Web Exclusive: Skyscraper Safety Improvements Advance After 9/11

by Elizabeth Pate

Today, skyscrapers in Asia and the Middle East are vying for the world’s height record. The desire to compete and build taller is nothing new. In the U.S., tall buildings have defined proficiency and progress since the mid-1800s. But, as the 10-year anniversary of the 9/11 terrorist attacks approaches, the safety of skyscrapers is being heavily evaluated by many. After the World Trade Center towers succumbed to a total collapse, the U.S. began looking beyond height, codes and standards to try to plan and implement substantially safer towers with more accessible evacuation options and capabilities than ever designed before.

But, the question remains, just how safe can a 100-story-plus building be? In order to improve high-rise safety, new towers will require stronger structural systems, more-reliable fireproofing and advanced exit stairs, among other things.

Organizations like the National Institute of Standards and Technology (NIST), the National Fire Protection Association (NFPA) and the International Code Council (ICC) have been investigating the possibilities and implementing recommendations over the years since the attacks. According to an online report by NIST, if high rises had better fireproof columns and floor trusses, buildings would be less likely to completely collapse if caught on fire.

Additional NIST-recommended improvements include adding encased concrete to all support columns and steel plates, installing air intake shafts to improve ventilation during fires, adding fire- and impact-resistant walls and shafts, and building extra-wide stairs to quicken evacuations.

While investigating the behavior of individuals during emergencies, NIST researchers found that the tenants of the World Trade Centers were unfamiliar with the building’s design and safety features. NIST reported that only 10% had entered a stairwell as part of an emergency drill.

Despite some building tenants being unfamiliar with their surroundings, others go as far as to plan and practice evacuation routes. According to John Mangels of Cleveland.com, the 57-story Key Tower in Cleveland holds yearly evacuation drills, requiring tenants to completely exit the building. The Associated Press reported in August, that Chicago has adopted an ordinance mandating high-rises to have emergency-evacuation plans. In addition, the city requires tall buildings to provide fire departments with the floor plans in order to help rescuers navigate the building during emergencies. Implementing strict evacuation policies in high-rise buildings could greatly improve the safety of tenants and rescue officials.

Although there has reportedly been much speculation over the years, the NFPA and ICC have followed the majority of the NIST recommendations. Included among the national code improvements are: additional stairways (depending on the building’s height); more robust fireproofing; impact-resistant walls around elevator shafts and stairwells; fortified elevators that firefighters (and, in some cases, occupants) can use in an emergency; stricter and more consistent fire-resistance standards for structural components; and improved evacuation plans and disaster drills.

According to the Dr. Sang Dae Kim, chairman of the Council on Tall Buildings and Urban Habitat, as buildings become taller and uniquely structured, engineering challenges will be faced. In order to prevent building disasters like what happened to the World Trade Center towers, advanced safety features will have to be implemented for future high-rise buildings.

For additional reading and reference material on elevator/escalator rescue, fire service operation and evacuation guidelines, visit our online bookstore here.

Night image: A rendering of the World Trade Center at night. © Silverstein Properties, Inc.
Construction image: Construction of the World Trade Center. Image taken by Joe Wollhead, courtesy of ©Silverstein Properties