Installation of polypropylene pipes should be carried out in a warm room. If you suddenly want or have an urgent need for installation at subzero temperatures. Keep in mind that such an installation will end up with great losses. I'll tell you why.
In the photos you see an example of improper storage.
Unfortunately, these pipes were temporarily laid at my site. But as it happens, I forgot to hide them from exposure to sunlight (ultraviolet radiation). Now you can't touch them. The fact is that at temperatures below zero, the properties of this pipe rapidly decrease. Therefore, moving them to a deep minus can affect the quality of the pipe.
For the sake of experiment, I took one pipe and began to fold it in two. With a little resistance, it broke.
In the warm season, it would just fold, but not burst.
Pipe cutting with scissors in the minus
Below, on the Gif (wait for loading), you see that when you try to cut off a piece of the pipe, it just broke off and flew off to the side like a bullet:
Welding polypropylene in the cold
In severe frosts, a weak apparatus will not be able to heat up as expected. But if this succeeds, then the quality of the weld will be at a low level.
Warming up will not be deep. When the pipe and fitting are pulled out of the "nozzles", the upper layer of heated polypropylene is cooled. This in turn, when docked, will lead to poor diffusion of polypropylene molecules. And this weakens the connection so that they can leak at the most inopportune time. And cause damage.
And that's what those say. documentation:SP 40-101-96 Design and installation of polypropylene pipelines
5.8. Resistance welding of polypropylene pipes and pipeline parts should be carried out at an ambient temperature of at least 0 ° C. The welding place should be protected from atmospheric precipitation and dust.
Therefore, some expensive and high-quality welding machines refuse to work at temperatures below five degrees Celsius. Don't violate the technology. And may Strength and Health be with you in the coming New Year!