an 8 in. nominal ductile iron pipe has a standardized outside diameter of 9.05 in. (229.87 mm), offers over 100 years of reliable service thanks to its nodular-graphite strength and cement-mortar lining, and meets both AWWA C151/A21.51 and ISO 2531/EN 545 dimensional standards. Its high pressure ratings (up to 350 psi), robust corrosion protection, and flexible joint designs (push-on, mechanical, flanged) make it ideal for potable water, wastewater, irrigation, and industrial systems.
Application Scenarios
Ductile iron pipe is widely used for municipal potable water transmission and distribution, ensuring safe, high-capacity flow in trunk and lateral lines.
It serves wastewater and sewage mains, where cement-mortar linings and external coatings resist corrosive effluents in gravity and pressure systems.
In irrigation and industrial applications, these pipes handle high pressures and various media—from agricultural networks to chemical plants and fire-protection mains.
Service Life
Modern ductile iron pipelines routinely exceed 100 years of service under normal conditions.
This longevity is achieved through recycled-content metallurgy, energy-efficient casting, and cement-mortar linings that virtually eliminate internal corrosion.
Advantages
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Exceptional Strength: The spheroidal graphite microstructure provides twice the tensile strength of gray iron, supporting pressure classes up to 350 psi.
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Corrosion Protection: Standard cement-mortar lining plus bonded zinc, asphaltic coatings, or optional polyethylene sleeving guard against both soil and water corrosion.
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Life-Cycle Cost Efficiency: Over a century, ductile iron pipe incurs lower total ownership and maintenance costs compared to plastic alternatives.
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Joint Flexibility: Push-on (Tyton®), mechanical, and flanged connections allow angular deflection and restrained systems to accommodate seismic shifts and ground movement.
International Standards
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ANSI/AWWA C151/A21.51 specifies dimensions and pressure classes for 3″–64″ centrifugally cast pipe in North America.
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ISO 2531 / EN 545 / EN 598 cover pipes, fittings, and joints for water and sewer applications in metric regions.
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Regional Norms: AS/NZS 2280 (Australia/New Zealand) and GB/T 13295 (China) ensure local compliance and interoperability .
OD Comparison Table
| Nominal Size | OD (in) | OD (mm) |
|---|---|---|
| 4 inch | 4.80 | 121.92 |
| 6 inch | 6.90 | 175.26 |
| 8 inch | 9.05 | 229.87 |
| 10 inch | 11.10 | 281.94 |
| 12 inch | 13.20 | 335.28 |
Standard ODs per AWWA C151 and BS EN 545.
Installation & Jointing
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Push-On (Tyton®) Joints: Offer watertight, quick-assembly connections with up to 5° deflection per joint.
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Mechanical Joints: Bolted glands provide positive restraint for high-pressure, seismic, or deep-burial conditions.
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Flanged Ends: Conform to ANSI/AWWA C115 and BS EN 1092-2 PN16 for direct bolting to valves and pumps.
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Backfill Recommendations: Use non-corrosive, compacted granular material (max 2″ particle size) per ANSI/AWWA C600 guidelines.
FAQs
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What pressure classes are available for 8″ DIP?
Standard classes range from 150 psi to 350 psi, depending on wall thickness per AWWA C151. -
Is polyethylene encasement required?
In corrosive soils, loose polyethylene sleeving per ANSI/AWWA C105 is recommended for added external protection. -
How should trench backfill be prepared?
Bedding and backfill must comply with ANSI/AWWA C600—typically granular material compacted to ~90% Proctor density. -
Are fittings standardized?
Tees, bends, and reducers follow ISO 2531/EN 545 dimensions and are offered in push-on, mechanical, or flanged ends.
Case Studies
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City of Peoria WAS Force Main: A 13,463 ft 8″ DIP force main installed in 1999 carried waste activated sludge with minimal maintenance until corrosion testing in 2020 prompted targeted rehabilitation.
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Arizona PVC Ban: Eight major Arizona water districts, including Phoenix and Mesa, mandate DIP only—citing life-cycle value and resilience over PVC 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 | ….. |
