A pedestrian merging flow model for stair evacuation

Pedestrian merging flows on stairs are defined as the confluence of a flow of pedestrians from a stair and pedestrians from each floor of a multi-storey building. This paper introduces a novel simplified mathematical model for the calculation of evacuation times on stairs which takes into account the impact of merging flows. The model allows calculating the impact of merging ratio (people accessing the stair landing from the floor and from the stair) on pedestrian flows and evacuation times at each floor in congested situations. The assumptions and implementation of the model are presented. A hypothetical model case study of a 10-floor building evacuation is investigated, where the results of the new model are compared with the results of an evacuation simulation model using SimTread. Advantages and limitations of the new model in relation to the existing methods adopted for the simulation of merging flows on stairs are discussed.     

A probabilistic approach for the analysis of evacuation movement data

This paper presents a probabilistic approach to analyse evacuation movement data. The approach relies on a detailed video analysis of people movement and pattern reconstruction. Conditional probabilities for travel path trajectories, walking speeds, and physical area occupied on stair landings are calculated for the evacuee population. The approach has been applied as a case study using data from an evacuation drill performed in a six-storey office building in the United States. The evacuation drill was filmed and occupant's behaviours on stairs were analysed using the new method. A comparison with the deterministic methods currently employed in engineering practice has been performed. The benefits of the probabilistic approach are discussed, including (1) a more accurate representation of people movement and (2) the use of probabilistic data for modelling purposes, i.e., model validation and model development.     

Evacuation travel paths in virtual reality experiments for tunnel safety analysis

A case study on the analysis of evacuation travel paths in virtual reality (VR) tunnel fire experiments is presented to increase the understanding on evacuation behaviour. A novel method based on the study of the parametric equations of the occupants’ evacuation travel paths using vector operators inspired by functional analysis theory and the new concept of interaction areas (IAs) is introduced. IAs are presented and calculated in order to represent the distance of an occupant from a reference point (e.g., an emergency exit, the fire source, etc.) over time. The method allows comparisons of travel paths between experimental groups as well as comparisons with reference paths (e.g. user-defined paths, real-world paths, etc.). Results show that a common assumption employed by evacuation models (the use of a hypothetical path based on the shortest distance) may be an over-simplistic approximation of the evacuation paths.     

基于能见度图的元胞疏散最短路径模型研究

近年来发生的火灾多在人员密集场所,当突发事件发生时,人员疏散往往特别困难,因此,规划行人在大型公众聚集建筑物中的疏散路径非常重要。基于能见度图建构的元胞疏散最短路径模型可直接用于实际的紧急疏散指示路径的规划,避免设置大量逃生指示装置致使工程成本过高及视觉不美观,并且也解决了有限制逃生指示装置数量当作限制条件的最大涵盖面积的求解复杂、空间大的问题。