Yes dear, but the 'global' collapse is when the entire building is falling. The free fall acceleration has been documented and 'peer reviewed' by none other than NIST itself. Your inability to understand this simple fact has left you befuddled.
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Wrong, Chris.
This is another area in which your "English" fails you.
In common parlance, all the components of the collapse could be considered part of a "global collapse". But this is NOT how NIST uses that term in Section 12, which talks about the details & timing of the collapse.
As you have been shown repeatedly now:
See NIST NCSTAR1-9 vol 2
In Section 12.6 Summary of findings [pg 603 (pdf 265)], NIST identifies FOUR distinct time intervals during which the building is collapsing:
Event | Event Name | Start Event / Time | End Event / Time | Reference
1 | Initial Local Failure for Collapse Initiation | floors collapse, -6 seconds (observed) | Column 79 buckles, -1.3 seconds (analysis) | pg 604, pdf 266
2 | Vertical Progression of Failure | Column 79 buckles, -1.3 seconds (analysis) | East Penthouse begins to descend, 0 seconds (observed) | pg 605, pdf 267
3 | Horizontal Progression of Failure | East Penthouse begins to descend, 0 seconds (observed) | North wall begins to descend, 6.9 seconds (observed) | pg 605, pdf 267
4 | Global Collapse | North wall begins to descend, 6.9 seconds (observed) | External wall complete collapse, >11 seconds (observed from video frames**) | pg 606, pdf 268
The start & stop times for these events are referenced to the start of the collapse of the east penthouse
** See NCSTAR1-9 vol 1, Fig 5-213 pg 285 (pdf 329) Figure 5–213. Frame from the Camera 9 video clip in Figure 5–192 shows the north face of WTC 7 11.0 s ± 0.2 s after the east penthouse began to move downward.
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This terminology is also illustrated in Figure 12-74 (pdf page 260), which distinguishes an energy peak "after horizontal collapse progression & global collapse initiation".
And in sections:
12.5.1
Aspects Prior to the Global Collapse
... which discusses Collapse initiation, Vertical Progression & Horizontal Progression.
12.5.2
Aspects Following the Collapse Initiation
... which discusses events starting at the collapse of the North Wall.
And finally, in the "Global Collapse" section (vol 2, page 586, pdf 248), which takes up the narrative "After the horizontal progression of column buckling in the core of WTC 7..."
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Now, you could reasonably argue that NIST
should have used a difference vernacular for the 4th interval, such as "External Wall Collapse", instead of "Global Collapse". But they didn't.
It doesn't matter what vernacular you use, as long as:
1. you understand what NIST really says (which you don't appear to), and
2. you are crystal clear about your usage when talking with others.
tom
That's kinda like one hand clapping, it can't be. If the columns were only connected on one side, then there would be sets of two adjacent columns tied together but not tied to adjacent sets all the way arround the building.
