NIST WTC 7 omissions

In a letter dated July 11, 2014 to Senator Barbara Boxer of California, Jim Schufreider, representing NIST, admitted (albeit indirectly) for the first time that NIST omitted the lateral support beams in its final report on WTC 7, published after a 7 year investigation + delay in November, 2008.

Unfortunately Mr. Schufreider’s letter to Senator Boxer made false statements and misrepresentations, probably in an effort to deceive the Senator so as to avoid meaningful oversight. To this day the question remains open whether NIST fulfilled its Congressional mandate in the National Construction Safety Team Act.

On October 1, 2002 the National Construction Safety Team Act (Public Law 107-231) was signed into law by President George W. Bush. The first “specific objective” of this Act was, “1. Determine why and how WTC 1 and WTC 2 collapsed following the initial impacts of the aircraft and why and how WTC 7 collapsed.” (NIST NCSTAR 1A, page xxvii).

Yet when NIST published its Final Report in November 2008 Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7, NIST NCSTAR 1 – 9, (2 volumes, 796 pages) it did not meet the first “specific objective” of this Act. Those of us familiar with NCSTAR 1-9 know of the many omissions and distortions it contained, most notably the incidental admission of free fall for over 105′ without any analysis of how that free fall might have occurred.

Evidence uncovered through a Freedom of Information Act (FOIA) request in late 2011 shows that two key structural features of Building 7 of the World Trade Center were omitted from the NIST analysis of why and how WTC 7 collapsed. These structural features are stiffeners and lateral support beams. If either of those structural features had been included in the NIST analysis, the collapse would not have occurred in the NIST model. This is important because the NIST analysis of WTC 7 relied entirely on computer models and not on the available physical evidence.

The Schufreider letter to Senator Boxer and the Senator’s cover letter to the author and Table 8-2 are farther down on this page.

Here are the drawings and Technical discusion from the William Pepper letter, based on the records uncovered in late 2011 through the Freedom of Information Act.

Technical Discussions

Among the problems with the Schufreider letter are the following. These comments are from engineers familiar with NCSTAR 1-9.

In his letter Schufrieder says “The NIST computer analyses of the WTC 7 collapse showed that G3005 did not fail laterally and therefore, the secondary beams S3007, G3007 and K3007–like the web stiffeners–had no bearing on the final NIST analyses nor on the conclusions drawn from them as to the most probable cause for the WTC 7 collapse.”

However, on page 353 of NIST NCSTAR 1-9 Table 8-2 says the northmost floor beam (that is G3005) began to buckle laterally at 2.10 seconds. Of course, this is with the lateral support beams omitted as seen in Figures 8-22 and 8-27.

As far as the contention that web buckling was not an issue and that is why they left off the stiffeners, that is also complete nonsense, as web buckling was not the failure mode they claim and they are ignoring the effect of the stiffeners on the failure mode they do portend (flange bending). The stiffeners are germane to that failure mode and they are clearly trying to avoid that conversation.

Regarding the stiffeners: The following statement is found on page 488 in NCSTAR 1-9:

Gravity shear loads in a beam were transferred to the bearing seat primarily in the proximity of the web on the bottom flange. Therefore, when the web was no longer supported by the bearing seat, the beam was assumed to have lost support, as the flexural stiffness of the bottom flange was assumed to be insufficient for transferring the gravity loads. Under such conditions, the beam was removed.

The bearing stiffeners prevent flange bending as well as web crippling. The lateral walk-off and removal of critical framing members from the ANSYS model was based on an assumed flange bending failure, so the stiffeners were required to be included in the analysis. In other words: if you leave the door open, obviously the dogs will get out.

Any further justification based on the lack of web crippling is irrelevant. Mr. Schufrieder is the Director of the Congressional and Legislative Affairs Office. He has either not read NCSTAR 1-9 carefully, and/or he does not understand it. Most likely he is simply parroting Mr. Newman’s response to David Cole

(End of engineers’ comments.)

The 2nd engineer was referring to the following NIST email, which prior to July 11, 2014 was NIST’s most detailed response regarding the stiffeners and lateral support beams.

To: (email address of attorney William Pepper)
Sent: 4/14/2014 4:06:31 P.M. Eastern Daylight Time
Subj: NIST Response to Your Letter to the Commerce OIG

Dear Dr. Pepper,

NIST has thoroughly reviewed the assertions in your letter to the Department of Commerce Office of the Inspector General dated Dec. 12, 2013 (received by NIST on Jan. 14, 2014), regarding our investigation of the collapse of World Trade Center 7 on Sept. 11, 2001. Based on our review, NIST finds no reason to modify or change our findings and conclusions.

As previously indicated when presented with similar questions, NIST remains confident of the technical work contained in the final report of the WTC 7 report issued on Nov. 20, 2008.


Michael Newman
NIST Public Affairs


Michael E. Newman
Senior Communications Officer
Public Affairs Office
National Institute of Standards and Technology
100 Bureau Drive, Stop 1070
Gaithersburg, MD 20899-1070

Senator Boxer cover letter July 11 2014 to MG

NIST Jim Schufrieder letter July 11 2014 p1NIST Jim Schufrieder letter July 11 2014 p2Table_8-2