An efficient partially dedicated strategy for evacuation of a heterogeneous population

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Abstract

When a heterogeneous population evacuates from a high-rise building, residents who occupy a large area and move at a slow pace, such as people in wheelchairs, tend to block pathways and significantly affect the evacuation of other occupants. In this study, we propose a partially dedicated evacuation strategy, in which an evacuation path is dedicated to a high-speed subpopulation of people without disabilities while another route is dedicated to the remaining heterogeneous population to minimize the blocking effect. The key factor in this strategy is determining the exact proportion of people without disabilities at each floor to each route. We use a time-expanded network flow model and a simulation-based optimization approach to solve the problem systematically. Simulation experiments show that the proposed evacuation strategy can reduce the average evacuation time of the entire population by 10%. The proposed partially dedicated evacuation strategy can be applied to other problems.

Introduction

Evacuation plans have become increasingly important in recent years and have thus attracted the attention of both building construction managers and researchers in the field of operations management [17]. Effective evacuation strategies, rapid initial response, regular fire drills, and disaster countermeasures are necessary to minimize the number of victims and the extent of property damage caused by disasters. In this study, we focus on the development of an effective evacuation strategy.

One of the important points to consider in the development of effective evacuation strategies for a building is the population of people with disabilities. Approximately 12% of the population in the US can be categorized as having physical, mental, or emotional disabilities [[7]]. As regards the population in Europe, 10–20% has various types of disabilities [11]. People with disabilities who use wheelchairs occupy a relatively large area because of the wheelchair space, and people with low stamina tend to move at a slow pace. These characteristics may cause them to block narrow exit passages and significantly affect the evacuation of the entire population of a building. A building manager who wants to set up an effective evacuation plan should consider the situation of the tenants with disabilities. Otherwise, the evacuation process could result in congestion and delays.

In the present study, we propose an efficient evacuation strategy for a heterogeneous population in a 24-story building environment. We propose a partially dedicated evacuation strategy, in which an evacuation path is dedicated to a high-speed subpopulation of people without disabilities while another route is dedicated to the remaining heterogeneous population to minimize the blocking effect caused by people with disabilities. The key factor in this strategy is determining the exact proportion of people without disabilities at each floor to the first dedicated route. We propose a hybrid approach that combines the network flow model and the simulation-based optimization approach to minimize the average evacuation time effectively and to solve the problem systematically. The effectiveness of the proposed approach is evaluated by using a simulation model. The proposed partially dedicated evacuation strategy can reduce the average evacuation time of the entire population of the simulated building by 10%.

Section snippets

Literature review

Researchers have studied evacuation strategies for high-rise buildings. One of the most popular strategies for high-rise buildings is phased evacuation, in which different parts of an area evacuate sequentially with different time delays. Cepolina [1] implemented a phased evacuation by controlling the alarm times and the egress routes of a building to minimize the building evacuation time. Cepolina concluded that a well-designed phased evacuation could reduce the building evacuation time.

Evacuation situation and simulation model

In this study, we use a 24-story office building located in the US. The length of the building is estimated to be approximately 102 m, and the width is approximately 46 m. Fig. 1 shows a typical floor layout of the building. The white area is the space where occupants can freely move. The gray polygons indicate stairs and the small polygons next to the stairs are refuge area. The building has exits on the first two floors. As shown by the arrows in the figure, occupants who use the left staircase

Building evacuation with dedicated strategy

Using the same evacuation situation assumed in the present study, Koo et al. [9] investigated the effect of occupants with disabilities on evacuation in a high-rise building. As shown in Fig. 2, residents whose occupied area is large and those who move at a slow pace, such as those in wheelchairs, may block pathways and significantly affect the evacuation of other occupants. Using simulation runs with 100 replications, Koo [8] showed that if the entire population consists of people without

Combined approach for the evacuation strategy

Network flow models are commonly used to find efficient evacuation strategies because they have high tractability for analyzing problems conveniently and for deriving an optimal solution easily. However, these models have problems with the lack of realism and practicality. Although such network models can be used to generate optimal evacuation strategies, these models are based on a simplified assumption and do not consider the details of the evacuation phenomenon, such as blocking effects.

Experimental results

We conducted all experiments on a PC with an Intel Core of 3.4 GHz and 8.00 GB RAM. We used CPLEX 12.6 library using C++ for the network flow model in Section 4.1, and we created our own program using C++ language for PSO in Section 4.2.

The experimental results are shown in Table 2. All the results are obtained using the modified version of the BUMMPEE with 20 replications. The numbers are the average evacuation times and the 95% confidence interval. The numbers in the first row (Homogeneous) and

Conclusion

In this study, we propose an efficient evacuation strategy for a heterogeneous population from a high-rise building. When a heterogeneous population evacuates from a high-rise building, occupants moving at a slow pace and occupying large areas, including people in wheelchairs, may block pathways and significantly affect the evacuation of other occupants. We propose a partially dedicated evacuation strategy in which an evacuation path is dedicated to a high-speed subpopulation of people without

Acknowledgments

We would like to thank Dr. Christensen for letting the authors use the BUMMPEE model and the building data for this study. We also thank the two anonymous reviewers for their constructive comments.

References (24)

  • ChristensenK. et al.

    Agent-based emergency evacuation simulation with individuals with disabilities in the population

    J. Artif. Soc. Social Simul.

    (2008)
  • EberhartR.C. et al.

    A new optimizer using particle swarm theory

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