Simulating a natural fire regime on an Atlantic coast barrier island complex in Florida, USA

The HFire fire regime model was used to simulate the natural fire regime (prior to European settlement) on Kennedy Space Center, Merritt Island National Wildlife Refuge, Canaveral National Seashore, and Cape Canaveral Air Force Station, Florida. Model simulations were run for 500 years and the model was parameterized using information generated from previously published empirical studies on these properties (e.g., lightning fire ignition frequencies and ignition seasonality). A mosaic pattern of frequent small fires dominated this fire regime with rare but extremely large fires occurring during dry La Niña periods. This simulated fire size distribution very closely matched the previously published fire size distribution for lightning ignitions on these properties. A sensitivity analysis was performed to establish which parameters were most influential and the range of variation surrounding empirically parameterized model output. Dead fuel moisture and wind speed had the largest influence on model outcome. A wide range of variance was observed surrounding the composite simulation with the least being 6% in total burn frequency and the greatest being 49% in total area burned. Because simulation modeling is the best option for fire regime reconstruction in many rapidly growing shrub dominated systems, these results will be of interest to scientists and fire managers for delineating the natural fire regime on these properties, the southeastern United States and other fire adapted shrub systems worldwide.     

局部蒸汽系统抑制熄灭油池火的实验研究

选取乙醇为燃料试样,进行不同条件下蒸汽灭火的全尺寸实验,研究了局部蒸汽系统抑制熄灭油池火的有效性及其影响因素,并探讨其灭火机理.实验结果表明:喷口直径是影响蒸汽灭火的关键因素,中等直径的喷口具有较好的灭火效率;喷口方位和燃料浓度也会影响灭火有效性;局部蒸汽系统的有效保护面积大于直接覆盖面积,对可燃气和氧气的稀释置换作用...     

New approach to calculate the probability of ignition

The probabilistic approach to the evaluation of fire hazard and the effectiveness of fire-precaution measures enables a rational response to the randomness of fire outbreaks. This article employs the statistical analysis methods to elucidate the causes for the ignition of fire on a random sample of industrial buildings in the Republic of Slovenia. The analyses are based on the Structural Equation Modeling (SEM), which is a well established and important statistical analysis technique in the fields of social science, biology, psychology and medicine, but hitherto rarely applied in safety research. The results of the study demonstrate that for the analyzed random sample of industrial buildings the frequency of fire outbreaks statistically significantly depends only on the presence and the probability of exposure to the heat sources (flames, sparks, and hot surfaces), but does not significantly depend on the available quantity of flammable materials within the industrial structure.     

建筑钢结构中钢构件的防火性能与抗火设计研究

首先有针对性地对当前国内外建筑钢结构中钢构件的防火性能与抗火设计研究背景做了较系统分析,接着,通过有限元程序,对当前应用非常广泛的半刚接门式刚架建筑在火灾高温下的受力性能进行了整体结构非线性分析。计算结果表明：随着温度的升高,钢构件节点的刚度不断下降,当节点的刚度下降到不能约束与其连接的梁柱构件时,结构将发生突然坍塌性...     

大空间建筑火灾中热烟气层发展规律的理论分析

对几类典型的大空间建筑火灾中热烟气层的发展规律进行了理论分析,并和文献中的实验结果进行了对比。理论分析表明热烟气层的发展速率除了与火源的功率和大空间的几何尺寸有关外,还取决于火羽流的种类。给出了轴对称火羽流、二维线性溢流和沿墙壁的二维线性火羽流情况下的热烟气层发展速率的表达式,对大空间建筑的火灾安全设计与灾害预测具有指导意义。     

Interpreting and using outputs from the Canadian Forest Fire Danger Rating System in research applications

Understanding and being able to predict forest fire occurrence, fire growth and fire intensity are important aspects of forest fire management. In Canada fire management agencies use the Canadian Forest Fire Danger Rating System (CFFDRS) to help predict these elements of forest fire activity. In this paper a review of the CFFDRS is presented with the main focus on understanding and interpreting Canadian Fire Weather Index (FWI) System outputs. The need to interpret the outputs of the FWI System with consideration to regional differences is emphasized and examples are shown of how the relationship between actual fuel moisture and the FWI System’s moisture codes vary from region to region. Examples are then shown of the relationship between fuel moisture and fire occurrence for both human- and lightning-caused fire for regions with different forest composition. The relationship between rate of spread, fuel consumption and the relative fire behaviour indices of the FWI System for different forest types is also discussed. The outputs of the CFFDRS are used every day across Canada by fire managers in every district, regional and provincial fire management office. The purpose of this review is to provide modellers with an understanding of this system and how its outputs can be interpreted. It is hoped that this review will expose statistical modellers and other researchers to some of the models used currently in forest fire management and encourage further research and development of models useful for understanding and managing forest fire activity.

Simulating dynamic and mixed-severity fire regimes: A process-based fire extension for LANDIS-II

Fire regimes result from reciprocal interactions between vegetation and fire that may be further affected by other disturbances, including climate, landform, and terrain. In this paper, we describe fire and fuel extensions for the forest landscape simulation model, LANDIS-II, that allow dynamic interactions among fire, vegetation, climate, and landscape structure, and incorporate realistic fire characteristics (shapes, distributions, and effects) that can vary within and between fire events. We demonstrate the capabilities of the new extensions using two case study examples with very different ecosystem characteristics: a boreal forest system from central Labrador, Canada, and a mixed conifer system from the Sierra Nevada Mountains (California, USA). In Labrador, comparison between the more complex dynamic fire extension and a classic fire simulator based on a simple fire size distribution showed little difference in terms of mean fire rotation and potential severity, but cumulative burn patterns created by the dynamic fire extension were more heterogeneous due to feedback between fuel types and fire behavior. Simulations in the Sierra Nevada indicated that burn patterns were responsive to topographic features, fuel types, and an extreme weather scenario, although the magnitude of responses depended on elevation. In both study areas, simulated fire size and resulting fire rotation intervals were moderately sensitive to parameters controlling the curvilinear response between fire spread and weather, as well as to the assumptions underlying the correlation between weather conditions and fire duration. Potential fire severity was more variable within the Sierra Nevada landscape and also was more sensitive to the correlation between weather conditions and fire duration. The fire modeling approach described here should be applicable to questions related to climate change and disturbance interactions, particularly within locations characterized by steep topography, where temporally or spatially dynamic vegetation significantly influences spread rates, where fire severity is variable, and where multiple disturbance types of varying severities are common.     

火灾扑救模拟演练DIS系统框架的研究

论述了分布式交互仿真 (DistributedInteractiveSimulation ,简称DIS)技术在火灾扑救模拟演练中的应用 ,给出其系统框架 ;详细描述了该DIS系统中的白方系统、蓝方系统和红方系统的具体组成功能部分 ;提出了实现这些功能的软件平台。最后给出了研究DIS在火灾扑救演练应用中的结论 ;指出未来的发展方向 ,强调了实际应用中可能出现的技术难点     

反应失控型火灾爆炸事故预测

介绍了一种预测反庆失控灾害的方法,通过实验测定容器的时间常数,预测能够引起反应失控的最低环境温度,发生反应失控时的危险温度,以及达到最大反应速度反需的时间,预测结果与实际情况具有良好的一致性。     

基于神经网络的火灾探测系统

本文提出了一种基于神经网络的火灾探测方法,其对火灾的各种状态进行了识别,提高了早期发现火灾的能力,实验结果表明,该方法在火灾自动探测中是一种十分有效的方法。