WTC 7 Collapse (11 Sep 2001) — and the Contested Initiation
eventIntelligence & Surveillance
A 47-storey building that nobody flew a plane into came down at 5:20 that afternoon - and for about two and a quarter seconds it fell as fast as a dropped stone.
Who they are
The collapse of World Trade Center Building 7 on 11 September 2001[1].[2][3]
What they do
The engine holds the dispute, not a side. What the two sides disagree about is narrower than people think.
How it works
The government's own investigators say the building burned for nearly seven hours and then collapsed because heat made a floor beam expand and push a girder off the shelf it was sitting on, starting a chain reaction. They also say, in their own report, that part of the fall happened at free fall - no resistance at all - for about 2.25 seconds across roughly eight floors, 105 feet. A team at the University of Alaska Fairbanks spent four years modelling it and concluded the opposite: that fire did not cause it, and that only every column failing at almost the same instant explains what the videos show. Their study was paid for by a campaign group, Architects & Engineers for 9/11 Truth, which their own report states on its cover.
Why it matters
Both sides agree the free fall happened. They disagree about what caused it. The engine names no verdict. Two things the popular account gets wrong are corrected here: the girder label everyone quotes as the government's is not the government's - it appears nowhere in 1.78 million characters of their reports - and the building's tenants included the SEC, the Secret Service and the CIA.
The engine's record — word for word
47-storey steel-framed building north of the main World Trade Center complex. NIST NCSTAR 1A, verbatim: WTC 7 "endured fires for almost seven hours, from the time of the collapse of the north WTC tower (WTC 1) at 10:28:22 a.m. until 5:20:52 p.m., when it collapsed. This was the first known instance of the total collapse of a tall building primarily due to fires." THE KINEMATICS NIST ITSELF RECORDS: "a freefall descent over approximately eight stories at gravitational acceleration for approximately 2.25 s", covering "approximately 8 stories or 32.0 m (105 ft), the distance traveled between times t = 1.75 s and t = 4.0 s". THE INITIATION NIST PROPOSES: thermal expansion drove a floor girder off its seat — "This movement was enough for the girder to walk off of its support at Column 79" — modelled in ANSYS for the initial failure event using thermal data for "the lower 16 stories". TENANTS, NIST Table 1-1: U.S. Securities and Exchange Commission (floors 11-13), U.S. Secret Service (floors 9-10), Central Intelligence Agency (floor 25, alongside IRS and Department of Defense), New York City Mayor's Office of Emergency Management (floor 23). THE DISPUTE, both sides in their own words. University of Alaska Fairbanks, Hulsey/Quan/Xiao, March 2020: "The principal conclusion of our study is that fire did not cause the collapse of WTC 7", requiring instead "the near-simultaneous failure of every column in the building"; they argue "NIST, by its own admission, did not include the partial height web stiffeners". FUNDING DISCLOSED: that study states on its own cover "Prepared for: Architects & Engineers for 9/11 Truth" and thanks AE911Truth "for providing the funding to conduct this research". NIST'S SIDE, equally: NCSTAR 1-9 section 8.7.4 is titled "Absence of Shear Studs on Girders" — the shear-stud question was addressed, not ignored. NOT HELD: the designation 'Girder A2001', which appears ZERO times across NCSTAR 1A and NCSTAR 1-9 combined (1.78 million characters) and is the UAF label, not NIST's. NOT HELD: a free-fall duration of 2.5 seconds; NIST's free-fall figure is 2.25 s, and its 2.5 s refers to the failure of Truss 2 and Columns 77-78. The engine names no verdict on initiation. The free-fall interval is not in dispute between the parties; the mechanism that produced it is.
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