6. NIST’s Evidence for Fire-Induced Failure

NIST investigator John Gross poses next to a piece of eroded, sulfidated steel from WTC 7 in October 2001.

6

NIST’s Evidence for Fire-Induced Failure

This chapter provides an overview of the analyses that NIST performed to support its hypothesis of fire-induced failure. The areas that will be examined include NIST’s analysis of “hypothetical blast scenarios” in WTC 7 and the possible use of thermite, NIST’s estimates of fireproofing dislodgement in WTC 1 and WTC 2, NIST’s testing of the steel temperatures, and NIST’s computer modeling.

In the last three chapters, we examined the evidence regarding the structural behavior of WTC 1, WTC 2, and WTC 7 during their destruction, as well as evidence showing the occurrence of high-temperature thermitic reactions. We found consistently that NIST either denied the evidence, ignored it, or provided speculative explanations not based upon scientific analysis. By contrast, the hypothesis of controlled demolition readily, simply, and completely explained all of the evidence examined.

In this final chapter, we will turn to evaluating the analyses that NIST performed to support its hypothesis of fire-induced failure. To guide our evaluation of NIST’s analyses, we will bring back the scientific principle discussed in Chapter 1: “Unprecedented causes should not, without good reasons, be posited to explain familiar occurrences…. [W]e properly assume, unless there is extraordinary evidence to the contrary, that each instance of a familiar occurrence was produced by the same causal factors that brought about the previous instances.”

Because NIST’s hypothesis involves an unprecedented cause to explain three instances of a familiar occurrence in one day, each of which exhibited nearly all of the features of the same causal factor that brought about previous instances of that occurrence — namely, the procedure known as “controlled demolition” — the question we will ask is whether