The 18-inch ductile iron pipe delivers exceptional performance in potable water, wastewater, and industrial systems, boasting a service life exceeding 100 years by design. It installs via push-on, mechanical, or flanged joints with established methods to ensure leak-proof performance in all soil and weather conditions. Manufactured to ISO 2531/EN 545/EN 598 and AWWA C151/C110 standards, its dimensions and material properties ensure global compatibility and interchangeability. Below you’ll find detailed technical data, price and spec comparisons across common sizes, the pipe’s key benefits, FAQs, and illustrative project examples—all written in clear, SEO-friendly English for an international audience.
Application Scenarios
Potable Water Distribution
Ductile iron pipe is the standard choice for municipal potable water mains due to its proven durability under pressure and minimal water-quality interactions.
Wastewater and Sewage Systems
Its robustness makes it ideal for gravity sewers and force mains handling wastewater and stormwater conveyance.
Industrial, Irrigation, and Fire Protection
Beyond water utilities, 18-inch ductile iron serves in irrigation networks, power plants, and fire-protection systems, where high strength and pressure ratings are essential.
Service Life
Modern ductile iron pipes are engineered for a minimum life expectancy of over 100 years, thanks to their corrosion-resistant linings and durable cast-iron matrix. Extensive field data confirm that, with proper installation and maintenance, pipes laid a century ago continue to perform reliably in many U.S. communities.
Installation and Connection
Three primary joint types are used with 18-inch ductile iron pipe:
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Push-on Joints (Tyton): Quick field assembly with rubber gaskets, ideal for rapid, weather-independent installation.
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Mechanical Joints: Use bolted glands for restrained connections in high-pressure or challenging soil conditions.
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Flanged Joints: Preferred for above-ground or supervisory applications where frequent disassembly may be required.
Installation guides outline three corrosion-protection methods (A, B, C) using polyethylene encasements and cement-mortar linings to safeguard joints and barrels under various soil resistivity levels.
International Standards
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ISO 2531 / EN 545: Defines dimensional, material, and testing requirements for potable water ductile iron pipes.
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EN 598: Applies when used in sewerage applications.
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AWWA C151 / C110: North American standards governing pipe thickness classes, mechanical joint dimensions, and cement-mortar lining protocols .
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ISO 4179 / ISO 8179: Specify inner lining and outer coating requirements to resist internal corrosion and external soil chemistry .
Other Series: Price and Parameter Comparison
Wall-Thickness and Dimension Table
| Nominal Size (DN/in) | Outside Diameter (mm) | Wall Thickness K9 (mm) | Wall Thickness K7 (mm) |
|---|---|---|---|
| DN 350 / 14″ | 378 ±1/-3.4 | 7.7 | 6.0 |
| DN 400 / 16″ | 429 ±1/-3.5 | 8.1 | 6.3 |
| DN 450 / 18″ | 480 [±] | 8.6 | — |
| DN 500 / 20″ | 532 [±] | 9.0 | 10.0 |
Price Comparison Table
| Nominal Size | Price Range | Unit | Region |
|---|---|---|---|
| 4″ | $22.71 | per foot | US |
| 10″ | $32.01 | per foot | US |
| 20″ | $76.54 | per foot | US |
| 48″ | $342.26 | per foot | US |
| 18″ | $450 – $650 | per meter | India |
Note: Actual pricing fluctuates based on region, material grade, joint type, and coating options. Always request a current quote from local suppliers.
Advantages
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Superior Strength & Flow: Allows a larger internal diameter compared to PVC for the same trench width, maximizing flow capacity.
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Corrosion Resistance: Cement-mortar linings and optional epoxy or polyurethane coatings protect against internal corrosion and tuberculation.
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Longevity: Recyclable iron matrix and robust linings underpin a 100+-year service life.
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Ease of Installation: Gasketed joints require no hot work, and polyethylene encasements simplify trench backfill conditions.
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Sustainability: High recycled content and energy-efficient in-service operation contribute to environmental goals.
Frequently Asked Questions
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Is minor cracking in cement lining normal?
Yes—thermal expansion differences can cause hairline cracks that self-heal under service conditions. -
What pressure ratings are available?
Commonly C25, C30, and C40 classes, corresponding to 250 – 400 m of head (350 – 575 psi). -
Can I mix joint types in one project?
Yes—push-on, mechanical, and flanged joints are interchangeable within ISO 2531 tolerances. -
How is external corrosion mitigated?
Through polyethylene encasement, bituminous paint, zinc or zinc-aluminum coatings, and optional epoxy overlays. -
What maintenance is required?
Periodic inspection of joint gaskets and coatings, plus cathodic protection checks where installed.
Case Studies
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City X Water Main Upgrade: A 24-month project replacing aging 18″ cement-lined cast iron with 18″ ductile iron pipe reduced break rates by 80 percent and met ISO 2531 standards for potable water.
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Metropolitan Sewage Interceptor: Installation of 18″ force mains via horizontal directional drilling under a river crossing employed mechanical joints to accommodate ground movement and achieved zero leaks in 5 years of monitoring.
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 | ….. |
