The primary materials used in the manufacturing of cast iron drainage pipes are supplied by vendors certified under the ISO9002 system.

Secondly, the internal anti-corrosion is lined with centrifugal cement sand slurry, requiring a smooth and even surface with no cracks.

Three: External corrosion protection uses zinc spraying and asphalt coating; zinc spraying as per...

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

Fifth, cast iron drainage pipes with a length of 6 meters and a wall thickness of K9 grade.

The quality requirements and testing methods for cast iron drainage pipe rubber rings should separately comply with the standard "ISO 4633-1996(E) - Gaskets for joints in water supply and cast iron drainage pipe lines."