摘要
大型公共建筑物的防火设计一直是非常重要的研究课题,由于这类建筑规模大、空间高、结构特殊、火灾危险程度高,其消防设计在防火分区、安全疏散、烟气控制、建筑结构防火保护、主动消防设施设置等方面对传统的“处方式”防火设计规范提出了挑战。本文将通过分析某大型书城的火灾特性,引入性能化防火设计方法在这类建筑中的应用。
结合工作实践,本文将围绕一个大型书城建筑实例----某大型书城的消防设计开展性能化防火设计研究。针对这类建筑存在的典型问题,通过设定消防安全目标、确定性能判据、建立火灾场景,考虑不确定因素,运用已开发的工程学方法对人员安全疏散时间、烟气蔓延、辐射热通量等进行模拟计算,对火灾探测和自动灭火设施进行分析选择,认为大型书城建筑采用至少与现行国家标准的规定等效的方法来实现建筑物的消防安全目标,能够解决现行标准与实际需要不相适应或某些不完善的规定所带来的问题。
通过对案例分析研究,本文认为大型书城建筑性能化防火设计研究的最终目的是保证人员生命安全和保证建筑结构安全,在模拟计算和量化分析的基础上,大型书城的防火分区可以将中庭连通的书城区域划分为一个区,在书城场地内可以采用防火卷帘进行防火分区划分;在人员疏散设计中,应尽可能利用书城卖场的空间设计较多的安全出口和增大疏散宽度,其安全出口数量、宽度和疏散距离可以根据人员安全疏散时间和烟气温度、沉降高度、CO2浓度、CO浓度、能见度模拟计算结果验证确定;在防排烟方式的选择上,应当根据建筑物的几何特点选取最适宜的措施,就大型书城建筑而言,采用自然排烟的方式是可行的。在分析火灾早期烟气蔓延特点和消防设施技术比较的基础上,在具有贯通中庭的大型书城中可以选择红外对射式感烟火灾探测系统和图像型火灾探测系统作为建筑的火灾报警系统。
The fire design for a large building of saling books is always a very important research subject. Because of the large scale, high space,high hazard of fire and particular construction of these buildings, their fire-protection designs, including fire compartmentation, safety evacuation, smoke control, construction protection and positive fire-protection device and etc.,put forward a challenge to the traditional‘prescriptive’fire-protection design codes. This article introduced the application of performance-based fire-protection design approaches in a large building of saling books based on analyzing their fire characteristics.
Combined with working practice, this article took a large books-store building in BeiJing as an example of a large building of saling books and made a performance-based fire-protection study on its fire design. Based on setting up the fire safety goals, performance criterion, fire scenario and uncertainty factor, this article simulated the occupants’evacuation time, smoke spread, radiation flow etc and determined fire detector and automatic extinguishing device by using the developed engineering method. And so these buildings’fire safety goals, which have the equivalent safety level with the existing national standard, can be achieved and those problems, which caused by some incompliment requirements or the existing codes not adapting to the practical need, can be solved.
With analyzing of the case study and based on simulating and analyzing quantitatively, this article, considering the goal of the performance-based fire-protection design is protecting occupants from being injured and keeping buildings from being damaged, thought that fire compartmentation of a large building of saling books can be divided according to their saling malls and fire compartmentation in the saling mall can be separated by the fire-proof screen. On the evacuation design, the quantity of safety exits around these buildings and the evacuation width should be increased if possible and the safety exit number, exit width and evacuation distance can be determined according to the simulating results on smoke layer temperature and height, concentration of CO2 and CO, occupants evacuation time and visibility.On the means of preventing and discharging smoke, the most proper measure should be determined according to their geometrical characteristics and the natural means of discharging smoke is feasible to the large building of saling books. Based on analyzing of smoke
引文
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