考虑多火灾场景的古城镇消防供水可靠性评估

Multi-fire scenario reliability assessment of water supply for fire protection in historic cities

针对云南省火灾事故频发的现状,评估古城镇消防安全对人民生命财产安全和文化遗产保护具有重要现实意义。提出火灾失效指数以筛选火灾失效风险高的建筑及组合。首先,利用美国联邦保险事务所的消防流量计算方法评估火灾时重要单体建筑的消防需水量。然后,构建水力模型评估消防管网供水能力。最后,通过计算建筑火灾失效指数以识别危险建筑及危险组合。将所提出的算法应用于云南省丽江市大研古城的消防管网。结果表明:单火灾场景的失效指数不仅与管道的管径、建筑附近消火栓数量和建筑的耐火等级相关,还与建筑的位置相关;随着火灾场景数量的增加,各建筑的失效指数均呈现不同程度的上升,最高可超过30%;建议在消火栓较少的区域增设消防管网附近的消火栓,以增强消防供水量,并优化远离水源建筑的消防设施。

Given the current situation of frequent fire accidents in Yunnan Province,assessing the fire safety of ancient towns is a task of great practical significance for the safety of people’s lives and property and the protection of cultural heritage.The fire failure indices is proposed to screen buildings and combinations with high fire failure risk.Firstly,the fire flow calculation method of the US Federal Insurance Office was used to assess the fire water demand of important individual buildings in the event of a fire.Secondly,a hydraulic model was then constructed to assess the water supply capacity of the fire network.Finally,the building fire failure indices is calculated to identify hazardous buildings and hazardous combinations.The proposed algorithm is applied to the fire pipe network of Dayan Old Town in Lijiang City,Yunnan Province.The results show that the failure index of a single fire scenario is not only related to the pipe diameter of the pipe,the number of fire hydrants near the building and the fire resistance class of the building,but also depends on the location of the building.With the increase of the number of fire scenarios,the failure index of each building shows a different degree of increase,and the maximum can be more than 30%.It is recommended to install additional fire hydrants near the fire pipe network in the area with fewer fire hydrants in order to increase the fire water supply capacity and optimise the fire fighting facilities in buildings far from water sources.