Sunday, May 23, 2010
The Physics of WTC 7
Posted by Adam Taylor
About a month ago I had a debate with several debunkers at once about the collapse of WTC 7. In particular, we debated about the period of free fall that occured during the collapse. Here are some of the more memorable responses I got from them:
"I'm still gonna say wiping out 30 meters of supports is too fucking obvious for a secret op." -Weirdo10o4
(Apparently it wasn't that obvious, as NIST needed a high school teacher to point it out to them.)
"consider that I can roll a bowling ball down a long flight of stairs. As it rolls down the stairs, it spends time in free fall--between each stair" -EdgemanLL2
(The very obvious difference of course is that when a ball rolls down the stairs, nothing is removed and the ball only free falls for a few inches. Building 7 was in free fall for about 100 feet, or 1/6 of its height.)
"It wouldn't need to give up any of its energy to buckle or crush anything." -CaptMandrake360
(I almost didn't even know how to respond to that.)
The main person I was really debating with was the infamous RKOwens4, who apparently thinks that NIST actually predicted the period of free fall.
"The only point I'm trying to make is that NIST DID predict it and DOES have an explanation for the 2.25 seconds of free-fall. So don't go around saying, 'The 2.25 second free-fall came as a total surprise to NIST' or 'NIST can't explain why the building fell at free-fall for 2.25 seconds.'
As I said, the NIST report on WTC7 actually PREDICTED a 2.25 second free-fall of WTC7, due to the buckling of 8 floors near the base of the building." -RKOwens4
I wasn't entirely sure how Mr. Owens came to this conclusion, as there was nothing about the building entering into free fall in NIST's draft report and, as mentioned above, David Chandler was the one who had to point it out to them. But perhaps he believes NIST's calculations did predict the free fall and NIST was just simply unaware of it. This seems unlikely though, when one looks at the differences between the Draft Report and the Final Report:
The Draft Report stated:
"The collapse time of the upper 18 floors of the north face of WTC 7... was 40 percent greater than the computed free fall time. This is consistent with physical principals." -NIST NCSTAR 1-9, Draft for Public Comment, 610
However, the Final Report states:
"The observed descent time of the upper 18 stories of the north face of WTC 7... was 40 percent greater than the computed free fall time. A more detailed analysis of the descent of the north face found three stages: (1) a slow descent with acceleration less than that of gravity that corrosponded to the buckling of the exterior columns at the lower floors, (2) a freefall descent over approximately eight stories at gravitational acceleration for approximately 2.25 seconds, and (3) a decreasing acceleration as the north face encountered resistance from the structure below." -NIST NCSTAR 1-9 (Final Report): 607
Note that the phrase "consistent with physical principals" is completely absent from NIST's newer passage. In fact, "consistent with physical principals" appears nowhere in NIST's final report. There is a "consistent with" statement in the final report, but it says nothing about physical principals. After giving its three stage analysis, NIST states: "The three stages of collapse progression described above are consistent with the results of the global collapse analyses discussed earlier in this chapter." -NCSTAR 1-9 (Final Report): 603
Basically, what NIST is saying is that its three stage analysis on this page is consistent with its three stage analyses on earlier pages! How nice of NIST to assure everyone that a later part of their report agrees with an earlier part of their report. It's apparently not consistent with physical principals, but it's consistent with their report! In any case, these facts show that there was absolutely no indication prior to publishing their final report that they had predicted free fall at all. It was one thing they said was impossible. However, this too was a detail Mr. Owens disagreed with:
"Can you provide me with a link to where they ever said that any period of free-fall would have been impossible from a fire-induced collapse?" -RKOwens4
I do wonder if Mr. Owens has actually watched NIST's technical briefing.
I also briefly discussed how the fires could not have been hot enough to cause the collapse in the first place. Mr. Owens was (not surprisingly) unconvinced.
"Now, go read the report and explain to me WHY expanding floor beams pushing the core columns out of alignment was not enough to cause the building to collapse. Tell me why, specifically." -RKOwens4
Specifically, because the fires could not possibly have been as hot as NIST stated to do that.
"raising those five floor beams to a temperature of 600°C would require an enormous amount of energy, far more than was available from the burning of the office furnishings underneath the floor beams." -Kevin Ryan
Debunkers can easily hand wave away Kevin Ryan's statement, as he is a "truther" and therefore has no credibility. But unfortunately for them, even Dr. Frank Greening, a long time debunker, agrees that the fires could not have been as hot as NIST says.
"NIST's collapse initiation hypothesis requires that structural steel temperatures on floors 12/13 significantly exceeded 300°C [570°F]--a condition that could never have been realized with NIST's postulated 32 kg/m2 fuel loading." -Dr. Frank Greening
While Dr. Greening does not believe the building was demolished, he does agree that NIST's report is false.
The above three videos are basically my response to these debunkers who feel there was nothing strange about the free fall of WTC 7.
Far from solving the mystery of WTC 7's collapse, NIST has done nothing but created more mysteries. And debunkers have certainly not solved them.