Width Of Exits Research Articles

Comparative Study of SFPE and Steering Modes in Pathfinder to Optimise Evacuation Routes

This paper investigates the possibilities of using an agent-based evacuation model to analyse the formation of queues at the exits of enclosed spaces and the evacuation process of people. The aim is to investigate how the density of people in a crowd affects the safe movement of people and how the width, number, and location of exits affect evacuation time. The analysis was carried out using the Pathfinder evacuation model, which provides two modes to simulate the movement of people: steering and SFPE. An enclosed space of 20 m × 30 m was investigated. First, the differences between the modes of the evacuation model to simulate the movement of people were compared. Then, the steering mode with limited door flow was set and the effect of the width, number, and location of the exits with a total width of 4 m on the evacuation time was investigated. The results of this study highlight differences in the simulation of the movement of people according to the different modes and provide valuable information for the design of safe escape routes. Proper design of escape routes can prevent an adverse situation that could arise when evacuating a large number of people.

A Case Study on the Evacuation of People during a Fire in the Workshop of a Large Factory

A workshop, as a crowded place, is quite easy to cause serious casualties and economic losses once there is a fire. In this paper, Pathfinder software was used to simulate fire emergency evacuation in a workshop of a large factory with building structural symmetry. According to the simulation results, several obstacles to the evacuation were discovered and further analyzed. The results showed that the main factors affecting the evacuation were the width of exits, the distribution of occupants and the effective evacuation width of stairs. Among them, only changing the width of exits had little influence on shortening evacuation time. While changing the effective evacuation width of stairs could greatly relieve the evacuation pressure, every increase of 0.5 m in the width of the staircase could shorten the evacuation time by 30.0 s. Meanwhile, the larger the number of people in high-rise buildings, the longer the evacuation time was. Therefore, the means of restricting people from entering the high-rise buildings in batches could be used to prevent personnel from being evacuated in time when a fire incident occurs.

Study on emergency evacuation in underground urban complexes.

With progressive urbanization and the development and utilization of urban underground space, underground urban complexes (UUCs) have been increasingly used. UUCs have brought much convenience to people's lives. However, due to their enclosed nature and complexity, it has been an urgent issue to avoid (or reduce) casualties and allow rapid and safe evacuation of people during an emergency. In this study, the evacuation simulation software Pathfinder was used. Based on the steering model, the variation of the total evacuation time and pedestrian flow at main exits with different simulated evacuation measures, congestion at key nodes and people's path selection were compared and analyzed. Then, the critical locations in the spatial layout of UUCs that were prone to evacuation bottleneck effects were focused on and determined. The evacuation effectiveness of UUCs in an emergency was studied to investigate the problems of emergency evacuation in UUCs. It is found that in UUCs, the bottleneck effects were likely to occur at stairway entrances and exits as well as supermarket checkout counters and caused severe congestion. These locations should be focused on during emergency evacuation. For key locations prone to evacuation bottlenecks, increasing the width of exits or setting up auxiliary evacuation channels could be an effective measure to improve evacuation efficiency. In addition, formulating rational evacuation rules can be a favorable measure for emergency evacuation. However, during the evacuation, the herd mentality in people has an uncertain (positive or negative) impact on evacuation effectiveness. Setting up diversion walls may improve evacuation efficiency and reduce congestion to a certain extent, while evacuation confusion and chaos are prone to occur after diversion. These findings in this study have significant implications for improving the emergency management of UUCs.

The safe evacuation of persons from a building operating within COVID-19 restrictions

Buildings’ environmental conditions were changed drastically around the world due to the COVID-19 pandemic hazards and restrictions. New social distance rules and organizational changes in the buildings appeared to require a modified fire safety evacuation analysis. The total number of building users under the revised requirements was often limited. Some additional restrictions, such as the reduction of evacuation exit availability, could cause escape problems in the case of fire. In order to determine how the pandemic restrictions could influence the evacuation conditions, a sports hall building was used to assess the impact of the restrictions on evacuation strategies. The research covered test evacuation simulations using the ‘Pathfinder’ modelling software, as well as manual calculations of the expected evacuation time. It was found that the pandemic social distance requirements could cause adverse evacuation conditions in the case of fire. The research helped formulate a simple mathematical algorithm for determining safety evacuation parameters under pandemic restrictions.Practical applicationThe surrounding conditions for new buildings are driven by the reduction of social distances imposed by the COVID-19 pandemic. It has been found that pandemic social distancing can significantly extend the time of the evacuation of people. This article proposes a new simple mathematical algorithm for determining the evacuation parameters under pandemic restrictions, which allows the estimation of the required minimum width of emergency exits. This is a practical tool for those responsible for ensuring safety in buildings.

