In its reports on WTC 7, NIST (the National Institute of Standards and Technology) claimed that, for the first time in history, fire caused the complete collapse of a large, fire-protected, steel-framed building. In 2008, NIST published analyses purporting to show that fire-induced thermal expansion caused the collapse-initiation of the building. [1]

The reliability of the NIST analyses would obviously depend upon the inclusion of all structural features pertinent to the collapse-initiation. Information relevant to this issue came to light in late 2013.

NIST’s WTC 7 report shows that Girder A2001– which was in the northeast corner of the building, under the 13^th floor and situated between Column 44 and Column 79 – was pushed off its seat at Column 79 by beams framing into it from the east due to thermal expansion of the beams caused by the raging fires produced by burning office materials. This failure caused the large area supported by Girder A2001 to collapse down eight stories, to the 5^th floor, leaving Column 79 laterally unsupported for nine stories, which caused it to buckle. This single column failure then caused a complete north-to-south interior collapse, which in turn precipitated a complete east-to-west interior collapse, ultimately leaving the exterior columns laterally unsupported and causing all of them to buckle nearly simultaneously.

When NIST’s WTC 7 report was issued in November 2008, the structural drawings for the building were inexplicably missing. Accordingly, the report could not be scrutinized from a structural standpoint.

A Freedom of Information Act (FOIA) request was successful in obtaining the release of a large number of the drawings in late 2011. [2] Review of the released WTC 7 drawings showed that there were two serious structural feature omissions from the NIST analyses relevant to the NIST “collapse initiation” theory. They were:

1. Steel plate stiffeners that provided critical support for girder A2001. [3]
2. Floor beams S3007, G3007, and K3007, which provided lateral support for beam G3005. [4]

Analyses performed by independent engineers show that when the stiffeners and lateral support beams are included, NIST’s probable collapse sequence is impossible, because:

1. The girder flange for column 79 could not bend or fail with the stiffeners present. [5]
2. Beam G3005 – which NIST claimed buckled from thermal expansion and led to the collapse of WTC 7 – could not have buckled if G3005’s omitted lateral support floor beams S3007, G3007, and K3007 were present. [6]

In December 2013, well-known attorney William F. Pepper, [7] serving as legal counsel for Architects and Engineers for 9/11 Truth, sent a letter to the U.S. Commerce Department’s Inspector General, reporting these omissions. “It is the unanimous opinion of the structural engineers who have carefully studied this matter,” said Pepper, “that an independent engineering enquiry would swiftly reach the same conclusion.” [8]

Pepper added that his clients, after being ignored by NIST for nearly two years, finally got a response from a NIST public relations officer, who acknowledged that the stiffeners had been omitted. However, besides ignoring the omission of the lateral support beams, this PR officer said that the stiffeners did not need to be considered. Pepper said that his clients were in “disbelief and aghast” that NIST would omit these material features and, when the omissions were brought to NIST’s attention, completely dismissed their critical importance.

NIST’s claim that the collapse of WTC 7 was initiated when Girder A2001 was pushed off its seat at Column 79 is untenable.

With the alleged initiating event ruled out, all of NIST’s claims about subsequent structural failures must be considered baseless and invalid.