A study on human pre-movement behavior under emergencies using system dynamics approach

Abstract

Currently, most of the evacuation models concern on occupants’ movement rather than motivations to the evacuation. How occupants think and act before their evacuation starts is a comparatively new area. The main purpose of this research is to identify the rational human behavior in case of fires or emergencies and develop a framework for the analysis of the pre-movement behavior process from a system point of view. It is a new trial to adopt system dynamics approach for the study of human pre-movement behavior and portray the dynamic relationships among people, fire and built environment in the pre-movement process. Firstly, this study summarized the major factors affecting human actions and decision making in fires. Previous studies have confirmed that panic behavior is not a usual response of people especially at the initial stage when they just acquired the fire cues. People will normally behave in a controlled manner and evacuation is not necessary the first action of people. The reactions of people before the commencement of evacuation may vary with the type of occupancy, occupants’ characteristics, fire cues, warning system and other related issues. In order to reflect the rational pre-movement behavior, the major factors were identified and summarized based on the observations in the real fire incidents instead of false beliefs. Secondly, a human pre-movement behavior model using system dynamics approach was proposed to represent the rational human behavior pattern in fires or emergencies. In general, pre-movement time elapsed from alarm activation to movement initiation is simplified as a specific delay time or a commonly used distribution. Due to the uncertainties and complexity in human behavior, few models can provide a reasonable explanation on the pre-movement system over time and its underlying structure and decision rules. The proposed model was specially designed to integrate the major variables that affect human perception and cognition process and formulate a general understanding of the behavior reactions adopted by the victims to cope with fire. Besides the major factors identified in the previous researches, psychological influence and social relationship among the occupants were also considered. It offers a new area to explore the pre-movement behavior pattern. System dynamics approach was employed to establish a conceptual model of human response to fires. Causal loop diagram provided a graphic framework to describe the information feedback which may stimulate the motivation of evacuation. Stock flow diagram performed a quantitative estimation of their influence on information interpretation and decision making. Therefore, the proposed model offers an opportunity to identify the main causes on the whole system with the feedback loops and conduct quantitative analysis on the state changes in the major variables through the simulation model. A field survey on a fire incident at Xi’an International Trade Center was also carried out. It aims to calibrate the simulation model and to provide evidence to improve the credibility of the proposed model. The comparison indicated that the two sets of data were in good agreements. This implied that the proposed pre-movement model was reasonable to reflect human reaction patterns under emergent situations. In addition, the factors associated with estimated pre-movement time were also discussed and summarized. The findings provide a comprehensive understanding of pre-movement behavior and categorize the possible factors related to people, fire and built environment. Finally, the proposed model was applied to analyze the performance of emergent management policies for a hypothetical room fire case. In total five different management strategies were designed for the implementation. The results agreed with the fact that occupants are reluctant respond to the warning system by itself but are very likely to respond to member of staff. It can be found that the proposed model is sufficiently general to any type of fire scenarios and evacuation management policy analysis and provide a practical way to estimate the performance of different management strategies at building planning stage.

Date of Award	16 Jul 2007
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Siu Ming LO (Supervisor)