Pedestrian evacuation modeling and simulation in multi-exit scenarios

This paper proposes a multi-exit evacuation model based on a continuous model for the pedestrian evacuation problem. Firstly, it is determined that the distance between pedestrians and exits, the pedestrian density near exits, and the width of exits are the main factors for exit selection. A pedestrian multi-exit selection model is defined by taking the three factors into account. Secondly, a pedestrian evacuation model is constructed by considering the impact of pedestrian psychological factors on expected speed and exit attractiveness. Finally, the multi-exit evacuation is simulated, and the pedestrian evacuation process is tested on three conditions. The effects of pedestrian density near the exit and the width of exit are analyzed on the final simulation. The simulation results show that the evacuation model can effectively simulate the pedestrian evacuation process in multi-exit scenarios.

Integrated agent-based simulation and evacuation risk-assessment model for underground building fire: A case study

To reduce the casualties of underground shopping malls after a fire and provide a reference for better emergency decision-making, this paper undertakes an in-depth study of the fire evacuation risk in underground shopping malls. First, no theoretical model exists for selecting the fire source location of the existing building evacuation fire. Considering the approach-avoidance behavior of people toward fires during evacuation and assuming the worst-case scenario, the authors propose a multi-exit fire-source-location-selection model. This study then simulates an underground shopping-mall fire using Pyrosim software. Finally, this study improves the existing evacuation risk-assessment model based on previous research and studies on underground buildings using this new model. The model presents the evacuation risk distribution in various areas within the building clearly, providing references for both the fire protection design for underground shopping malls and forming fire-emergency plans. Moreover, the number of people in the building, pre-movement time, and safety exit widths significantly influence fire evacuation risk in underground shopping malls; specifically, the number of people in the building and the pre-movement time are positively correlated with the evacuation risk, whereas the width of safety exits is negatively correlated. The number of people inside the building has the greatest impact on the evacuation risk.

Emergency evacuation simulation at starting connection of cross-sea bridge: Case study on Haicang Avenue Subway Station in Xiamen Rail Transit Line

Due to the underground nature and dense concentration of people around transit stations, emergency evacuation during fire accidents can become a noticeable problem in subways. This study numerically simulated the crowd dynamics during fire evacuation in the Haicang Avenue Subway Station in Xiamen. The uniqueness of the case study is that this subway station is built as the starting connection of a cross-sea bridge at the seashore. Total evacuation time was affected by factors such as the width of the evacuation channel, proximity to exits, crowd density, and evacuation speed. Parameters in the computer modelling were obtained through proportional measurement algorithms and on-the-spot investigations, video recording, and personnel tracking at a mirror station. The study simulated the evacuation process in four scenarios using variables such as the number of passengers and width of evacuation stairs. When crowd dispersion increases, a longer evacuation time is needed. Suggestions are made to optimise the positions of outlets and to increase the width of exits to alleviate congestion.

A Multistory Building Evacuation Model Based on Multiple‐Factor Analysis

Emergency evacuation is an important issue in public security. To make a considerate plan, various situations are presented including blocking the accident area and letting the emergency access path available. In order to offer dynamic evacuation routes due to different circumstances, a multistory building evacuation model is proposed. Firstly, to analyse the patency of the building, an evacuation formula is applied after binary processing. The function of evacuation time and some other parameters is given by means of regression analysis. Secondly, the cellular automata (CA) algorithm was applied to illustrate the effect of the bottleneck. The response of evacuation time could be approximately optimized through calculating time step of the CA simulation. Finally, the value of maximum evacuation population density could be determined according to the analysis of CA simulation results, which was related to the switch state of the emergency channel. The emergency evacuation model was simulated by using the Louvre museum as an example. The results of the simulation presented some feasible evacuation routes in all kinds of situations. Furthermore, the functional relationship would also be given among evacuation time with the diversity of tourists, pedestrian density, and width of exits. It can give a different perspective that the multistory building evacuation model shows excellent adaptability to different circumstances.

