Risk of fire emergency evacuation in complex construction sites: Integration of 4D-BIM,social force modeling,and fire quantitative risk assessment

Construction industry is claimed to be the fourth most dangerous sector by number of fatalities. In complex construction sites, emergency evacuation risk assessment is a challenging task due to their ever-changing nature. This study developed a model to analyze the risk of fire emergency occurrence, and risks which are associated with evacuation performance (in response to that emergency) through an integrated approach in complex construction sites. To analyze the evacuation scenarios more realistically, we utilized Social Force Model (SFM) simulation engine. Using SFM for simulating the evacuation of complex construction sites has not been adequately addressed in the literature. Microscopically simulating the evacuation scenarios for all workdays of the studied complex project required high computation efforts. To tackle this computation challenge, a parallel computing technique was coupled with SFM simulation engine. More importantly, in this paper site’s evacuation performance was evaluated multi-objectively considering evacuation time and evacuation safety. The construction site’s emergency scenarios were modeled by 4D-BIM, potential for trigger fire emergency was determined by a fire ignition Quantitative Risk Assessment (QRA) module, and site evacuation was simulated by SFM simulation engine. The proposed framework handled the collaboration of 4D-BIM, fire QRA module, and SFM engine. This research study benefited from data driven from a real mega project. The findings demonstrated that analyzing the risk of evacuation through an integrated approach by the proposed model could render more realistic results. The results also provided the project managers with a reliable safety decision-making support.     

建筑物火灾中的人群疏散研究

建筑物火灾是我国频发的安全事故,所以应研究建筑物火灾人群安全疏散问题。由于在建筑物火灾中,人群疏散时出现拥堵,存在不安全因素,造成人员伤亡。针对在现有的研究中未考虑人员行为的影响,提出了智能体(Agent)的人群行为建模技术在建筑物火灾中的人群疏散仿真中的应用方法。仿真结果显示基于Agent的行为模型可以仿真出人员特性及决策过程对人群疏散的影响,弥补现有的人群疏散模型的不足。仿真结果证明,Agent的行为建模技术具有仿真火灾全过程中人员疏散行为的功能,适用于建筑物火灾中的人群优化疏散策略。     

A BIM-based visualization and warning system for fire rescue

Structural fires are common disasters. In Taiwan, about 100 firefighters die during fire rescues each year, primarily because they are unaware of the causes of the fire and unfamiliar with the location’s environment. Meanwhile, evacuees often die in the panic of evacuation. To solve these problems, this research proposes a Building Information Modeling (BIM)-based visualization and warning system for fire rescue. A fire dynamics simulator (FDS) simulates various conditions of structural fires in conjunction with the visualization and integration properties of BIM, and the simulation results for temperature, carbon monoxide, and visibility can be integrated and presented in the BIM model for briefing purposes before rescue operations begin. In addition, this research integrates Internet of Things (IoT) technology, which allows real-time situation monitoring. In the event of a fire, the BIM model will immediately display the situation of the fire scene and control LED escape route pointers according to the actual situation. The primary objective of this system is to provide useful information to firefighters such that they can be aware of the fire’s environment and create an effective rescue plan. Moreover, the automated LED escape route pointer may assist the building’s occupants to escape, provide the firefighters with valuable information, and allow them quickly to discover hazards so that the number of casualties can be minimized.     

Temperature heterogeneity during travelling fire on experimental building

In order to follow modern trends in contemporary building architecture which is moving off the limits of current fire design models, assumption of homogeneous temperature conditions used for structural fire analysis needs to be validated. In this paper it is described, how temperature distribution in a medium-size fire compartment has been investigated experimentally by conducting fire test in two-storey experimental building in September 2011 in the Czech Republic. In the upper floor, a scenario of travelling fire was prepared. It has been observed that as flames were spreading across the compartment, considerable temperature gradients appeared. Numerical simulation of the travelling fire test conducted using FDS (Fire Dynamics Simulator) has been compared with simulation of compartment fire under uniform temperature conditions to highlight the potential impact of the gas temperature heterogeneity on structural behaviour. The temperature measurements from the fire test have been used for validation of the numerical simulation of travelling fire. The fire test has provided important data for design model of travelling fire and shown that its impact on structural behaviour is not in agreement with the assumption of homogenous temperature conditions.     

