A Tunable Diode Laser Absorption Diagnostic for Studying the Fire Suppression Mechanism of Aqueous High Expansion Foams

Using direct-tunable diode laser absorption spectroscopy, we obtained simultaneous oxygen, water vapor, and temperature measurements in situ during aqueous high expansion foam-suppressed fires in a foam-adapted cup burner apparatus. Foams with expansion ratios ranging from 55:1 to 129:1 were delivered at various rates; measurements were obtained 5.5 cm above and 1.5 cm outside the cup burner exit. By monitoring water vapor as foam advances through the cup burner chimney with and without the flame present, we are able to quantify evaporation due to the presence of the thermal and radiating field. We are also able to measure the impact on the oxygen concentration resulting from flame consumption of oxygen versus release of oxygen from evaporating foam bubbles. By analyzing video captured during each foam injection event, foam velocities during fire suppression and in the absence of the flame were measured.     

Guidance for Advanced Fire Suppression in Aircraft

The U.S. Department of Defense (DoD) Next Generation Fire Suppression Program (NGP) was born of necessity. Atmospheric science had made it clear that fully halogenated compounds containing chlorine or bromine posed a threat to the earth’s ozone layer. An extensive, multi-year search by the DoD found that the best commercially available alternative to halon 1301, CF₃Br, for fire suppression in aircraft carried significant weight and storage volume penalties. In 1997, the NGP began, with an objective that evolved to “develop and demonstrate technology for economically feasible, environmentally acceptable and user-safe processes, techniques, and fluids that meet the operational requirements currently satisfied by halon 1301 systems in aircraft.” Ten years later, the NGP has revitalized the science of fire suppression. There have been advances in delivery of a flame extinguishing chemical to a fire, knowledge of chemical interactions with flames (and limitations to the effectiveness of such chemicals), screening of a large number of chemicals as potential fire suppressants, identification of the properties of fluids that make for effective and safe fire suppression, identification of effective fire suppressant chemicals, engineering of non-fluid suppression systems for improved effectiveness and efficiency, and evaluation of the true cost of a new fire suppression system. The final report of the NGP will be available in book form and on CD this autumn. See the NGP web site () for ordering information.     

An Evaluation of Total Flooding High Expansion Foam Fire Suppression Systems for Machinery Space Applications

Full-scale fire tests were conducted to identify the fire extinguishing capabilities and limitations of High Expansion Foam Fire Suppression Systems (HEFFSS) in shipboard machinery space applications. A total of 35 tests were conducted in this evaluation utilizing the equipment and foam concentrates from three manufacturers. Each manufacturer was responsible for the design of their respective system. These designs were based on the minimum SOLAS/FSS Code requirements plus some additional capacity to provide a factor of safety for these tests. Each system was evaluated against the three large fire scenarios described in the International Maritime Organization's (IMO) gaseous agent test protocol (MSC/Circ. 848). The reason the HEFFSS test protocol (MSC/Circ. 670) was not used is discussed in the article. In addition to the tests in MSC/Circ. 848, parametric assessments of fill rate, fire size and type, and the use of inside air (the products of combustions) to make the foam were also conducted (one parameter for each of the three systems). In summary, there were significant differences in capabilities between the three systems. All three systems easily extinguished the pan fires included in this evaluation independent of the type of fuel (heptane or diesel). The differences in system capabilities were observed during the extinguishment of the spray fires (namely the heptane spray fires). The heptane spray fires presented a major challenge to the HEFFSS and in some cases, were not extinguished.     

地铁消防应用细水雾灭火的问题探讨

本文对地铁消防中应用细水雾灭火系统的几个主要问题提出了自己的观点,并通过分析提出解决问题的看法为目前正在征求意见的国家细水雾设计规程和地铁工程应用细水雾灭火系统提供一些参考。     

The Development of a Fire Safety Evaluation Procedure for the Property Protection of Parish Churches

Incidences of fires in churches are currently exceeding those in all other historic building types. This trend is destroying irreplaceable national treasures as England and Wales contains one of the greatest collections, in terms of number and antiquity, of ancient parish churches in the world. This paper describes the development of a decision making tool to aid the custodians of parish churches in evaluating the existing fire safety provision and in gauging the cost of upgrading fire safety for property protection exclusively. The principles behind the evaluation procedure are detailed and the mechanics of assessment demonstrated. The tool, referred to as Fire(SEPC) [Fire Safety Evaluation Procedure for the Property Protection of Parish Churches] is unique in its evaluation configuration in that an acceptable level of fire safety is dependent on the vulnerability of the fabric and contents of individual churches.     

