Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

The flow velocity of gases in gobs directly influences the kinetics and intensity of gaseous components release during heating and cooling of coal.The assessment of fire hazard is performed on the basis of concentrations of particular gases in a mine air.These concentrations differ in coal heating and cooling phase which was proven in the study.This paper presented the results of the experimental study on temperature distribution in a simulated coal bed in heating(50–250°C)and cooling(250–35°C)phases as well as its correlation to variations in concentration of gases released in these phases and flow rates of gases flowing through the coal bed.The research was performed on twenty-two samples of bituminous coals acquired from various coal beds of Polish coal mines.Considerable differences were observed between heating and cooling phases in terms of the concentrations of gases taken into account in calculations of self-combustion index.In the heating phase temperature increase resulted in the decrease of concentrations ratios of ethane,ethylene,propane,propylene and acetylene,while in the cooling phase these ratios increased systemically.The effect of air(in heating phase)and nitrogen(in cooling phase)flow rate on the self-ignition index CO/CO2 was also determined.

Challenges of Tomorrowm——Fire Hazards of Systems Using Renewable Sources of Energy

Dramatic climate change, caused by over consumption of coal, oil and other traditional energy sources, as well as exhaustion of their reserves, imposed technological need to look for their substitution with new, renewable energy sources. The exploitation of these new forms of energy, solar, wind, earth and bio-fuels, initiated the development and application of new technologies, so far unused in practice. Rapid development and wide application of installations for use of renewable energy in many households and companies opened a whole new risk and danger in the fire protection field. With the purpose of introducing this problem to engineers in the area of fire protection, health and safety at work, this paper systematically presents various types of facilities for exploitation of renewable energy sources as well as potential dangers, risks and issues related to their safe operation.

Fire hazard in transportation infrastructure:Review,assessment,and mitigation strategies

This paper reviews the fire problem in critical transportation infrastructures such as bridges and tunnels.The magnitude of the fire problem is illustrated,and the recent increase in fire problems in bridges and tunnels is highlighted.Recent research undertaken to address fire problems in transportation structures is reviewed,as well as critical factors governing the performance of those structures.Furthermore,key strategies recommended for mitigating fire hazards in bridges and tunnels are presented,and their applicability to practical situations is demonstrated through a practical case study.Furthermore,research needs and emerging trends for enhancing the“state-of-the-art”in this area are discussed.

Hazard analysis system of urban post-earthquake fire based on GIS

The authors study the structure, functions and data organization for the hazard analysis system of urban post-earthquake fire on the platform of GIS. A general hazard analysis model of the post-earthquake fire is presented. Taking Shanghai central district as background, a system for hazard analysis of the post-earthquake fire and auxiliary decision-against fire is developed.

Precision Fire Hazard Divisions for Collective Forest in Southern China

This paper focuses on how to build the model of precision fire hazard divisions in the level of forest resources sub-compartment.Based on 3D GIS technology and characteristics of forest fires in collective forest of southern China,this study utilized Lin’an City,Zhejiang Province as the experimental area.Forest fire factors were divided into 11 indexes from the three categories(social and economic factors,forestry characteristics,and meteorological characteristics) and weighted for analysis.Next,three eigenvectors(one for each category) were created to build a nonlinear mathematical model called precision fire hazard divisions for forests.Then,the model was used to optimize and test forest fire hazard divisions with the least squares.Results showed that experimental and theoretical values of error were less than 0.1. Thus,in the experimental area this model and the fire occurrence history matched.

基于锥形量热仪的氧化煤燃烧特性研究

为了研究氧化煤的燃烧特性,以朱集西煤矿1/3焦煤为研究对象,在不同预氧化温度(80℃、140℃、200℃)下对煤样进行氧化处理10 h,并以原煤为对照,利用锥形量热仪测试煤样的点燃时间、热释放速率、总热释放量等主要燃烧特征参数。结果表明:随着预氧化温度的提高,煤样点燃时间I_(TT)、CO气体变化呈现先减小后增大的趋势,热释放速率峰值P_(HRR)、总热释放量T_(HR)、CO_(2)气体变化、质量损失速率R_(ML)峰值呈现先增大后减小的趋势。结合测试数据,并计算出火灾增长指数G_(FI)和火灾性能指数P_(FI),得出氧化煤与原煤的火灾危险性程度大小关系为140℃氧化煤样>80℃氧化煤样>原煤>200℃氧化煤样。

Investigation on Fire Protection System of Highrise Buildings in the Context of Bir Uttam Aminul Haque Avenue in Dhaka, Bangladesh

