Brian Ross wrote on Sep 21
st, 2019 at 2:23pm:
The fires did not burn hot enough to melt steel or for the steel to fail because of the heat it absorbed, the fires as evident by the black smoke were fuel rich diffuse fires which burn between 500°C to 700°C.
This temperature will reduce the steels yield point and ultimate tensile strength but it is not enough to bring down the towers, don’t forget the structural steel in the towers would have had a safety factor of between 1.5 to 3 as standard if not more.
The maximum temperature of the fire would have been realised within the first 30 seconds of the explosion while its radiative heat intensity may have been initially high it was not concentrated as we saw from the blast and most would have gone into the atmosphere, the big fire ball.
What was left of the unburned jet fuel created the black smoke which in itself reduces the radiative heat of the fire even further, so the fires didn’t burn hot enough to melt steel and they didn’t burn hot enough for the steel to fail structurally.
We have seen many examples of building burning for days lit like a torch and yet never in the history of modern high rise buildings has fire brought one of them down, the twin towers are the exception and not the norm.
Now about the refractory lining of the steel structure, while I agree with you in principle that some of the refractory lining would have come off the steel structure around the impact zone ONLY in my opinion not enough would have come of and that’s beside the point because like I said above the fires were not hot enough to cause collapse through heating of the steel.
The refractory lining a few floors further from the impact zone would not have come off.
You make it sound as though all the refractory lining from top to bottom of the steel structure just peeled of once the planes hit.
Refractory lining once it sets is like concrete, trying to get it off is not easy, you will need a jack hammer, easy to apply not easy to remove.
NIST the people that denied all the non-government engineers and architects who wanted to inspect the site to determine why the buildings fell for future design best practice. The people that instead of creating the greatest forensic site ever over at least 6 months, had the steel cut and shipped to china within a month, these same people that didn’t let anyone else on site bar themselves, you want me to believe those people.