PVC drainage pipes are primarily made from polyvinyl chloride (PVC) resin, with appropriate amounts of stabilizers, lubricants, fillers, colorants, etc., extruded and molded via plastic extruders and injection molding machines. The production process involves cooling, curing, shaping, inspection, and packaging to complete the manufacturing of pipes and fittings. Common specifications for PVC drainage pipes are as follows: nominal outer diameters include 50mm, 75mm, 90mm, 110mm, 160mm, 180mm, 200mm, 250mm, etc. The standard length of PVC-U pipes is generally 4m or 6m, with other lengths determined through negotiation between suppliers and buyers.