关于中庭建筑防排烟系统设计中排烟量的探讨

中庭建筑发生火灾的情况下,排烟系统设计的目标是应确保烟气层在认可的安全高度之上以利于室内人员的逃生或是使烟气层下降到危险高度所需的时间大于建筑物内人员安全撤离所需要的时间,因此排烟量的确定是排烟系统设计的关键.本文对中庭建筑火灾中2种火源工况下产烟量的计算公式进行了介绍,并与我国高规中确定排烟量的方法进行了对比.研究结果表明,对于轴对称羽流,NFPA模型能给出较好的预测结果;对于阳台喷射羽流,还存在一定的争论,对该情况下的羽流卷吸机理还需进行更深层次的研究;由换气次数确定的排烟量,尽管方便使用,但还存在许多不足,不能满足性能化分析的要求.本文的研究结果为我国相关规范的制订和性能化设计提供一定的依据.     

Analyses of smoke management models in TFT-LCD cleanroom

This study evaluated the effectiveness and performance of smoke management models in a TFT-LCD cleanroom. Several smoke management models are discussed in a distinct 3-level cleanroom compartment. The tools used included a fire dynamics simulator (FDS) and SIMULEX. The design fires were 3 MW and 5.4 MW in ultra fast fire, respectively. In life safety, both a downward smoke exhaust system and upward smoke exhaust system, incorporating a decrease of filter fan unit air supply rate, could be used in a cleanroom, according to the simulation results of performance-based design. For occupant evacuation, the SIMULEX results showed a total evacuation time less than smoke layer descending time, which descended to 1.8 m height from floor to smoke layer in all FDS simulations. In view of property protection, insurance companies generally require significantly higher standards of property protection. For 3 MW or more heat release rate, smoke was hardly controlled by any smoke exhaust system in the cleanroom without sprinklers.     

Enclosure Smoke Filling and Management with Mechanical Ventilation

Enclosure smoke filling and management are addressed from the standpoint of the volumetric flow rates commonly used for mechanical ventilation system design. In this context, fire-induced gas expansion is treated as a volumetric source term. A two-layer analysis developed previously for enclosure smoke filling without mechanical ventilation is extended to consider the impact of mechanical ventilation on smoke layer descent rates and conditions within the smoke layer. A spreadsheet-based model of enclosure smoke filling developed in conjunction with the previous unventilated analysis is also extended to consider both mechanical extraction and injection systems. Some implications of mechanical ventilation on the development and descent of a smoke layer in an enclosure fire are discussed.     

大空间烟气控制性能化设计影响因素模拟

利用FDS数值模拟大空间烟气流动情况,探讨大空间火灾烟气控制系统性能化设计中的影响因素.针对设计火灾荷栽、火源位僵、大空间的形状系数和大空间体积对烟气层高度和烟气温度的影响进行模拟分析,对大空间火灾烟气控制系统的性能化设计具有重要意义.     

某办公大楼中庭的消防安全性能化分析

提出了中庭采用自然排烟所带来的消防问题。采用计算流体力学(CFD)方法对烟气在中庭中的传播进行了模拟分析。通过对模拟结果的分析，提出了有关加强中庭消防安全措施的建议。     

试析高层建筑防排烟系统的常见问题

防排烟系统设施是高层建筑保障人民生命财产安全不可缺少的消防安全设施.防排烟系统共有三种类型:自然排烟系统、机械排烟系统、机械加压送风系统.由于部分设计、施工人员对防排烟设施的结构、作用、性能缺乏了解,对国家规范标准理解不够透彻,往往导致在设计、施工中出现防排烟系统设施配置被忽略或有配置而功能不全等现象.本文主要列举了高层建筑的3种防排烟系统在设计、施工和验收中的若干常见问题,以期引起设计、施工、管理和使用人员的重视.     

Application of symbolic mathematics in modelling fire for providing a safe environment

Symbolic mathematics should be a good tool for fire hazard assessment in performance-based design. Fire environment can be predicted interactively in a personal computer. The concept is further demonstrated in this paper by taking the model FIRM as an example. This is a two-layer zone model upgraded from an earlier model ASET, but allowed to have a vertical opening. In this way, the two key equations on smoke layer temperature and interface height are much more difficult to solve, on comparing with ASET.     

某高大空间热烟试验研究

对大空间的防排烟设计主要参考"中庭"的要求进行设计,消防验收中对其防排烟系统的有效性只能依据是否符合规范来评定.许多大空间建筑超出了规范涵盖的建筑形式,参考规范中"中庭"的要求进行防排烟的设计和评价已不再适宜.在澳大利亚热烟试验标准的基础上对某大空间的烟控系统进行测试,通过对烟气层高度和烟气层温升变化等数据的分析,研究大空间烟控系统的排烟效果.结果表明:热烟试验能够模拟火灾烟气的流动,可用于评价大空间排烟系统的有效性及消防验收.     