Rapid high-rise building construction of different occupancies is becoming popular in Dhaka due to its economic gain and functional flexibility. Fire prevention poses a significant difficulty to this type of construction due to its complexity and economic worth as well. Therefore, construction of high-rise building without following the proper fire safety measures, is a common practice at present in the city and it poses a greater threat to urban life considering its associated loss. Even though, most of the owners or authorities do not respect the construction code and the majority of them lack sufficient awareness and basic fire control knowledge and practice. More often, they are unable to comprehend the magnitude and severity of severe fire hazards, and recognize the causes and implementing effective mitigation measures are rare. As a result, the number of fire hazard in high-rise construction is increasing day by day. Hence, investigating the present condition of high-rise buildings (already built) in terms of Fire Protection System is imperative to prevent the upcoming fire hazard. An urban chunk of 33 plots along with Bir Uttam Aminul Haque Avenue, located in Banani, has been chosen for the study area considering its vulnerability to fire hazard. Among these buildings, STAR Tower and HBR Tower, these two high-rise buildings are assessed thoroughly using FRI (Fire Risk Index) Method. The method is semi-quantitative in nature with seventeen parameters associated with fire protection. This assessment represents a scenario in what extent fire codes are being followed in the selected area. It concludes that most of the buildings lack in providing protection against fire hazards for not following the code strictly. This research provides some recommendations which can be followed to improve the fire safety measures in this existing context. It is expected that this research could be a unique addition to firefighting knowledge by contributing to mitigating the consequences of fire related hazards in any densely populated city like Dhaka.

GIS, Forest Fire Prevention and Risk Matrix in the National Forest of Khoudida, Sidi Bel Abbes, Algeria

Forest fires in Algeria are ravaging an average of more than 32,000 hectares annually despite the prevention and control plan put in place. They are the most damaging factor of degradation of the forest and weigh heavily on the environment and the local economy. Conventional methods for fire prevention and control are time consuming and are not always reliable in view of the complexity and diversity of forest ecosystems. The main idea behind this study is to use the GIS and remote sensing for the development of a fire risk map of the Khoudida State Forest (Algeria). The approach adopted involves three parameters that control the fire behavior, which are: the top-morphology of the field, the combustibility of the plant cover and hazards. For each factor its correlation with risk was evaluated;the combination of the slope, altitude and exposure parameters in the topo-morphological index and the hazard map made it possible to evaluate the average risk for an area of more than 2132 hectares, 1521 hectares high and only 493 hectares, respectively 51.4%, 36.7% and 11.9%.

A Fire Risk Modelling and Spatialization by GIS

The management of the forest fire risk starts with it assessment. This assessment made the object of several works of research and many models of fire risk have been related. The model that interests us here is that established for Mediterranean forests. This last is conceived according to a sum weighted model integral three factors, where each is affected by a weight, function of his influence on the propagation of the fire. However, this model remains critically and deserves a development and an improvement. For it, and seen the importance and the influence of climatic condition in the departure and in the propagation of fire, we propose, in this paper, to improve this formula by the addition of another climatic factor (marked ICL), and to present it under a product shape while respecting the same definition of the risk. The application of the proposed model, suggested uses the technical geomatics to mapping the degree of the fire risk. In this setting, a SIG has been established and applied on a forest of Bouzareah clump in Algiers. Originality as it will allow the understanding of fire hazard and vulnerability of the environment for a better control of risk.

基于事故树分析的矿井火灾危险性评价

针对矿井生产条件,采用事故树分析方法,对矿井火灾危险性进行全面评价,通过构建事故树模型分析矿井火灾事故的成因、发展路径及后果,识别关键危险节点和风险因素,结合矿井实际生产情况对火灾危险性进行定量评估,提出了针对性的防控措施。研究结果表明,事故树分析方法能够有效识别矿井火灾的危险源和潜在风险,为矿井火灾预防和安全管理提供有力的支持,此结果对于提高矿井火灾危险性评价的准确性和有效性及促进矿井安全生产具有重要意义。

矿用电缆护套热降解动力学与火灾危险性探究

针对矿用电缆护套的燃烧性能,为电缆安全设计和合理选用提供依据,通过TGA/DSC和CONE探究了MYQ、MHYV和MKVV型电缆护套热降解特性和火灾危险性。结果表明:3种护套的热降解过程均可分为3个阶段,热失重主要发生在前2个阶段,且第一阶段的失重率最大;MYQ护套受温度影响最大,但是热解过程最缓慢;MHYV和MKVV护套受温度影响较小,但是热解反应最剧烈,且2种护套热解过程相似。MYQ护套的火灾危险性远大于MHYV和MKVV护套。根据计算得出的3种电缆护套的热解活化能,采用广义主图法确定了每种护套各个阶段的热解反应模型。研究结果可为电缆护套材料热解和火灾危险性研究以及电缆护套安全设计提供参考。

