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Commerce's NIST Updates Progress of World Trade Center Investigation

Access to All Essential Data Has Been Obtained

The Commerce Department's National Institute of Standards and Technology (NIST) has obtained access to all of the essential information needed for its two-year federal building and fire safety investigation into the World Trade Center (WTC) disaster of Sept. 11, 2001, NIST Director Arden Bement Jr. today announced. NIST's success in gaining this information from a variety of organizations and agencies is included in an update report presented at the third meeting of the National Construction Safety Team (NCST) Advisory Committee. This panel of experts advises the NIST Director on investigations conducted under the NCST Act.

Details about NIST's access to the information needed for the WTC investigation, as well as the status of the investigation's progress since an interim technical report was issued in May 2003, may be found in a 41-page document (.pdf) available online at

"Since our interim technical report in May, the WTC investigation has achieved a number of milestones critical to its successful completion next fall," Bement said. "These accomplishments bring us even closer to achieving the desired outcome for our overall response to the WTC disaster: improvements in the way people design, construct, maintain and use buildings, especially high-rise buildings."

The public update released today details how the WTC investigation team has:

  • completed the selection process for all major contractors and experts to augment NIST's in-house capabilities for the investigation;
  • built comprehensive models for analyzing the most probable structural collapse sequences (from aircraft impact to collapse initiation) and simplified models to supplement results from detailed models;
  • completed the majority of the analysis of the recovered WTC structural steel in its possession;
  • conducted nearly all of the laboratory fire tests on mockups of typical WTC workstations to provide data for fire dynamics computer models;
  • initiated work on fire endurance testing of typical WTC floor systems based on the ASTM E 119 standard under both specified and as-built conditions;
  • collected and is analyzing some 6,200 photographic images and 5,800 video clips to document the evolution of fire and smoke conditions and damage to the WTC buildings;
  • received all necessary approvals for and has commenced its first-person data collection effort involving WTC occupants, families of victims and first responders;
  • progressed in its analysis of building and fire codes and practices, including a detailed review of the extraordinarily large volume of documents on the design, construction, operation, maintenance and modifications to the WTC towers and WTC 7;
  • been developing a detailed chronology of events related to the emergency response and evacuation efforts that occurred on Sept. 11, 2001;
  • sorted, categorized and begun analyzing first responder communications data in order to better define the events of Sept. 11, 2001, and document the performance of the emergency communication system;
  • obtained, reviewed and analyzed data on active fire protection systems installed in the WTC towers and WTC 7 (specifically the sprinkler and standpipe systems, the fire alarm systems and the smoke management systems) to evaluate their design, capabilities and performance; and
  • conducted—concurrently with the investigation—11 research and development projects (including work on fire safety design and retrofit of structures, and the emergency use of elevators) and a dissemination and technical assistance program as part of NIST's overall WTC response plan.

Under the NCST Act, signed into law in October 2002, NIST is authorized to investigate major building failures. 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.

As a non-regulatory agency of the U.S. Department of Commerce's Technology Administration, NIST develops and promotes measurement, standards and technology to enhance productivity, facilitate trade and improve the quality of life.

Released December 2, 2003, Updated January 7, 2021