1. The primary materials used in manufacturing ductile iron pipes are supplied by vendors certified through the ISO9002 system.

2. Internal corrosion protection is achieved through centrifugal method cement sand slurry lining, requiring a smooth and even surface with no cracks.

3. External corrosion protection is achieved through zinc spraying and asphalt coating, with zinc spraying adhering to the international ISO 8179 standard.

4. Ductile iron pipes should comply with the GB/17219 safety evaluation standards for water supply equipment and protective materials for drinking water.

5. Ductile Iron Pipe, 6M in length, with K9 grade wall thickness.

6. The quality requirements and testing methods for rubber rings should separately comply with the "ISO 4633-1996(E) Sealing rings for joints in water and drainage pipelines" standard.