In municipal water supply, drainage pipe networks, water conservancy projects, park construction and other projects, ductile iron pipe has become the mainstream pipe for underground networks due to its high strength, good toughness, corrosion resistance and long service life. Correct selection of specifications and models is directly related to project quality, construction efficiency and later operation and maintenance costs.
Today we systematically sort out the common specifications, pressure ratings and application scenarios of ductile iron pipes to make selection clearer and more professional.
Nominal Diameter (DN) Specifications
Ductile iron pipes are marked by nominal diameter DN, covering a full range from small-diameter branch pipes to large-diameter main pipes. Common specifications are as follows:
Small diameter: DN80, DN100, DN150, DN200
Suitable for community water supply, fire pipelines, courtyard pipe networks, household branch pipes, etc.
Medium diameter: DN300, DN400, DN500, DN600
The most commonly used specifications for municipal secondary mains, township water supply and drainage, industrial park pipe networks.
Large diameter: DN800, DN1000, DN1200, DN1400... up to DN2600
Suitable for urban main pipe networks, long-distance water conveyance projects, sewage treatment, large-scale water conservancy projects.
Pressure Ratings and Standards
Ductile iron pipes are classified by pressure capacity. The most commonly used grade in municipal engineering is K9, which complies with the national standard GB/T 13295, featuring stable pressure bearing, reliable joints and anti-settlement.
Standard pressure ratings:
K7, K8 (low-pressure working conditions)
K9 (mainstream standard for municipal engineering)
K10, K12 (high-pressure, heavy-load and special working conditions)
Pipe Length and Joint Type
Standard length: 6 meters
Common joint: T-type flexible joint, with fast installation, strong sealing performance and adaptability to slight foundation settlement.
How to Select Quickly?
Community and building water supply → prioritize DN100, DN150, DN200
Municipal roads and park pipe networks → prioritize DN300~DN600
Main pipelines and large-scale water conservancy → select large diameters of DN800 and above
Reasonably matching diameter and pressure rating can meet usage needs and effectively control project cost.