中庭机械排烟量计算方法探析

阐述了中庭防排烟系统机械排烟量的性能化计算方法,即以区域模型为理论基础,结合中庭建筑特征设定火灾热释放率后进行火灾烟气层高度和排烟速率等计算,并给出了计算实例。     

中庭防排烟系统性能化设计

阐述了中庭防排烟系统性能化设计的一般过程，详细分析了各个设计步骤，对重要的设计参数如烟层高度，能克服分层的最小火灾规模，烟层温度，不同类型烟羽流的质量生成率、排烟量、排烟口个数和排烟面积进行了量化。     

Measurement of the smoke layer interface in fires

In the normal case, as we all know, when there is a fire, smoke will arise along with the fire. The height of the smoke layer interface is an important parameter to assess a fire hazard. A smoke generator was used in a hot smoke test. The test verified the feasibility of two methods of measuring the smoke layer interface: ocular estimate and thermocouple measurement. The findings show that the ocular estimate is less accurate because subjective factors of the observer lead to changes of the data while the thermocouple measurement is more accurate. It has a delay in measurement, so revision of the delay should be taken into account and the two methods can be complementary.     

某大型商业综合体消防安全性能化设计

介绍某大型商住综合体B地块商业部分防火设计难点及相应的性能化设计解决方案。应用DETECT-T2、FDS、Pathfinder等数值模拟方法,从火灾危险性、火灾增长速率、最大热释放速率、排烟量、烟气流动、人员疏散等方面验证该解决方案。结果表明,该性能化设计方案满足了人员的安全疏散需求,达到了规范原则要求的同等水平。     

超高层综合办公楼防排烟系统设计探讨

详细介绍某超高层综合办公楼防排烟系统设计过程,对避难层通风、加压送风系统的分段、竖向排烟系统的设置、注意事项等进行了阐述,供设计参考。     

Effluent fire product — A crude approach to fire gas hazard assessment

The author proposes a method for classifying the various factors influencing the life safety hazard posed during fires. Five fire hazard components are identified as oxygen deficiency, toxic combustion products, smoke particulates, hot gases, and flame exposure. Note: This paper is a contribution of the National Bureau of Standards and is not subject to copyright.     

侧部重点排烟与水喷淋协同作用下隧道烟气运动研究

合理的水喷淋设计参数及排烟策略，可保证隧道有效排烟和烟气层的稳定性，为人员安全疏散提供有利环境。为研究侧部排烟模式下烟气失稳临界状态时最佳喷水流量和排烟口设计参数，采用FDS 对15 MW 火灾规模下，不同喷水流量、排烟量、排烟口间距及排烟口高度下19 组工况进行模拟计算。结果表明：喷淋流量越大，烟气层高度越高，隧道整体温度降低，改变喷水流量对控制烟气层的稳定性效益不大，隧道空间内有烟气滞留；排烟量为70 m3/s、排烟口间距为50 m、排烟口高度为3.2 m 或4.0 m 为烟气层稳定临界状态时的排烟口最佳参数，此时侧部抽吸力向上的分力与烟气的热浮力大于水喷淋拽曳力，烟气层较稳定，隧道空间内无旋涡烟气滞留，有利于排烟和人员疏散。     

剧场建筑性能化排烟设计探讨

分析了常规排烟设计方法在剧场建筑排烟设计申存在的问题,重点讨论了性能化排烟设计方法在剧场建筑排烟设计申排烟量计算、烟层高度设计、排烟口位置选择等方面的设计方法。     

Application of FDS to Adhered Spill Plumes in Atria

In a recently published article (Poreh et al., Fire Saf J 43(5):344–350, 2008), Poreh et al. carried out a number of experiments in a small-scale atrium. They investigated the mass flow of the spill plume in case of fire emerging from an adjacent room or corridor. Based on these experiments, the equation for the mass flow rates of adhered spill plumes in atria was adjusted. In our article, we repeat the experiments in a computational fluid dynamics (CFD) program. The results agree well, both with the experiments and the suggested formula. After this first validation, large-scale CFD-simulations are carried out. It appears that the equation suggested by Poreh et al. is only valid in the case of a uniform smoke layer depth. If the smoke layer has a more complex configuration, the formula is no longer reliable for the design of the smoke and heat exhaust ventilation system.     

五洲会友国际大酒店暖通空调设计

五洲会友国际大酒店初步设计为四星级,后根据酒店管理方要求,改为五星级酒店。概要介绍了该酒店通风、空调和防排烟系统的设计,重点介绍了通风、空调系统设置、厨房通风系统设计和防排烟。