Assessment of legibility of egress route in a building from the viewpoint of evacuation behavior

Abstract

A new framework for a fire safety design method is now in preparation based on the concept of performance-based design in Japan (Tanaka, 1995. State of the Art — Development of a Performance-based Fire Safety Design Method of Building in Japan. Proceedings of Mini-Symposium Fire Safety Design of Buildings and Fire Safety Engineering. Building Research Institute). In this paper, the authors focus on the legibility of the egress route as an important performance factor in assuring the safety of occupants in buildings, and intensively discuss its assessment. Relevant, previous work on the evaluation of the legibility of the egress route is reviewed and studied. The paper considers the legibility of egress route as the geometric access potential of the egress route network in the architectural plan. The legibility of the egress route is a function of the physical measures that allow quantitative evaluation of how quickly occupants can escape or how easily they can find exits. From this point of view, the travel distance during an evacuation is one of the most effective and quantifiable measures of the legibility of the egress route. The assessment of the travel distance based on several assumptions of the occupants' probable choice of egress route is introduced. A network modeling technique is utilized to represent the configuration of the egress route and to calculate the travel distance. Through numerical computations, an effective configuration is determined such that the average expected travel distance across the possible layouts of the egress route is minimized.