FBI calls half of populace with 9/11 doubts potential terrorists

[Gravitycollapse]

121. Jet A burns in open air at about 600 degrees. That was enough to auto-ignite...

Most objects within the building excluding any sort of fire proofing, concrete or the steel itself.

The fire was then stoked by updrafts that occur along the perpendicular surface of excessively tall buildings. Which allowed it to burn at temperatures high enough, including the fact that the fireproofing was knocked from the steel girders,to sufficiently weaken the steel support structure.

The thing is, collapse does not necessitate that the entirety of the steel support structure was compromised. It only requires that enough was compromised to make it incapable of withstanding the weight of the upper floors. Once that limit was exceeded, the upper floors collapsed down. This exerted a far greater strain on the steel and lowered the level at which the steel must have been weakened to foment the collapse. So, the other parts of the support structure that were not sufficiently weakened to give under normal conditions were obliterated because of the extra force exerted from the acceleration of the upper floors.

None of this requires that the fire burn at the melting point of steel. It is in fact the case that the point at which hardened steel begins to become excessively malleable is substantially lower than the melting point of steel.