建筑火灾中人员疏散响应过程推理与评估模型研究

为了预防建筑火灾发生和减少火灾中人员的伤亡,利用消防大数据分析技术和贝叶斯网络分析方法,研究了建筑火灾发展过程及人员疏散响应过程的推理与动态评估方法。通过对建筑消防设施响应状态和火灾中人员心理和行为特征的分析,探讨了火灾阶段划分方法和人员疏散行为的分类,提出了火灾中人员伤亡的轨迹交叉理论,进而构建了基于贝叶斯网络的建筑火灾动态风险和人员疏散安全评估框架。分别探讨了建筑火灾发展、人员疏散响应等2 条研究主线的推理过程,探讨了疏散条件评估过程。研究表明,该模型可通过对建筑特征、消防设施状态信息以及人员响应信息等消防大数据进行融合,实现火灾中人员疏散响应过程推理与动态风险评估,从而提高建筑消防安全管理水平     

性能化防火设计中人员疏散问题安全性的一种评估方法

提出了一种在性能化防火设计中人员疏散问题安全性的评估方法，该方法是把火灾烟气运动规律、建筑物结构和人员疏散特点结合的研究成果，分别计算建筑物中不同单元内的火灾荷载阚值，在发生火灾时，烟气达到危险状态的时间和人员疏散所用的时间，比较这两个时间来确定建筑物防火设计是否达到性能化防火中人员安全疏散的要求。该方法从控制建筑物内火灾荷载的多少和建筑物的结构出发，在现行的计算软件的基础上．可用于实际的火灾安全工程设计和火灾安全咨询。     

宾馆火灾逃生调查

通过对5起中小型宾馆火灾中的55名人员的逃生问卷调查，了解火灾现场及逃生人员的基本概况、火灾发生时人员所处的初始环境状态、火灾逃生行为反应及逃生途中的信息。研究表明，中小型宾馆类建筑在火灾时，服务人员和安全保卫人员能忠于职守，有效组织引导旅客疏散，是宾馆安全疏散的基本保障；疏散楼梯分隔使用，是造成火灾重大伤亡事故的主要原因；疏散标志失效，加重了火灾伤亡；疏散楼梯被封堵，加重了灾情。分析总结的火灾逃生经验，对于中小型宾馆类建筑逃生设计提供了可以借鉴的资料。     

A probabilistic occupant response model for fire emergencies

The present paper describes a probabilistic occupant response model for fire emergencies, which is integrated into a fire risk analysis model called CUrisk. Based on the PIA process, i.e., Perception, Interpretation and Action, the occupant response model predicts the probabilities of occupants perceiving fire signals due to direct perception, receiving fire alarms due to the activation of local alarms, sprinklers, the central alarm and the voice alarm, being warned by the other occupants and fire department, and taking actions including pulling the fire alarm, warning other occupants, calling the fire department, and commencing evacuation. The occupant response model is applied to predict the probabilities of evacuation initiation for a number of scenarios that consider combinations of fire detection and alarm systems for a mid-rise building. The results of the model show that asleep occupants need much longer response time to start evacuating and have lower probabilities of starting evacuation than awake occupants, which are consistent with what is observed in reality. Additionally, fire protection systems with only local alarms and only sprinklers connected to the central alarm can be improved significantly with systems with smoke detectors alone or combined with sprinklers connected to a central alarm, which result in higher probabilities of evacuation initiation with shorter delay times.     

