What is plastic deformation?
Although It can occur on all types of materials, in this case it is more of a concern with plastic piping and plastic deformation is the stretching and expansion of a pipe over time due to continued pressure and flow of fluid within. Freezing greatly accelerates this deformation unless the yield strength is reached and a pipe just fails and breaks or splits. An Example for a Copper Line: Ever repair a 1/4 in copper air conditioner water line and cut the split bad piece out and then add a new copper piece with a union coupling? Now try to put a new brass ferrule and nut on the old copper you prepared for the splice. The old copper swelled and these new pieces can’t be put on. The old copper already swelled to a larger diameter. Now you have to replace the whole run. That’s plastic deformation.
