NIST’s World Trade Center Investigation
For Immediate Release: September 8, 2006
(9/8/2006, ARCHIVE, incorporated into 9/19/2011 update)
What is NIST?
What are the goals of NIST’s investigation of the World Trade Center disaster?
Additionally, under the National Construction Safety Team (NCST) Act, signed into law in October 2002, NIST is authorized to investigate major building failures in the United States. The NIST investigations will establish the likely technical causes of the building failure and evaluate the technical aspects of emergency response and evacuation procedures in the wake of such failures. The goal is to recommend improvements to the way in which buildings are designed, constructed, maintained, and used.
When did the investigation begin and when will it be completed? The investigation officially began on Aug. 21, 2002. When the NCST Act was passed in October of that year, the WTC investigation was moved under its authorities. The final report on the collapses of WTC 1 and 2 was issued on Oct. 26, 2005. The investigation of the collapse of WTC 7 will be completed in 2008.
In addition to the investigation into the collapse of the WTC buildings, is NIST conducting related research or programs?
For example, the final report from the investigation of the WTC towers included 30 recommendations for improving building and occupant safety derived from the findings. In March 2006, the first proposed changes to model building codes (used as templates for codes legislated, implemented, and enforced by state and local jurisdictions) based upon and consistent with the NIST WTC recommendations were submitted to the International Code Council (ICC).
The proposed changes—submitted by building code experts associated with two ICC committees, the National Institute of Building Sciences and the U.S. General Services Administration—address areas such as increased resistance to building collapse from fire and other incidents, use of spray-applied fire resistive materials (commonly known as “fireproofing”), performance and redundancy of fire protection systems (i.e., automatic sprinklers), elevators for use by first responders and evacuating occupants, the number and location of stairwells, exit path markings, and fuel oil storage/piping.
In May 2007, the ICC adopted the first set of these building code changes. NIST is committed to continuing our work to support industry and the nation's building and fire safety officials so that the remaining recommendations also are fully considered.
A Web-based system for tracking the progress toward implementing all of the NIST WTC recommendations may be accessed at http://wtc.nist.gov.
Will the results of the investigation help prevent future disasters?
The results of the NIST investigation also will support and guide future work to develop and disseminate guidance and tools, assess and reduce vulnerabilities, and produce the technical basis for cost-effective changes in national practices and standards. A private-sector coalition—representing key industry, standards, codes, and professional organizations—has worked with NIST to establish the response plan to meet these longer-term needs. The goal of the longer-term program is to produce cost-effective retrofit and design measures and operational guidance for building owners and emergency responders.
How has the investigation been funded?
Is NIST consulting with outside experts?
Did the investigation include an examination of the “human” element?
The data were analyzed to study the movement of people during the evacuations, decision-making and situation awareness, and issues concerning persons with disabilities.
No one was in WTC 7 when it collapsed, so that investigation does not include a “human” element.
What is the National Construction Safety Team Advisory Committee?
Does NIST agree with the recommendations for studies put forth by the Building Performance Assessment Team (BPAT)? The BPAT, led by the American Society of Civil Engineers (ASCE) and sponsored by the Federal Emergency Management Agency (FEMA), was designed to study the event of Sept. 11, 2001, at the WTC Complex, provide preliminary assessments, and serve as the foundation for a more extensive technical and scientific investigation. Or as the BPAT Report executive summary states: “to present recommendations for more detailed engineering studies to complete the assessments and produce improved guidance and tools for building design and performance evaluation.”
The NIST response plan addressed all of the major recommendations contained in the report issued by the BPAT. The NIST plan also identified other critical issues that needed study, especially in areas that impact life safety and engineering practice.
How has NIST kept the public informed? NIST established a secretariat to coordinate NIST-level activities in support of the investigation and to maintain ongoing liaison with the Executive Branch, Congress, the public, and the news media. NIST has maintained an ongoing liaison with the professional community, the public, and local authorities over the course of the investigation through briefings, presentations, and opportunity for comment on key investigation reports. NIST also assigned a special liaison to interact with the families of building occupants and first responders.
A Web site dedicated to the WTC investigation has been maintained at http://wtc.nist.gov. The final report on the WTC towers is available there in its entirety (43 documents totaling some 10,000 pages).
The Web site also provides access to the WTC investigation archives where the public can follow the complete history of the effort so far, including the two interim progress reports, two public updates and 22 news releases issued during the WTC towers portion of the investigation, as well as documentation from eight public meetings, eight media briefings, seven meetings of the NCST Advisory Committee, and the September 2005 technical conference on putting the NIST recommendations from the WTC towers study into practice.
Can NIST’s findings be used in court?
The NCST Act gives NIST the authority to subpoena information or witnesses during an investigation. Was the power used in the WTC investigation?
Has NIST previously conducted building collapse and fire investigations?
Besides the WTC investigation, NIST has conducted one other study under the authorities of the NCST Act, an investigation of the Feb. 20, 2003, fire at The Station nightclub in West Warwick, R.I. This work was completed in June 2005.
Examples of past failure investigations that NIST either has led or participated in include:
To respond to a number of the questions raised, NIST has posted a fact sheet on the investigation Web site (http://wtc.nist.gov/). The fact sheet explains how NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to 9/11, or that missiles were fired at or hit the towers. Instead, the fact sheet describes how photographs and videos from several angles clearly showed that the collapse initiated at the fire and impact floors and that the collapse progressed from the initiating floors downward, until the dust clouds obscured the view.
NIST respects the right of others to hold opinions that do not agree with the findings in its report on the collapses of WTC 1 and 2. However, the WTC Investigation Team stands solidly behind the collapse mechanisms for each tower and the sequences of events (from aircraft impact to collapse) as described in the report.