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Analysis of the characteristics and application prospects of ultra-fine dry powder fire extinguishing system

Edit:Jiangsu Yongtai Fire Engineering Co., Ltd.UpDate:2019-12-09

Analysis of the characteristics and application prospects of ultra-fine dry powder fire extinguishing system

Dry powder fire extinguishing agent was a dry powder fire extinguishing agent based on sodium bicarbonate developed by American Ansul Company in the 1930s. The research and application history of dry powder fire extinguishing system is also earlier. In 1969, dry powder fire extinguishing equipment has been used for the protection of automobile depots and oil storage tanks; in 1970, China has used dry powder fire extinguishing equipment for the protection of quenching oil tanks (pools) and indoor transformers; in 1975, the former Soviet Union's fire fighting information introduced that dry powder Fire extinguishing equipment is used to protect large alcohol storage tanks. From 1974 to 1975, Tianjin Fire Research Institute and Jilin Chemical Industry Company's Fertilizer Plant and other units jointly conducted an experimental study on the dry powder automatic fire extinguishing system for oil storage tanks, and conducted intermediate fire extinguishing tests on medium-sized aviation kerosene tanks. Later, the Tianjin Fire Research Institute also developed two Class D dry powder fire extinguishing agents, a Class D dry powder fire extinguishing agent using sodium chloride as the main raw material and a BCD dry powder fire extinguishing agent using sodium bicarbonate as the main raw material. Two types of dry powder fire extinguishing agent were used for the research of engineering application of dry powder fire extinguishing system of D type; moreover, it was not promoted and applied because of cost and other reasons.

In short, the dry powder fire extinguishing systems that are more mature in engineering applications are BC and ABC dry powder fire extinguishing systems. Class D dry powder fire extinguishing systems are not mature enough. They were basically imported from Italy before. The ultra-fine dry powder fire extinguishing technology was developed by Wuhan in 2001. Green Fire Fighting Equipment Co., Ltd. is the first new type of dry powder fire extinguishing agent qualified in China. For a long time, domestic companies have stopped using pipeless fire extinguishing devices (including short pipe network cabinet fire extinguishing devices). Superfine dry powder manufacturers are developing ultrafine dry powder fire extinguishing device systems. Among them, Wuhan Green Fire Fighting Equipment Co., Ltd. submitted inspections of qualified gas cylinder types and components in accordance with the "General Technical Conditions for Dry Powder Fire Extinguishing System Components" (16668-2010) in May this year. The two series of superfine dry powder fire extinguishing device systems of pressure storage type provide useful practice and test data for the research and development and inspection of domestic superfine dry powder fire extinguishing device systems. This article briefly introduces related technologies.

I. Superfine dry powder fire extinguishing agent

The fire extinguishing component is the core of the dry powder fire extinguishing agent. The substances that can play the role of fire extinguishing are: KCO, KHCO, NaCl, etc. At present, the common domestic dry powder fire extinguishing agents are: ammonium phosphate, sodium bicarbonate dry powder fire extinguishing agent. There is an upper limit for each type of fire extinguishing particles. All particles with a particle size smaller than the critical particle size have a fire extinguishing effect. Particles larger than the critical particle size have a sharp decrease in fire extinguishing efficiency, but their momentum is large, and aerodynamic pulling force is exerted on small particles by air. Forcing small particles to follow, and toward the center of the flame, instead of being blown away by hot air before reaching the flame, reducing the efficiency of fire extinguishing. The particle size of commonly used dry powder fire extinguishing agents is between 10 and 75 μm. The surface area is relatively small. Therefore, the quantitative specific dry powder has a small total specific surface area, a large mass of individual particles, a fast sedimentation rate, and a slow decomposition rate when heated, resulting in a small ability to capture free radicals, so the fire extinguishing ability is limited, and it is limited to a certain extent Use range of dry powder fire extinguishing agent. The particle size of the dry powder extinguishing agent is directly related to its fire extinguishing efficiency. The larger the critical particle size of the fire extinguishing component, the better the fire extinguishing effect. Therefore, preparing ultra-fine fire extinguishing powder that can be evenly dispersed and suspended in the fire space to ensure the particle activity of the fire extinguishing components and reduce the amount of fire extinguishing agent used per unit space is a very effective means to improve the fire extinguishing efficiency of dry powder fire extinguishing agent. Superfine dry powder fire extinguishing agent is a new product developed based on this theory. It has successfully extended the dry powder fire extinguishing technology to large-area full flooded automatic fire extinguishing.