基于无人机技术的村落建筑群火灾蔓延模型的构建

摘 要：建筑信息匮乏、缺乏图纸是村落建筑群火灾防控面临的首要问题。针对传统的现场测绘工作量大、费用高、获取数据信息不精确等问题,在现场勘察获取典型单体建筑详细建模数据的基础上,采用无人机倾斜摄影技术获取村落建筑群地理信息数据,并建立村落建筑群火灾蔓延分析模型。进一步采用简化分析方法确定建筑群不同建筑起火后的火灾蔓延情况及火灾蔓延损失。最后以云南省某村落为研究对象,建立了该村落的火灾蔓延模型并分析了火灾蔓延风险。结果表明：该方法能有效获取村落建筑群火灾蔓延模型的建模数据,并为后续的火灾蔓延风险分析提供数据支持。     

A probabilistic model of fire spread with time effects

The paper outlines the principal elements of a probabilistic model that analyses the spread of fire in multi-compartment buildings with respect to time. The analysis uses a graph theoretic network and an event hierarchy to determine the probability of fire spreading to different locations. The probability of fire spreading between compartments is based on a comparison of the probability density functions of the expected fire resistance and the fire severity: failure being the condition that severity exceeds resistance. The model is designed as a comparative tool to compare the performance of different fire safety strategies by calculating a ‘cost index’ for each design, based on the probable extent of fire damage in the building. The analysis gives attention to the compatibility of fire resistance and fire severity, and their conversion in real time parameters.     

A probability-based Monte Carlo life-risk analysis model for fire emergencies

The paper proposes a probability-based Monte Carlo life-risk analysis model for fire emergencies. Based on the hazardous conditions in each compartment of a building and the evacuation path of each occupant, the model calculates the probabilities of injury and death determined by fractional effective doses due to heat and toxic gases, considers the probability of death due to fire spread, and produces the probabilities of injury and death for each occupant. Then these probabilities for all occupants are summed to give the total probabilities of injury and death in a Monte Carlo run, and statistics about the total probabilities of all Monte Carlo runs are produced for each fire scenario. According to the statistics and scenario composition, the expected risks of injury and death in the building are calculated. The model is applied to a life risk analysis of 6- and 12-storey apartment buildings. The results show that for these buildings, injuries and deaths are mainly limited to the rooms of fire origin and the effects of building area and the number of storeys on life risk are slight. The predictions for different layouts are in good agreement with the numbers of injuries and deaths given by Canadian and US statistics.     

真实火灾安全思想

本首先介绍了影响建筑物真实火灾严重程度的主要参数。同时简要介绍了建筑物真实防火评估的主要模型,并对每个模型重点介绍了所需要的数据以及产生的结果。本还介绍了欧洲研究项目“真实火灾安全思想”的主要成果和进展。本最后提出了一个创新的方法,即在结构抗火设计中考虑主动保护措施的影响。     

The modeling of fire spread in buildings by Bayesian network

Fire spread modeling is very important to fire safety engineering and to insurance industries involved in fire risk–cost analysis of buildings. In this paper, the Bayesian network is introduced. The directed acyclic graph of a fire spread model is presented. When the fire ignition location is known, the fire spread model based on the Bayesian network from the compartment of fire origin to another compartment can be built, and the probability of fire spread can be calculated by making use of the joint probability distribution of the Bayesian network. A specific application for an office building is presented for a case without sprinkler and one with sprinkler installed.     

Fire Risk Index for Historic Buildings

Fire protection engineers and preservation architects have long recognized the difficulty in applying building and fire codes to historic buildings. Small, older buildings of significant historic value need an efficient approach to performance-based evaluation. One technique that has gained acceptance is fire risk indexing. The Historic Fire Risk Index described in this paper uses a linear additive model of multiple attribute evaluation to produce a measure of relative fire risk. Weights are established to indicate the importance or significance of fire risk parameters. Then, for each specific historic structure, parameter grades, i.e., the amount or degree that a parameter is present, are determined from information collected in a detailed site survey. Fire risk is evaluated by the scalar product of the parameter weights and grades, producing a single numerical value representing the level of fire safety provided in the building. This is a more rational and more transparent method than the risk indexing systems currently published in model codes and standards.     

某高层建筑交易大厅性能化消防设计

基于某高层建筑交易大厅结构设计不符合消防规范的情况,结合结构特点及建筑内人员和消防设施的设置,提出性能化消防设计的思路。设定火灾场景,利用FDS模拟烟气运动,利用Pathfinder模拟人员疏散。结果表明,建筑消防设计能够满足火灾人员安全疏散的要求,为类似建筑消防设计提供参考。     

Analyses of the effects of cooling and fire spread on steel-framed buildings

An existing computer model capable of predicting the response of three-dimensional semi-rigid steel framed buildings, including continuous floor systems, at elevated temperatures has been extended to include the possibility of extensive strain reversal within the material constitutive relationship. This allows the behaviour in cooling and the effect o f fire spread on steel-framed buildings to be investigated. A number of examples are presented to give an indication of the likely effects of cooling behaviour within the analysis. An initial study has also been made into the structural effects of fire spread from a single ignition point into adjacent bays of a two-dimensional steel building frame. It is shown that some of the distortions caused by the fire are increased by progressive fire spread, as compared with simultaneous burning across the same range of compartments.     

