muddyboots wrote:
dude, almost ANYTHING can get hot enough to weaken steel when it's in a wind tunnel and gets enough oxygen. How do you think smiths heat iron and steal up? Lots of fuel and lots of oxygen.
Ask one of our firefighter friends how hot a good forest fire can get with lots of wind and lots of dry wood.
Quote:
Jet fuel burns at 800º to 1500ºF, not hot enough to melt steel (2750ºF). However, experts agree that for the towers to collapse, their steel frames didn't need to melt, they just had to lose some of their structural strength--and that required exposure to much less heat. "I have never seen melted steel in a building fire," says retired New York deputy fire chief Vincent Dunn, author of The Collapse Of Burning Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to expand at both ends, but when it can no longer expand, it sags and the surrounding concrete cracks."
"Steel loses about 50 percent of its strength at 1100ºF," notes senior engineer Farid Alfawak-hiri of the American Institute of Steel Construction. "And at 1800º it is probably at less than 10 percent." NIST also believes that a great deal of the spray-on fireproofing insulation was likely knocked off the steel beams that were in the path of the crashing jets, leaving the metal more vulnerable to the heat.
However, the idea that fire temperatures -- much less steel temperatures -- were anywhere close to 1800º F runs contrary to experience with building fires. Fire tests by Corus Construction recorded maximum steel temperatures of about 680ºF in UNINSULATED parking garages. The claim that insulation was knocked off the WTC steel is routinely invoked in defenses of the official story to make the weakening of the steel seem more plausible.
But jet fuel wasn't the only thing burning, notes Forman Williams, a professor of engineering at the University of California, San Diego, and one of seven structural engineers and fire experts that PM consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified by the combustible material inside the buildings, including rugs, curtains, furniture and paper. NIST reports that pockets of fire hit 1832ºF.
"The jet fuel was the ignition source," Williams tells PM. "It burned for maybe 10 minutes, and [the towers] were still standing in 10 minutes. It was the rest of the stuff burning afterward that was responsible for the heat transfer that eventually brought them down."
a popular mechanics article. With plenty of atribution, people you can actually look up and find in a google search. I believe them.