Public Perceptions of High-rise Building Emergency Evacuation Preparedness

In light of the events of September 11, 2001, a concern in the fire safety community is that the public attitudes toward emergency evacuation procedures and preparedness may have changed and that current assumptions about occupant behavior may no longer be valid. In 2006, a survey of high-rise building occupants was conducted to explore their knowledge of high-rise building safety and emergency evacuation procedures and their attitudes and perceptions about high-rise safety and emergency evacuation procedures. Some 244 residential building occupants in Chicago, New York City and San Francisco and 228 commercial building occupants in Boston, Chicago, Detroit, Houston, Los Angeles, Miami, and Philadelphia were surveyed. The study revealed that the events of September 11, 2001 have heightened occupants concerns about safety in high-rise buildings. Eight in ten commercial building respondents participated in a fire drill in the last year, compared to 18% of residential building respondents. Among both survey respondents, the most frequent top-of-mind suggestion to building management to improve safety was “more fire drills.” Almost all occupants know where the fire exits are. And, keeping with conventional wisdom, most occupants believe using elevators is unsafe during a fire, however, 28% also believe that going to the roof is a possible alternative to using the stairs. These findings support the need for continued public education about emergency evacuations procedures in high-rise buildings.

大空间建筑人员疏散问题的性能化设计

通过对大空间建筑火灾特性的研究,结合目前许多大空间建筑的消防设计无法满足现有规范要求的现实问题,分析大空间建筑中火灾状态下人员的具体情况,结合建筑实际情况采用性能化方法,解决大空间、大体量建筑的人员安全疏散的问题,并列举了工程实例进行说明.     

Predicting Human Behavior During Fires

Evacuation models, including engineering hand calculations and computational tools, are used to calculate the time it takes to evacuate a building, which can then be used in an engineering safety analysis. However, there is a lack of available data and theory on occupant behavior for use by evacuation models to estimate evacuation time results and their uncertainty. In lieu of data and theory, evacuation models (and users) make assumptions and simplifications about occupant behavior, which can inappropriately characterize the time it actually takes to evacuate a building. The purpose of this paper is to reevaluate current egress modeling techniques and advocate for the inclusion of a robust, comprehensive, and validated conceptual model of occupant behavior during building fires. This paper begins by describing the current state of evacuation modeling of human behavior in fires and identifying gaps in current behavioral prediction techniques. The second part of the paper outlines a model of occupant decision-making during emergencies, referred to as the protective action decision model (PADM); a theory that can serve as the basis for the development of a conceptual model of occupant decision-making and behavior during the pre-evacuation period of building fires. The PADM provides a framework that describes the decision-making steps that influence protective actions taken in response to natural and technological disasters—including perceiving information, paying attention to the information, comprehending the information, establishing the nature of the threat, personalizing the risk, searching for potential protective actions and choosing one of these, and then performing that action. The paper ends with a discussion of how to adapt and expand the PADM in order to develop a predictive conceptual model of the pre-evacuation period for use by computer evacuation models.     

Movement on Stairs During Building Evacuations

The time that it takes an occupant population to reach safety when descending a stairwell during building evacuations is typically estimated by measureable engineering variables such as stair geometry, speed, density, and pre-observation delay. In turn, engineering models of building evacuation use these variables to predict the performance of egress systems for building design, emergency planning, or event reconstruction. As part of a program to better understand occupant movement and behavior during building emergencies, the Engineering Laboratory at the National Institute of Standards and Technology has collected stair movement data during fire drill evacuations of office and residential buildings. These data collections are intended to provide a better understanding of this principal building egress feature and develop a technical foundation for future codes and standards requirements. Fire drill evacuation data has been collected in 14 buildings (11 office buildings and 3 residential buildings) ranging from six to 62 stories in height that included a range of stair widths and occupant densities. A total of more than 22,000 individual measurements are included in the data set. This paper provides details of the data collected and an analysis of the data. The intention is to better understand movement during stairwell evacuations and provide data to test the predictive capability of building egress models. While mean and standard deviation of the distribution of movement speeds in the current study of 0.44 m/s ± 0.19 m/s are observed to be quite similar to the range of values in previous studies, mean local movement speeds as occupants traverse down the stairs are seen to vary widely within a given stairwell, ranging from 0.10 m/s ± 0.008 m/s to 1.7 m/s ± 0.13 m/s. These data provide confirmation of the adequacy of existing literature values typically used for occupant movement speeds and provide updated data for use in egress modeling or other engineering calculations.     