Agent-based simulation of affordance-based human behaviors in emergency evacuation

Complex cognitive processes corresponding to human control behaviors cannot be easily inferred using (1) a logical rule-based model, (2) a statistical model, or (3) an analytical predictive model. Predicting human behaviors in complex and uncertain environments like emergency evacuation is considered almost impossible (at least NP hard) in systems theory. In this paper, we explore simulating human behaviors using affordance-based finite state automata (FSA) modeling, based on the ecological concept of affordance theory. To this end, we introduce the conceptual and generic framework of affordance-based human behavior simulation developed through our previous work. Following the generic framework, formal simulation models of affordance-based human behaviors are developed, especially for emergency evacuation, to mimic perception-based dynamic human actions interacting with emergent environmental changes, such as fire. A “warehouse fire evacuation” case is used to demonstrate the applicability of the proposed framework. The human action planning algorithms in the simulation model are developed and implemented using the Adjusted Floor Field Indicators, which represent not only the evacuee’s prior knowledge of the floor layout but the perceivable information about dynamic environmental changes. The results of our simulation study verify that the proposed framework accurately simulates human fire evacuation behavior. The proposed framework is expected to capture the natural manner in which humans behave in emergency evacuation and enhance the simulation fidelity of analyses and predictions of perceptual human behaviors/responses in the systems by incorporating cognitive intent into human behavior simulations.     

基于FDS和元胞自动机动态耦合的火灾疏散模型

为研究火灾场景下温度、烟气和CO浓度等灾害因子对疏散的影响,建立基于FDS和元胞自动机动态耦合的火灾疏散模型。将FDS的网格和元胞自动机的元胞一一对应,将由FDS运行得到的灾害数据通过Python等技术手段实时加载到元胞中,使灾害数据持续影响行人转移概率,从而实现灾害和疏散的动态耦合;以单层教学楼作为仿真场景进行模拟分析,对火源位置和热释放速率等因素进行讨论,得出这些因素对行人疏散进程的影响规律;将模型与传统软件和同类方案进行对比。研究表明,火灾导致的高温和烟气会影响行人对疏散路径和安全出口的选择;热释放速率越大,行人越早处于危险状态,同时处于危险状态的行人也越多;该模型相比传统疏散软件不仅能考虑火灾产生的致灾因子对行人疏散的动态影响,还能确定行人最早处于危险状态的位置和时间,并用可视化的方式表现出来。     

可视化隧道火灾仿真系统开发

FDS(Fire Dynamics Simulator)作为一种高效的火灾模拟软件,前处理操作集中在一个data文本文件中,需要操作人员熟知各输入数据参数的格式,而且在对非规则边界隧道进行火灾模拟时有很大局限性.为了简化操作,实现非规则边界隧道的建模,通过应用一种由矩形方块拟合圆弧墙或斜线墙的算法来实现非规则边界隧道建模,并通过实现与DXF文件的接口来简化建模过程,大大改善了软件的可操作性能;最后给出了用该软件对非矩形边界隧道火灾的数值模拟应用.通过编制可视化软件并集成了非规则边界隧道建模算法,简化了隧道火灾仿真的建模操作,可以很好地解决隧道火灾仿真问题.     

Integration of Smoke Effect and Blind Evacuation Strategy (SEBES) within fire evacuation simulation

Many fire evacuation models have been proposed in recent years to better simulate such as an emergency situation. However most of them do not respect a recommendation of fire evacuation experts regarding the fact that evacuees should follow the boundaries of obstacles or wall to find the exits when their visibility is limited by smoke. This paper presents an agent-based evacuation model with Smoke Effect and Blind Evacuation Strategy (SEBES) which respects that recommendation by integrating a model of smoke diffusion and its effect on the evacuee’s visibility, speed, and evacuation strategy. The implementation of this model enables us to optimise the evacuation strategies taking into account the level of visibility. The obtained simulation results on a realistic model of the Metro supermarket of Hanoi confirm the important impact of smoke effect and blind evacuation strategy on the number of casualties.     

Incorporation of BIM-based probabilistic non-structural damage assessment into agent-based post-earthquake evacuation simulation

Earthquakes can cause severe damage to structural and non-structural elements of buildings; consequently, they pose high risks to human lives. To mitigate such risks, attention has been paid to enhancing the indoor environment for increased building safety. Yet little effort has been made to assess a building occupants' evacuation behaviors in response to damage to the indoor environment. This paper addresses this issue with a novel simulation framework that couples human behaviors with changes to the indoor building environment during post-earthquake evacuation. In particular, we present a building information modelling (BIM)-based prototype that simulates seismic damage to the non-structural indoor elements and visualizes its impacts on evacuation using a color-coded heat map. The simulated damage is then used as input to an agent-based model for post-earthquake evacuation. Using a probabilistic method to assess the non-structural elements' damage states, we are able to evaluate the impact of indoor damage on the evacuation process. We performed a trial of our prototype for a hypothetical earthquake in an educational building. The results revealed how the average evacuation time would increase as the earthquake intensity increases (from 38.6 s for the no-damage scenario to 122.9 for the highest-damage scenario). The proposed prototype has the potential to be joined with other tools, such as finite-element-based simulation, to incorporate structural analysis as well. Planners and designers can explicitly use our model's output to analyze the post-earthquake evacuation with the indoor non-structural damage to assess different building design geometries that increase the chances of a suitable evacuation process.     

