1. PP-R pipes have lower hardness and rigidity than metal pipes, so they should be protected during handling and construction to avoid mechanical damage from inappropriate external forces. After concealed installation, the pipe locations should be marked to prevent damage during subsequent renovations.
2. PP-R pipes exhibit some low-temperature brittleness below 5℃. Exercise caution during winter construction; use a sharp tool to cut the pipe slowly. Do not subject installed pipes to heavy pressure or impacts; if necessary, cover vulnerable areas with protective materials.
3. PP-R pipes are prone to aging and degradation under prolonged UV exposure. When installed outdoors or in direct sunlight, a dark protective layer must be applied.
4. Except for connections to metal pipes or water appliances using threaded inserts or flanges, all other connections using PP-R pipes should be heat-fused to ensure a seamless, leak-free system.
5. PP-R pipes have a relatively high coefficient of linear expansion (0.15mm/m℃). When installing exposed or concealed (non-direct burial) pipes, technical measures must be taken to prevent pipe expansion and deformation.
6. After pipe installation, a pressure test must be conducted before sealing the pipes (direct burial) and before covering them with a decorative layer (non-direct burial concealed installation). The test pressure for cold water pipes is 1.5 times the system working pressure, but not less than 1 MPa; the test pressure for hot water pipes is 2 times the working pressure, but not less than 1.5 MPa. The test time and method are specified in the technical regulations.
7. When laying PP-R pipes openly or in non-direct burial concealed installations, supports and hangers must be installed as specified.
8. After cooling for the specified time, complete the connection.
