NIST Collapse Model

More than six years after starting its investigation, the National Institute of Standards and Technology (NIST) issued its final report on Building 7 in November 2008.  The most important part of NIST’s report was a collapse model that bore no resemblance to the observed collapse.  In Part 3 of NIST Finally Admits Freefall, Mr. Chandler explains the centrality of the model in NIST’s investigation:[i]

“NIST’s so-called investigation actually consists of finding a way to reproduce the mysterious collapse of the building using a computer model.  The assumption is that if the computer model can be made to reproduce the observed collapse pattern, that must be how it happened… The very process of running the model until it produces the kind of results you’re looking for is called selection bias.  If you think about it, NIST’s methodology is explicitly based on selection bias.  Even if you can show what might have happened, it doesn’t show what actually did happen.”

Despite adjusting its inputs to achieve the desired result, the NIST model does not come close to reproducing the observed collapse:[ii]

Building 7 Collapse - NIST Model

This is also apparent by watching the two video animations of NIST’s collapse model and comparing them to video footage of the observed collapse.

WTC 7 NIST Model vs. Reality

The clearest discrepancy is the deformation of the external structure in the model, which does not occur in the observed collapse.  Mr. Chandler identifies a second glaring discrepancy, saying:

“One fact we do know about NIST’s model is it does not allow for free fall.  The best they could do is 5.4 seconds for the building to crumple down through 18 floors.  Crumpling absorbs energy, and that makes free fall impossible.  There’s nothing in the models we have been shown that even resemble a three-stage collapse with a free fall component.  After all, as Shyam Sunder put it himself, ‘free fall happens only when there are no structural components below the falling section of the building.’  Any natural scenario is going to involve a progression of failures and these don’t happen instantaneously.”

Although NIST’s model is false, based on its failure to reproduce the observed collapse, it cannot be falsified because NIST did not release its modeling data.  Mr. Chandler explains:

“NIST claims their computer model can account for the observed phenomena, so let’s look at NIST’s model – except we can’t.  The software they used to do the modeling is available, but their model actually consists of all the numbers and measurements and assumptions together with any tweaks to the system they might have used to get it to come out the way they wanted.  If that information were released, their results could be checked by anyone with the appropriate skills and software tools.  But NIST has not released the numbers.  All we have been shown are some of the selected animated outputs they were able to get their model to produce… The very fact that NIST has not released their model strongly suggests they don’t want their results checked.  In other words, their results are intended to be taken strictly on faith.”


[i] http://www.youtube.com/watch?v=v3mudruFzNw&feature=related

[ii] NIST NCSTAR 1-9A, “Global Structural Analysis of the Response of World Trade Center Building 7 to Fires and Debris Impact Damage,” Washington, DC. November 2008. p.111. http://wtc.nist.gov/NCSTAR1/NCSTAR1-9index.htm