Class K8 DN100 ductile iron pipe combines robust strength, excellent corrosion protection and 100 + year design life, making it ideal for potable water, sewage, irrigation, gas and fire‑protection mains. Specialty linings (cement‑mortar) and external coatings (bitumen, polyethylene sleeving) virtually eliminate internal and external corrosion, while flexible joints simplify field assembly. In the K‑series, K7→K8→K9→K12 represent increasing wall thickness and pressure capacity; price varies accordingly from ~$420–800 USD/ton. All products comply with GB/T 13295‑2019, ISO 2531, EN 545/598 and related international standards.
Applications
Class K8 DN100 pipe delivers safe, reliable service in:
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Potable water networks, ensuring consistent pressure and hydraulics over long runs.
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Sewage and drainage, resisting abrasion and surge in wastewater mains.
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Irrigation systems, handling variable flow rates in agriculture.
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Gas distribution, when suitably coated and tested per ISO 8180.
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Fire‑protection mains, offering high surge capacity and ductility.
Service Life
Modern ductile iron pipe routinely exceeds 100 years under normal operating conditions. A Black & Veatch analysis for Huntsville Utilities shows a 50‑year PV savings of over $17 million versus alternatives, driven by lower pumping and replacement costs. Life‑cycle assessments also credit ductile iron with reduced leaks and repair events, further extending overall service life.
Installation & Connection
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Push‑on (Tyton) joints use a resilient gasket for fast, reliable sealing without bolts.
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Mechanical joints employ gland-and-bolts to create restrained or unrestrained connections, ideal for fittings and valves.
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Flanged joints (ANSI B16.1, EN 1092) allow easy disassembly for maintenance and high axial loads.
Product Series Comparison
| Class | Nominal Wall Thickness | Pressure Capability | Typical Price (USD/ton) |
|---|---|---|---|
| K7 | ~6–8 mm | PN10 (1.0 MPa) | $420–530 |
| K8 | ~7–10 mm | PN12.5 (1.25 MPa) | $500–600 |
| K9 | ~8–12 mm | PN16 (1.6 MPa) | $540–660 |
| K12 | ~10–15 mm | PN25 (2.5 MPa) | $650–800 |
International Standards
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GB/T 13295‑2019: Ductile iron pipes & accessories for water/gas applications.
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ISO 2531:2009/2003 / EN 545:2006 / EN 598:2007: Pipe dimensions, linings, joint performance.
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ISO 8180: Polyethylene sleeving for external corrosion control.
Advantages
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Exceptional Longevity: 100 + year life cycle reduces replacement frequency.
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Structural Strength: High tensile (≥420 MPa) and bending resilience.
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Corrosion Resistance: Cement‑mortar lining, bitumen or zinc coatings, polyethylene sleeving.
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Versatile Connections: Multiple joint types for diverse field needs.
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Sustainability: Fully recyclable, lower greenhouse‑gas footprint vs. PVC/HDPE.
FAQ
Q1: When to choose K8 vs. K7 or K9?
Choose K7 where minimal wall thickness suffices (lighter cover), K8 for standard mains, K9 or K12 for higher pressures or deep‑burial scenarios.
Q2: What external corrosion protections are available?
Options include polyethylene sleeving (ISO 8180), bitumen paint, zinc‑enriched coatings, plus optional cathodic protection.
Q3: What sizes are available?
DN 80–2600 mm in standard 6 m lengths (custom cuts 5.6–5.8 m).
Case Studies
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Huntsville, AL: A 50‑year life‑cycle analysis showed $17 million PV savings versus alternative materials, driven by energy and maintenance benefits.
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Florida Everglades Test Site: Ductile iron pipe with polyethylene encasement performed “excellent” in highly corrosive soils, validating ISO 8180 sleeving efficacy.
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 | ….. |
