EVD-106
NIST NCSTAR 1A: WTC 7 collapse initiated by fire-induced buckling of Column 79
engineering reportofficial governmentauthenticoriginal
Provenance
- Source
- NIST NCSTAR 1A — Final Report on the Collapse of World Trade Center Building 7 (2008)
- Date
- 2008-11-20
- Page
- NCSTAR 1A Executive Summary
- SHA-256
- 9613584f374cb8de3aa2e82b0f84d0dc18addf3a71770e691739ec5e81892b1f
- Classification
- unclassified
- Copyright
- public domain
https://nvlpubs.nist.gov/nistpubs/Legacy/NCSTAR/ncstar1a.pdf
Quality 3.88 / 5components retained
Prov5
Auth5
Ind2
Contemp2
Corr4
Spec5
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Chain4
Observation
NIST attributes WTC 7's collapse to fire-induced failure beginning at Column 79, with global collapse at 17:20.
Interpretation
Official H005 support. Uniqueness of the event is a fact about the historical record, not automatically a proof of the mechanism.
Source text
INTERPRETATION (NIST 2008): Fires following debris impact from WTC 1 caused thermal expansion that failed a key girder, leaving Column 79 unsupported over nine stories. Its buckling produced the east-penthouse descent and then global collapse at 17:20:52. NIST states this is the first known instance of a tall building collapsing primarily due to fire. Alternative investigators treat that uniqueness as a reason to doubt, not as confirmation. Hulsey (EVD-123) later modelled that fire would not produce the observed symmetry.
Hypothesis linkage
NIST Column 79 fire-induced sequence.
NIST fire-only probable sequence.
NIST fire sequence, no demolition order.