Featured Research

from universities, journals, and other organizations

Final World Trade Center 7 Investigation Report On September 11, 2001 Collapse Released

Date:
November 28, 2008
Source:
National Institute of Standards and Technology
Summary:
The National Institute of Standards and Technology has released its final report on the Sept. 11, 2001, collapse of the 47-story World Trade Center 7 in New York City. The study is strengthened by clarifications and supplemental text suggested by comments on the draft WTC 7 report, but the revisions did not alter the investigation team's major findings and recommendations, including identification of fire as the primary cause for the building's failure.

Graphic showing the buckling of WTC 7 Column 79 (circled area), the local failure identified as the initiating event in the building's progressive collapse.
Credit: NIST Building and Fire Research Laboratory

The National Institute of Standards and Technology (NIST) today released its final report on the Sept. 11, 2001, collapse of the 47-story World Trade Center building 7 (WTC 7) in New York City. The final report is strengthened by clarifications and supplemental text suggested by organizations and individuals worldwide in response to the draft WTC 7 report, released for public comment on Aug. 21, but the revisions did not alter the investigation team’s major findings and recommendations, which include identification of fire as the primary cause for the building’s failure.

The extensive three-year scientific and technical building and fire safety investigation found that the fires on multiple floors in WTC 7, which were uncontrolled but otherwise similar to fires experienced in other tall buildings, caused an extraordinary event. Heating of floor beams and girders caused a critical support column to fail, initiating a fire-induced progressive collapse that brought the building down.

In response to comments from the building community, NIST conducted an additional computer analysis. The goal was to see if the loss of WTC 7’s Column 79—the structural component identified as the one whose failure on 9/11 started the progressive collapse—would still have led to a complete loss of the building if fire or damage from the falling debris of the nearby WTC 1 tower were not factors. The investigation team concluded that the column’s failure under any circumstance would have initiated the destructive sequence of events.

Other revisions to the final WTC 7 report included:

  • Expanding the discussion of firestopping, the material placed between floors to prevent floor-to-floor fire spread;
  • Clarifying the description of thermal expansion as it related to WTC 7’s shear studs and floor beams; and
  • Explaining in greater detail the computer modeling approach used to define where and when the fire in WTC 7 started and the extent of window breakage as a result of fire.

With the release of the final WTC 7 report, NIST has completed its federal building and fire safety investigation of the WTC disaster that began in August 2002. A three-year study of the collapses of the WTC towers (WTC 1 and 2) was completed in October 2005. More than 20 changes in the U.S. model building and fire codes have already been adopted based on the findings and recommendations from the investigation.

NIST will now work with various public and private groups toward implementing additional changes to the U.S. model building and fire codes including those based on the 13 recommendations from the WTC 7 report (one new and 12 reiterated from the towers investigation).

The complete text of the final WTC 7 report, and a video describing the WTC 7 investigation findings are available on the NIST website.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology. Note: Materials may be edited for content and length.


Cite This Page:

National Institute of Standards and Technology. "Final World Trade Center 7 Investigation Report On September 11, 2001 Collapse Released." ScienceDaily. ScienceDaily, 28 November 2008. <www.sciencedaily.com/releases/2008/11/081120144246.htm>.
National Institute of Standards and Technology. (2008, November 28). Final World Trade Center 7 Investigation Report On September 11, 2001 Collapse Released. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2008/11/081120144246.htm
National Institute of Standards and Technology. "Final World Trade Center 7 Investigation Report On September 11, 2001 Collapse Released." ScienceDaily. www.sciencedaily.com/releases/2008/11/081120144246.htm (accessed April 19, 2014).

Share This



More Matter & Energy News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Horseless Carriage Introduced at NY Auto Show

Horseless Carriage Introduced at NY Auto Show

AP (Apr. 17, 2014) An electric car that proponents hope will replace horse-drawn carriages in New York City has also been revealed at the auto show. (Apr. 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins