Escaping with your life

Of the many horrors of September 11, 2001, the sight of people falling and jumping to their deaths from the Towers of the World Trade Center will not be soon forgotten by anyone watching. The sight brutally expressed the desperation of those trapped above the raging fires, unable or unwilling to descend through the wounded structures. Even in light of the eventual collapse of the structures, the terrible situation above the crash locations made very clear a fundamental failing of escape strategies of all tall and supertall buildings. In the event of a catastrophic compromise of the emergency fire stairs, people trapped above the disaster have no options for escape. Rescue from above is dangerous and extremely time-consuming and waiting for fire suppression can risk many lives and cause unimaginable suffering. Also, in light of the recent collapse of the World Trade Center towers in New York City, it is clear that there may arise situations in which the amount of time necessary for a full evacuation of a tall building exceeds the amount of time that the structure can resist instability and collapse. Therefore, there is an existing need to investigate building systems that provide augmented means that substantially increase the efficiency with which people may be evacuated and protected during these catastrophic events. This article proposes several augmentations of existing egress systems while accepting current net to gross floor area ratios necessary for these types of buildings to remain economically and operationally practical. Under moderate emergency conditions, such as small and localized fires, emergency systems in tall buildings have performed well. However, during catastrophic events tall buildings are challenged with exceedingly difficult egress scenarios, fire suppression demands and structural performance requirements. As a result of very large occupancies, limited floor space and the increasing heights of the most recent tall buildings, the challenge of quickly and completely evacuating the interior spaces of these types of buildings should again be addressed. Building codes, both local and national have established a high level of design and specification for fire ratings, alarms, communication systems, suppression technologies and evacuation plans that address the life-threatening conditions of a tall building emergency. This paper does not intend to question the effectiveness of these existing regulations. This proposals contained within are assessed in terms of their potential effectiveness in alleviating current problems during emergency situations as well as the practicality of their inclusion in both new designs and existing buildings.