I had to make that point to someone here or another thread who said "how can it spread when the walls are made of steel?"
Well, lots of people are idiots about that sort of thing. I’m not Navy; I’ve never served a day in anyone’s military, but I’ve seen the phenomenon in action in civilian life.
A ‘good’ civilian example of how that works (to try to explain it to people that don’t get it) is a car having a catalytic converter fire. The catalytic converter is of course in a metal shell, and it is separated from the interior by the metal body of the fire. At the same time, though, the cat can get hot enough to ignite the carpet and other interior components of the car on the other side of the metal floorboard, despite the air gap and the fact that the fire is still contained in the converter itself.
If your car suddenly smells like burning interior materials and you pull over and the catalytic converter is glowing bright yellow to white under your car? Yeah, your car interior is about to go up. Cat-con fires burn at 2000-2400F.
Er, “the metal body of the fire” should be “the metal body of the car”.