隧道用火灾报警系统技术

公路等各种隧道的火灾探测非常重要,关系到交通以及人民生命、社会财产的安全。传统的火灾探测技术误报和漏报率较高。目前火灾探测技术有了较大的进步,文章介绍几种新的火灾探测技术。     

Investigating the influence of route turning angle on compliance behaviors and evacuation performance in a virtual-reality-based experiment

Route turning is one of the most essential and ubiquitous physical features in the complex building environment. Under the influence of route turning, evacuees’ approaching perspective to an emergency sign could vary, affecting their information perception and behavioral compliance during the evacuation. Although conventional simulation methods assess the effectiveness of the emergency sign in the visible region, they fail to consider evacuees’ wayfinding behaviors and interaction with the emergency sign. It remains unclear whether the route turning angle affects evacuees’ compliance for detecting and responding to the emergency sign. To investigate such an influence, a virtual-reality-based method for assessing human evacuation behaviors in building fire evacuations was proposed. In this study, two evacuation routes with different turning angles in a shopping mall were created and implemented in a virtual-reality environment, and 67 subjects participated in the immersive virtual-reality-based experiment. All participants took the two routes to find the nearest exit for evacuation in a fire event, aiming to evaluate the effect of the route turning angle on the evacuation process. The participants were asked to complete a questionnaire at the end of the experiment. Next, statistical analyses were conducted on evacuation results, information perception, and evacuation performance of the participants. The results indicated the route turning angle significantly affected participants' behavioral compliance with emergency signs. The results also suggested the route turning angle was influential on participants’ information perception and evacuation performance. Besides, a significant effect on rotation change, wayfinding pause, and speed deviation were observed. This study validates the effectiveness of investigating evacuees’ interaction with emergency signs using virtual-reality technology and has potential implications for complex building path planning and evacuation simulation modeling.     

基于多智能体的森林火灾人员疏散仿真

森林火灾发生时, 对在林火蔓延过程中灾区人员疏散进行建模与仿真能够检查疏散方案是否合理, 从而为合理救灾提供指导意义. 目前对人员疏散模拟与仿真虽然有很多研究, 但对于森林火灾下人员疏散尚缺乏合适的仿真模型, 给科学救助决策带来很大困难. 为此, 提出将多智能体引入森林火灾蔓延及灾区人员疏散模型研究中, 并借助于Repast平台进行仿真, 实验结果表明本文方法能够为森林火灾人员疏散模拟与仿真提供正确的解决途径.     

分区域变尺度网格的社区火灾场景数值仿真

目的 火灾场景数值仿真对消防救援和应急疏散具有重要意义。火灾场景仿真需要对室内外地物及环境进行精细建模和大量数值计算,而传统地图和空间分析无法满足日趋复杂的建筑物消防场景表达。为此本文基于室内外地图研究基础,构建面向社区安全的火灾场景数值仿真模型。方法 通过传统制图技术建立社区地物分布模型,利用室内制图技术建立建筑物内部场景,利用3维建模技术重建社区室内外3维模型,引入火灾数值模拟方程进行仿真计算。根据社区建筑物分布和其内部结构复杂程度的差异,提出分区域变尺度的网格划分方法,以提高计算效率。结果 通过对红树湾社区进行"精细"、"粗糙"和"分区域变尺度"3种不同方法的仿真实验,分析火灾模型的计算速度、温度场及烟气扩散情况。与精细网格方法相比,分区域变尺度方法和粗糙网格方法的计算速度是其8倍和24倍,烟气最低能见度误差为2 m和13.5 m,分区域变尺度方法相较于粗糙网格方法与精细网格方法的温度变化曲线更加吻合。分区域变尺度方法的模拟精度更接近于精细网格方法,同时效率得到提升。结论 本文提出的火灾场景仿真模型将室内制图应用扩展到社区消防研究,实验结果表明,所提出的分区域变尺度网格划分方法能够在保证数值模拟精度的前提下提高仿真效率,具有重要的应用价值。     

A hybrid hierarchical agent-based simulation approach for buildings indoor layout evaluation based on the post-earthquake evacuation

In the aftermath of severe earthquakes, building occupants evacuation behaviour is a vital indicator of the performance of an indoor building design. However, earthquake evacuation has been systematically neglected in the current building design practice. Arguably, one of the primary reasons for this is that post-earthquake evacuation behaviour is complex and distinct from all other types of evacuation behaviours such as fire. Thus, a comprehensive approach to considering the integration of human evacuation behaviour and a building's indoor layout design, mainly focused on non-structural damage, has been consistently neglected in the literature. In this paper, a hierarchical hybrid Agent-Based Model (ABM) framework integrated with a Cellular Automata (CA) and a 2D Building Information Model (BIM) damage visualisation to consider an approximation of non-structural damage has been developed. The proposed ABM incorporates learning mechanisms and human psychological aspects influencing evacuees' utility during the navigation process. The proposed approach was verified by comparing the results to previous real-life post-earthquake evacuation data and a “model to model” comparison of results from the existing relevant studies. The model prototype was successfully tested to simulate the pedestrian evacuation process from one floor of the new engineering building at The University of Auckland, New Zealand. The proposed simulation approach has been carried out for two different internal layout design alternatives where five population sizes are evacuated through different scenarios. The outputs from this study can be used to improve the design's compatibility of the building's indoor layout with the occupants' post-earthquake evacuation behaviour.     

