The secondary seal part of the floating roof tank is prone to fire, so fixed foam extinguish-ing system and fire fighting cooling water system are usually be allocated during the design phase.How-ever, in the foam ejection acceptance check of storage tank foam fire extinguishing system , it is found that the foam mixture produced by the foam generator flows to the foam weir plate ring area along the tank wall. The foam enters into the tank roof through the weir plate, but it does not cover the height of secondary seal, thus it is unable to put out the seal ring fire. Through the foam ejection test, it is found that the direct failure cause of the fire extinguishing is the insufficient height of the foam weir plate . By measuring the height of the 5 × 104 m3 foam weir plate and the secondary sealing ring, the time for foam to cover the secondary sealing ring and the foam solution needed are calculated, and it is put forward that the height of the foam weir plate height should be increased to 0. 9 m, and the foam re-serve should be improved, ensuring that the continuous foam ejection time can be more than 1 hour and 19 minutes.The corresponding risk control countermeasures are put forward.%浮顶罐易发生火灾的部位为二次密封圈,通常在设计阶段为其配置固定泡沫灭火系统和消防冷却水系统,然而在储罐泡沫灭火系统泡沫喷射验收中,发现泡沫混合液通过泡沫产生器发泡后,沿罐壁流至泡沫堰板环形区域内,泡沫通过堰板进入罐顶,未覆盖至二次密封的高度,无法扑灭密封圈火灾.通过泡沫喷射试验,找到导致灭火失败的直接原因是泡沫堰板高度不足,通过测量5×104 m3储罐的泡沫堰板和二次密封圈的高度,计算泡沫覆盖二次密封圈的时间和消耗泡沫液量,将泡沫堰板高度增加至0.9 m,并增加泡沫储备量,确保泡沫连续喷射时间大于1 h 19 min,并提出了相应的风险控制对策.
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