Ultrafine Particles Extinguishing Agent And Flame Interaction

This paper focuses on superfine particles fire extinguishing agent (SPFEA) of different granularity, with the purpose of investigating its interaction with local fire. The dry powder fire extinguishing agent, 95% of which is NH4H2PO4, is super-fined and surface modified for anti-gather, and prepared to SPFEA of different granularity. Referring to the domestic and foreign standards of normal dry powder fire extinguishing agent, the concept of "least agent dosage" is employed to estimate anti-fire efficiency. In the experiments, the interaction details between SPFEA and A, B and K type local fire, and the influence on anti-fire efficiency from ejection parameters are studied by self-designed equipments. The study results reveal that smaller granularity presents higher efficiency when SPFEA sizes in 5-20 μm. However, the efficiency is also determined by fire type. To gasoline, SPFEA shows best efficiency to B type fire, followed by K type, A type. Higher ejection pressure and proper ejection angle increases efficiency. Inverted extinguisher performs better in anti-fire. Both of broader and narrower spout are not good for putting out fire.