高大空间红外光束感烟探测器安装高度对其报警时间的影响

高大空间建筑火灾在烟气蔓延特性、火灾探测报警系统、自动灭火系统等方面与传统建筑火灾有很大不同。本文通过对高大空间建筑火灾烟气运动、探测与报警技术进行综合性的分析和研究,分析了高大空间羽流、顶棚射流、近壁面回流与传统建筑火灾的共性及差异,研究了安装高度与红外光束感烟型火灾探测器报警时间的关系,为大空间建筑内火灾探测器的合理设置提供参考。     

谈高大开放式空间火灾自动报警系统设计

高大开放式空间建筑火灾自动报警系统的设计是现代建筑电气设计的新兴和难点领域。本文结合工程实例分析了高大空间建筑火灾探测存在的烟雾分层、烟雾稀释等问题,比较了极早期火灾探测器与传统火灾探测器的优缺点。论述了高大开放式空间建筑火灾自动报警系统选用极早期空气采样探测器的合理性。     

高大空间厂房火灾自动报警系统设计的体会

在高大空间厂房火灾自动报警系统设计中,传统探测器已不能满足要求,空气采样早期烟雾探测器及线型光束图像感烟探测器克服了传统探测器的缺点,在高大空间厂房获得了成功应用,以某卷烟厂高架库、制丝车间为例,讲述其在火灾自动报警系统设计中的应用。     

大型剧院火灾自动报警系统设计

结合大型剧院火灾自动报警系统工程设计实例,分析、比较剧院入口大厅、观众厅及舞台区域高大空间火灾探测器的选择,阐述在高大开放式空间建筑中怎样合理地选择火灾探测器。     

室内滑雪场火灾自动报警设计探讨

火灾自动报警作为建筑物内前期火灾预警的重要系统,起着非常关键的作用。在自动报警系统中,火灾探测器的选择尤为重要。在设计某大型室内滑雪场之时,根据滑雪场的环境、温度、结构等客观因素进线分析对比,对高大空间探测器的选择及布置给出方案。虽然线型光束图像感烟火灾探测器、图像型火灾探测器的特性,比较契合在高大空间的场所设置。然而,不同建筑物都会有不同的特点,设计时应根据建筑物内部环境和空间结构的特殊性,正确选用不同的火灾探测器。     

高大空间火灾早期探测获得成功——吸气式感烟探测报警系统在北航体育馆的应用

目前对于高大空间的火灾早期探测的解决方案，仍为国内外防灾专业领域的一个主要研究内容。由于高大空间的净空很大，易产生烟雾分层现象，同时气流运动受到空调系统循环方式的影响，烟雾粒子难以上升至红外光束感烟探测器或点型感烟探测器附近，加之上述探测设备灵敏度的限制，极易产生漏报或延迟现象。随着近年来火灾探测技术的发展，吸气式感烟探测报警系统应运而生，为高大空间的火灾早期探测提供了一种全新且高效的方法。由中国建筑科学研究院防火所完成的北京航空航天大学体育馆火灾自动报警系统工程的二次设计及施工，便将吸气式感烟…     

有关吸气式烟雾探测火灾报警系统设计的探讨

结合工程设计实例,分析了在特殊环境和高大空间采用传统火灾探测器的缺陷,介绍吸气式烟雾探测器特点和吸气式烟雾探测火灾报警系统的应用前景。     

高大空间建筑早期烟雾探测报警系统设计改进

根据高大空间建筑特点、环境因素对火灾自动报警系统的影响,结合工程实例,对高大空间建筑中早期烟雾探测报警系统最大探测区域面积的使用率进行研究。通过分析早期烟雾探测报警系统各项设备的特性,设置位置、高度、长度等指标,对现有早期烟雾探测火灾报警系统设计及产品提出改进方案．     

大型空间火灾的预防——吸气式感烟探测系统的应用

正现代建筑结构比较复杂,这使得其火灾和烟气防护变得非常困难。大型中庭和开放空间以及高大的天花板等建筑特点,使得传统的火灾和烟气探测方法不可使用,或者不再有效,且难以维护和运行。大型开放空间容易产生高速气流和烟气分层(源于较高的天花板和/烟雾的稀释),使得烟气难以抵达点型感烟探测器,并使得传统的探测装置难以正常运     

大空间烟雾探测报警技术——红外光束线型感烟火灾探测器及高灵敏度吸气型感烟探测器

介绍了两种运用于大空间建筑上的火灾烟雾探测报警产品——红外光束线型感烟火灾探测器和高灵敏度吸气型感烟探测器 ,详细阐述了其工作原理和应用特点 ,并对其工程使用情况做了简要说明。     