Usage of Cool Burning as a Contributor to Bushfire Mitigation

This paper considers and describes the cool burning techniques long utilized by Australian Indigenous people as a contributor to bushfire mitigation. Indigenous fire management involves lighting the “cool” fires in selected areas between March and July, in Australia, during the early dry season. The fires burn gradually, reducing fuel loads and creating fire breaks and not all of the area is burnt. Late in the dry season, when the weather is very hot, the method removes fuel for larger fires while maintaining and protecting habitat for mammals, reptiles, insects and birds. The management of Indigenous cultural fire offers an Indigenous viewpoint for wider control of fire and cultural fire management is an opportunity for collaborations to encourage Aboriginal empowerment with public and private sector organisations. Effective cool burning in contemporary prescribed burning activities can be achieved through implementation of good training, strong partnerships, carefully considered on ground practices and appropriate and effective techniques.

基于PDCA循环管理法构建大型公立医院消防设施故障识别与隐患治理工作模式

目的探讨大型公立医院消防设施故障识别与隐患治理工作模式的构建与应用效果。方法案例医院2022年在消防设施故障识别与隐患治理工作中开展PDCA循环管理,运用PDCA循环管理法的思路和框架,梳理消防设施维护管理中存在的问题并分析原因,制定改进措施。结果改进措施实施后,隐患识别能力提高,隐患整改周期缩短,隐患数量减少,建立了可持续的消防设施故障识别与隐患治理工作流程。结论基于PDCA循环管理法的消防设施故障识别与隐患治理工作模式可作为大型公立医院消防安全隐患治理的有效方法,具有推广价值。

高层建筑消防安全隐患及对策分析

随着我国城市化进程的加速,高层建筑数量不断增加,具有安全隐患多、火灾蔓延快、灭火困难等特点。如果发生火灾,极易造成巨大的财产损失和人员伤亡。从火灾发生、发展、灭火和救援4个方面总结了高层建筑的火灾特点,基于事故“4M”要素理论将高层建筑存在的消防安全隐患分为内部人员隐患、硬件设施隐患和安全管理隐患,并根据上述隐患进行分析,提出了提高高层建筑内部人员消防安全意识、严格执行高层建筑消防防火设计标准规范、明确消防安全管理责任主体、严格实施高层建筑消防日常监督管理和审核验收、构建基于物联网的高层建筑消防安全管理一体化平台等对策,从而提升消防安全管理的信息化水平。

基于小班尺度的北京市密云区森林火灾危险性评价

【目的】森林火灾危险性评价是实现科学林火管理工作的重要前提和基础,基于小班尺度开展森林火灾危险性评价及其空间特征分析,可为林火精细化管理提供依据。【方法】以密云区为研究对象,基于2019年森林资源二类调查小班数据、森林可燃物数据、气象数据、重要火源点等数据,构建密云区森林火灾危险性评价体系,应用层次分析法和熵权法相结合的主客观赋权法确定评价体系中各指标权重,根据评价体系中最终权重采用加权综合评价法计算各小班的危险性指数,依据自然断点分级法划分为高、中高、中低、低4个等级;采用全域和局域莫兰指数判断各小班之间的空间自相关性和聚集分布特征。【结果】(1)基于小班尺度综合4类因子构建体系,权重分布比例合理,可较好地开展火灾危险性评价;(2)研究区内高等级、中高等级、中低等级、低等级危险性的小班面积占比分别为12.75%,19.01%,41.70%,26.54%。其中,高等级危险性小班以灌木林、侧柏林、油松林为主,小班面积占比分别为38.40%、25.76%、24.13%;(3)高等级危险性小班分布在研究区范围的东部以及中南部区域,从乡镇尺度分析,呈片状分布于巨各庄镇、高岭镇和新城子镇;(4)小班危险性的全域莫兰指数为0.2413(大于0),说明密云区各小班存在一定的正相关性,即小班呈现出聚集分布的特征,采用局域莫兰指数分析发现火灾危险性等级为高-高聚集型小班的面积达34637.77 hm^(2),占密云区面积的15.56%。【结论】(1)构建的森林火灾危险性评价体系中,野外火源所占权重最大,是影响森林火灾危险性的主要因素;(2)高等级危险性小班区域灌木林占比较高,且聚集分布特征明显,根据权重结果,建议增强对野外火源和重点人群的监督和管理;另一方面,制定可燃物清理的标准和要求,定期在农林交错地区和火源点周围进行可燃物清理作业。

