And just for Tony and his explosive-proof window nonsense; How far away will 9 pounds of TNT shatter glass?
HINT: Not far away enough.
For the sake of logical honesty: One doesn't have to accept the premise that column 79 had to be broken at the location where NIST thinks it broke. In fact, I think Tony disagrees with that scenario. I kinda remember words to effect that, in his asessment, the columns under EMC may hay failed much higher up. I also think that a CD expert might not have targeted such a massive column directly; instead, he might remove bracing first by attacking connections over several floors. If you time these milliseconds apart, you could certainly avoid the huge pressure amplitude of a 9-lb-charge.
In actual highrise demolitions, charges average something like half a pound. For example, the
Landmark Tower in Fort Worth:
R. G. Pickard said:
The explosive charges used to bring down the Landmark Tower weighed only 364 pounds, consisting of 198 pounds of 60-percent nitroglycerine-based gel in 1-1/4 inch sticks, and 166 pounds of RDX (a C-4 derivative). The explosives were supplied by Buckley Powder Company.
To break structural steel, 369 linear shaped armor-piercing charges were required. Concrete columns were broken with the larger charges of RDX ranging from 2 ounces to 12 ounces at a density of 600 grains to 4,000 grains per lineal foot.
166 lbs of RDX, chopped into charges of 1/8 lbs to 3/4 lbs; those are described as the "larger charges", and were used to break concrete columns. If those were on average 1/4 lbs, then there were roughly 600 of those charges.
"198 pounds of ... nitroglycerine-based gel in 1-1/4 inch sticks" apparently were used to break structural steel, coming in "369 linear shaped armor-piercing charges". If I get that right, each linear shaped charge weighed, on average, 0.54 lbs.
At any rate, that should give us an idea. The
Landmark Tower had about 62% the height of
WTC7, but only perhaps 15% of its volume and mass.
ETA: And this is how it sounded when these quarter-to-half-pounders were detonated, "with 120 different sequenced and delayed detonations of 8 milliseconds or greater" (i.e. ca. 3 pounds of explosives going off simultaneously):
AWESOMELY, unmistakably loud (but didn't break glass on neighboring blocks).
Demo work on the Landmark Tower began 4 months prior to the day it was brought down. I suppose most of this was cleaning out the building, removing windows, and laying bare the structural elements.