The Killer Fires Theory is Pure Fantasy
The simple facts of temperatures:
- 1535ºC (2795ºF) - melting point of iron
- ~1510ºC (2750ºF) - melting point of typical structural steel
- ~825ºC (1517ºF) - maximum gas temperature increase
imparted by a hydrocarbon flame
burning in the atmosphere without pressurization or pre-heating
(premixed fuel and air - blue flame)
Diffuse flames burn far cooler.
Oxygen-starved diffuse flames are cooler yet.
The fires in the towers were diffuse -- probably well below 800ºC.
Their dark smoke showed they were oxygen-starved --
particularly in the South Tower.
Containment of heat can elevate temperatures a few hundred degrees,
but temperatures above 1100ºC are at the upper end
of fire compartment tests.