U.S. National Institute of Standards and Technology (NIST) code revision recommendations in the wake of the World Trade Center terrorist attacks are being implemented in new high-rise construction including One World Trade Center, the lead building of the new World Trade Center complex.
(http://www.scientificamerican.com/article.cfm?id=twin-towers-forensic-investigation-revise-building-codes)
NIST issued 31 recommendations to improve the safety of high-rises and the emergency responses in the face of major threats, and 23 changes to the 2009 editions of the International Codes and another 17 changes to the 2012 editions, responsive to the recommendations, have been adopted.
New requirements include:
• Buildings taller than 420 feet are now required to include an extra exit stairwell or a specially designed elevator that occupants can use for evacuations.
• Stairwells in buildings more than 75 feet high must now have glow-in-the-dark markings that show the exit path even when lighting is out or dim.
• Spray-applied fire-resistive materials must perform four times more effectively than current requirements in buildings 75 to 420 feet tall, and more than seven times better in buildings taller than 420 feet.
