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Rich256

wrote:
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

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.