中庭建筑烟气流动控制分析与防排烟

介绍了中庭的火灾特点以及中庭建筑防排烟的现状,分析了中庭建筑烟气流动过程,并且通过结合美国消防协会(NFPA)的商业街、中庭及大空间烟气控制系统设计指南NFPA92B和美国国家建筑规范BOCA中有关中庭烟层界面的预测方法,叙述了中庭建筑烟气控制的方法和中庭烟气控制系统设计计算的一般步骤。     

建筑火灾烟气蔓延规律及控制

根据建筑火灾烟气特点，分析总结烟气发生机理和烟气蔓延的动力模型，并给出各种烟气控制方法，为地下工程选用合适的火灾烟气控制系统建立理论基础。     

坡地对建筑火灾烟气流动的影响分析

从紧靠建筑的坡地对烟气流动的作用、烟气分布特性等方面分析不同坡度的坡地对建筑烟气流动的影响,得到不同楼层窗口温度变化及着火层室内烟气层高度变化。提出此类建筑火灾烟气的控制方法、工程实践中存在的问题,提出提高建筑消防安全性的措施。     

坚持以人为本高度重视建筑防排烟——从防火设计审核、工程施工监督验收遇到的问题谈起

笔者根据多年防火工作实践,阐述烟气是导致火灾建筑中人员伤亡的主要原因,并分析了高层建筑和地下人防商业街防排烟系统存在的问题,提出烟气控制的种种技术措施。     

建筑火灾烟气运动与控制研究方法的回顾与评价

介绍了建筑火灾烟气运动与控制的主要研究方法——实验方法、数值模拟方法、调查与实测方法的特点及应用情况,回顾了它们各自的发展历程,并列举了典型成果,同时指出了它们在使用过程中存在的问题与不足,旨在为初涉建筑火灾烟气运动的研究人员提供思路。     

高大空间建筑自然排烟系统性能化防火设计

基于性能化防火设计的方法,以自然排烟量等于烟气产出量为基本要求,利用火灾烟气模型和火灾动力学理论,计算出高大空间建筑火场烟气各物性参数,较系统的提出了大空间建筑的自然排烟系统开窗面积的理论计算方法。以某室内商业步行街为例,理论计算分析了不利火灾场景下烟气流动和排烟效果,该建筑现有排烟口面积满足排烟要求。     

建筑防排烟系统设计常见问题分析与探讨

建筑防烟、排烟设计是建筑防火安全设计的重要组成部分。组织合理的烟气控制方式,建立有效的烟气控制设施是确保人员的安全疏散和消防扑救顺利进行的必要保证。本文结合工程实际,对建筑防排烟系统设计中容易忽视的一些问题,进行了初步探讨,并阐述了自己的观点。     

中庭建筑烟气控制分析及其防排烟措施探讨

针对目前建筑消防规范对中庭建筑防排烟措施的要求不完善,全面分析了中庭建筑烟气控制的原理,并从建筑防火、防排烟的角度,对国内常见的中庭建筑进行了分类,提出了不同类型中庭建筑的防排烟措施。     

中庭内火灾烟气流动规律的研究

本文分析了中庭建筑内的火灾烟气运动特点,同时开展了一系列全尺寸对比性试验,并对实验数据与理论模型进行了比较。结果表明。中庭内烟气层的发展基本上仍可用区域模型来计算。     

中庭烟气控制研究现状与展望

综述国内外中庭烟气控制研究现状。讨论了中庭建筑的类型与结构、中庭烟气控制系统、排烟方式、排气效率、烟气填充过程与时间常数、烟气早期分层与烟气探测、控制烟气流动的中庭与相邻空间之间的气流问题以及喷洒系统对烟流的影响等。同时分析了我国现行规范( 高规) 中有关中庭防火设计的规定及存在的问题,并提出今后的研究方向     

