I've been a Cornell Staff member for about thirty years, and pretty much every work day, I work with metal. Mostly machining, but also, bending, shearing, welding, annealing, heating, heat treating, etc.. One thing I've learned through my experience, is that gradually heated steel loses its strength gradually, not instantly. Since WTC7's free fall and symmetric drop displayed all the characteristics of a controlled demolition, and none of a fire induced collapse, I've always been skeptical of the government's "explanation" - that gradual heating of parts of the steel frame due to limited office fires caused WTC7's drop.