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I am wondering what the chemical validity is of jet fuel actually melting the steel beams that held up the twin towers during the September attacks.

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Jet Fuel type A (Jet A) burns at approximately 2,230 °C. 0.2% carbon steel has a maximum forging temperature (i.e., the point at which it'll melt) at about 2410 °C, while 1.5% carbon steel is at about 1920 °C. This also doesn't take into account effects that happen with how aerosolized jet fuel will burn, which is, much hotter, and strange effects that'll happen as everything else has it's surface area very spontaneously increased, subjected to a large amount of kinetic energy at once, and then lit on fire.

Not to mention everything else burning at the same time. Finely shredded aluminum is very flammable.

Also: As a final note: The steel didn't actually have to melt, persay. It only had to weaken enough that the mechanical forces of the skyscraper that it was supporting became too great for the softened steel, at which point it'll all collapse in a chain reaction.

TL;DR: Conspiracy theories are BS.

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  • $\begingroup$ Also, thermite reaction. $\endgroup$ – Ben Norris Jun 13 '16 at 21:21
  • $\begingroup$ Doubtful, but possible. The grain size needed would be difficult to attain. $\endgroup$ – orlando marinella Jun 14 '16 at 0:22
  • $\begingroup$ You've got ALL facts and numbers wrong. "Jet fuel" does not have such a defined temperatue when burning, that depends a lot on circumstances. The aerosol created on impact burns away immediately, consuming all the oxygen, leaving the bulk of the fuel to just burn steadily with air flowing in from outside. Iron melts at 1536°C, steel slightly below, depending on carbon content etc. Steel is forged at 950-1250°C. To ignite aluminium, you have to powder it. How should a plane crash do that, esp. when it melts at 930°C? $\endgroup$ – Karl Jun 14 '16 at 23:02
  • $\begingroup$ Karl: There's many different factors. I took the value of the maximum temperature of Jet Fuel Composition A, used in the United States since the 1960s, as a reference. From there, you don't need to melt the steel, like I said. In fact, jet fuel probably can't melt steel beams. All it needs to do is threaten the structural integrity of the beam, and the whole thing would come down around it. Also, I specifically mentioned that a termite reaction or any kind of explosive reaction involving aluminum is extremely unlikely. Also, there's a very strong possibility that the aerosolized jet fuel burnt $\endgroup$ – orlando marinella Jun 15 '16 at 0:26
  • $\begingroup$ at a much higher temperature. This is a well observed phenomenon, and is the primary mechanism for fuel-air explosives. $\endgroup$ – orlando marinella Jun 15 '16 at 0:26

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