Exit dynamics of occupant evacuation in an emergency

A two-dimensional Cellular Automata model is proposed to simulate the exit dynamics of occupant evacuation. Concerning the exit width and the door separation, we put forward some useful standpoints: (1) exit width should be bigger than a critical value, and the door separation should be neither too small nor too big; (2) for single-exit door, with the increase of exit width, the flux per unit width will decrease but the total flux will always increase; (3) the total flux of the exit is an increasing nonlinear function of the exit width; (4) the optimal value of the door separation does not vary with the value of exit width; (5) the layout of exits should be symmetry. Those results are helpful in performance-based design of building.