An Analysis of Evacuation under Fire Situation in Complex Shopping Center Using Evacuation Simulation Modeling

As the economies grow, a number of high-rise buildings and large complex shopping canters have been built in Korea. However, these buildings are huge and complex in their size and structure. Therefore, agents will face evacuation problems under the fire situation. Unless agents evacuate rapidly, they will suffer from the suffocation and poisoning to death. This paper analysed relevant to both human and structures evacuation factors through the agent-based model. The agents are classified for simulation modelling into three cases and four groups. Each case contains different number of agents and each of the four groups shows different levels of exit awareness. Also through the potential route plan of each group, analysed total evacuation time is analysed. As a result, it is found that human conflict is responsible for the total evacuation time as the conflict between the familiar and the unfamiliar occurs within the interior structure. Thus, the spatial environment factor that evacuation time of case best is 8’22” but other cases up to 60’. It is also an effective way for evacuees to be provided with optimized width of exits near high density area. To reach out further, future studies may implement other various factors such as toxic gases and transportation vulnerable.

A study of escape time from an underground street in a mountainous city

Taking the underground street in Three Gorges Plaza in the Shapingba District, Chongqing, as an example, the present study focused on a densely populated underground street downtown in a mountainous city, in which the issue of emergency evacuation in case of fire was discussed. The total evacuation number could be worked out according to the 'method of trip generation rate'; the length of escape routes and the width of escape exits were counted, and the maximum capacity of people for each emergency exit was calculated according to the unit capacity. Based on the above data, the escape route was built by the iterative programming algorithm so as to check the safety of the current underground street in the mountainous city, in order that technical support can be provided for effective countermeasures. Thus, the emergency evacuation capability of a downtown underground street in a mountainous city can be enhanced. Keywords Civil air defense projects, escape routes, escape time, mountainous city, underground street. Language: en

Setting the Width of Emergency Exit in Pedestrian Walking Facilities

To improve the safety of pedestrian evacuation and the utilization efficiency of emergency exits in pedestrian walking facilities, the method of computing the width of emergency exits was presented in this paper. These factors of influencing the setup of exit width were analyzed from the process of pedestrian evacuation, the capacity of pedestrian passing exit and the strategy of pedestrian selecting exit. It is shown that the setup of exit width is dependent on the capacity of passing exit, the strategy of exit selection and the total sum, initial site, and aggregation degree of pedestrians in walking facilities. It is also found that the total capacity of passing exits will be low with the number of exits rising under the condition with a fixed total width of exits. The procedure of setting exit was presented to compute the number, site and width of every exit in pedestrian facilities through an example.

Simulation of Pedestrian Evacuation with the Optimal Exit Layout Based on a Dynamic Parameters Model

A dynamic parameters model is established based on cellular automata (CA) to simulate pedestrian evacuation in this article. The dynamic parameters are formulated to simplify tactically the decision-making process of pedestrians, which can reflect the pedestrian judgment on the surrounding conditions and determine the pedestrian's choice of action. The pedestrian moving rules are proposed according to two-dimensional cellular automaton Moore neighborhood. The simulation results of this model are compared and analyzed with previous model. It is clear that our model corresponds with the actual and shows the advanced nature. The evacuation time versus pedestrian density and exit width are studied. There is a linear relationship between evacuation time and pedestrian density, whereas there is a nonlinearly relationship (negative exponential) between evacuation time and exit width. Moreover, the authors consider the effects of the crowd distribution in evacuation process, and the optimal exit layout is given in a determined system, such as the optimal position and width of exits, providing safety guiding for the pedestrian in enclosed environments, and avoiding and/or reducing the number injuries.

