Key Points of Fire Dry Powder Fire Extinguishing System Design I. General Provisions 1The protective areas with fully submerged fire extinguishing systems shall comply with the following provisions: (1) When dry powder is sprayed, the opening of the protective zone that cannot be automatically closed should not exceed 15% of the total inner surface area of the protective zone, and the opening should not be located at the bottom. (2) The fire resistance limit of the enclosure structure and doors and windows should not be less than 0.50h, and that of the ceiling should not be less than 0.25h; the allowable pressure of the enclosure structure and doors and windows should not be less than 1200Pa. 2Protected objects using local fire extinguishing systems shall comply with the following provisions: (1) The air velocity around the protected object should not be greater than 2m/s, and windproof measures should be taken when necessary. (2) There should be no shield in the sprinkler range between the sprinkler and the protected object. (3) When the object of protection is flammable liquid, the distance between the liquid level and the edge of the container should not be less than 150 mm. When flammable gas, flammable and flammable liquid supply is available in the protective zone or object, the supply of gas and liquid must be cut off before or at the same time the dry powder fire extinguishing system is started. 3Sodium bicarbonate dry powder fire extinguishing agent is suitable for flammable gas, flammable liquid and melting solid fire, and ammonium phosphate dry powder fire extinguishing agent is suitable for flammable solid surface fire. 4The storage capacity of fire extinguishing agent in the combined distribution system shall not be less than that of a protective zone or protected object with the largest required storage capacity. 5The sum of protected areas and protected objects protected by the combined distribution system shall not exceed 8.When the total number of protective areas and objects exceeds 5, or the fire extinguishing agent can not be restored to normal working state within 48 hours after spraying, the fire extinguishing agent should be prepared.Standby should not be less than the storage capacity of the system design.The standby dry powder storage container should be connected with the system network and can be switched from the main dry powder storage container. 2. Fully submerged fire extinguishing system 1The design concentration of fire extinguishing agent in fully submerged fire extinguishing system should not be less than 0.65Kg/m_. 2The dry powder injection time of fully submerged fire extinguishing system should not exceed 30s. 3Pressure relief outlets should be installed in the protective zone and on the external wall, and the height of which should be 2/3 higher than the net height of the protective zone. 3. Local application of fire extinguishing system The dry powder injection time of indoor partial application fire extinguishing system should not be less than 30 seconds; the dry powder injection time of outdoor or indoor partial application fire extinguishing system should not be less than 60 seconds. 4. Prefabricated fire extinguishing devices 1Prefabricated fire extinguishing devices shall comply with the following requirements: the storage of fire extinguishing agents shall not exceed 150 kg; the length of pipelines shall not exceed 20 m; and the working pressure shall not exceed 2.5 MPa. 2A set of prefabricated fire extinguishing devices should be used to protect a protective area or object.The maximum number of prefabricated fire extinguishing devices used in a protective area or object shall not exceed 4 sets, and shall be started at the same time, and the action response time difference shall not exceed 2 seconds.
Key Points of Fire Dry Powder Fire Extinguishing System Design
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