Indoor Spatial Model and Accessibility Index for Emergency Evacuation of People with Disabilities

Abstract

Although indoor emergency evacuation drills, simulations, and plans are addressed and well covered in literature, little attention is currently paid to the evacuation of people with disabilities (PWD). Routing is a major process in all indoor emergency evacuations, simulations, and plans. Current indoor emergency evacuation routing algorithms find the shortest path or attempt to balance the traffic on exit doors. However, accessibility is more important than travel distance during the emergency evacuation of PWD. A spatial model, an accessibility index assigned to appropriate elements in the spatial model, and a way-finding technique are the major requirements of such routing. Existing spatial models of buildings are general purpose, fall short of efficiently and effectively handling emergency evacuations, and do not take into account the requirements of PWD. This paper proposes a spatial model for indoors which is specifically developed for the routing requirements of PWD during emergency evacuations. The accessibility index of an element in the spatial model represents the element’s level of accessibility to PWD. Once the accessibility indexes for the elements of the spatial model are determined, an appropriate algorithm is applied to find the optimum exit route. The proposed spatial data model and egressibility measures are visualized for an 8-story building. The results showed that: (1) 84% of stairways, 23% of doors, 2% of hallways, and the only ramp are inaccessible; (2) 19% of the building is inegressible for PWD; (3) the cost of the most accessible egress route increases for the higher floors; and (4) if elevators stop working, all floors except the ground floor will become inegressible for PWD.