发电厂电缆夹层早期火灾演化特征及探测技术研究

摘 要：通过全尺寸电缆夹层试验平台,开展了电缆夹层早期（阴燃及初期）火灾探测试验,研究了温度场和CO气体蔓延特性,通过试验及模拟研究相结合的方法,对比分析了不同响应阈值的点型感烟、点型感温、吸气式感烟、缆式线型感温探测器的有效性。研究结果表明：阴燃及初期火灾温度场衰减均呈现指数函数关系;到火源的距离不同,阴燃火灾CO气体传播平均速度基本相同,而初期火灾CO气体传播平均速度随到火源的距离增加而降低;缆式线型探测器报警时间比吸气式探测器提前69%,比点型感烟探测器提前82%;各探测器初期火灾响应时间比阴燃火灾平均提前56%;阴燃火灾条件下点型感温探测器出现漏报现象;高阈值火灾探测器与低阈值探测器相比,响应时间延迟10%～20%。     

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。     

吸气式感烟火灾探测器(单管/四管)等12种产品介绍

正1吸气式感烟火灾探测器(单管/四管)1.1概述吸气式感烟火灾探测器(单管/四管)是吸气式感烟探测系统的一部分,该系统是一种高级微粒探测系统,可用在需要早期预警或更早期火灾预警的场所。产品型号有JTY-GD-8100S和JTY-GD-9400S(见图1)。该系统通过一系列的采样孔不断地在其所监控的环境中进行空气采样,以此来检测所处环境的烟粒浓度。     

核电厂RCP主泵间火灾探测改进和设计要点分析

文章对核电厂RCP主泵间火灾探测进行了研究,分析了RCP主泵间火灾探测方式;分析了吸气式感烟探测系统采样管路存在的问题,提出了相关改进措施,阐述了电源故障报警等细节的设计要点.     

风电机舱火灾探测试验研究

在介绍风电机舱基本结构,分析风电机舱内火灾探测器选用,介绍风电机舱火灾危险性的基础上,设计典型火灾工况,开展实火试验,对火灾探测系统的性能进行检测及验证。结果表明,火焰探测器对于液压系统部位及齿轮箱部位的油火识别速度较快,吸气式感烟探测器能识别机舱各部位各种类型火灾,吸气式感烟探测器和火焰探测器结合使用能够及时准确地监测风电机舱内各类火情。     

吸气式感烟探测器缺陷分析及处理方案的研究

吸气式感烟探测器误报率高是方家山核电工程项目JDT系统调试过程中较为突出的问题。本文对这个问题进行了分析,并研究了相应处理方案,提出通过取样孔变径、取样管路变更、控制设备安装及运行环境、防止减少沉积物脱落等方法来降低吸气式感烟探测器误报率。     

吸气式感烟火灾探测器在极早期火灾探测中的应用

对吸气式感烟火灾探测器的国内外标准发展进行了简要介绍,重点介绍了吸气式感烟火灾探测器—ASD535的原理、结构、特点、组网方式以及采样管设计方法,并以某数据中心为例进行了应用设计,最后指出了吸气式感烟火灾探测器的应用优势。     

感烟式火灾探测器失效原因分析及对策

本文从感烟式火灾探测器的典型结构、功能等方面,结合产品实际应用,分析了感烟式火灾探测器可能出现的失效模式,及其产生的原因,并就探测器不报和误报的各种原因提出了相应的对策措施。     

大空间建筑火灾自动报警探测器应用

在大空间建筑内,需要根据建筑物的特点选择合适的火灾探测器。根据火灾的多种特征物理量,合理地采用不同类型的火灾探测器组合,可以更全面地探查大空间建筑物内的火灾情况。本文结合具体工程案例从性能参数、安装要求及工程选择应用方面对大空间建筑中常用的线型光束感烟火灾探测器、管路吸气式感烟火灾探测器及图像型火焰探测器进行探讨。     

某数据中心火灾自动报警及联动控制系统设计

以某数据中心工程为例,介绍数据中心的火灾自动报警系统设计,着重阐述建筑物内探测器及联动灭火系统的设置:数据机房采用吸气式感烟火灾探测器与感烟探测器的组合联动气体灭火系统;共享中庭采用双波段红外火焰探测器联动自动水炮灭火系统。并介绍了高压细水雾灭火系统、气体灭火系统、大空间智能灭火系统的联动控制程序。     

变电站电缆沟火灾探测试验与数值仿真研究

摘 要：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%。     

吸气式感烟探测器在高大空间应用的试验研究

通过实体试验,研究高大空间场所中吸气式感烟火灾探测器的不同布置方式,对于不同火源类型、不同火源位置和不同气流干扰条件的响应性能,指出在高大空间建筑中该类型火灾探测器的布防原则和方式。     