奥运场馆火灾分析中软件集成方法的研究

根据奥运场馆防火安会分析的需要，研究了火灾模拟和结构分析一体化系统的集成方法，并开发了结构火灾模拟分析系统——SFSAS系统，该系统基于AutoCAD图形平台进行二次开发，通过快速建模系统和前处理模块、模型转换模块、数据共享模块以及后处理模块，将FDS和ANSYS集成，形成一个一体化拿过程的分析系统，利用该系统对奥运场馆进行火灾安全分析，可以为场馆结构的防火设计和结构安全评估提供依据。     

FDS中非矩形边界隧道的自动建模

FDS(Fire Dynamics Simulator)作为一种高效的火灾模拟软件,在对非长方体隧道进行火灾模拟时有很大局限性。文章提出了一种用矩形方块来拟合圆弧墙或斜线墙的算法;通过编制可视化软件来自动生成FDS输入数据,解决了在FDS中对非矩形边界隧道的建模问题;最后给出了一个在FDS中对非矩形边界隧道火灾的数值模拟实例,验证了算法的可行性。     

虚拟现实技术在火灾领域中的应用

该文从工程应用的角度较为详细地介绍了组建火灾虚拟现实系统过程中硬件选型、软件设计、多用户“参与”的实现和虚拟环境中火灾模型的选取原则等 ,并建立了基于微型计算机、WindowsNT等软硬件环境下火灾虚拟现实系统结构     

基于元胞自动机模型的人员疏散仿真研究

公共安全是经济发展和社会稳定的基础。近年来由于火灾、地震、恐怖活动等突发因素诱发的公共场所人员安全事故屡见报道,在公共场所的安全设计中,安全疏散性能已成为至关重要的因素。为解决上述问题,人员疏散的计算机仿真对提高公共场所的安全疏散性能具有重要意义。对于出口距离最近的原则建立人员疏散的二维随机元胞自动机模型,其中考虑人员绕行的影响,并利用Matlab软件编写了疏散过程的程序,对大空间疏散人群进了仿真,得到了人员疏散基本规律及疏散时间。研究表明:考虑人员绕行的模型更能体现真实的疏散情景。     

Behavioral,data-driven,agent-based evacuation simulation for building safety design using machine learning and discrete choice models

To improve occupant safety during building emergencies, evacuation simulations have been widely used for building safety design. Since occupant behavior is a determining factor for the outcome of building emergencies, accurately capturing how occupants make decisions and integrating occupants’ decision-making processes in evacuation simulations is important. In this study, based on the results of fire evacuation experiments in a virtual metro station, how different social (crowd flow) and environmental (visual access and vertical movement) factors would affect individuals’ wayfinding behavior was predicted using machine learning and discrete choice models. The trained models were further employed in agent-based evacuation simulations to examine crowd evacuation performance under different building design scenarios. Both the machine learning and discrete choice models could accurately predict individuals’ directional choices during emergency evacuations. Different building attributes could collectively influence occupant behavior, leading to distinct exit choices and evacuation times. While both the trained machine learning and discrete choice models generated similar results, the discrete choice model had better interpretability. Moreover, by comparing the trained models in this study with a model developed in a prior study, it was found that agents had significantly distinct responses to different building designs. Critical factors (e.g., type and size of buildings, occupants’ familiarity with the building) for the applicability of evacuation models were identified. Furthermore, recommendations were provided for future research that aims at employing evacuation simulations for building design evaluation and optimization.     

井下火灾中逃生人员健康度评价模型

在井下火灾逃生过程中,矿井人员在有害环境影响下的身体状况对其逃生的成功与否具有决定性作用。提出了井下火灾中逃生人员健康度的概念,综合分析了热辐射、有毒气体、烟尘颗粒及缺氧等危害因素对井下人员健康度的影响。基于模糊综合评价方法,建立了上述危害因素对逃生人员健康度的影响评价模型,并建立了人员在逃生过程中的健康度的动态评价方法。利用火灾模拟软件FDS对井下火灾实例进行了简单模拟,模拟结果验证了该评价方法的实用性和有效性。人员健康度能够对复杂灾害环境中的逃生人员状态进行综合评价,为井下灾害中的逃生路径决策提供量化的标准。