incendiary that includes sulfur, would explain the sulfidation and formation of a liquid eutectic (Jones, 2006 and 2007). These anomalies combined with the fact that there is no prior instance of a tall building undergoing total collapse due to fire led us to reevaluate the hypothesis of fire-induced failure for the collapse of WTC 7.
Figure 1.6 WTC 7 was in free fall for approximately 2.25 seconds over a distance of approximately 8 stories or 32.0 meters (NIST, 2008, NCSTAR 1A).
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