火灾引发超高层建筑非连续倒塌模拟研究

为了解超高层建筑发生火灾后变形特征及失稳后的非连续坍塌过程,掌握引起变形和坍塌的原因,将三维颗粒流软件(PFC3D)作为模拟平台,设置核心筒-框架结构的超高层建筑火灾区域,并模拟坍塌过程。在考虑钢筋和混凝土共同作用结果的基础上,提出火灾区域中构件属性设置方法及模拟步骤。分析得到造成建筑结构摆动的3种原因,一是火区位置不同导致上部结构对火区的压力不同,二是火区位置不同导致结构受到的约束不同,三是受热膨胀性使构件产生不同程度变形。结果表明:燃烧温度为500℃,3 h后建筑发生摆动,表现出对火区位置和燃烧时间敏感的特征。1 000℃下1 h内,建筑物首先发生破坏的是梁构件,然后是承重柱。即建筑一旦进入结构破坏阶段,坍塌将是迅速且不可逆的。     

不同控烟方式下火灾烟气运动演化规律比较分析

为优化选择与确定最优控烟方式,最大限度地减少人员伤亡和财产损失,利用火灾场模拟软件FDS对南宁市某地下超市火灾烟气的运动过程进行数值模拟,分别探讨了自然排烟、机械排烟、喷水灭火系统、机械排烟与喷水灭火复合系统4种火灾场景下烟气的运动过程,揭示出不同场景下火灾烟气的运动演化规律.结果表明,与自然排烟相比,机械排烟对于降低CO(低0.21％)和CO2(低2.6％)体积分数效果明显,能有效阻止O2(高1.8％)体积分数与能见度降低(延缓120 s);喷水灭火系统能有效降低烟气温度(降低200℃),在一定程度上抑制O2(高1.0％)体积分数的降低;机械排烟与喷水灭火复合系统能有效降低CO(低0.24％)和CO2(低3.4％)体积分数及烟气温度(降低270℃),还能阻止O2(高3.2％)体积分数与能见度降低(延缓160s);机械排烟、喷水灭火系统均对地下超市火灾烟气蔓延有较强的阻碍作用,但每个独立系统的控烟效果远不及机械排烟与喷水灭火复合系统明显.     

Adaptation potential of ecosystem-based management to climate change in the eastern Canadian boreal forest

Ecosystem-based management (EBM) of forests is gaining acceptance for its focus on the maintenance of the long-term integrity of ecosystem processes, but climate change challenges this view because of its impacts on these very processes. We have therefore evaluated the robustness of EBM to projected climate change, considering the role of climate on forest growth and fire regime in a boreal forest of eastern Canada. A climate sensitive growth index model was calibrated for three commercial species and used to project the evolution of merchantable volume for two climate scenarios (B1 and A2) under conventional and EBM strategies. Current burn rate and burn rates under future climate scenarios were also considered. Under the most extreme projected climate scenario, the periodic timber supply could be reduced by up to 79% through direct (growth reduction) and indirect (fire) effects. However, ecological indicators show that EBM is a more robust forest management strategy than conventional one demonstrating its adaptation potential to climate change at least in the short term.     

An experimental and modeling study of continuous liquid fuel spill fires on water

The spread of burning fuel spilled from oil product containers during offshore storage and transportation may cause large damage and trigger further accidents. Some analytical models already exist to predict the spread and burning behavior of liquid fuel spill fires, however, few experimental studies have been conducted to verify the model results. In this paper, continuous n-heptane spill fire experiments were conducted in a rectangular trench covered with water. The burning area, fuel spread rate, and thermal flux with different discharge flow rates and ignition delay times were investigated by both experimental and modeling means. The spill fire burning area, with 5 typical phases during burning, has a quasi-steady value which is directly proportional to the discharge rate but irrelevant to the ignition delay times. The steady burning rate, as the ratio of discharge rate over burning area, was estimated. A spread model was modified to simulate the spread of continuous liquid fuel spill fires in a one-dimensional channel, based on the balance between gravity and viscous forces. A cuboid solid flame model was used to compute the thermal flux from spill fires. The burning fuel spread and the heat flux calculated by the models agree with the experimental results.     

基于马尔科夫灰色残差GM(1,1)模型的火灾损失预测

科学地预测火灾事故及其损失,对于制定火灾防控措施具有重要的现实意义。应用基于马尔科夫的灰色残差GM(1,1)模型,对2002—2011年全国火灾损失进行模拟和预测,结果表明,该模型预测精度明显高于GM(1,1)模型,为火灾损失的预测提供了一种简单而可靠的新途径。     

地铁站火灾人员安全疏散研究综述

为提升地铁站火灾疏散能力,减少灾时人员伤亡和财产损失,国内外大量的研究成果服务于地铁应急预案的制定。分别从研究手段和研究对象方面对国内外近年来的文献进行梳理,分析了地铁站火灾疏散中的烟雾特点、人员应急行为特征和心理反应、疏散中的瓶颈和疏散路径。系统地分析了影响地铁站火灾疏散的因素,比较了不同学者地铁站火灾疏散中存在的差异以及有待改进的地方,从改善地铁设计管理方面和提升人员疏散能力方面提出了建议。     

考虑环境适应性和环境防护的火灾黑匣子设计

目的为了清楚记录火灾事故过程,便于灾后调查分析及预防火灾。方法对火灾现场的环境条件及其复杂性进行研究,并在此基础上,提出考虑环境适应性和环境防护的火灾黑匣子系统的设计思路,进行初步设计。结果火灾黑匣子的外部防护壳体采用了高强度的合金材料,确保了外壳具有较高的硬度和强度,保证了抗电磁干扰能力。内部是主要由二氧化硅凝聚物和石棉粉组成的多重复合结构,具有较好的抗高温火烧性能。结论该设计下的黑匣子实现了对日常使用和恶劣火场环境下的火灾数据的记录、存储与再现的问题。     

某液化天然气接收站及码头消防安全系统分析

参考国内外相关标准规范对山东LNG接收站及码头防火设计和消防系统配置进行了系统研究,对消防水系统、高倍数泡沫灭火系统、干粉灭火系统和消防站等关键消防设施进行了重点论述。     

苯储罐区火灾爆炸风险分析及对策措施

针对苯储罐区所处的区域位置及火灾爆炸危险性,运用道化学火灾、爆炸危险指数法对苯储罐区的火灾、爆炸风险进行分析评价,得出其安全措施补偿前后的火灾、爆炸指数,确定危险等级,并提出了预防火灾爆炸事故的对策措施。