火灾模型在火灾安全分析中的应用

以单元式住宅火灾为例,讨论了火灾模型在火灾安全分析中对几种情况下的火灾的应用。区域火灾模型能够算出有关房间内烟气层的高度、温度和代表有害组分浓度随时间的变化,据此可以较好估算烟气对人员安全的影响。     

Fire detection using smoke and gas sensors

Fire detection systems located in aircraft cargo compartments are currently based only on smoke detectors. They generate about 200 false alarms per year for US registered aircraft. The number of false alarms is growing as more planes are outfitted with smoke detectors and air travel expands. Moreover, the survivability of an aircraft in a fire scenario depends on the early detection of the fire. A fire detection system is developed based on the simultaneous measurements of carbon monoxide, carbon dioxide, and smoke. The combination of the rates of rise of smoke and either carbon monoxide or carbon dioxide concentration provides a potential fire alarm algorithm to increase the reliability of aircraft smoke detectors, and to reduce the time to alarm. The fire detection system with the alarm algorithm detected fires that were not alarmed by smoke sensors, and alarmed in shorter times than smoke sensors operating alone.     

Evaluation of Navigation Sensors in Fire Smoke Environments

An experimental study was performed to quantify the performance of eleven common robotic navigation rangefinding technologies and camera systems in fire smoke environments. Instruments evaluated included two IR cameras, two visible cameras, two sonar systems, radar, a single-echo LIDAR, a multi-echo LIDAR, a Kinect? depth sensor, and night vision. Small-scale smoke layer experiments were performed to isolate the effect of smoke visibility and gas temperature on instrument performance. Dense, low temperature smoke tests were used to evaluate instrument performance as the smoke visibility dropped below 1 m while the smoke temperature remained below 100°C. Light, high temperature smoke tests were used to evaluate instrument performance as the smoke reached a temperature above 250°C with the visibility above 5 m. Results from the tests show that radar systems and infrared cameras outperform the other rangefinders and cameras tested for these scenarios. A series of large-scale experiments were then performed to locate objects in a smoke filled room and hallway. Distances from the LIDAR were subject to error when the visibility reduced below 4 m. Infrared stereo vision and radar could locate the distance to target objects immersed in the smoke to within 10% and 1%, respectively, independent of smoke visibility level.     

地铁车站的火灾烟气控制设计

分析大型地铁车站空间、功能特点,从火灾荷载、人员密度、烟气蔓延特性、防排烟系统设计难度等方面入手,以某大型地铁站为例,利用实地烟热试验对站厅层和站台层的防排烟设计进行了研究,分析了试验项目、评价指标和测量指标。结果表明,对于复杂的地铁车站,通过优化灭火设施和防排烟系统,科学合理划分防烟分区,对重点区域进行防火分隔,严格控制地铁车站公共区域可燃物量,可有效控制火灾和烟气的发展蔓延,确保人员安全疏散的时间要求。     

Fire simulation in road tunnels

The catastrophic tunnel fires since the year 1999 and a series of accidents in some tunnels in the summer of 2001 triggered extensive discussions and proposals relating to tunnel safety. When a fire occurs in a tunnel, and in absence of sufficient air supply, large quantities of smoke are generated, filling the vehicles and any space available around them. Unless a strong flow is created and maintained, hot gases and smoke migrate in all directions. With a weak airflow, smoke forms a layer along the tunnel ceiling and can flow against the direction of forced ventilation, interfering with personal evacuation. This paper shows the results of a computer fire simulation in a tunnel and the results of this simulation: air velocity, air temperature and wall temperature in the case of fire. The simulation started before the emergency ventilation system is activated and continued with the fans activated to control the smoke.     

地铁车站火灾烟气的蔓延与控制

采用FDS计算模拟了北京地铁某典型车站不同火灾情况下的三维烟气流场,结果显示,当火灾发生在离出口楼梯间较近的站厅时,烟囱效应对烟气控制起决定性的作用,并且此时不需要机械排烟.当站台中部发生火灾时,只有机械排烟和挡烟装置配合使用才可以有效地控制烟气.重点对出口通道能否满足人员疏散时温度、风速、能见度的要求进行了分析.     

