Development and application of a fire station placement model

This paper describes the development and application of a fire station placement model. The model is formulated as a mathematical programming model which locates p sites out of m candidate sites such that some function of the travel times of the first and second arriving fire units is maximized subject to several constraints. Among these constraints are limitations in the maximum allowable travel time to points in a region, requirements that certain sites be included or excluded, and a specification that a given number of existing sites be included.The model uses as an objective function a utility function based on the subjective preferences of fire department officials to travel times of the first and second arriving fire units. A modification of the Teitz and Bart node substitution heuristic is used to find the solution to the model.The model is applied to fire station locational decisions in Albany, NY. The model was run a number of times to provide insights into how some strategic decisions might be made. Reference: Jack M. Reilly and Pitu B. Mirchandani, Development and Application of a Fire Station Placement Model,Fire Technology, Vol. 21, No. 3, August 1985, p. 181.     

铁路客站站房性能化设计

针对大型、特大型铁路客站站房消防安全设计的实际问题,对铁路客站的性能化设计进行了初步探索。     

基于容量有限的嵌套型消防站层次覆盖选址模型

为科学规划消防站选址,实现有限资源下应急资源的合理配置,提高消防站覆盖效率,提出一种基于容量有限的嵌套型消防站层次覆盖选址模型。首先,基于层次和嵌套,提出选址时应对消防站进行分级,允许高级别消防站覆盖范围内嵌套建立附属低级别消防站,实现重点区域的多重覆盖及提高郊区的覆盖效率;其次,基于消防站容量有限,在一定范围内使同级同类消防站负担火灾风险平均化;最后,设计基于遗传算法的求解流程并进行算例分析。研究结果表明：与广义最大覆盖模型相比,层次覆盖选址模型覆盖火灾风险更大,对火灾风险高的区域覆盖更全,同级同类消防站之间覆盖火灾风险差距更小。     

消防站合理布局配置有关问题的初探

城市消防站的布局配置问题直接关系社会消防安全成本,直接影响政府的消防投资力度,如何科学的使用有限的资金投入,解决急需问题,防止重复配置资金浪费,尤其是对小城市和农村乡镇消防站的布局配置,提出了自己的看法和建议.     

消防站成本效益分析研究

从经济学的角度出发,对消防站的成本投入与效益产出进行了估算,比较了不同情况下的成本效益分析方法,提出采用效益成本比率法(BCR)对消防站进行成本效益分析,为消防站建设投资决策提供了科学的技术手段和依据.     

基于熵权TOPSIS法的城市消防站选址模型

从消防站的固定费用、正常费用、行驶距离和通行时间等多个优选指标综合考虑,建立了基于熵权TOPSIS法的城市消防站选址模型.采用主客观相结合的熵权法来确定指标的权重系数,进而将TOPSIS法与熵权系数综合集成进行消防站点的优选.实例应用计算的结果表明,该模型用于城市消防站最优站址的确定是可行的,结果合理、可靠,为城市消防站选址的最优化提供了一种有效的分析方法和决策依据.     

关于消防站建设的思考

介绍了山西省太原市的消防站建设工作状况,对其出现的问题进行了因素分析,并针对实际情况,对消防站的建设工作进行了思考、探索,为经济建设及和谐社会的建设提供更好的消防环境。     

基于火灾风险的城市消防站布局评估技术

从城市消防站布局评估需求出发,论证构建了包括用地类型、人口密度、容积率、平均楼层数等4个指标在内的区域火灾风险评估指标体系,并给出了指标分值赋值方法、区域火灾风险计算方法和区域火灾风险等级划分依据.基于区域火灾风险评估结果,提出了不同火灾风险水平下的消防响应标准,建立了基于消防站响应覆盖率、消防站交叉响应覆盖率和消防站...     

火电厂消防设计中冷凝器污垢累积规律的神经网络预测模型

为了防止火电厂锅炉消防设计中冷凝器因结垢而引起锅炉的火灾和爆炸事故,需要对冷凝器污垢系数的发展规律进行预测。设计了一种结合K-均值算法和Chebyshev 神经网络的污垢系数预测模型,针对Chebyshev 神经网络的弊端,应用K-均值算法对其进行改进,将污垢系数随时间发展的曲线分为启动阶段、粘附阶段和老化阶段3 类。结果表明,改进Chebyshev 神经网络模型有效地预测了冷凝器污垢系数发展规律,得到的输出结果比渐进预测和幂率预测模型的预测结果更准确,该模型具有算法简单、收敛速度快的特点。     

水电站不同火源强度烟气运动模拟

应用FDS模拟水电站地下主厂房火灾烟气填充与流动动态过程,分析不同火源强度下烟气分层规律.重点分析火源强度为10 MW时的烟气填充过程、顶棚射流温度和横向烟气温度的变化特点.结果表明,烟气到达某一高度的时间随火源强度的变化服从一阶指数衰减;顶棚射流温度和烟气层横向温度变化具有很强的规律性;下层空气温度不高但浓度相对较高;同一水平面的烟气浓度分布很不均匀,距火源30 m以外处的浓度是距火源中心10 m以内处浓度的2～3倍.     