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。     

Monitoring Multiple Aspects of Fire Signatures for Discriminating Fire Detection

Numerous researchers are exploring multisensor detection as the principal means of discriminating between fire and nuisance sources. Multisensor detectors can monitor multiple aspects of a wide variety of signatures produced by flaming fires, non-flaming fires, and nuisance sources. This paper describes one program of small- and large-scale experiments that has been conducted using a prototype advanced fire detector with multiple gas sensors. An elementary analysis is applied to demonstrate that spacing guidance can be rationally developed for multiple gas sensors to detect fires of a particular threshold fire size, i.e., heat release rate. Discriminating between flaming fires, non-flaming fires, and nuisance sources could be achieved using either a threshold concentration or CO₂ rate-of-rise to identify flaming fires and a CO or CO₂ rate-of-rise for non-flaming fires. Time to detection was also compared to commercial smoke detectors, and the reductions in time were noted.     

Detection of smoke gases by solid state sensors — A focus on research activities

Conventional smoke detection in fire alarm systems is based on a measurement of either physical properties of smoke aerosols (ionization and optical detectors), temperature increase (thermal detectors) or electromagnetic radiation emitted by the fire (radiation detectors). Not much emphasis has been put on smoke gases as signatures of various types of fires. In this paper the most elementary gases produced in CEN-norm fires are qualitatively discussed in order to define levels of gas concentrations reached on time scales typical of early fire warning. Based on that information, various principles and the current state of the research and development of solid state gas sensors are presented and discussed. These are, in particular, the solid state electrolyte, the metal oxide semiconductor, the silicon semiconductor device element and, finally, the microcalorimeter. It is concluded that, with the exception of the last mentioned operating principle, solid state gas detection could provide a viable alternative or additional means for the detection of smouldering or pyrolytic fires at an early stage.     

缩尺度试验火烟气特性实验研究

基于4种标准试验火开展缩尺度试验火烟气特性实验,研究试验火烟气特性在其尺度逐渐缩减过程中的变化规律,分析火灾烟气减光系数随时间的变化以及货架火灾探测器、吸气式感烟火灾探测器、点型感烟火灾探测器对各尺度试验火的报警响应特性。给出适用于高灵敏火灾探测器检测和评价的缩尺度试验火做法建议。     

早期空气采样探测系统在高大建筑物内的应用

在一些大型工业厂房、大型库房、中央大厅、体育馆等高大建筑的消防设计过程中,选择何种形式的火灾探测器成为一个困扰我们的问题。传统的点型探测器在这种高大空间很难提供有效地保护,因为探测器通常安装在指定的位置,由于烟雾具有分层现象,烟雾都很难到达顶部的探测位置,以致于无法准确报警。而能够检测到烟雾浓度的光束型感烟探测器系统则相对不够灵敏,而且需要有固定的安装位置。钢结构建筑在日照和风力作用下都会稍有位移,导致光束不能对准。再者,对探测器的日常维护和试验在此类高大建筑中通常很难且需要昂贵的设备。因此,需要选择一种更加适合高大空间建筑内的探测器,使其既要弥补传统探测器的不足,又要达到灵敏度高、安装可靠、适应性强、维护简便等要求,而空气采样式极早期烟雾探测系统则正是能够实现上述全部要求的火灾报警系统。     

Rapid Detection and Suppression of Mining Equipment Cab Fires

The National Institute for Occupational Safety and Health (NIOSH/PRL) conducted a series of large-scale experiments to evaluate the effectiveness of optical flame detectors, photoelectric smoke detectors, and combined ionization and photoelectric smoke detectors for rapidly detecting mining equipment cab fires. The detector alarm times were then used to trigger the discharge of a fire inerting system inside the cab to suppress cab material fires. This paper discusses the types of fire detectors tested, the experiments that were conducted, and the results that were obtained. Conclusions are that rapid detection of equipment cab fires can be achieved to trigger the discharge of a fire inerting system inside the cab to protect the operator in the cab.     

Method of Determining Smoke Detector Spacing in High Ceiling Applications

Simple tools for the design application of smoke detectors in commercial spaces with high ceilings and/or complex geometries do not exist due to the complexity in accurately estimating smoke densities and smoke detector activation characteristics. The response of commercial smoke detectors to UL/ULC standard flaming acceptance test fires and non-standard test fires in large open spaces with ceiling heights varying from 3 m to 21 m with radial distances from the fires up to 11.4 m is measured. Two algebraic models intended for unconfined ceilings, the two-zone computer model CFAST and the computational fluid dynamics computer model FDS are compared against each other and the experimental results. The ability to predict obscuration levels and detection times for these fires is evaluated. Recommendations are made for using the various models in commercial applications.     

浅论某大空间建筑火灾探测器的设计研究

以某展览建筑的主展厅这一大空间区域为模型,介绍了几种火灾探测器的特点和适用性,分析了如何合理选择和设置火灾探测器,通过采用红外光束感烟探测器和火焰探测器相结合的方式,以实现火灾的早期探测。