NIST World Trade Center investigation team calls for improvements

NIST research structural engineer Nicholas Carino describes laboratory tests used to estimate the amount of fireproofing that was dislodged from various structural elements within the WTC buildings when the aircraft were flown into them on Sept. 11. The specimens shown include steel bars and plates that have been coated with the same type and depth of sprayed fire-resistive material as was used in the WTC buildings. Full size image available through contact

At press and public briefings in New York City on June 23, investigators from the National Institute of Standards and Technology (NIST) called on organizations that develop building and fire safety codes, standards and practices--and the state and local agencies that adopt them--to make specific changes to improve the safety of tall buildings, their occupants and first responders. The recommendations result from the agency's investigation of the fires and collapses of New York City's World Trade Center (WTC) towers following the terrorist attacks of Sept. 11, 2001.

Based on the findings of the most detailed examination of a building failure ever conducted, the NIST team made 30 recommendations. "We believe these recommendations are both realistic and achievable within a reasonable period of time, and should greatly improve the way people design, construct, maintain and use buildings, especially high-rises," said WTC Lead Investigator Shyam Sunder. "The recommendations also should lead to safer and more effective building evacuations and emergency responses. However, improvements will only be realized if they are acted upon by the appropriate organizations."

The recommendations, contained within 43 draft reports (totaling some 10,000 pages), were released for a six-week public comment period. A few of the recommendations include:

• improving standards and codes for preventing progressive collapse;
• enhancing the fire resistance of structures with better "fireproofing" materials and tests;
• requirements for sprinklers, fire alarms and other "active" fire protection systems that address the greater risks of taller buildings;
• designing tall buildings to accommodate full building evacuations if needed; and installing fire-protected and structurally hardened elevators.

For further information see: http://www.nist.gov/public_affairs/releases/wtc_briefing_june2305.htm.