PVC water pipe freezing – A study of what it takes to break the pipe

In the winter of 2017/18, I performed a careful study of what it takes to break a pvc water pipe through freezing.

I created a series of 1 foot pipes and filled them with different amounts of water to see how much water it takes to break. A second set of pipes had 100% filled pipes but with differing concentrations of anti-freeze.

I also tested a larger set of PVC in case size matters and poly black pipe to see how it fared.

What I found out and subsequently learned was this:
1) Only one pipe broke, and it did so on the first night. The 100% water filled pipe. I had a 90% filled which never broke and neither did any of the others

2) A little anti-freeze goes a long way. My 100% filled, 10% concentration pipe did not break.

3) Black poly pipe is tough

4) The danger temperature is just above freezing. Progressively colder temperature does not create more bursting

5) When water freezes, it reaches maximum expansion (minimum density) at just before freezing and then has a jump to a less expansion. A discontinuity.

6) There are factors that cannot be easily tested and could still cause pipe breakage. Ground movement, rodents, leaks into pipes, pressure from above by heavy vehicles, defective pipe and more can all conspire to cause pipe breakage. These guidelines are not perfect.

Here’s the summary video of my experiment.