Evacuation performance of individuals and social groups under different visibility conditions: Experiments and surveys

Xie, Wei; Lee, Eric Wai Ming; Cheng, Yanying; Shi, Meng; Cao, Ruifeng; Zhang, Yuchun

doi:10.1016/j.ijdrr.2020.101527

Cited by 62 publications

(24 citation statements)

References 38 publications

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“…Among them, limited visibility was chosen because it could reduce pedestrians' walking speed and impedes evacuation [10][11][12][13]38]. Limited visibility caused by smoke was simulated using non-transparent eyepatches (extinction coefficient 1.0, visible distance 1-2 m), which have been used in various experiments [11,39]. Although an eyepatch is different from actual smoke, it was chosen because it was safe and participants could have similar experiences.…”

Section: Methodsmentioning

confidence: 99%

Consideration of the Door Opening Process in Pedestrian Flow: Experiments on Door Opening Direction, Door Handle Type, and Limited Visibility

et al. 2020

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The door is a section prone to bottlenecks and is an important element in the study of pedestrian flow. Therefore, characteristics of doors (e.g., width, location, and the distance between doors) have been taken into consideration in the existing literature related to doors. According to several previous studies, it appears likely that the door opening process (DOP) influences pedestrian flow. However, the number of studies examining the DOP remains small. Therefore, to enhance understanding of pedestrian flow, we examined two door characteristics that could affect the DOP (opening direction (swing door: push or pull) and handle type (knob, lever, and panic bar)) and limited visibility. We conducted a walking experiment to take all variables (10 cases; 10 participants per case) into account. Statistical analysis was performed on the difference in movement times, and the results were as follows: (1) inclusion of the DOP affected pedestrian flow; (2) when visibility was limited, movement times with DOP inclusion increased significantly regardless of the door opening direction and handle type; (3) when the door opening direction was ‘push’, regardless of limited visibility and door handle type, movement times with DOP inclusion were significantly lower; and (4) the door handle type did not result in any significant difference in movement times with DOP inclusion. In addition, we calculated the delay time based on the experiment results, to include the DOP in pedestrian flow (push 1.96–2.88 s, pull 3.91–4.43 s; limited visibility: push 7.38–12.56 s, and pull 12.88–16.35 s). The results of this study could be used as basic data for the development of codes/regulations, engineering guidance, and egress models for doors.

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Section: Methodsmentioning

confidence: 99%

Consideration of the Door Opening Process in Pedestrian Flow: Experiments on Door Opening Direction, Door Handle Type, and Limited Visibility

et al. 2020

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“…For instance, controlled experiments with participants wearing partly opaque eyepatches suggest that maintaining social groups may delay the evacuation under normal visibility conditions and that suboptimal structures (such as large groups walking side by side) are then seen. To the opposite, under reduced visibility groups had a positive effect, with an enhanced tendency to follow one another towards the exit, often by means of physical contact (Xie et al, 2020). Note in passing that the ability to infer somebody else's movement direction improves substantially with experience (Mojtahedi et al, 2017), so the inference might be more successful for socially related people.…”

Section: ) Complexity Of the Evacuation Processmentioning

confidence: 96%

Social groups in pedestrian crowds: review of their influence on the dynamics and their modelling

Nicolas

Hafinaz

2021

Transportmetrica A: Transport Science

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Pedestrians are often encountered walking in the company of some social relations, rather than alone. The social groups thus formed, in variable proportions depending on the context, are not randomly organised but exhibit distinct features, such as the well-known tendency of 3-member groups to be arranged in a V-shape. The existence of group structures is thus likely to impact the collective dynamics of the crowd, possibly in a critical way when emergency situations are considered. After turning a blind eye to these group aspects for years, endeavours to model groups in crowd simulation software have thrived in the past decades. This fairly short review opens on a description of their empirical characteristics and their impact on the global flow. Then, it aims to offer a pedagogical discussion of the main strategies to model such groups, within different types of models, in order to provide guidance for prospective modellers.

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“…High smoke emissions generally result in reduced visibility and thus lower evacuation efficiency. Furthermore, smoke will actively accumulate in the indoor area with the (semi)closed spaces, which in turn prolongs the evacuation process [4]. This increase in evacuation time is a major cause of death for evacuees because of the longer period of smoke and toxic gas inhalation [5,6].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Air Purifier on Smoke Detector Revealed by Fire Dynamics Simulation

Kim

Rie

2022

Sustainability

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In the present study, the relevance of the airflow to the response time of the smoke detector has been investigated regarding the different air purifier locations by Fire Dynamics Simulator (FDS). Particular attention has been devoted to the impact on the smoke detector response with different device types, i.e., top-discharge and front-discharge air purifiers. Additionally, the response delay rate regarding the fire sizes (200 kW and 550 kW) was also evaluated with the top-discharge type purifier. The obscuration plots suggest that the response delay rate generally increases when the air purifier and the smoke detector are in a straight line. The change in the delay rate of the detector was distinct for the top-discharge type device due to the formation of a current barrier by the ceiling jet flow, and a nearby physical barrier (e.g., wall) can further suppress the flow diffusion during a fire event. The delay rate tends to decrease with the increment of the fire intensity.

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Evacuation performance of individuals and social groups under different visibility conditions: Experiments and surveys

Cited by 62 publications

References 38 publications

Consideration of the Door Opening Process in Pedestrian Flow: Experiments on Door Opening Direction, Door Handle Type, and Limited Visibility

Consideration of the Door Opening Process in Pedestrian Flow: Experiments on Door Opening Direction, Door Handle Type, and Limited Visibility

Social groups in pedestrian crowds: review of their influence on the dynamics and their modelling

The Effect of Air Purifier on Smoke Detector Revealed by Fire Dynamics Simulation

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