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Cold Water And Fire

Everyone wants to know what to in case of a fire. Will cold water work better?

emergency fire hose

Photo: Shazz Mack (flickr)

Technically cold water will douse a fire faster than hot water, but of course it's not that simple.

Would cold water put out a fire faster than hot water?

One of the main ways water puts out a fire is by cooling the burning material to below the temperature at which it burns, so it would seem a good assumption that cold water would work better at extinguishing fire.

Cold Water… Brr

Technically cold water will douse a fire faster than hot water, but of course it’s not that simple.

Remember, water takes heat from the fire, it cools it. The main way it takes heat from the fire is by becoming steam. When the water hits the fire and turns to steam it absorbs a lot of heat, making the burning material too cool to burn.

Although it is true that technically cold water will put out a fire faster than hot water, most of the cooling effect comes from changing the water into steam, not from raising the temperature of the water. In fact there’s less than a 1% advantage in using cold water.

  • dimitri poppeliers

    How was 1% figure determined?  Raising water from 70 to 212 deg-F requires 140 Btu.  Turning it to steam takes another 900 Btu.  That’s closer to 10%?

  • dimitri poppeliers

    OK I forgot we’re comparing cold 32 deg water to 70 deg room temperature water.  So that difference is 40 Btu out of 1080 to take it to boiling which gives you 4%??

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