Class K9 DN1000 ductile iron pipe delivers PN 25 (2.5 MPa) service pressure with a nominal wall thickness of 12.6 mm, supporting flows in large municipal water, wastewater, and industrial networks—often lasting 100+ years in benign soils and 50–80 years under aggressive conditions. Installation is streamlined via push-on (Tyton/T-type), restrained (K-type), or self-restrained joints per ISO 2531, EN 545/598, ISO 4179, and ISO 8179. Compared to K7 and K8 (thinner, lower PN; lower cost) and K12 (thicker, higher PN; higher cost), K9 balances strength and economy—with list prices around USD 430–550 per m in typical volumes. Global standards compliance, proven durability, and case studies from Central Arkansas Water and Qatar’s Mega Reservoir underscore its reliability.
Application Scenarios
Class K9 DN1000 pipe is widely used for:
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Municipal potable water and raw water transmission, providing high-capacity flow with minimal head loss in urban and industrial networks.
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Gravity and rising sewer mains, plus stormwater drainage, where leak-free performance and structural robustness are essential.
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Fire-fighting systems (hydrants, sprinkler mains) requiring surge resistance up to 40 bar when combined with restrained joints.
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Mining, slurry transport, agricultural irrigation, and hydroelectric conduits, leveraging its high tensile strength (> 420 MPa) and ductility.
Service Life
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Design life > 100 years in benign soils, backed by DIPRA’s longevity studies.
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50–80 years in aggressive soils when protected with cement mortar lining, zinc/bitumen coatings, epoxy, or polyethylene sleeving.
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Low total cost of ownership through high recycled content, recyclability, and minimal maintenance.
Installation & Connections
Push-On (Tyton/T-Type) Joints
Flexible, gasketed joints allow quick, field-ready assembly, accommodate up to 5° deflection per joint, and maintain 100% leak-free performance when installed per ISO 2531.
Restrained (K-Type) Joints
Mechanical restraints lock socket and spigot against axial thrust, ensuring zero-leak performance under surge and vacuum and permitting pre-backfill pressure testing.
Self-Restrained Joints
Clamped harnesses provide axial restraint up to PN 16 without separate hardware, ideal for tight trenches and rapid installation.
Series Comparison & Price
| Class | Wall Thickness (mm) | Pressure (PN) | Ballpark Price (USD/m) |
|---|---|---|---|
| K7 | 9.8 | PN 10 | ~360–450 (≈ 15–20% below K9) |
| K8 | 11.2 | PN 16 | ~390–500 (≈ 10–15% below K9) |
| K9 | 12.6 | PN 25 | 430–550 |
| K12 | 16.8 | PN 40 | ~560–700 (≈ 25–30% above K9) |
Pricing varies with order volume, coating options, and regional market conditions; contact suppliers for firm quotations.
International Standards
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ISO 2531: Ductile iron pipes, fittings, accessories & joints for water pipelines
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EN 545 / EN 598: European drinking-water and sewerage requirements
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ISO 4179: Internal cement-mortar lining
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ISO 8179: External zinc + bitumen coating
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ISO 21053: Life-cycle analysis & sustainability for ductile iron pipes
Advantages
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High Tensile Strength & Ductility (> 420 MPa) withstands surge pressures and ground movement.
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Outstanding Corrosion Resistance via multi-layer linings/coatings, proven in aggressive soils.
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Fast, Leak-Free Assembly reduces labor and downtime.
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Environmentally Sustainable: high recycled content, fully recyclable at end-of-life.
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Global Compatibility ensures ease of procurement across regions.
FAQ
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What defines Class K9 for DN1000?
Wall thickness = 9 × (0.5 + 0.001 × 1000) = 12.6 mm, rated PN 25 per ISO 2531. -
How long will it last?
100 years in benign soils; 50–80 years in aggressive soils with standard protection.
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Which joint type suits surge-prone systems?
K-type restrained joints provide axial thrust resistance and zero-leak performance under transients. -
What linings/coatings are standard?
Cement-mortar lining (ISO 4179); external zinc (≥ 130 g/m²) + bitumen (ISO 8179); optional epoxy or LPS sleeving. -
Is it potable-water approved?
Yes—EN 545 compliance, cement-mortar lined, zinc-coated, PN 25 flanged connections.
Case Studies
Central Arkansas Water, USA
Switched to DN1000 ductile iron mains for critical high-capacity zones. Over 5 years, reported zero failures, reduced maintenance by 40%, and documented lifecycle cost savings of 25% versus previous materials.
Mega Reservoir Project, Qatar
Supplied DN1000 K9 pipes to one of the Middle East’s largest reservoirs. Onsite feedback praised ease of handling, rapid assembly, and corrosion protection under extreme desert conditions.
Santa Cruz Mountains Wildfire Recovery, USA
After HDPE pipe failures in the 2021 CZU Lightning Complex Fire, DN1000 K9 ductile iron pipe was selected for its fire resistance and reliability, restoring 4.5 million gallons/day supply with zero thermal damage.
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 | ….. |
