First, I want to express my gratitude to you for sacrificing your valuable family time on a Sunday to instruct us on the vagaries of sprayed fire resistant material. I feel that others on this forum don't show you the appreciation you deserve, but I hope that by the time your fourth anniversary on Topix arrives (soon!), we can all pull together and demonstrate how much we have learned from you, so that you will not feel all your teaching efforts are for naught. You are a tremendous asshat to this humble community, but I fear we do not show our appreciation for your gifts of time and wisdom.<quoted text>
Fire retardant isn't designed for large scale fires on multiple floors that input heat into a system for hours on end. It's designed for typical office fires where passive and active fire protection systems can allow for people to escape and for fire fighting to take place.
Your idiotic canard that free fall=demolition still has zero qualification and you making the exact same ignorant claim over and over with various proxy induced socks will not make your wet dream come true. All NIST is commenting on regarding the transfer loading assembly over the ConEd power station is that fire didn't directly cause it to fail and that the global failure of the structure was causedby column 79 which was integral to the overall structural stability of the building.
The very simple reality is that fire can and does cause conditions in steel structures where the threat of structural failure is very real. There are no reputable materials experts or engineers arguing against that fact. NIST's theory isn't that fires were present in one area for long periods of time causing failure in that particular spot. It's theory is that the fires caused damage in various locations and that the accumulated damage from conditions such as thermal heating and linear expansion created stresses not designed for in joints which ultimately failed....
That being said, I confess I am confused over the significance of SFRM ratings. Could you please explain how a 3-hour protection rating for steel insulation could be defeated by a 20 to 30 minute fire, fueled by typical office contents? The insulation is not designed for this? Also, given that steel is a thermal conductor and that heat is constantly being wicked away from the fire zones and radiated away, how could steel temperatures rise to the point where structural failure manifested?
When you say that heat was inputed into the system for hours on end, what was preventing the system from radiating that heat away just as quickly? From the videos available, it appears that the vast majority of WTC-7 was not affected by fire at any given time, and so the heat inputs into the system were far outweighed by distributed "heat outputs."
I eagerly await your answer.