Research on the Design and Safety Performance of Building Smoke Control and Exhaust Systems
建筑防排烟系统设计与安全性能研究

摘要

建筑火灾中，烟气是造成人员伤亡的主要因素，防排烟系统的效果直接影响人员疏散及消防救援效果。介绍了火 灾烟气的性质以及流动传播特点，对比了自然排烟、机械排烟以及加压送风等防排烟方式的工作机理及其适用范围。 火灾烟气流动性极强、遮挡视线明显、有毒有害，容易在建筑物内部竖井中产生“烟囱效应”，使火灾范围进一步扩大。 防排烟系统主要目的是火灾发生时保证疏散通道内无烟，便于人员逃生。对于排烟风机的选择上，比较轴流式及离心 式的优劣，排烟风机需满足能在280℃环境中正常运行不少于30分钟的要求，同时对排烟风机进行检测应满足相关的 国家标准规定；关于排烟管道的设计，在保证排烟顺畅的前提下，尽量缩短管道长度，降低弯头数量以及合理使用导 流叶片以提高排烟能力。防排烟系统的检查要点为：楼梯间剩余压力应在40～50Pa之间，前室剩余压力应在25～30Pa 之间，排烟口风速不宜大于 10m/s，系统联动时间不应超过 2s。研究表明，防排烟系统的设计必须以建筑物的安全为 前提，在保证烟气控制的同时兼顾人员的安全以及系统的可靠性的基础上进行合理的布置。

Abstract

 In building fires, smoke is the main factor causing casualties, and the effectiveness of smoke control and exhaust systems directly affects personnel evacuation and fire rescue. This paper introduces the properties of fire smoke and its flow and propagation characteristics, and compares the working mechanisms and applicable scopes of natural smoke exhaust, mechanical smoke exhaust, and pressurized air supply systems. Fire smoke is highly mobile, significantly obstructs visibility, and contains toxic and harmful substances. It is also likely to produce a “chimney effect” in vertical shafts inside buildings, further expanding the fire-affected area. The main purpose of a smoke control and exhaust system is to keep evacuation routes smoke-free during a fire, thereby facilitating safe evacuation. In the selection of smoke exhaust fans, the advantages and disadvantages of axial-flow fans and centrifugal fans are compared. Smoke exhaust fans should meet the requirement of normal operation for no less than 30 minutes in an environment of 280°C, and their inspection should comply with relevant national standards. For the design of smoke exhaust ducts, the duct length should be shortened as much as possible, the number of elbows should be reduced, and guide vanes should be reasonably used to improve smoke exhaust capacity while ensuring smooth smoke discharge. The key inspection points of smoke control and exhaust systems are as follows: the residual pressure in stairwells should be between 40 and 50 Pa, the residual pressure in antechambers should be between 25 and 30 Pa, the air velocity at smoke exhaust outlets should not exceed 10 m/s, and the system linkage time should not exceed 2 seconds. The study shows that the design of smoke control and exhaust systems must be based on building safety, and should be reasonably arranged on the basis of ensuring smoke control while taking into account personnel safety and system reliability.