Before September 11, 2001, building codes in the United States focused on structural stability and routine fire safety. Buildings like the World Trade Center Twin Towers were considered safe because they could withstand hurricane-force winds and even the impact of a small plane. A typical fire did not spread beyond a few floors, so skyscrapers weren’t required to provide enough escape routes for speedy evacuation of the entire building. Using fewer stairways and slim, lightweight construction materials, architects could design skyscrapers that were slender, elegant, and amazingly tall.
After September 11
After two hijacked jet planes struck the Twin Towers on September 11, 2001, teams of architects and engineers studied ways to make skyscrapers safer. The National Institute of Standards and Technology (NIST) compliled their findings in a hefty report. New York City, which suffered the most catastrophic losses on 9/11, took the lead passing legislation to save lives in the event of another terrorist attack.
In 2004, Mayor Michael Bloomburg signed Local Law 26, which required tall buildings to incorporate improved sprinkler systems, better exit signs, an additional stairway, and other features to help people exit quickly during emergencies.
Nationally, change came more slowly. Some people worried that more demanding building code laws would make it difficult, if not impossible, to construct record-breaking skyscrapers. They wondered whether architects would be able to design beautiful, slender skyscrapers with enough stairways or elevators to meet the new safety regulations.
Critics also charged that new, more rigid safety requirements would increase construction costs. The General Services Administration (GSA), a federal agency that manages government property, said the expense of installing additional stairways would outweigh the safety benefits.
By 2009, the push for new construction standards won out, bringing sweeping changes to the International Building Code and the International Fire Code, which serve as the basis for building and fire regulations across the USA. The International Code Council (ICC) approved additional changes for 2012.
The new safety regulations require:
- Additional stairways
- More space between stairways
- Stronger walls in stairwells and elevator shafts
- Reinforced elevators for emergency use
- Stricter standards for construction materials
- Better fire-proofing
- Backup water sources for the sprinkler system
- Glow-in-the-dark exit signs
- Radio amplifiers for emergency communications
Architects face difficult challenges as they grapple with more demanding safety codes. In New York City, disputes over the design of "Freedom Tower" are legendary. As safety concerns mounted, the original concept posed by architect Daniel Libeskind morphed into a less graceful skyscraper designed and re-designed by architect David Childs.
The final design, now named One World Trade Center, resolved many complaints. New concrete materials and construction techniques have made it possible to incorporate fire-safety features with open floor plans and transparent glass walls. Still, some fans of the original Freedom Tower design say that Childs sacrificed art for the sake of an impossible-to-achieve notion of security.
So, what is the future for skyscrapers? Do the new safety laws mean shorter, fatter buildings? Absolutely not! Completed in 2010, the Burj Khalifa in the United Arab Emirates shattered world records for building height. Yet, while it rises a whopping 2,717 feet (828 meters), the skyscraper incorporates multiple evacuation lifts, super-high-speed elevators, thick concrete reinforcement in the stairways, and many other safety features.
Of course, a building as tall as Burj Khalifa poses other problems. The maintenance costs are astronomical and the demands on natural resources extreme. These shortfalls point out the real challenge that every designer faces.
The Bottom Line
Designing buildings has always meant working within rules. In addition to fire codes and safety laws, modern-day construction must meet established standards for environmental protection, energy efficiency, and handicap accessibility. Local zoning ordinances impose additional restrictions that can affect anything from paint colors to architectural style. And then, of course, successful buildings also respond to the demands of the landscape and the needs of the client and the community.
As new rules are added to the already complex web of regulations and restrictions, architects and engineers are doing what they have always done so well: innovate. Watch the horizon for up-and-coming skyscrapers like the 120-story Post Office Redevelopment Tower in Chicago and the 115-story Ping An International Finance Center in Shenzhen.
- High-Rise Intl. Building Code Changes Reflect Lessons Learned from 9/11, article by Barbara A. Nadel, FAIA. Nadel is also the author of the essential Building Security: Handbook for Architectural Planning & Design (Compare Prices)
- National Institute of Standards and Technology World Trade Center Disaster Study
- Building Regulatory Systems in a Post-September 11 World, NIST Building and Fire Research Laboratory (PDF file)
- New York City Department of Buildings World Trade Center Building Code Task Force Report (PDF file)
- 9-11 Commission Report
- How Has Skyscraper Design Changed Since 9/11?, PBS NOVA
- Agency Fights Building Code Born of 9/11, New York Times