WTC investigation identifies standards, codes issues

The National Institute of Standards and Technology (NIST) team conducting the federal building and fire safety investigation into the World Trade Center (WTC) disaster of Sept. 11, 2001, announced on June 18 that it has identified a series of issues about test methods, standards, codes and emergency operations currently used for buildings that merit further analysis as the investigation moves toward completion. At a press briefing in New York City, lead investigator Shyam Sunder released the second major progress report on the WTC investigation in which these issues and the interim findings that led to their identification are documented. Sunder said that the team's final report---scheduled for release as a draft document in December 2004---would feature recommendations for improvements in the way people design, construct, maintain and use buildings, especially high-rises.

Among findings discussed in the report are:

• working hypotheses for the collapses of WTC 1 and WTC 2 ("The Twin Towers") and WTC 7, a 47-story building that fell later in the day on 9-11;
• key visual observations on the building, fire and smoke conditions in all three WTC buildings (the WTC towers and WTC 7) from analysis of a large collection of photographic and videographic images;
• a summary of what has been learned from computer models used to analyze aircraft impact damage, fire and smoke behavior, and collapse mechanisms;
results from experimental work to analyze steel recovered from the WTC and laboratory fire tests of WTC structural components/office environments; and
• information gained from nearly 1,200 first-person interviews of WTC surviving occupants, first responders and families of victims.

The complete report, including appendices, is available on the comprehensive NIST WTC investigation Web site, http://wtc.nist.gov.

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