Class 250 ductile iron pipe combines robust pressure capacity with proven longevity, making it a top choice for water, wastewater, irrigation and industrial networks. Engineered to a nominal working pressure of 250 psi (with a 100 psi surge allowance), its nodular-iron body features a shop-applied cement-mortar lining and versatile external protection to achieve an expected service life exceeding 100 years. Installation is streamlined via push-on, mechanical, restrained and flanged joints, ensuring rapid, leak-tight assembly in the trench or at the pump vault. Fully compliant with ANSI/AWWA C150/A21.50–91, C151/A21.51, C104/C105, C110/C111, ISO 2531, EN 545 and EN 598 standards, it delivers a competitive wall-thickness and life-cycle cost profile versus Class 52, 53, 150 and 350 series.
Application Scenarios
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Municipal potable water distribution: Class 250’s 250 psi rating supports high-pressure loops and feeders in urban and suburban zones.
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Wastewater and sewer mains: Cement-mortar lining resists tuberculation in gravity and force mains, minimizing cleaning cycles.
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Agricultural irrigation networks: Specialized irrigation ranges of ductile iron pipes deliver low friction losses and exceptional durability in field conditions.
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Industrial process piping: Flanged Class 250 fittings link directly to pumps, valves and metering assemblies in chemical and power plants.
Service Life
Modern ductile iron pipelines, when coated with cement-mortar and properly sleeved, routinely outlast 100 years in typical soil environments. Detailed life-cycle analyses confirm Class 250’s low operating costs and minimal maintenance burden yield superior total-cost performance versus PVC and other materials over a century-long horizon.
Installation and Jointing
Push-On & Mechanical Joints
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Push-on joints employ a lubricant-coated gasket for quick, trench-side assembly without bolting.
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Mechanical joints use gland-and-bolt restraint gaskets (e.g., Field-Lok®) rated for 250 psi, eliminating thrust-block requirements in many layouts.
Restrained & Flanged Connections
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Restrained joints lock spigot into bell under pressure surges, safeguarding against separation in bends and dead-ends.
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Flanged ends bolt to equipment via ANSI B16.1 250 psi patterns or AWWA C207 configurations, yielding rigid, dismantlable connections.
Corrosion Protection
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Internal lining: Centrifugal cement-mortar per ANSI/AWWA C104 forms a high-pH barrier against tuberculation.
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External coatings: Options include bonded zinc, asphaltic enamel or epoxy; loose polyethylene sleeving per AWWA C105 can be added for aggressive soils.
International Standards
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ANSI/AWWA C150/A21.50 – Pressure-class thickness definitions
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ANSI/AWWA C151/A21.51 – Pipe dimensions and tolerances
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ANSI/AWWA C104/C105 – Lining and encasement specifications
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ANSI/AWWA C110/C111 – Mechanical & push-on joint performance
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ISO 2531:2012, EN 545, EN 598 – International benchmarks for water and sewage applications
Comparative Parameters (Classes 52, 53, 150, 250, 350)
| Class | Working Pressure | Surge Allowance | Joint Types | Wall-Thickness Range | Diameters Available |
|---|---|---|---|---|---|
| 52 | 200 psi | 100 psi | Mechanical only | 6.8–9.9 mm | 4″–48″ |
| 53 | 250 psi | 100 psi | Mechanical only | 7.2–10.9 mm | 4″–48″ |
| 150 | 150 psi | 100 psi | Push-on, MJ, restrained, flanged | 6.4–22.5 mm | 3″–64″ |
| 250 | 250 psi | 100 psi | Push-on, MJ, restrained, flanged | 7.1–24.3 mm | 3″–64″ |
| 350 | 350 psi | 100 psi | Push-on, MJ, restrained, flanged | 8.0–27.6 mm | 3″–64″ |
Advantages
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Exceptional Durability: Over a century of proven field performance
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High Strength: Meets AWWA tensile and impact standards under deep cover and surge events
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Corrosion Control: Cement-mortar lining plus coatings/sleeving minimize internal and external degradation
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Installation Flexibility: Multiple joint systems adapt to any trench or above-ground scenario
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Sustainability: Up to 90 % recycled content; fully recyclable at end-of-life
Frequently Asked Questions
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What does “Class 250” mean?
It denotes a nominal working pressure rating of 250 psi, with a 100 psi surge allowance, per ANSI/AWWA C150 tables. -
How long will Class 250 pipe last?
With proper lining and encasement, service lives regularly exceed 100 years. -
Which joint type installs fastest?
Push-on joints need only bell-hole prep and no bolting, speeding trench-time. -
Can it be used in corrosive soils?
Yes—pair with loose polyethylene sleeving per AWWA C105 or epoxy coating for aggressive environments. -
What diameters are available?
Nominal sizes from 3″ to 64″ cover most distribution and transmission needs.
Case Studies
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University of Michigan LCCA: A 1 000 ft, 8″ Class 250 main demonstrated lower total cost of ownership over a 100-year design life versus PVC in a detailed life-cycle cost analysis.
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Louisville Water MRRP: Rehab of early-20th-century iron mains—including Class 250 pipes—in the Main-Replacement & Rehabilitation Program reduced annual break rates by over 70 %, extending system life with targeted cleaning and relining.
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 | ….. |
