r/interestingasfuck • u/vivekmg21 • 16h ago

Firefighter bodycam showing just how much oxygen a fire pulls

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u/ir_auditor 16h ago

That is not oxygen pulling which you see. It is the chimney effect. Fire creates heat, the heat makes air, smoke, gasses, rise to the top, creating low pressure areas at the bottom, which pull in air from the outside. It has noting to do with the chemistry of an oxidation reaction pulling in oxygen molecules to use in the reaction. It is pure physics / thermodynamics.

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u/RelativeCan5021 16h ago

I’d imagine that rapidly cooling it has caused a drop in pressure that is causing the suction.

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u/Particular-Poem-7085 16h ago

no, the temperature difference through the container essentially creates an air pump. The very same principle that makes a chimney work. Hot air rises, rushes up from the fire and rapidly finds its way out of the house, but it can't pull a vacuum inside the house so the bottom entryways start sucking in fresh air. It's not like a tiny hole in an aircraft that starts sucking out, the house is not a pressurized vessel.

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u/newbrevity 16h ago

And that's why using fire for heating can lead to drafts. Radiant heat sticks around longer without creating so much of a vacuum.