Three levels.
1. PPR-AL-PPR three-layer composite pipe is composed of three layers of polypropylene layer, aluminum film layer and polypropylene layer. It has good heat resistance, corrosion resistance and thermal stability.
2. PPR-AL-PERT three-layer composite pipe is made of polypropylene layer, aluminum film layer and polymer layer. It has good heat and frost resistance, as well as better thermal conductivity.
3. PPR-FRP three-layer composite pipe is made of polypropylene layer, glass fiber layer and polypropylene layer. It has good corrosion resistance, frost resistance and heat resistance, and has a long service life. easy to maintain.