WTC Twin Towers Investigators Urge Improved Skyscraper Safety

A federal agency that investigated the fires and collapses of the World Trade Center’s twin towers following the September 11, 2001 terrorist attack today recommended changes in building standards, fire codes and emergency response methods to improve the safety of skyscrapers.

The U.S. Commerce Department’s National Institute of Standards and Technology to called on the 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 government organization goes not have authority to require changes in building codes and standards. But based on the findings of the most detailed examination of a building failure ever conducted, NIST is making 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 at a press briefing in New York City. “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 today for a six-week public comment period. They cover specific improvements to building standards, codes and practices; changes to evacuation and emergency response procedures; and research and other appropriate actions needed to help prevent future building failures.

The recommendations on improving structural integrity call for more reliable means of predicting failure in structures subjected to multiple hazards and nationally accepted standards for wind tunnel testing of prototype structures and estimating wind loads for tall buildings.

To enhance the fire resistance of structures, NIST recommends improving the technical basis for determining appropriate construction classifications and fire rating requirements—especially for buildings greater than 20 stories in height—and making related code changes now by considering a variety of factors including timely access by emergency responders, full evacuation of occupants and redundancy in fire protection systems.

Active fire protection recommendations include enhanced fire protection systems that provide redundancy and accommodate greater risks associated with increasing building height and population, more open spaces and higher threat profiles of particular buildings. Also, the panel recommends real-time secure transmission of data from fire alarm systems for use by emergency responders at any location.

Building evacuation could be improved, according to the report, if tall buildings were designed to accommodate full building evacuation of occupants, including having stairwell and exit capacity that accommodates counterflow due to access by emergency responders.

The agency also urges consideration for future use such advanced evacuation technologies as protected or hardened elevators, exterior escape systems and stairwell navigation devices.

NIST’s investigation of the WTC towers fires and collapses was conducted under the National Construction Safety Team (NCST) Act. The act gives NIST the responsibility for conducting fact-finding investigations of building-related failures that result in substantial loss of life. NIST has no regulatory authority under the NCST Act.