Fire extinguishing mechanism and application scope of fire extinguishing dry powder fire extinguishing system Extinguishing mechanism Types of dry powder fire extinguishers: 1Ordinary dry powder fire extinguishing agent: can extinguish B, C, E fire, also known as BC dry powder fire extinguishing agent (typical: based on sodium bicarbonate) 2Multipurpose dry powder fire extinguishing agent: can extinguish B, C, E fire, also known as ABC dry powder fire extinguishing agent (typical: based on ammonium phosphate) 3Special dry powder fire extinguishing agent: It can extinguish class D fire, also known as D dry powder fire extinguishing agent. Matters needing attention: The BC and ABC dry powder are incompatible. Type BC dry powder is not compatible with protein foam or chemical foam.Because dry powder has great damage to protein foam and general synthetic foam. (3) For some highly diffusive gases, such as hydrogen and acetylene, it is difficult to dilute the odor of the whole space after dry powder injection. For precision instruments and instruments, residues will be left behind. Dry powder is not suitable for fire extinguishing. 2. Fire extinguishing mechanism of dry powder 1Chemical inhibition. 2Isolation. 3Cooling and asphyxiation. Classification of System Composition I. System Composition Dry powder fire extinguishing system consists of dry powder fire extinguishing equipment and automatic control equipment.The former consists of dry powder storage container, driving gas bottle group, starting gas bottle group, pressure reducing valve, pipeline and nozzle; the latter consists of fire detector, signal feedback device and alarm controller. II. Systematic Classification 1According to the way of fire extinguishing, it can be divided into fully submerged dry powder extinguishing system and partially applied dry powder extinguishing system. 2According to the design, it can be divided into design type dry powder fire extinguishing system and prefabricated dry powder fire extinguishing system. 3According to the protected object, it can be divided into combined distribution system and unit independent system. 4According to the storage mode of driving gas, it can be divided into gas-storage dry powder fire extinguishing system, pressure-storage dry powder fire extinguishing system and gas-fired dry powder fire extinguishing system. Scope of application I. Dry powder fire extinguishing system can be used to extinguish the following fires 1Gas fires that can cut off the gas source before extinguishing fire. 2Flammable, flammable liquids and melting solid fires. 3Combustible solid surface fire 4Fire with equipment. 2. Dry powder fire extinguishing system shall not be used to extinguish fires of the following materials 1Chemical substances and strong oxidants that can rapidly oxidize without air, such as nitrocellulose and explosives. 2Active metals such as potassium, sodium, magnesium, titanium, lead and their hydrides.