The PVC pipe has a trademark on the drainage pipe that reads the national standard. The writing on PVC drainage pipes is generally: first, the trademark, company name, pipe material, pipe use (water supply or drainage), pressure level (water supply pipe), production standard (national standard, industry standard or enterprise standard), production batch number (for example: production Date. Production machine number, inspection personnel code, etc. The pipe must be marked with the manufacturer's name, material name, specifications, wall thickness, production standard (national standard or enterprise standard), production line code, production date, etc. The manufacturer also stamps the inspector number.