Results from a cost-effective, decision-making model for building fire safety and protection

Presented in this paper are results obtained from the application of a cost-effective, decision-making system model that is used to appraise the level of fire safety and protection in office buildings. The effects of fire spread are calculated using two performance parameters; namely the fire-cost expectation and the expected risk to life. Designs in conformity with building code requirements and alternative building designs were considered.

Following consideration of various risk assessment procedures, it was decided to adopt a decision criterion which identifies alternative designs that are equivalent (in terms of expected risk to life) to code-specified designs, and which achieve such performance at a lower fire-cost expectation. On the basis of the decision criterion described herein, alternative designs were identified that are shown to be more cost-effective than designs in conformity with building codes. For the selected alternative designs, it was found that whilst both the fire-cost expectation and the capital cost of building construction are significantly lower, a similar level of life safety is maintained for occupants, compared with designs in conformity with building code requirements.

The system model can be used as a basis both to make immediate changes to current building code provisions, and for the introduction of a performance-based approach to design. In addition, the model can be used to identify those areas of research which have a major impact on the provision of cost-effective fire safety and protection provisions in buildings, and which accordingly are deserving of further investigation.     

基于BIM和元胞自动机的建筑#br# 火灾救援路径动态规划研究

建筑物发生火灾时,建筑物复杂的内部环境以及火灾的实时蔓延会给参与室内救援工作的消防员带来隐患甚至生命危险。为提高消防员建筑火灾室内救援效率,文章提出了基于BIM技术和元胞自动机的消防员救援路径动态规划系统。该系统中,创新性将BIM建筑模型与元胞自动机有机结合,建立了一种新型元胞自动机路径规划智慧模型,该模型利用场景分层和碰撞检测的方法自动识别建筑物的各种构件和内部环境,具有很高的智能性和普适性;在火场中添加动态障碍物模型和随机灾变火模型,并利用实时检测方法研究真实火场的动态性对消防员救援路径的实时影响,使消防员科学、高效地避开静态、动态障碍物并安全完成救援。使用该系统对一座单层大空间体育馆进行实例模拟,验证了该系统的适用性,为制定建筑火灾消防救援策略、实现高效精准救援以及智慧消防提供技术支持。     

用于模拟建筑火灾的风险分析模型CUrisk的开发和火灾案例分析

加拿大卡尔顿大学开发了火灾风险计算机模型CUrisk，用以评估四层木结构商品建筑的火灾安全设计。该模型包括系统模型和许多子模型。系统模型用于设定风险分析框架及控制子模型数据流。它还负责计算每个火灾场景的生命危险值。其他子模型包括火灾增长、烟气运动、边界失效火灾蔓延、人员反应和疏散以及建筑造价和经济损失等模型。利用子模型的输出数据，系统模型可计算三个决策参数：对生命的预期风险、对受伤情况的预期风险以及消防成本预期。这些参数是以可能的火灾场景及相关概率为基础的。文章简要介绍了CUrisk模型，并介绍了运用该模型对四层商业建筑所进行的多火灾场景风险分析的结果。     

基于故障树和贝叶斯网络的仓储类建筑火灾风险评估

以降低仓储类建筑火灾风险为目的,通过分析影响仓储类建筑火灾发生原因,分析顶层事件与基层事件之间自上而下的因果关系,建立故障树,并将其映射到贝叶斯网络中,通过计算得出事件发生的先验和后验概率,并将两者有效的联系起来。给出各事件发生的重要度指标有结构指标、概率指标和关键指标,分别进行定量分析指出仓储类建筑最有可能存在的风险。文章以2010—2020年十年期间仓储类建筑火灾发生案例为样本对本文提出的模型进行验证。检验结果:文章提出贝叶斯网络模型能够有效评估仓储类建筑风险等级并降低火灾事故发生。     

在建民用建筑火灾风险评估模型构建及应用

为客观评估在建民用建筑消防安全状况,构建并应用了一套实用性较强的火灾风险评估模型。分析在建民用建筑火灾特点以及致灾因素,构建在建民用建筑火灾风险综合评价体系。应用层次分析法确定各层级权重,利用模糊综合评价法进行综合评判,建立不同施工阶段在建民用建筑火灾风险评估模型。应用该模型对某在建民用建筑进行安全评估,指导火灾隐患整改,并对整改前后安全风险进行对比。评估结果表明,在建民用建筑最大风险因素为用火用电管理,此结论与实际状况较为相符。     

商店建筑一次火灾消防用水量的研究

商店建筑火灾扑救需要大量的消防用水,而现有规范对一次火灾消防用水量的规定远不能满足实际的要求.通过时大量商店建筑火灾案例的分析,确定了影响火场消防用水量的主要因素,并在此基础上建立了适合我国国情的消防用水量计算方法.最后依据该计算方法,对商店建筑周围消防给水设施的设置提出了建议.     

