Technical requirements for plastic composite piping：
1. Colors are typically black, blue, or white; high-temperature tubes are usually orange, or can be agreed upon by both parties based on supply and demand.
2. The inner and outer surfaces of the pipe should be smooth and even, allowing for minor concave and convex indentations due to natural shrinkage. Bubbles, cracks, decomposition变色 lines, and visible scratches are not permitted. The ends of the pipe should be cut cleanly and flat.
3. The pipe end caps are well-fused with the pipe material, free of cracks, with smooth fusion joints, and without scratches or burrs.