Extended evacuation time. The time necessary for full building evacuation increases with building height. (See the SFPE Handbook of Fire Protection Engineering18 and Engineering Guide to Human Behavior in Fire19 for more information.) In the case of very tall buildings, full building evacuation via stairways might be impractical. A “defend-in-place” strategy has been employed in many building designs by (1) designing compartments allowing people to remain in place, e.g., residential units; (2) temporarily evacuating people to areas of refuge on a floor; or, (3) moving people to dedicated refuge floors elsewhere in the building. Recently, times for full building evacuation have been reduced by employing elevators specifically designed to supplement the egress system of a building. Buildings employing assembly occupancies with large occupant loads on the upper floors of a tall building require special consideration.