Question

At what temperature do steel beams melt, And what temperature is jet fuel when exposed to fire. The jet fuel temperature is not enough to melt steel beams, So how did the twin towers fall.

Answer 1

Steel beams have different grades but in general they melt around 2500F. Jet fuel burns at 800° to 1500°F, not hot enough to melt steel. But the prolong exposure of steel beams to the high temperature fire from jet fuel weakened them. With the beams weakened, the buildings collapsed eventually.