a solid aerosol-forming compound that includes potassium nitrate as an oxidizer. Inhibiting the chain reaction of the above componentsĬondensed aerosols' primary extinguishing mechanism involves the fourth element of the fire tetrahedron by means of chemical reactions with the free radicals of the flame, therefore interfering with the combustion process of the fire.They act on the four elements of what is known as the " fire tetrahedron:" the disparate components that combine to create the chemical reaction underlying any fire. Wet chemical systems generally found in foam extinguishers must, similarly to dry chemical systems, be sprayed directionally onto the fire.Ĭondensed aerosol suppressants, as with gaseous suppressants, use four methods to extinguish fires. The condensed aerosol agent can be delivered by means of mechanical operation, electric operation, or combined electro-mechanical operation. This can be contrasted with dry chemical systems, which must be directly aimed at the flame. They are effective regardless of the location and height of the fire. The particulates also remain airborne significantly longer and leave much less residue within the protected area.Ĭondensed aerosols are flooding agents. The solid particulates have a considerably smaller mass median aerodynamic diameter (MMAD) than those of dry chemical suppression agents. Then, the extinguishing material is "condensed" and cooled within the device, and discharged as solid particles.Ĭompared to gaseous suppressants (which emit only gas) and dry chemical suppression agents (which are powder-like particles of a large size – 25–150 micrometers), the National Fire Protection Association defines condensed aerosols as those that release finely divided solids of less than 10 micrometers in diameter. The condensed aerosol microparticles and effluent gases are generated by an exothermic reaction the particles remain in vapor state during the process of being generated within the device. It is similar to but not identical to dry chemical fire extinction methods.Ĭondensed aerosol fire suppression employs a fire-extinguishing agent consisting of very fine solid particles, as well as gaseous matter. Nozzle of a mounted aerosol fire suppression systemĬondensed aerosol fire suppression is a particle-based method of fire extinction. ![]()
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