Class K9 DN1500 ductile iron pipes are the backbone of modern large-scale infrastructure projects, offering unparalleled strength, corrosion resistance, and longevity. Designed to meet ISO 2531 and GB/T 13295 standards, these pipes are ideal for high-pressure water supply, municipal drainage, and industrial fluid transport systems. With a nominal diameter of 1500mm, they excel in demanding environments such as coastal regions, seismic zones, and heavy-load urban networks. Leading suppliers leverage advanced centrifugal casting and dual-layer zinc-bitumen coatings to ensure compliance with international durability benchmarks, achieving a lifespan exceeding 100 years.
Application Scenarios
Ductile iron pipe is widely used for potable water transmission and distribution, wastewater collection, irrigation networks and fire-protection mains due to its strength and corrosion resistance. In municipal water systems, it supports pressures up to 10 bar in K9 class, ensuring reliable flow in both high-rise and remote neighborhoods. It’s также favored in agricultural irrigation for its durability in abrasive soils and in industrial drainage for handling aggressive effluents when lined appropriately.
Service Life
Modern ductile iron pipe is engineered to exceed 100 years of service under standard operating conditions. Advances in cement-mortar linings and external coatings have effectively mitigated internal corrosion, preserving hydraulic capacity over a century. In many U.S. utilities, cast-iron systems installed in the early 20th century remain in service, attesting to the material’s longevity.
Installation and Connection
Joint Types
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Push-On (T-type): Quick assembly with resilient rubber gaskets allows angular deflection and simplifies installation in tight trenches.
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Mechanical Joint (K-type): Bolted gland and gasket assembly offers a restrained connection capable of withstanding higher thrust loads.
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Self-Restrained: Incorporates anchoring features within the joint to eliminate the need for thrust blocks in certain installations.
Trenchless Methods
Directional drilling, microtunneling and pipe-jacking techniques are compatible with DI pipe, reducing surface disruption and accelerating project schedules.
Connecting to Other Materials
Flange adaptors, EZ-Flange and Uni-Flange couplings enable seamless transitions between ductile iron and steel, PVC or HDPE pipelines.
Product Series Comparison
| Class | Wall-Thickness Class (ISO 2531/EN 545) | Approx. Rated Pressure | China Price Range (USD/m) | US Price (USD/m) |
|---|---|---|---|---|
| K7 | K7 (e.g. 6.0 mm @ DN1500) | ~7 bar | 400–600 | $388 – 450 |
| K8 | K8 (e.g. 7.2 mm @ DN1500) | ~8 bar | 420–650 | $410 – 560 |
| K9 | K9 (e.g. 8.1 mm @ DN1500) | ~9 bar | 450–720 | $460 – 520 |
| K12 | (often classed C40 or >K9, e.g. 9.5 mm) | ~12 bar | 500–800 | $700 – 900 |
Estimated as ±10% of K9 market price to reflect material and thickness differences.
International Standards
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ISO 2531:2009: Defines material, dimensional and testing requirements for DI pipes, fittings and accessories.
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EN 545: Specifies requirements for drinking water supply pipelines of DI pipes and fittings.
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EN 598: Covers DI pipes and fittings for sewerage applications.
Advantages
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High Strength & Ductility: Resists internal pressure, external loads and ground movement better than cast iron.
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Corrosion Resistance: Cement-mortar lining and epoxy coatings extend life and maintain hydraulic efficiency.
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Flexible Jointing: Allows angular deflection up to 16° per joint, reducing the need for bends.
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Low Maintenance: Proven maintenance-free operation for a century in many installations.
FAQ
Q1: What is the typical service life of K9 pipes?
With proper design and lining, K9 pipes often exceed 100 years of service.
Q2: How do I connect DI pipe to PVC or steel?
Use flange adaptors or Uni-Flange/EZ-Flange couplings sized to match pipe OD and pressure class.
Q3: Are thrust blocks required for self-restrained joints?
In many cases, self-restrained joints eliminate thrust blocks, but verify based on soil conditions and local codes.
Q4: What factors influence price differences between classes?
Key drivers include wall thickness (material volume), joint type, coatings and market demand.
Case Studies
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Monte Vista Water District (CA, USA): Achieved a projected 100–125 year service life with cement-mortar lined DI mains, outperforming alternatives by 3–5% in lifecycle cost savings.