NIST对一起车站夜总会火灾的调查：火灾的科学模拟

1概述2003年2月20日,在美国罗得岛州的西沃里克市的车站夜总会发生了1起大火。那天晚上正举行音乐会,在音乐会进行过程中,烟火装置将墙壁上的泡沫隔音材料以及舞厅的部分站台天花板点燃。从当时在火灾现场的新闻记者拍摄的录像中可以看到,火势沿着舞厅的天花板迅速蔓延。1min后     

普通消防站车辆的优化配备

对现阶段普通消防站值勤车辆进行分析,并有针对性地提出几种普通消防站应配备的值勤车辆,分析其特点与战斗编组。     

综合体微型消防站消防能力评估研究

微型消防站对防控火灾事故、保障人民生命财产安全具有重要作用。微型消防站的合理使用可构建立体化消防安全体系,提升城市火灾的纵深防御能力。本文以上海市某综合体微型消防站为例,开展了城市综合体微型消防站消防能力评估研究,建立了微型消防站消防能力模糊综合评估模型,对指导和推动此类消防站建设有一定的参考价值。     

抽查式消防监督检查量化模型研究

阐述了“抽查式消防监督检查”的涵义和必要性 ,重点讨论了该检查方式的量化标准和抽查的具体单位这两个核心问题。同时 ,运用数理统计原理 ,提出了三种不同类型的随机抽样方法 ,并建立了相应的量化模型     

A phenomenological model of near-field fire entrainment

A phenomenological model of air entrainment into combusting regions of axisymmetric fire plumes is developed and compared with some existing experimental entrainment data. The model considers engulfment of ambient air into a fire plume due to the action of the toroidal vortices that are formed periodically close to the source of an axisymmetric fire. It is shown that the diffusive entrainment rates of air towards a wrinkled flame sheet representing the turbulent diffusion flame severely underpredicts the entrainment rates by at least two orders of magnitude, suggesting that the turbulent large-scale engulfment is the primary mechanism of entrainment. By describing the entrainment process as periodic engulfment of ambient air around the toroidal vortex rings and the frequency of formation and passage of these vortex rings in combusting regions of fire plumes, it is shown that the modeled entrainment process gives good agreement with the experimentally determined fire plume entrainment or plume mass fluxes. This model accounts for the physical processes of unsteady fire plume dynamics, including the effects of pulsations for the first time. The model predicts the plume mass flux to grow linearly with height above the fire source and to be independent of the fire heat release in the visible flame region. The predicted scaling with respect to the source diameter appears to be in the range suggested by the experimental data. Overall, this new model provides a better foundation for the scaling of entrainment rates in the near-field of fire plumes. The methodology can be extended to predict entrainment rates in other periodic unsteady vortex dominated flows, such as pulsating buoyant non-reacting plumes.     

A model to evaluate tunnel fire characteristics

This paper presents a semi-empirical model for the determination of the physical characteristics of fire in tunnels. Classically, a fire is simply associated to its heat release rate. By definition, the heat release rate is given by the product of the smoke mass flow rate by the temperature rise in the smoke. However, for a given fire, the values of these two quantities remain correlated and more, the size of the fire is not independent of the released heat. This study is focused on heptane pool fires which offer the advantage of involving only one combustible in the combustion process and of linking the fire size to pool size. The purpose of this note is to develop a model able to define for a given heptane pool diameter, a set of values for heat release rate, smoke flow rate and smoke temperature. From an analysis of the combustion products, the burning rate and the air entrainment rate into the flame, a system of equations is derived. A comparison with international recommendations is made.     

A stochastic combustion model for fire plumes

The paper presents a new model for turbulent mixing and combustion of fuel jets and buoyant plumes. It approximates the lateral distributions of velocity, density, and species concentrations with top-hat profiles. It calculates the downstream evolution of the mixture p.d.f. by use of a coalescence-dispersion concept. The model involves only two empirical turbulence coefficients: an entrainment coefficient and a mixing parameter. The relatively simple mixing model leads to integral solutions for the combustion rate, plume width, and flame radius versus downstream position. The model permits both fuel and oxidant to exist at each height with the combustion rate controlled by internal mixing. At this time the model has not been tested against experiment. It is also possible that detailed numerical evaluations of its predictions will lead to further simplification of approximations needed for engineering applications.     

A multi-layer zone model for predicting fire behavior in a fire room

A multi-layer zone fire growth model is developed to predict the fire behavior in a single room. The fire room volume is divided into an arbitrary number of horizontal layers, in which the temperature and other physical properties are assumed to be uniform. The principal equations for each laminated horizontal layer are derived from the conservation equations of mass and energy. The implemented fire sub-models are introduced, including combustion, fluid flow and heat transfer models. Combined with these sub-models, the zone equations can be integrated with Runge–Kutta method for the gas temperature and species fractions of each layer for each time step. The results of the sample calculations are compared with the experiments conducted by Steckler and the University of Canterbury. In general, a good agreement between experimental and theoretical results is obtained.