Sublethal Effects of Fire Smoke

Fire smoke toxicity has been a recurring theme for fire safety professionals for over four decades. There especially continue to be difficulty and controversy in assessing and addressing the contribution of the sublethal effects of smoke in hazard and risk analyses. The Fire Protection Research Foundation (FPRF), the National Institute of Standards and Technology (NIST), and NFPA have begun a private/public fire research initiative, the International Study of the Sublethal Effects of Fire Smoke on Survival and Health (SEFS) to provide scientific information on these effects for public policy makers. The papers in this issue of Fire Technology present results from the first phase of the project: estimates of the magnitude and impact of sublethal exposures to fire smoke on the U.S. population, the best available lethal and incapacitating toxic potency values for the smoke from commercial products, the potential for various sizes of fires to produce smoke yields that could result in sublethal health effects, and state-of-the-art information on the production of the condensed components of smoke from fires and their evolutionary changes during transport from the fire.     

对《高层民用建筑设计防火规范》防排烟问题的几点建议

作者就《高层民用建筑设计防火规范》实施四年多来的体会,对规范中设置排烟设施所规定的建筑高度,内走道、中庭排烟要求,以及制订建筑防排烟专用规范管理问题提出建议。     

Smoke Damage Potentials in Industrial Fire Applications

A methodology is presented for the evaluation of smoke damage contours through the coupling of smoke damage functions, deposition profiles and damage thresholds. Previously developed smoke damage functions and deposition velocities are used to illustrate “far-field” smoke damage potentials both for materials representative of semiconductor fabrication facilities as well as large warehouse storage applications. For semiconductor fabrication, smoke damage associated with leakage current (LC) is important, while smoke staining is of primary interest in warehouse storage. Smoke deposition velocities, a key component to quantifying smoke deposition profiles, were determined in a small (1.0 m³) and large (1,200 m³) enclosure. Both enclosures resulted in comparable values. The velocities ranged from 1.2 to 7.3 × 10^?4 m/s. To determine smoke damage potential contours for semiconductor fabrication facilities, electronic circuit board targets were used. Smoke damage was quantified by LC (i.e., shorting). The average normalized LC values for polyvinylchloride, polycarbonate, and nylon ranged from 0.72 to 6.1 × 10^?4 A m²/g. For warehouse storage facilities, filter targets were used. Smoke damage was quantified by brightness change and odor (i.e., volatile organic compounds, VOC) measurements on the targets. Representative materials were liner board, polystyrene, and polymethyl methacrylate. The smoke damage threshold value for brightness change was 0.012 g/m² and for odor was 0.025 g VOC/m². Resulting contours showed strong radial dependency with distance from the fire/smoke source. Smoke damage reached ~28 m for semiconductor fabrication facilities, while for warehouse storage facilities, it was up to 100 m.     

高层建筑火灾烟气控制模式的数值分析

根据我国现有高层建筑所采用的主要防排烟方式,采用CFD的方法完成了火灾时烟气的不同控制模式的模拟,并对不同的防排烟模式的模拟结果进行比较.结果表明当采用走道排烟加前室门设置空气幕或前室和楼梯间的加压防烟时,其烟气空气效果基本一致,均不能满足整个建筑的安全疏散时间的要求,但空气幕防烟较加压防烟所需新鲜空气量更少,能有效防止火灾的进一步扩大和控制烟气扩散.当采用空气幕加前室或楼梯间加压的组合防烟时,能较好的控制烟气的扩散,满足安全疏散时间的要求,即可以用空气幕和加压的组合来代替传统的前室和楼梯间加压的防烟方式.本文的研究成果可以为合理的设计高层建筑火灾时烟气的控制方式提供了一定的理论依据.