Study on the exit-selecting behavior in underground indoor space with fire using a virtual experiment

•A virtual computer platform for the evacuation test is designed and established.•Exit-selecting behavior under fire and low visibility are studied.•Arranging the exits evenly are helpful to shorten the time of seeking the exits.•People prefer to spend more movement time reducing queuing time. The fires in underground indoor space often result in limited field of vision, thus revealing the characteristic of exit-selecting behavior under the influence of fire and limited view is the basis for optimizing exit layout and emergency evacuation strategies for the underground spaces. In this study, an interactive virtual environment is presented and using which an evacuation experiment is carried out to test human exit-selecting behavior in fire scenario. The results show that when the view is limited, more exits and arranging the exits evenly are helpful to shorten the time of seeking the available exits. If there is congestion in front, as long as the information on the exits is sufficient, some people (more than 20%) will re-select the other exits. Furthermore, people prefer to spend more movement time reducing queuing time. When the dynamic temperature field is used to show the participants a spreading fire, the virtual fire plays a certain threat, so most of subjects (96.7%) prefer the exit away from the fire source. Moreover, if there are other pedestrians, the evacuation decision-making process of personnel is the game process among selecting the fastest path, keeping away from the exits near the fire source and avoiding high temperature field. The results also show that individual age has an obvious correlation with the participants’ ability of escaping in the virtual evacuation environment. Specifically, the ability tends to become weaker as the age increased. This study will be useful to understand the human exit-selecting behavior and movement characteristics in the influence of fire and limited view by using a cheap and safe method.