The US Commerce Department’s National Institute of Standards and Technology (NIST) announced the results today of their, three-year scientific and technical building and fire safety investigation into the collapse of WTC 7 on 9/11 - which has intrigued many observers.
The fall of the 47-story World Trade Center building 7 (WTC 7) was "primarily due to fires," and "was the first known instance of fire causing the total collapse of a tall building". No shit Sherlock!.
"“Heating of floor beams and girders caused a critical support column to fail, initiating a fire-induced progressive collapse that brought the building down.” Appartently ..."temperatures “hundreds of degrees below those typically considered in current practice for fire resistance ratings." induced thermal expansion which played a "key role". Philadelphia's One Meridian Plaza, a 38-story skyscraper that burned for 18 hours in 1991, did not collapse due to ..."differences in the design of the structural system. "
“Video and photographic evidence combined with detailed computer simulations show that neither explosives nor fuel oil fires played a role in the collapse of WTC 7,” Apparently from the Q&A sheet supplied the fires were of "debris" which "burned out of control." , th sprinklers failed to work because the city water main had been cut. Which debris burned for six hours ?
Well that's what NIST WTC Lead Investigator Shyam Sunder told the press when introducing the long awaited report .Plus 3 videos ( with sub titles for the hard of understanding )you can see here
NIST found that the impact of debris from the collapse of WTC 1 ignited fires on at least 10 floors of WTC 7, and the fires burned out of control on six lower floors. The heat from these uncontrolled fires caused thermal expansion of the steel beams on the lower floors of the east side of WTC 7, damaging the floor framing on multiple floors. Eventually, a girder on Floor 13 lost its connection to a critical interior column that provided support for the long floor spans on the east side of the building. The displaced girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the fifth floor. Many of these floors had already been at least partially weakened by the fires in the vicinity of the critical column. This collapse of floors left the critical column unsupported over nine stories.
“When this critical column buckled due to lack of floor supports, it was the first domino in the chain,” Sunder explained. “What followed in rapid succession was a progression of structural failures. Failure first occurred all the way to the roof line—involving all three interior columns on the most eastern side of the building. Then, progressing from east to west across WTC 7, all of the columns in the core of the building failed. Finally, the entire façade collapsed.”
If you want to comment on the report you have 3 whole weeks until noon Eastern Daylight Time on Sept.15, 2008. The draft and recommendation is available online http://wtc.nist.gov
Comments (instructions for submission are available at http://wtc.nist.gov/ can be submitted via:
e-mail to firstname.lastname@example.org;
fax to (301) 869-6275; or
surface mail to WTC Technical Information Repository, Attn: Stephen Cauffman, NIST, 100 Bureau Dr., Stop 8611, Gaithersburg, Md. 20899-8610.
Better minds, sharper brains, skilled engineers, sceptical demolition men will take some time to plough through this.
We are struck by the ruse of getting the defence in first...
"WTC 7 did not enter free fall. According to NIST analysis of WTC 7 video, the building collapsed 18 stories in 5.3 seconds. If the building exhibited free fall, this process would have taken just 3.9 seconds. The actual collapse time exceeded the free fall time by 40 percent."
There is also a wonderful explanation about why thermite wasn't used ... and why in three years they examined no physical evidence.
If you believe that ....
The building was empty ... a useful precaution as the BBC warned everyone 20 minutes before it fell that ... er ... it had already fallen.