ANSI - American National Standards Institute
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ANSI Founding Member Drafts Findings on World Trade Center Collapse

Federal Report Commissioned by FEMA and ASCE Details Horrific Events Leading to Buildings' Demise; Recommended Changes to Codes and Standards Forthcoming From NIST

New York, Apr 01, 2002

As featured on the front page of The New York Times, a draft report commissioned by the Federal Emergency Management Agency (FEMA) and the American Society of Civil Engineers (ASCE) details for the first time the series of events leading to the collapse of the twin towers of the World Trade Center. [Editor's note: The article appeared on the front page of the Friday, March 29, 2002 issue of The New York Times.]

New York Times reporters, James Glanz and Eric Lipton, indicated that the report findings point to two factors that caused the towers to collapse: the inferno that drove temperatures up to 2,000oF and the failure of the buildings' fire suppression systems. According to the article, the report stated, "The fire, combined with [the failure of the fireproofing, sprinkler systems and the water supply for hoses] brought down the towers even after they had shown surprising and lifesaving resiliency to massive structural damage caused by the impact of two hijacked airliners."

Although the final report will not be released until late April or early May, Glanz and Lipton indicated that the draft "simultaneously supports and rejects many of the theories about what happened to the towers on September 11th." For example, one third of the 20,000 gallons of jet fuel carried collectively by the two airplanes exploded into fireballs over lower Manhattan and burned off after the planes crashed into the buildings, causing little structural damage to the surrounding area. However, "the remaining fuel burned within minutes, setting ablaze furniture, computers, paper files and the planes' cargo over multiple floors [of the towers] and ignit[ed] a catastrophic inferno that brought the [buildings] down."

Ordinarily, the Times article pointed out, "fire suppression systems" in commercial properties "are designed to allow a high rise blaze to burn itself out before [causing] the [structure to collapse]." In this case, the report concludes that these critical systems experienced "across the board failures" whose implications are extremely difficult to determine due to "the extraordinary circumstances of the attack." However, they do "raise disturbing questions about the safety and integrity of other tall buildings in out of control fires."

John E. Durrant, P.E., executive director for ASCE's Structural Engineering Institute and spokesperson for the ASCE/FEMA Building Performance Study team that compiled the report, said, "ASCE regularly undertakes the study of structural performance related to natural and other disasters. September 11th was no exception. I suspect that the evaluation of the structural damage to the World Trade Center included in the report may well be used in the development of and revisions to structural codes for buildings." The Times reported that the National Institute of Standards and Technology (NIST), an agency of the U.S. Department of Commerce and an ANSI government member, has begun a $16 M two-year inquiry into current building codes and standards. Durrant indicated that NIST will use the final report as the basis for its investigation into specific recommended changes to building codes and standards.

ANSI initially reported ASCE's involvement in the study of the disaster sites in the Autumn/Winter 2001 issue of the ANSI Reporter, the Institute's quarterly newsmagazine, as in feature article of the September 11th relief efforts of its members and constituents. ASCE, a founding member of ANSI and America's oldest engineering society celebrating its 150th anniversary this year, did not delay in putting together a team to study of the disaster sites of the World Trade Center and Pentagon. The organization declared its intent on September 11th to study the disaster sites and by the 12th had already composed a Building Performance Study team.

Later in the month, ASCE received funding and support from FEMA to continue its study and has worked with the agency ever since to compile the comprehensive report that includes an analysis of the structural damage to the towers and the surrounding buildings. Durrant indicated, "ASCE has a strong working relationship with FEMA and we have successfully collaborated with them in past; this project was no exception." Currently, the report is undergoing an extensive review by the team in preparation for the publication of a final report that will be publicly accessible from ASCE and the Government Printing Office (

"Like a horse with a bum leg," Glanz and Lipton insist, "the buildings, though wounded, still stood," providing a brief window of opportunity for thousands of tenants to escape. The towers' resiliency mirrors the heroism of the rescue personnel who defied the horror inflicted by the terrorists to sacrifice their lives for a higher good. It is hoped that the resulting improvements to building safety provided by the ASCE/FEMA report and the NIST investigation will ensure the security of future generations to come.