Burning jet fuel on the ground burns at 550F, when it is compressed into a turbine engine and mixed with alot of oxygen it burns at 1500F. 99.9% of the jet fuel burned up in the initial explosion, there might have been enough fuel left over to burn for a couple minutes maximum. Why people think that the explosion didn't burn up all the jet fuel is beyond me. After the first couple minutes the fires were all ordinary office fires, which by the way were bandied about as the reason the fires weakened the structure. No where did the commission state that it was the jet fuel that caused the fire to get so hot, they say it was the office furniture that did it. So if office furniture can do that, how come it didn't do it in Beijing? Because office furniture cannot do that.This building did not have its steel melt because it was normal combustibles burning. In the trade center, it was burning jet fuel. There is a HUGE difference in the burning temps of jet fuel versus wood and plastic.
Jet A Fuel must reach ASTM specification D1655 (Jet A) [4]
Jet A-1 Jet A Flash point > 38 °C (100.4 °F) Autoignition temperature 210 °C (410 °F) Freezing point < −47 °C (−52.6 °F) < −40 °C (−40 °F) Open air burning temperatures 287.5 °C (549.5 °F) Density at 15 °C (59 °F) 0.775 kg/L to 0.840 kg/L Specific energy > 42.80 MJ/kg
Steel Melts at 2,500F, and loses 90% of its strength at 1300F. 550 is no where close to 1300.
The wind load controlled the design allowables. The WTC, on this low-wind day, was likely not stressed more than a third of the design allowable, which is roughly one-fifth of the yield strength of the steel. Even with its strength halved, the steel could still support two to three times the stresses imposed by a 550°C fire.
Lets not forget that all of the metal in the Twin Towers were covered with a slurry of Asbestos, basically asbestos was glued onto all the exposed metal work so that a fire would not have much effect. Guess how resistant to fire Asbestos is? you need fires in excess of 2500F to do anything to it. Even if a little was torn off by the plane, 99.9% of it is still in place. A floor on fire does not become heavier, all the floors below the impact site should have never collapsed, each floor is designed to hold up many more times weight than what they actually do, to get the floors to crush you would need approximately the weight of 8 WTC towers on top to cause such an effect.