An experimental study of visibility effect on evacuation speed on stairs

Staircases are key structures in vertical evacuation in buildings. In this work, individual upward evacuation experiments in staircases under four visibility conditions were performed to study the evacuation speed for both male and female pedestrians. The relationship between evacuation speed and floor level was analyzed. It was found that the influence of visibility was much more significant on the females than on the males. Group upward and downward evacuation experiments were also conducted. With the decrease of visibility, the evacuation time increased first and then became equal gradually. Under synergistic effect of visibility and evacuation distance, the visibility became the most important factor influencing the evacuation speed. A relationship model between evacuation speed and population density was developed through statistical methods, which was compared with the model in the SFPE Handbook.