Class K9 DN800 ductile iron pipe offers PN 25 (2.5 MPa) nominal pressure, 11.7 mm nominal wall thickness, and a design life exceeding 100 years in benign soils—making it ideal for critical water, sewage, and industrial networks. Installation flexibility comes via T-type push-on, K-type restrained, and self-restrained joints for rapid, leak-free connections across DN 80–1600 mm. Compared to K7, K8, and K12, K9 balances cost and durability (480–650 USD/m), while meeting ISO 2531, EN 545, EN 598, ISO 4179, and ISO 8179 standards for global compatibility.
Application Scenarios
Ductile iron Class K9 DN800 is used for:
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Potable & recycled water supply in urban and industrial networks.
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Irrigation & raw water mains in agriculture and mining.
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Gravity & sewer rising mains, and stormwater drainage systems.
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Fire-fighting mains (hydrants & sprinklers) requiring high surge resistance.
Its DN 800 size provides high flow with low head loss over long distances, ideal for large-scale distribution and process conveyance.
Service Life
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100+ years design life in benign soils, proven by field and lab data.
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50–80 years in aggressive soils with zinc/epoxy coatings, cement-mortar lining, or LPS sleeving.
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Recyclable at end-of-life; high recycled iron content reduces environmental impact.
Life-cycle studies show ductile iron’s total cost of ownership is among the lowest across pipe materials.
Installation & Connections
T-Type Push-On (Tyton) Joints
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Gasketed, quick-assemble “T-type” joints for DN 80–2000 mm.
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Internal cement lining (ISO 4179) and external zinc + bitumen coating (ISO 8179).
K-Type Restrained Joints
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Mechanical restraint for DN 1200–2600 mm; axial thrust lock for surge protection.
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Suitable for pre-test before backfill; zero-leak performance under vacuum/surge.
Self-Restrained Joints
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Restraint harnesses clamp socket and spigot to prevent joint separation up to PN 16.
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Complying with ISO 2531/EN 545; suitable for DN 80–1600 mm installations.
Series Comparison & Price
For DN 800, the K-classes differ as follows:
| Class | Wall Thickness (mm) | Pressure Class (PN) | Price (USD/m) |
|---|---|---|---|
| K7 | 9.1 (t = 7×1.3) | PN 10 | 370 – 430 |
| K8 | 10.4 (t = 8×1.3) | PN 16 | 400 – 500 |
| K9 | 11.7 (t = 9×1.3) | PN 25 | 480 – 650 |
| K12 | 15.6 (t = 12×1.3) | PN 40 | typically 25% ↑ over K9* |
*Exact K12 pricing upon request; premiums reflect thicker walls and higher testing pressures.
Thicker walls increase impact strength and surge resistance but at higher material cost.
International Standards
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ISO 2531:2009 – Ductile iron pipes, fittings, accessories & joints for water.
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EN 545 / EN 598 – European water & 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.
Compliance ensures global interoperability and procurement ease.
Advantages
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High Tensile Strength & Ductility withstands surge pressures & ground movements.
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Long-Term Corrosion Resistance via multi-layer linings & coatings.
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Fast, Leak-Free Installation reduces labor & downtime.
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Environmentally Sustainable: recycled content, fully recyclable.
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Proven Reliability in critical infrastructure worldwide.
FAQ
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What wall thickness does Class K9 DN800 have?
Nominal thickness = 9 × (0.5 + 0.001×800) = 11.7 mm. -
Can it handle fire-fighting pressure?
Yes—PN 25 rating (2.5 MPa), tested to 3.5 MPa for site tests. -
How long will DN800 K9 last?
100 years in benign soils; up to 150 years with advanced coatings in aggressive environments.
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Which joint suits high-rise and surge-prone systems?
K-type restrained joints provide axial restraint and leak-proof service. -
Is DN800 K9 potable-water approved?
Yes—internal cement lining meets ISO 4179; external coatings comply with ISO 8179; EN 545 certified.
Case Studies
Nîmes Métropole (France)
Two DN800 UltraGrip® Amplified flange adaptors were installed on a potable water network upgrade. Installers praised the ease of handling, wide tolerance fit, and zero-leak performance, even under reducers and gate valves.
Municipal Water Supply Upgrade (Asia)
A city replaced aging mains with DN800 K9 pipe, resulting in 30% fewer maintenance calls, improved pressure stability, and lifecycle cost savings of 20% over alternatives.
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 | ….. |