Modelling the evacuation of a high-rise office building in Istanbul

The use of advanced computer models for the analysis of evacuation problems in buildings under fire conditions or terrorist attacks has become an increasingly important research area. Until recently, most safety considerations regarding the evacuation of a building are taken on the basis of some deterministic rules prescribed in fire codes. However, these rules and design principles may not be sufficient to explain the complex interaction between a vast numbers of variables affecting the evacuation process. Also, the characteristics of a fire can differ from building to building and occupants can demonstrate distinctly different behavioural patterns and physiological characteristics. As a result, potential weaknesses, particular to the investigated building, can go unnoticed which, in turn, may result in disastrous consequences during an emergency. The study concentrates on two issues: firstly, what methodology should be pursued to accurately model an evacuation problem and the derivation and extent of parameters needed to fully utilise the potentials of the advanced computer models, in this case, the buildingEXODUS; the second issue is an investigation of the evacuation behaviour in a high-rise office building in Istanbul. It is found that exit knowledge and the preferences of occupants can severely slow down the evacuation process. Fires closer to the ground floor increase the death toll significantly. Failure in the activation of the sprinkler system or the absence of the system altogether can have disastrous effects on the loss of life.     

A Risk-Based Method of Deriving Design Fires for Evacuation Safety in Buildings

This article presents a risk-based method for building fire safety design. Because the design fire is the most critical aspect of a building fire safety design, this article uses reliability theory to derive design fires from the fire risk acceptance criteria. The fire scenarios are modeled by an event tree, where different fire protection systems are presented as pivotal events. The number of casualties is estimated by the occupant number and the probability that an untenable condition is reached before occupants evacuate to a safe location. Using the probability and consequence of each fire scenario, the expected risk to life is used to integrate the fire risk acceptance criteria into the determination of the target reliability index. A global optimization method is then applied to the reliability index to obtain the design fires for each scenario. A case study was conducted to demonstrate an application of this proposed method.     

A Post-fire Survey on the Pre-evacuation Human Behavior

A delay in the pre-evacuation reaction may be one of the reasons causing occupants to be ‘trapped’ in a dangerous zone. Under fire situations, people are found to behave differently in that some may start evacuation immediately, some may ignore the fire alarms and engage in their activities and some others may participate in fighting the fire. These behavioral reaction patterns are influenced by some factors, such as occupant characteristics, building characteristics and fire characteristics. The purpose of this study is to investigate the pre-evacuation behavior of occupants under fire and explore the associations between these factors and the human behavior. To obtain the human behavioral information in real fire, a post-fire survey for a multi-storey office building fire in a major city in Mainland China was carried out with the assistance of local fire professionals. Some of the possible factors that might influence the occupants’ actions at recognitions and response stage were examined. It was reckoned that the behavioral reaction at recognition and response stage was mainly dependent on the human characteristics and building characteristics except the fire characteristics. The results also implied that pre-evacuation time was typically influenced by the occupant characteristics.     

Human behavior in fires—a review of research in the United Kingdom

In recent years research into human behavior in fires has been carried out in several countries for improving provisions for life safety currently prescribed in firesafety codes. This technical note reviews briefly the findings of human behavior studies in the United Kingdom with particular reference to buildings with a large number of people at risk. According to one of the main conclusions of this paper, for successful evacuation, early detection should be followed by timely and convincing communication to building occupants information about the existence, location, and spread of fire. This can be achieved by computer-based informative fire warning systems, which is the subject matter of another technical note.     