矿用胶带和电缆燃烧特性试验研究

为了防范矿用胶带和电缆燃烧火灾,文章采用FTT锥形量热仪测试并研究了其燃烧特性,并使用火灾危险性指标进行分析。试验测试胶带、电缆外护套和电缆绝缘层在30、40、50 kW/m^(2)热辐射强度下的燃烧特性,建立了热释放速率经验预测模型。结果表明:热释放速率曲线在上升阶段和下降阶段分别呈现出幂函数和指数函数规律;热辐射强度的增大使材料热分解加快,燃烧反应历程缩短,点燃时间缩短,耐热能力变弱,火灾危险性增大。

城市供水管网抗震功能评估与指标对比

为了对城市供水管网抗震功能作出合理评估,从居民日常生活和城市火场消防两个角度,建立了城市供水管网抗震功能评估方法。该方法首先根据设定的场地峰值加速度并基于管线的地震易损性模型和用户节点的火灾风险模型生成供水管网地震灾害物理破坏情景,然后据此修改供水管网水力模型并利用压力驱动的节点配水量模型进行管网水力平差,最后根据水力平差结果进行了供水管网震后生活需水功能评估和消防需水功能评估,探讨了消防需水对生活需水的影响;同时,揭示了不同峰值地面加速度作用下服务性指标与可靠度指标之间的关系。研究结果表明:在相同峰值地面加速度作用下,基于服务性指标的评估数值均要大于基于可靠度指标的评估数值。在较小峰值地面加速度(0.2 g、0.25 g)作用下,震后生活需水和消防需水均可同时得到满足,消防需水对生活需水影响不大;在较大峰值地面加速度(0.40g、0.45g)作用下,由于管网破坏比较严重,震后生活需水和消防需水均不能得到较好的满足,消防需水对生活需水影响也不大;而在中等峰值地面加速度(0.30 g、0.35 g)作用下,消防需水对生活需水有较大影响,约7%左右。

阻燃材料火灾危害评估方法研究进展

阻燃材料火灾危害评估是预防、管理和控制可燃聚合物材料火灾隐患的基础,同时也是选择适当阻燃体系并评价阻燃剂对聚合物综合影响的关键环节。从燃烧产物的角度分析了材料燃烧的特征,凝练出评估体系的热解行为、热量和CO_(2)释放、烟和毒性气体释放3个层面的准则。重点综述了单一维度材料火灾危害评估方法的研究进展,研究表明,需要集合火灾场景等才能获得具有逻辑意义的材料综合火灾危险评价。展望了阻燃材料的发展方向,阐释了材料火灾安全性评价的多属性决策过程的本质。讨论本质危害性权重分析过程并归纳了其发展趋势,即通过层次网络分析取代层次分析衡量元素之间更复杂的相互依赖关系和反馈,以减少传统方法的弱点和错误。进一步通过研究案例总结了材料火灾危害指标波动性和相关性的客观权重维度,并强调了指标数据的纯样归一化预处理方法对获得可解释性权重的重要作用。纳什均衡对权重的融合兼顾了主客观权重分析的优点,该体系有助于全面认知材料火灾危害的系统性和整体性特征。

列车火灾隐患分析研究和应用

[目的]火灾事故是地铁运营中主要的安全事故,为将火灾隐患降低至可接受水平,确保列车的安全运行,特进行本研究。[方法]将EN 50126-2:2017《铁路应用-可靠性、可用性、可维护性和安全性(RAMS)的规范和证明第2部分系统安全方法》的安全分析方法应用在城市轨道交通车辆火灾隐患分析中;通过对着火源和易燃物的识别,建立各系统火灾隐患清单;结合HAZOP(危险与可操作性分析)法,对导致火灾发生的部件进行详细分析,并识别火灾发生原因;在车辆设计中对不同场景进行火灾隐患识别,提出减轻措施,并跟踪管理风险解决措施直至风险降低到可接受的水平。[结果及结论]将地铁车辆火灾隐患分析中识别出的火灾区域,应用至火灾仿真分析场景方案中,通过仿真结果对地铁车辆火灾隐患区域进行了再次修正,并将研究结果应用至火灾报警系统设计中,能够更加合理布置火灾报警探测。

复合材料火灾适航风险性评估方法及应用

目的 研究复合材料在火灾适航风险性评估的方法。方法 采用单项指标对复合材料进行火灾危险性分析所得结果缺少可信度,选取9个指标作为火灾评估参数,结合试验数据进行分析,量化复合材料的火灾危险性,直观地体现每种材料在不同危险方面的差距。结果 提出了一种适合于民机上的复合材料火灾适航风险评估的方法,该方法能够较为全面地评估民机复合材料的火灾危害指数。结论 该方法将为复合材料的防火适航审定提供基础数据和理论支撑,有助于复合材料的适航符合性设计和符合性验证。