Even under perfect air-fuel conditions, there's just not enough energy in the reaction of a gasoline-air thermobaric weapon to heat the mass of the air and the fuel to 15,000 degrees.

Even the best thermobaric weapons rarely exceed 5,400 deg F.

The City of Bellingham Fire Department is a bit less well educated that I'd hoped a fire department might be!

However, in a furnace-like environment, such as a burning building can tend to be, the internal temps can, under certain temperatures, become much hotter, but only when the air, and to a lesser extent, the fuel, is pre-heated by the fire itself. Even then, I seriously doubt it exceed 7,000 deg F.

Apparently, the

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I am Mugs, of the Alien clan of Usa, Nordamerica, a Terran, of Sol. A human.

Whoever says "perception is reality" is daft. It's merely an abstraction, and often not a very good one.