Knowledge Points of Dry Powder Fire Extinguishing System A Classification Method Dry powder fire extinguishing system can be divided into pressure storage cylinder type dry powder fire extinguishing system and pressure storage type dry powder fire extinguishing system. According to the structural characteristics of the system, it is divided into pipe network dry powder fire extinguishing system, prefabricated dry powder fire extinguishing system and dry powder gun fire extinguishing system. Two Pressure Storage Dry Powder Fire Extinguishing System Pressure-storage dry powder fire extinguishing system is also called pressure- storage system. There is no driving device and separate driving gas storage device in the system. Dry powder fire extinguishing agent and driving gas are pre-mixed in the same container, the quantity is generally less and the transmission distance is shorter. Three Prefabricated Dry Powder Fire Extinguishing System Prefabricated dry powder fire extinguishing system is a set of fire extinguishing devices which pre-assemble dry powder storage devices and sprinklers according to certain application conditions. Prefabricated dry powder fire extinguishing device is mainly composed of cabinet, dry powder storage container, driving gas storage bottle, powder conveying pipeline, dry powder sprinkler, fire detector and fire alarm controller. It is mainly used to protect specific small equipment or small space. It can be used for local protection or full submergence protection. On-site Inspection of Four Dry Powder Storage Containers The inspection of dry powder storage containers mainly includes three aspects: appearance quality inspection, sealing surface inspection and filling quantity inspection. Filling inspection requires that the actual filling capacity should not be less than the designed filling capacity, nor more than 3% of the designed filling capacity. It can be checked by checking the product's factory qualification certificate and weighing measurement when filling fire extinguishers. Field Inspection of Five-Gas Storage Bottle, Pressure Reduction Valve, Selection Valve, Signal Feedback Device, Sprinkler, Safety Protection Device, Pressure Alarm and Controller 1.The height difference between dry powder storage container and driving gas storage bottle of the same specification is not more than 20 mm. 2.For start-up gas storage bottles of the same specification, the height difference shall not exceed 10 mm. Six dry powder pipeline 1.Casing shall be installed at the place where the pipeline passes through the wall and floor.The nominal diameter of the casing is at least 2 grades larger than the nominal diameter of the pipeline. The length of the casing through the wall is equal to the thickness of the wall. The length of the casing through the floor is 50 mm higher than that of the floor.The gap between pipeline and casing is filled with fire-proof sealing material.When the pipeline passes through the deformed joint of the building, it is necessary to set up flexible pipeline section. 2.The end of the pipeline is fixed by anti- sloshing bracket, and the distance between the bracket and the end nozzle is not more than 500 mm. Seven sprinkler head For the pressure storage system, the maximum installation height of the sprinkler is not more than 7m when the full submerged fire extinguishing system is used, and the maximum installation height of the sprinkler is not more than 6m when the local application system is used. For gas storage cylinder system, the maximum installation height of sprinkler is not more than 8m when full submerged fire extinguishing system is used, and the maximum installation height of sprinkler is not more than 7m when partial application system is used. Eight-Water Pressure Strength Test Before the hydraulic strength test, the ambient temperature is measured with a thermometer to ensure that the ambient temperature is not less than 5 degrees. If the ambient temperature is less than 5 degrees, the necessary anti-freezing measures should be taken to ensure the normal operation of the hydraulic test. In addition, the test pressure should be calculated according to the design documents before the test to ensure that the test pressure of hydraulic strength is 1.5 times the maximum working pressure of the system. In hydraulic strength test, the tes