TOXIC HAZARD ASSOCIATED WITH FIRE EXTINGUISHING AEROSOLS: THE CURRENT STATE OF THE ART A N D A METHOD FOR ASSESSMENT

Total-flooding aerosol systems, widely applicable now, were engineered in the last decade of the 20Ih century. For an actuator they offer an extinguishing aerosol generator that houses an aerosol generating composition charge. The composition constitutes a formed heterogeneous mixture of an oxidizer (nitrate potassium, perchlorate potassium), a binding fuel (phenol formaldehyde resin, epoxy resins, rubbers, etc.) and various purpose additives (stabilizers, catalytic agents, etc.). Compositions are chemically stable under normal conditions. However, when heated by an electric helix, a pyrotechnic cartridge or a fire source, they start burning intensively and emitting a solid-phase extin-guishing aerosol. A high extinguishing efficacy of the aerosol is observed, in case its mass proportion of a solid phase to a gaseous phase ranges from 50/50 to 40/60 [I]. The solid phase aerosol includes mostly fine particles of alkaline salts and hydroxides (K,CO, 2H,O, KHCO,, KOH, KCI, KNO,). The mass frac-tion of a particle size from 0.1 up to 5 micrometers is equal to 85-90%. Due to small particle sizes, the buoyant aerosol is able to occupy a whole volume of the protected premises for a long time [ I, 21. Gaseous combustion products contain chiefly nitrogen (N,) and carbon dioxide (CO,). Also registered are nitrogen oxides (NO,), carbon oxide (CO), and water vapors. Ammonia (NH,), hydrogen chloride (HCl), hydrogen cyanide (HCN), hydrogen carbons, and some other compounds are also present