How do public water pipes not freeze in very cold weather? If house pipes freeze easily when there isn’t enough heat to keep the water in a liquid state, then why don’t pipes under the street freeze?
In: Engineering
They are buried below the frost line. They are kept deep enough that the radiant heat of the earth keeps them above freezing. This is usually about 4 feet deep as a decent safety margin in the lower 48, not sure about Alaska though, I bet they go deeper.
A major factor is that the ground is a pretty dense insulator against the cold. Also, sometimes the pipes that emerge from the ground outside do actually freeze and sometimes rupture.
I would not have guessed that thermal heat underground would be enough to combat the cold. Thanks for the responses.
Here in Alberta (Canada) the frost can reach 4′ so we bury pipes (and building foundations) lower than that so they aren’t exposed to freezing temperatures. Pipes are generally buried quite a bit deeper than that…up to 8′ or even more.
The ground has a very good capacity to keep things warm. If you bury it under 6 feet of dirt I can assure you it’s a very good isolation. Also they’re bigger and so they freeze less easily bc there’s more water to freeze
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