There are two reasons that cause deterioration of Pressure Water Pipes during their usage period. These; HEAT and LIGHT. Decomposition by heat occurs with the release of hydrogen chloride. Due to this released gas, yellowing occurs in the color of the pipe.
According to the degree of deterioration, first reddening, reddish, brown and black colors are seen in the pipe color, respectively. When PVC pipes do not contain UV additives, they deteriorate when exposed to UV rays or gamma rays.
PVC-U pipes are not fragile because they are in crystalline structure. However, in materials such as Polyethylene and Polypropylene, it has a crystal structure of 80-85%. The reason why the crystal is important here is; The more crystalline it has, the more brittle it becomes under sunlight.
If we explain the point that causes this, the molecules of Polyethylene and Polypropylene material are connected parallel to each other and is in a mixed way, so it is difficult to break the bonds of PVC.