Eli5 – does boiling water work as efficiently to put out a fire as cold water or even room temp water?

Question

Or does the molecular structure change in a certain way once heated, and in turn can steam put out a fire.

In: Chemistry

Answer 1

Converting water to steam takes ~5-6 times as much energy as heating it from cold water or room temperature to the boiling point. The boiling water can absorb a bit less energy before it’s gone, but the difference isn’t that big. If you have enough water then you still have the other effect – removing the oxygen supply.

Pure steam can put our a fire, too, by displacing the oxygen (and potentially cooling the fire a bit, depending on its temperature – but not as efficient as water). But you’ll need a lot of steam to do so, and probably some closed room. Which is dangerous on its own.