Evaluation of the Fire Suppression Effectiveness of Manually Applied Compressed-Air-Foam (CAF) System

Mobile compressed-air-foam (CAF) systems represent a new type of fire suppression system, which is gaining popularity among fire services. Properly engineered CAF systems produce superior quality foam with high momentum. However, until now, there has not been a study to systematically evaluate the fire suppression effectiveness of mobile CAF systems. NRC has carried out a project to evaluate the effectiveness of a mobile CAF system in suppressing fully developed compartment fires. Several full-scale compartment fire tests were conducted to compare the fire suppression performance of a manually applied CAF system with that of hose stream application using water alone and using water-foam solution, under similar conditions. The study showed that a CAF system is much more effective in suppressing the compartment fire compared to hose stream application with water only or with foam-water solution. A CAF system with a 95 L/min (25 GPM) water flow rate suppressed the test fire better than the hose-stream application with water only or with foam-solution using 360 L/min (95 GPM). The CAF system suppressed the fire and cooled down the fire compartment (to 200°C) much quicker than the water alone or foam-solution. Also, the total amount of water used to control the test fire was much less with the CAF system than with the water alone or foam-solution.     

火探管式自动探火灭火系统的应用

火探管式自动探火灭火系统,作为一种新型的探火灭火设备,目前在我国的推广应用还非常有限。本文系统论述了该套设备的组成、工作原理和设计原则,并结合工程实践给出了具体的应用方法,供日后该系统在国内的推广应用参考借鉴。     

Development and Evaluation of Fire Barriers to Reduce Fire Hazards on large mining Equipment

The National Institute for Occupational Safety and Health has developed and evaluated various fire barriers for their effectiveness in preventing the spraying of pressurized hydraulic fluids onto simulated turbocharger hot surfaces, and in preventing the ignition of flammable vapors and mists onto barrier outer surfaces. This initial study, however, needs to be followed by a larger investigation that deals with barrier effectiveness in preventing or reducing hydraulic fluid fires within compartments of operating equipment, and barrier physical endurance under hostile environments within compartments. Some of the barriers were also evaluated for their effectiveness in suppressing simulated turbocharger fast-developing fires (initial fires, 32 kW). For the evaluation, modeled engine compartments with simulated turbocharger surfaces of 600°C, initial fires of 32 kW, and a pressurized hydraulic fluid spray system, were used. Also, conceptualized designs of some of the fire barriers, set within the compartments of typical mining equipment, have been reported to provide further guidance toward barrier fabrication and installation. The fire barriers included a parachute silica cloth barrier lined with flexible stainless steel foil; a one-panel insulated stainless steel barrier with a water-spray system; a foldable multi-panel insulated stainless steel barrier; and, an open–close steel strip barrier. Results show that all four fire barriers were effective in preventing the spraying of pressurized hydraulic fluids onto simulated turbocharger hot surfaces. Most of the barriers were also effective in preventing the ignition of flammable vapors and mists onto barrier outer surfaces. Results also show that the parachute barrier and the one-panel barrier with a water-spray system were effective in suppressing simulated turbocharger initial fires of 32 kW.     

建筑材料用硬质聚氨酯泡沫(PUR)的燃烧特性与防火对策

介绍了当前在日本建筑市场上面向建筑材料所使用的聚氨酯产品的种类以及具有代表性的应用实例。对高分子聚合物的燃烧特性以及在建筑领域一般火灾安全性方面的问题进行了说明。同时，对与节能相关的建筑材料的情况进行了描述。对PUR／PIR泡沫以及由此生产出的建筑材料的燃烧性能，末端客户的使用条件及依据阻燃规定的讨论仍在进行中。如何向末端客户提供符合使用条件的具有燃烧特性的PUR／PIR泡沫将成为满足今后环境保护与节能措施技术要求的新课题。     

Suppression Performance Comparison for Aspirated,Compressed-Air and In Situ Chemically Generated Class B Foams

This contribution describes the experimental program undertaken to test the performance of a novel firefighting foam against the current Class B foam technology. The novel foam involved the use of a chemical reaction between dissolved species to generate inert nitrogen gas in situ; hence in situ generated nitrogen foams (ISNF). The experimental program encompassed the utilisation of the DEF(AUST)5706 test standard for measuring the suppression and burnback performance of the ISNF as well as that of compressed air foams (CAF). All tests were performed using the same two types of surfactant concentrates (one telomer and one PFOS-based) in order to accurately determine the effect of the generation technology on the foam performance. The three kinds of foams (i.e., aspirated, CAF and ISNF) were characterised in terms of their bubble size distributions and drainage rates. Bubble size analysis placed the size distribution of the ISNF midway between those of aspirated and compressed air foams, whilst drainage performance was found to be only slightly superior to the aspirated foam. The results of the experiments showed that in situ nitrogen foams are able to achieve good performance, similar to that of aspirated and CAF technologies. Further work is needed to optimise foam formulations for ISNF so that surfactants are not affected by the chemistry of nitrogen generation and by the presence of salts formed during chemical reactions.     