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Black & Veatch Report (2012): Over a 50-year period, DI pipe’s energy and maintenance savings represented a present-value benefit exceeding $17 million for a midsize utility.
ductile iron pipe dimensions
| Pipe body weight （kg/m) | |||||||||||||||
| (Inside Diameter) | (Outside Diameter) | Socket Weight | K8 | K9 | K10 | C class | Total weight of Active Length=6M (kg) | Total weight of Active Length=5.7M (kg) | |||||||
| DN(mm) | OD(mm) | ≈ kg | Class | kg/m | K8 | K9 | K10 | C class | K8 | K9 | K10 | C class | |||
| 80 | 98 | 3.40 | 12.20 | 12.20 | 12.20 | C40 | 9.10 | 77.00 | 77.00 | 77.00 | 58.00 | 73.00 | 73.00 | 73.00 | 55.00 |
| 100 | 118 | 4.30 | 14.90 | 15.10 | 15.10 | C40 | 11.12 | 93.70 | 95.00 | 95.00 | 71.00 | 90.00 | 91.00 | 90.00 | 68.00 |
| 125 | 144 | 5.70 | 18.90 | C40 | 119.00 | ||||||||||
| 150 | 170 | 7.10 | 21.80 | 22.80 | 22.80 | C40 | 16.48 | 138.00 | 144.00 | 144.00 | 106.00 | 132.00 | 138.00 | 137.00 | 101.00 |
| 200 | 222 | 10.30 | 28.70 | 30.60 | 30.60 | C40 | 22.62 | 183.00 | 194.00 | 194.00 | 146.00 | 174.00 | 185.00 | 185.00 | 139.00 |
| 250 | 274 | 14.20 | 35.60 | 40.20 | 44.30 | C40 | 32.63 | 228.00 | 255.00 | 280.00 | 210.00 | 218.00 | 244.00 | 267.00 | 200.00 |
| 300 | 326 | 18.90 | 45.30 | 50.80 | 56.30 | C30 | 43.90 | 290.00 | 323.00 | 357.00 | 282.00 | 278.00 | 309.00 | 340.00 | 269.00 |
| 350 | 378 | 23.70 | 55.90 | 63.20 | 69.60 | C30 | 51.88 | 359.00 | 403.00 | 441.00 | 335.00 | 343.00 | 384.00 | 420.00 | 319.00 |
| 400 | 429 | 29.50 | 67.30 | 75.50 | 83.70 | C30 | 60.78 | 433.00 | 482.00 | 532.00 | 394.00 | 414.00 | 460.00 | 506.00 | 376.00 |
| 450 | 480 | 38.30 | 80.00 | 89.30 | 99.00 | C30 | 73.30 | 515.00 | 575.00 | 632.00 | 472.00 | 492.00 | 550.00 | 597.00 | 450.00 |
| 500 | 532 | 42.80 | 92.80 | 104.30 | 115.60 | C30 | 87.20 | 600.00 | 669.00 | 736.00 | 566.00 | 572.00 | 638.00 | 702.00 | 540.00 |
| 600 | 635 | 59.30 | 122.00 | 137.30 | 152.00 | C30 | 120.62 | 791.00 | 882.00 | 971.00 | 783.00 | 755.00 | 842.00 | 926.00 | 747.00 |
| 700 | 738 | 79.10 | 155.00 | 173.90 | 193.00 | C25 | 142.15 | 1009.00 | 1123.00 | 1237.00 | 932.00 | 963.00 | 1071.00 | 1179.00 | 889.00 |
| 800 | 842 | 102.60 | 192.00 | 215.20 | 239.00 | C25 | 177.07 | 1255.00 | 1394.00 | 1537.00 | 1165.00 | 1197.00 | 1330.00 | 1465.00 | 1112.00 |
| 900 | 945 | 129.60 | 232.00 | 260.20 | 289.00 | C25 | 197.68 | 1521.00 | 1691.00 | 1863.00 | 1446.00 | 1452.00 | 1613.00 | 1777.00 | 1257.00 |
| 1000 | 1048 | 161.30 | 275.00 | 309.30 | 343.20 | C25 | 266.28 | 1811.00 | 2017.00 | 2221.00 | 1759.00 | 1729.00 | 1925.00 | 2118.00 | 1679.00 |
| 1100 | 1152 | 194.70 | 362.80 | 2372.00 | |||||||||||
| 1200 | 1255 | 237.70 | 374.00 | 420.10 | 466.10 | C25 | 373.88 | 2482.00 | 2758.00 | 3034.00 | 2481.00 | 2370.00 | 2632.00 | 2894.00 | 2369.00 |
| 1400 | 1462 | 279.30 | 547.20 | 3563.00 | |||||||||||
ductile iron pipe Mechanical property
| Mechanical Property | |||||||
| Nominal Diameter | Hydraulic test | Tensile strength | Elogation | Yield strength | Bending strength | Brinell hardness | Thickness of cement lining |
| DN(MM) | Mpa | Mpa | % | Mpa | Mpa | HB | mm |
| DN80-DN300 | 5 | ≥420 | ≥10 | ≥300 | ≥590 | ≤230 | 3 |
| DN350-DN600 | 4 | ≥420 | ≥10 | ≥300 | ≥590 | ≤230 | 5 |
| DN700-DN1000 | 3.2 | ≥420 | ≥10 | ≥300 | ≥590 | ≤230 | 6 |
| DN1100-DN1600 | 2.5 | ≥420 | ≥7 | ≥300 | ≥590 | ≤230 | ….. |