Simulation of Mass Fire-Spread in Urban Densely Built Areas Based on Irregular Coarse Cellular Automata

Mass fire-spread is a potential threat to some densely built urban areas by its devastating destructions. Especially in case of a large earthquake when multiple fires break out simultaneously, fire-spread hazard is likely to overwhelm fire-fighting capabilities and enlarge damage area. To explore fire-spread behavior and assess its damages, a simulation model of fire-spread in densely built urban areas is developed. Cellular Automata (CA) is a Bottom-up dynamics model that can reproduce a complicated phenomenon by setting up simple rules in a cell space. However, the traditional grid-based cells of CA are not suitable for modeling building-to-building fire-spread behavior. Therefore, an irregular coarse CA schema is proposed in this paper. Two sub-processes are involved urban mass fire-spread, i.e. (I) fire-developing in a single building and (II) fire-spread among buildings. When a fire is developing in a single building, the building will experience 5 fire stages along time, which become the states of cell. While fire spreads among buildings, there are 2 spread patterns: (I) short-range direct flame contact, radiation and convection spread and (II) long-range firebrand spotting spread. In relation to the 2 spread patterns, 2 sets of neighborhoods and rules of CA are formulated respectively. To verify the newly developed model, 100 times of individual random simulations for a real site fire-spread in Kobe City after Hanshin Earthquake (1995, Japan) are performed using an integrated GIS-CA-fire tool developed in the paper. Comparing the simulation results with the local observations, the general feature of fire-spread is found similar, and it is proved that the newly developed model is reliable to simulate urban fire-spread. Furthermore, based on the simulated results, a loss assessment model is formulated to calculate economic and life losses after fire-spread.     

基于未确知聚类的高层建筑防火风险评估系统

目前,高层建筑的火灾防控难题一直未得到有效解决。针对高层民用建筑防火能力风险评估中评估指标获取不科学、指标体系差异大的问题,运用典型火灾事件分析法,结合《建筑设计防火规范》,科学获取影响高层建筑防火能力的12个主要不确定性风险因素,构建了更为科学的高层建筑防火能力风险评估指标体系。在此基础上,引入未确知聚类理论,构建了基于未确知聚类的高层建筑防火能力风险评估模型。并以8栋典型高层民用建筑火灾风险数据为例,进行实证分析。研究成果表明,该风险评估系统可行有效。研究成果可为高层民用建筑火灾风险防控提供一种新的方法和途径。     

村寨建筑群火灾蔓延风险简化评估方法

针对火灾蔓延模拟工作量大、对防火构造考虑不充分等问题,结合云南勐卡老寨的火灾蔓延风险评估,提出了一种基于网络模型的村寨建筑群火灾蔓延简化分析方法。该方法通过现场勘查和简化计算确定建筑火灾向周边蔓延的路径,建立建筑群火灾蔓延网络的邻接矩阵,进一步结合网络节点遍历算法确定出不同火灾场景下的蔓延范围,在此基础上分析了不同火灾场景、不同区域的火灾蔓延风险。     

基于火灾场景的建筑物人员疏散研究

以南京某高校图书馆为例,依据“最不利影响”原则,充分考虑气象因子、建筑结构和可燃物等环境因子,利用建筑信息模型和时空分析模型模拟火灾产生因素的时空规律,构建火灾场景,剖析人员疏散时所能承受危险源的阈值,获取了4个季节建筑物内部的危险区域。结合室内路网模型和路径搜索算法,规划设计了人员疏散的生命安全保障路径,且与时间最短路径和距离最短路径进行对比分析,评估生命保障路径的疏散效果。通过上述研究,实现建筑物火灾的时空模拟和人员疏散的动态规划,为制定城市火灾应急响应的适应性措施提供理论基础和技术支持。     

Case studies in building smoke control

Smoke control systems for three buildings are described. Each of the buildings is low-rise three or four stories high. In each case a smoke control system using the HVAC system to limit or direct smoke migration from large portions of occupied space was used. Each of the buildings contained an interconnected space through the height of the building. One of the buildings uses a mall concept; the second, a modular concept of multiatria; and the third, a lobby concept. The results of smoke control tests for each building are presented. It was found that a building pressurization system with roof vents failed to satisfy the smoke control criteria of limiting smoke spread from one floor to another. The design was changed to provide exhaust fans at the roof, which were subsequently tested and performed satisfactorily. Tests of the lobby concept and of the multi-atria were satisfactory.