“Supposedly, they were not subject to burning, but I can’t see how.”
I have a cousin that builds non typical homes. Rammed earth, straw bale, shipping containers, super adobe.
You can take a propane brush torch to a straw bale wall and it won’t burn. First it’s covered in cement spray coated over a thin wire mesh held in by pins.second it’s so densely packed inside that oxygen cannot get to the individual straw fibers is a solid mass. The insulation value of the straw is so high even with fire outside it the inside of the wall would be as t room temp. A raw highly compressed straw bale not covered in cement when you torch it smolders and chars without actively burning it’s too packed to burn anything but the outside layer slowly away, much like an ablative reentry heat shield. Straw bale with metal roofs and tempered windows would have survived these fires for sure. These are high radiant heat wind driven fires much like a firestorm the heat pulse is high and quick but they move on fast too. The chances of the cement spray coating failing is slim and even then a extended char event would still leave the structure standing.
Of course rammed earth , super adobe, and bagged earth structures cannot burn either.
Thank you.