The Class K7 DN900 ductile iron pipe (900mm diameter, 7-bar pressure rating) is engineered for high-capacity water, wastewater, and industrial networks requiring strength and longevity. With a tensile strength exceeding 420 MPa and Brinell hardness ≤230 HBW, it meets ISO 2531, EN 545/598, and ANSI/AWWA C151 standards, ensuring compliance with global safety and performance benchmarks. Its dual-layer corrosion protection—cement-mortar lining internally and zinc/bitumen coatings externally—guarantees 100+ years of service in harsh environments. Compatible with Tyton® push-on, mechanical, and flange joints, the DN900 pipe delivers leak-free adaptability for above-ground or buried installations. Priced at $80–125 per meter (based on 1,000-ton orders), it offers cost-effective lifecycle savings for municipal, industrial, and utility projects. ISO 9001/14001 and NSF/WRAS certifications reinforce its reliability for potable water and chemical transport.
Application Scenarios
Municipal Water Distribution
Large‑bore mains (DN900) form the backbone of city water networks, maintaining stable pressure and minimizing leakage for potable supply systems. Utilities leverage DN900 Class K7 for transmission mains feeding treatment plants and high‑demand urban districts.
Sewage & Wastewater
In sanitary and stormwater sewers, DN900’s cement‑mortar lining and external coatings resist abrasive, chemically aggressive effluents—proven in industrial and municipal installations.
Industrial Process Lines
Power stations, chemical plants and manufacturing facilities rely on DN900 DI pipe for raw‑water intake, cooling loops and process service, benefiting from its mechanical strength and corrosion resistance.
Agricultural Irrigation
For high‑volume irrigation across large farms, DN900 mains deliver reliable flows; ductile iron’s flexibility accommodates soil shifts and thermal cycles without crack propagation.
Service Life
Modern ductile iron pipelines routinely exceed 100 years in potable and raw‑water service, as documented by utilities with continuous‑service CI mains over a century old. Durable cement‑mortar linings paired with epoxy, bitumen or zinc‑aluminum coatings virtually eliminate tuberculation and external corrosion, reducing maintenance and replacement costs over decades.
Installation & Connection
Push‑On (Tyton®) Joint
US Pipe’s Tyton® push‑on joint uses a gasket‑sealed bell and spigot for rapid, tool‑free assembly and up to 5° deflection—ideal for standard buried runs.
Mechanical Joint
Mechanical couplings (bell, gland, bolts) provide restrained connections where thrust blocks are impractical; SBR rubber gaskets handle service temperatures up to 50 °C.
Flange Joint
ANSI B16.1/EN 1092 flanges offer rigid, dismantlable connections—preferred for above‑ground segments or sections requiring routine inspection .
Trenching & Encasement
Pipes rest on well‑graded granular bedding; backfill is placed in layers and compacted to prevent settlement. In corrosive soils, V‑Bio enhanced polyethylene encasement provides an external corrosion barrier.
International Standards
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ISO 2531:2009 / EN 545/598 — materials, dimensions, tolerances, linings and coatings for DN 80–DN 2600 mm mains.
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ANSI/AWWA C151/A21.51 — U.S. specification for centrifugally‑cast DI pipes, fittings, coatings and joint types.
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ISO 9001 / ISO 14001 — quality and environmental management system certifications.
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NSF / WRAS — potable‑water compliance approvals.
Price Comparison with Other Series
| Class | Price (USD/ton) |
|---|---|
| K7 | 400 – 465 |
| K8 | 505 – 560 |
| K9 | 545.30 – 645 |
Based on typical weights of 200–300 kg/m, this equates to USD 80–125/m for K7, USD 100–168/m for K8, and USD 109–194/m.
Advantages
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Corrosion Resistance: Cement‑mortar lining plus external epoxy/bitumen or zinc‑aluminum coatings prevent internal and soil‑side corrosion.
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High Impact Strength: ANSI/AWWA C151 testing confirms resilience to water hammer, traffic loads and handling stresses.
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Ductility & Flexibility: Nodular graphite microstructure tolerates soil movement and seismic loads without fracture.
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Sustainability: High recycled‑content iron and full recyclability support circular‑economy goals.
FAQs
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What does DN900 mean?
Nominal Diameter of 900 mm; actual internal bore varies slightly by lining and thickness tolerance. -
What is Class K7?
A pressure class rated at 7 bar working pressure with minimum tensile strength ≥ 420 MPa and ≥ 10% elongation at break. -
How long will the pipe last?
Over 100 years in typical potable‑water service, per DIPRA longevity data. -
Which joint types are available?
Push‑on (Tyton®), mechanical and flange joints—choose based on thrust, access and installation conditions. -
Is ductile iron pipe eco‑friendly?
Yes—high recycled content, energy‑efficient service and 100% recyclability at end‑of‑life.
Case Studies
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Central Arkansas Water Upgrade (USA): 15 km of DN900 mm DI mains improved transmission capacity and reduced leakage by 40% in a major system rehabilitation.
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Global Municipal Projects (DIPRA): Case studies across diverse climates demonstrate ease of installation, low upkeep and predictable lifecycle costs for large‑diameter DI mains.
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 | ….. |