Simulation of pedestrian evacuation based on an improved dynamic parameter model

An improved dynamic parameter model is presented based on cellular automata. The dynamic parameters, including direction parameter, empty parameter, and cognition parameter, are formulated to simplify tactically the process of making decisions for pedestrians. The improved model reflects the judgement of pedestrians on surrounding conditions and the action of choosing or decision. According to the two-dimensional cellular automaton Moore neighborhood we establish the pedestrian moving rule, and carry out corresponding simulations of pedestrian evacuation. The improved model considers the impact of pedestrian density near exits on the evacuation process. Simulated and experimental results demonstrate that the improvement makes sense due to the fact that except for the spatial distance to exits, people also choose an exit according to the pedestrian density around exits. The impact factors α, β, and γ are introduced to describe transition payoff, and their optimal values are determined through simulation. Moreover, the effects of pedestrian distribution, pedestrian density, and the width of exits on the evacuation time are discussed. The optimal exit layout, i.e., the optimal position and width, is offered. The comparison between the simulated results obtained with the improved model and that from a previous model and experiments indicates that the improved model can reproduce experimental results well. Thus, it has great significance for further study, and important instructional meaning for pedestrian evacuation so as to reduce the number of casualties.

Simulation of pedestrian evacuation with asymmetrical pedestrian layout

Simulation of pedestrian evacuation from a room with multi-exit and asymmetrical pedestrian layout is presented based on an improved dynamic parameter model in this paper. The computation and the count-area of imaginary distance are improved based on the Max-Min evacuation path selection of actual and imaginary distance in order to reduce evacuation imbalance caused by the asymmetry of pedestrian layout. An imbalance coefficient is introduced to describe the asymmetry of pedestrian layout. The effects of pedestrian layout asymmetry on the evacuation time are analyzed respectively from fixed and unfixed pedestrian initialization site. The simulation results of the improved and original models are compared and analyzed, and the improved model can effectively reduce evacuation imbalance. Simulation results show that under normal evacuation condition with considerring reasonable pedestrian and jam around exits, evacuation time is hardly affected by pedestrian and exit layout and depends mainly on cognition coefficient, total width of exits and pedestrian initialization amount.

A methodology for the sizing and positioning of emergency exits in tunnels

The reference law for the construction of new tunnels belonging to the Trans-European Road Network currently calls for the implementation of emergency exits when the expected traffic in the tunnel is larger than 2000 vehicles/hour per lane and the length of the tunnel is more than 1000 m. Emergency exits must allow the road users to abandon the tunnel afoot and in safety and to reach a safe place in case of accident or fire. Apart from allowing pedestrian flow outside the tunnel, such exits also have to provide a pedestrian route for access to the tunnel by first aid services. Emergency exits can provide a path toward an emergency tunnel which leads pedestrians to the outside or to shelters with escape routes separated by the tube of the tunnel. The Italian legislative decree n. 264, published on October 5th, 2006, imposes that the distance between emergency exits must not exceed 500 m. Sizing emergency exits can be submitted to the application of the technical norms of prevention and protection by fires. The legislation related to the minimum safety requirements for tunnels of the Trans-European Road Network does not clearly state anything concerning this aspect. This paper proposes a methodology for the verification of correct spatial positioning and sizing of the width of emergency exits of road tunnels, considering such width as a function of the expected vehicular flow for the tunnel, the distance between two emergency exits, the number of lanes in the tunnel and the average coefficient of occupation of the transiting vehicles.

Simulation of pedestrian evacuation with asymmetrical exits layout

A simulation of pedestrian evacuation from a room with asymmetrical exit layout is presented based on the improved Dynamic Parameter Model in this paper. A special technique is introduced to compute two basic dynamic parameters: Direction- parameter and Empty- parameter considering the effects of pedestrian jam around exits and the width of exits on evacuation path selection in order to reduce evacuation imbalance caused by the asymmetry of exits layout. Two new coefficients: cognition coefficient and imbalance coefficient are introduced to respectively describe pedestrian cognitive ability and the layout imbalance of exits. The simulation results of the improved and original models are compared and analyzed. Simulation results show that evacuation time depends on the cognition coefficient and imbalance coefficient under normal evacuation condition with reasonable pedestrian. It is also found that there are phase transitions and critical points in the simulation curves of evacuation time against cognition coefficient and that the pedestrian flow shows distinctive characteristics at different phases. The values of critical cognition coefficient points depend on the initial pedestrian density and imbalance coefficient.