Comment: thanks, the approach is not to guess at how much heat (fuel)

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thanks, the approach is not to guess at how much heat (fuel)

was available for absorption but how much had to be available to reach a given temperature. One ton of carpet/upholstery etc. per worker if thirty floors were on fire is clearly not believable, (this is only to bring the structure to 1800F, far short of melting.) Since the fires were likely confined to nearly ten floors at most, this would increase the carpet requirement to 3 tons per worker, burning with blast furnace efficiency.

You don't have to worry about steel absorbing heat faster than it can be dissipated, and melting in one place, until you reach the kinds of temperatures you find in a blowtorch. I'm not sure what the minimum temp is, but an oxy-acetylene blowtorch will hit temperatures of 5000F to 6000F, which is how it cuts steel. By thermal diffusivity I think you do mean thermal conductivity, which in steel, like all metals, is high. Steel containing 0.5 percent carbon has a thermal conductivity of 18.23 W/(K)(m) (Watts per Kelvin Meter, basically how fast heat will travel through a given quantity of metal.)

Now lets add up all the carpet, computer plastic, chair plastic and upholstery we can think of which might be present per worker and see if we can get to one ton if 30 floors are burning hot, 130 tons per floor, 3 tons per worker if ten floors are burning. All with some kind of forced air supply blowing into it like a giant bellows. We're working backwards, so to speak, not to show what is possible, but to show what is impossible.

A man who views the world the same at fifty as he did at twenty has wasted thirty years of his life.
-- Muhammad Ali