火灾中端板连接件的屈服线模型的研究进展

特定温度下连接件的设计一般只考虑初始刚度和塑性抗力,然而结构在高温作用下发生大变形时其延性和破坏模式就显得更为重要。本文通过对T型连接模型的分析得到大变形,包括发生破坏的部位处端板连接件的性能。基于虚功原理建立的该模型,能很容易地应用于端板连接,而且能考虑到T型连接的翼缘和螺栓同时屈服后的材料硬化。同时还包括对这两个构件相容性的分析。对常温和升温环境中T型连接试验的验证表明:提出的模型可以预测T型连接的多种性能特征。通过与有限元分析结果对比发现:该模型可以很好地反映端板连接的性能。     

Assessment of the Fire Dynamics Simulator for Modeling Fire Suppression in Engine Rooms of Ships with Low-Pressure Water Mist

Water mist-based fire-extinguishing systems are gaining acceptance for the protection of ship machinery spaces. The use of simulation tools presents a great potential for taking a performance-based design (PBD) approach to these fire scenarios. The Fire Dynamics Simulator (FDS) is the most frequently used and validated fire modeling software; however, studies of low-pressure water mist fire suppression modeling in ship engine rooms are rare. This paper contributes to the current literature by using the FDS to model a series of fire suppression scenarios defined by the International Maritime Organization (IMO) Circulars, including spray and pool fires with heptane and diesel oil, as well as exposed and obstructed fires. The simulation results are compared to data from full-scale tests conducted at recognized fire testing laboratories. Furthermore, an analysis of both the experimental and model uncertainties is carried out to assess the simulations performance. In general, a good agreement in compartment temperature evolution and fire extinguishing time is found for the modeled fire scenarios. The results support the application of FDS in a PBD approach for the design of water mist fire extinguishing systems for machinery spaces in ships. In this way, designers and engineers could model different machinery volumes and nozzles spacings that differ from those prescribed for a one story square engine room of the IMO, and, thus, predict the evolution of temperatures and extinguishing times for get the authorities approval.     

商场火灾可能性的模糊综合评判

针对商场建筑火灾安全问题,依据商场火灾可能性的影响因素,参考建筑设计防火规范并征求专家意见,建立了商场火灾可能性的评判指标体系,并运用模糊综合评价对商场建筑火灾进行了可能性评判,通过评判得出商场建筑各火灾单元的安全等级.该方法应用于上海市第一百货商店的火灾可能性评价,结果客观、准确.     

适应土性要求的盾构用气泡剂的开发研究

土压平衡式盾构施工中,气泡作为优良的土体改良剂得到了广泛的应用.而我国的盾构用气泡剂向来以进口为主.近年来随着国内地铁建设的大规模开展,对于气泡剂的国产化要求越来越强烈.开发能适应所有地层地质条件的盾构用气泡往往成本太高,不太现实.针对不同土性地层,在现有气泡剂主剂的基础上,通过考虑其特殊的添加剂开发具有针对性的气泡剂;并通过试验对自主开发的气泡剂与进口的气泡剂的气泡性能、土性的改良效果进行了对比研究.研究结果认为,自主研发的气泡剂具有很强的针对性,可替代进口气泡剂而满足施工要求.     

火灾探测综合评估试验台测控系统集成

火灾探测综合评估试验台是为火灾探测器的综合性能评估测试而设计的大型试验装置,评估的结果可以指导产品开发和改进以及用户选型参考。本平台的测控系统需要协调多个部件协同工作,共同完成每一项试验过程,在系统设计中具有重要作用。简要介绍了平台结构和功能,对测控系统的总体方案、集成方法和软件设计过程进行了论述。实际测试结果表明系统达到预期设计目标。     

燃油火灾试验炉的研制

燃油试验炉可模拟实际火灾 ,对建筑构件进行受火试验 .构件火灾试验主要是检测构件的耐火等级或研究构件在火灾下的工作机理 .为适应建筑业防火工作和科研方面的需要 ,借鉴国内外同类试验室建造试验炉的经验 ,研制试验炉 ,其功能基本符合 ISO83 4及 GB9978-88的要求     

空气槽孔燃烧器的研究开发

以理论和实验相结合的方法,对空气槽孔燃烧器进行了开发研究,较好地解决了家用燃气快速热水器烟气中CO含量不稳定,小负荷时黄焰、回火,熄火噪音大,表面过热等问题,并以实验样机对燃烧器和热水器整机进行了验证。     

某钢筋混凝土冷冻库火灾后结构性能测评

本文通过对某钢筋混凝土冷冻库火灾事故后的现场勘查,推定建筑火灾温度分区,同时初步鉴定评定构件损伤状态等级。并对过火构件进行材料性能检测,对建筑物整体及梁柱构件进行变形测量。根据现场检测鉴定结果为后续加固处理方案提供依据。该冷冻库灾后结构性能的评测可为类似工程提供参考。     

气溶胶灭火机理及应用探讨

本文对气溶胶的灭火过程,特点进行了深入研究,着重分析了探讨了气溶胶灭火剂的灭火原理,应用范围及其发展前景。