Freezing pipe bursting mechanism


OK, this thread is as attractive to trolls as any, but for serious discussion- what is the actual mechanism of a pipe cracking/bursting due to the water freezing?
OK, we all know water expands when frozen, and this is the root of it, but beyond that... I'll sketch out what I believe the mechanism is using a series of examples.
make a big "U" out of a copper pipe, like this:
| | | | -----------------------------------
fill that puppy with water. Freeze under the following conditions:
1) leave ends open, start freezing at middle, freeze whole pipe working out towards the ends. predicted outcome- no burst pipe
2) Leave right-hand end open, seal left-hand end. Freeze from left to right predicted outcome- no burst pipe
3) Leave right-hand end open, seal left-hand end. Freeze from right to left predicted outcome- burst pipe
4) leave both ends open. Freeze from ends towards middle. Predicted outcome- burst pipe.
Further prediction: the point where the pipe cracks/bursts will be at a point where there is water in the pipe, not ice.
Discuss.
Dave
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snipped-for-privacy@yahoo.com wrote:

You forgot:
5) Put closed valve at one end. Freeze from middle or other end towards valve. Burst pipe.
6) Put closed valves at both ends. Freeze from anywhere. Burst pipe.
More generally....block the pipe in two places, then start freezing the enclosed water. It's got nowhere to go, so it bursts the pipe.
Chris
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I've seen some pipes that have burst.
Before the pipe bursts, is will swell up. This forms a reservoir which only makes the problem worse because there is more water to freeze the next time and the plug can't move up or down the pipe.
I've seen a really big bulb in copper, maybe 2 inches on a half inch pipe. Galvanized should swell less before breaking.
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wrote:

I've seen stainless steel tubing 1/8" in dia balloon to about 1/2" for approx 1" in length. This occurred over time as trapped water went through many freeze/ thaw cycles before it finally split along the sausage like aneurism. As a note, to illustrate the power of expanding ice, it takes about 20,000 psi (tension) to cause such a failure. This actually happened on a aircraft part and it was jet fuel that leaked out all over the rear of the aircraft and onto the tarmac. If it wasn't noticed and the engines started it would have blown everything sky high. MLD
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snipped-for-privacy@yahoo.com wrote:

As freezing conditions a not normally a 'point source' problem, it is most likely that it will start to freeze over several feet of pipe. Even with both ends open it is stillpossible to wind up with a broken pipe. The interior of pipe is rough (galv) and you can get one or more 'ice plugs' and cause a burst between them.
Haryr K
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snipped-for-privacy@yahoo.com wrote in

That's an awfully small dog.
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snipped-for-privacy@yahoo.com wrote:

With the above conditions I would say that the pipe bursts at the last point to have water - not "where there is water". Obviously the ice expanding that breaks the pipe. If the section of pipe with water is sealed from both ends, either valve or ice, it will break.
Perhaps one of the reasons that although I never blow out my sprinkler lines I have never had a broken pipe. That and having black plastic. The lines drain such that the only water is at the very end of the lines. I expect that evaporates before it gets cold enough to freeze.
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A couple years ago the feds mandated new faucets leak under the severe pressure like over 10K PSI to minimize burst pipes when freezing.
it was a good idea. sorry i read this awhile ago but dont have a link
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