Modelling total evacuation strategies for high-rise buildings

This paper focuses on the use of egress models to assess the optimal strategy in the case of total evacuation in high-rise buildings. The model case study consists of two identical twin towers linked with two sky-bridges at different heights. Each tower is a 50-floor office building. The use of either horizontal or vertical egress components or a combination of them is simulated. The egress components under consideration are stairs (either 2 or 3 stairs), occupant evacuation elevators, service elevators (available or not for the evacuation of the occupants), transfer floors and sky-bridges. Seven different evacuation strategies have been tested which consider the total evacuation of a single tower. The evacuation scenarios have been simulated with a continuous spatial representation evacuation model (Pathfinder). In order to perform a cross validation of the model results, two strategies involving the evacuation using stairs or occupant evacuation elevators have also been simulated using a fine network model (STEPS). Results refer to the analysis of total evacuation times. The simulation work highlights the assumptions required to represent the possible behaviours of the occupants in order to qualitatively rank the strategies. The lowest evacuation times are obtained simulating strategies involving the sole use of occupant evacuation elevators and the combined use of transfer floors and sky-bridges. This study suggests that the effectiveness of evacuation strategies involving the combination of stairs and elevators significantly decreases in high-rise buildings if they are not combined with appropriate messaging/signage to guide occupants in their behaviours.     

机械停车库防火性能化没计案例分析

针对北京某医院宿舍楼配套地下机械停车库工程存在的主要消防设计问题进行分析研究,确定消防设计安全目标,进而对火灾场景、火灾规模、烟气控制和人员安全疏散等多方面问题进行了深入研究和探讨,提出适用于该项目的消防安全策略、评估方法和模型,为类似工程的实施提供了一定的借鉴经验。     

A system for the analysis of fire reports, and its application to health care buildings

A system of analysing fire reports is described, which evaluates the success of failure of the building elements and occupants in mitigating the consequencies of ignition. To handle fire reports a method of categorising the fire growth sequence in terms of both flame and smoke spread was developed. Three tactics (ignition prevention, fire control and evacuation) which mitigate the consequencies of ignition were derived from a hierarchy of fire safety and their interrelationship was examined. The application of this analysis method to two sets of the reports of fires in health buildings was undertaken and its success validated the proposed methodology.     

高层建筑消防隐患分析与防火监督策略研究

文章通过文献资料法进行分析,得出相应的结论:高层建筑火灾具有可燃物多、蔓延速度快、人员疏散困难等特点,存在消防设计与施工不规范、消防安全管理意识薄弱、消防安全检查工作落实不到位等消防隐患,需要围绕消防设计与施工管理、消防安全教育、消防安全检查制度、消防远程监管系统等方面工作,做好高层建筑防火监督工作。     

ESM: a building evacuation simulation model

Evacuation simulation model (ESM) is a tool for simulating evacuation in building fires. This model can simulate the optimized evacuation, the phased evacuation and the “Evacuability”, which is defined as the percentage of successful evacuees to the total occupants in the building evaluated. It is also capable of tracing the occupants in every compartment of the building at every time step, and describing the values of passages between compartments during simulation. ESM is a network model consisting of stocks connected by flows. The stocks stand for the compartments, such as rooms, corridors, hallways, stairs, landings and lobbies. The flows represent the passages between compartments. Using ESM, the evacuation safety of buildings can be evaluated.     

关于借用相邻防火分区疏散宽度与距离的分析

安全疏散是建筑防火的重要内容,各防火分区的疏散设施首先要能满足本分区内人员的安全疏散需要。实际工程中存在因使用功能、平面布置等,部分防火分区内的疏散设施不能独立满足本分区安全疏散,需借用相邻防火分区的情况。分析了借用相邻防火分区疏散存在的问题,并通过数值模拟计算进行了验证,同时提出了完善相应技术要求的建议。     

超高层建筑消防安全对策案例分析

总结近年来发生的超高层建筑重大火灾,分析其存在的技术难题。结合参与的国内超高层建筑消防设计与性能化论证项目,详细论述广州市等大城市在超高层建筑防火功能分区设定与性能化审核、电梯在人员疏散中的应用、超高层建筑的重力给水等方面的技术解决策略,并根据整体消防安全理念,提出超高层建筑火灾防治技术发展的新方向。