Using suppression and detection devices to steer CFD fire forecast simulations

Firefighters would greatly benefit from a technology based on predictive fire simulations, able to assist their decision making process. For those simulations to be useful, they need a certain degree of precision and resolution that can only be provided by CFD type fire models. But CFD simulations typically take large periods of time to complete, and their results would thus not be available in time to be of use during an emergency. Due to the high complexity of fire spread dynamics that arises from the interaction between solid and gas phase and the corresponding physical-chemical processes (e.g. pyrolysis), the spread of the fire cannot be predicted from first principles in real-time using contemporary computers, and has to be given as parameters to the model. Data can be incorporated into the model to characterise the fire, but only a limited range of measurements are recorded in current buildings. While it might be possible that buildings of the future incorporate a higher density of sensors than contemporary buildings, it is likely that emergency response systems will have access only to conventional data such as smoke detectors and sprinkler activation time for the foreseeable future. In this study the use of conventional detection and suppression devices for the estimation of fire characteristics by means of an inverse modelling framework is explored. Additionally to the growth rate of the fire, the location of the fire origin is successfully estimated. Inverse CFD modelling and tangent linearisation is used to assimilate the data. The nature of the incoming data is consistent with current detection and suppression devices, in such that only a time of activation is recorded and fed into the model. It is shown that the growth rate of the fire and the location of its origin can be correctly and efficiently estimated using sprinkler and smoke detector activation time only. It is further shown that the estimated spread rate is not sensitive to fire origin location.     

Smoke detectors in apartments and one-family houses: Fire risk, property loss and the presence of smoke detectors

This study compared the changes in fire risks and average monetary compensation for property loss before and after the distribution of 21 000 free home smoke detectors from a local insurance company. Life safety and injuries to people were not considered. To control for changes that were not due to the large increase in smoke detector coverage, a second insurance company in the same geographical area was added as a comparison, or control group. Average monetary compensation and fire risks were compared for small, medium-sized and heavy fires. The results showed no general effect of the sharp increase in smoke detector coverage on fire risk and compensation paid by the insurance companies. For the heavy fires, though not for the small and medium-sized fires, there was a significant decrease in compensation paid by the company with the free smoke detector. The reduction in compensation paid was small compared to the yearly costs of the batteries for the smoke detectors. The results were discussed in terms of smoke detectors as a technical device and a self-selection of fire safety conscious persons to the group that install a smoke detector in their homes.     

变电站电缆沟火灾探测试验与数值仿真研究

为探讨火灾探测器灵敏度对电缆沟火灾响应的影响程度,验证火灾监控系统的准确性,应用点式温度探测器、点式烟雾探测器、电缆式感温探测器和吸入式烟雾探测器4种火灾探测器,在标准变电站电缆沟防火分区内进行了全尺寸电缆火灾试验,测试不同灵敏度火灾探测器的火灾报警序列。根据电缆沟的实际尺寸,利用FDS搭建模拟明火和阴燃两种不同火灾场景,对不同灵敏度火灾探测器的温度场、有毒气体质量浓度和火灾报警顺序进行了分析和讨论。试验结果表明,在变电站电缆沟火探测中,电缆式感温探测器、吸入式烟雾探测器、点式感烟探测器火灾平均响应时间分别为41.2,111.4,331.8 s;吸入式感烟探测器的灵敏度对探测结果影响较大,其火灾报警响应时间比电缆型线性温度探测器约延迟50%。     

地铁车厢火灾探测器选择研究

分析地铁和地铁车厢火灾特点及其引发的严重后果;探讨地铁车厢中火灾探测器的选择;分析比较点型感烟探测器和吸气式感烟火灾探测器在地铁车厢中应用的优劣势;得出吸气式感烟火灾探测器更能满足地铁车厢中早期火灾探测需求的结论。     

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.     

超高空间线型光束感烟火灾探测器安装参数

在内部高度为27m的大空间实验室开展明火实验,通过分析地面以上25m和26m两个高度烟雾浓度和温度数据及多组线型红外光束感烟火灾探测器报警情况,研究大空间内20m以上高度线型红外光束感烟火灾探测器安装参数。实验结果表明,对于内部举架高度在20～27m的超高大空间,线型红外光束感烟火灾探测器在顶棚附近安装时,相邻两组探测器光束轴线的水平间距仍不宜大于14m,宜安装在距顶棚垂直高度0.3～1.0m范围内或尽量接近顶棚安装。     

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。     

Influence of fire ignition locations on the actuation of smoke detectors and wet-type sprinklers in a furnished office

Experiments were conducted in a full-scale model office equipped with movable and fixed fire loads to explore the influence of ignition source (movable fire load(s)) conditions on smoke detector and sprinkler actuation. The interior plan dimension is 5.7 m × 4.7 m and the net ceiling height is 3.3 m. Both northeast and southeast wings have a 2.1 m × 0.9 m single door to be opened. Seven fire scenarios (seven different ignited fire load configurations) under natural ventilation were investigated experimentally. The results show that the amount of fire load at the initial stage in a room fire does not markedly affect smoke generation and does not significantly impact the actuation time of the smoke detectors. When the fire source is located near a corner, the plume corner effect greatly increases; smoke detectors and sprinklers can activate quickly and effectively actuate the fire suppression. When the fire source is located in the room's center, given the uncertainty regarding smoke detector and sprinkler actuation, it may not be possible to control the fire spread.     

中庭火灾烟气流动的大涡模拟

采用大涡模拟的方法,对中庭火灾烟气的流动过程进行了模拟,了解了中庭烟气的蔓延过程,得到了烟气的速度场和温度场、顶棚射流的速度和温度的详细结果。模拟结果表明,大涡模拟能比较准确地预测中庭内烟气的流动状态,可用于指导中庭建筑的防火设计。