Numerical studies on evacuation for supertall commercial buildings

Long evacuation time during an emergency for offices in supertall commercial buildings is a deep concern and was discussed in this article. Different codes and regulations for safe egress were reviewed. A building of fixed floor area but heights varying up to 500 m was taken as an example. The required total evacuation times for selected offices in this building were estimated by four different empirical expressions. The height, population density, and stair width of the supertall building were varied during the calculation. The estimated evacuation times were justified with reference to the local codes on means of escape. Even with a lower population density of 4.5 persons per square meter, which is only half of the allowed value specified in the Hong Kong code, the estimated minimum total evacuation time was 26.9 min. The evacuation time for a supertall commercial building with high occupant loading is very long. Evacuation by elevator is recommended to be an alternative. Safe evacuation strategy for supertall buildings should therefore be watched carefully.