Class K8 DN1500 ductile iron pipe offers a 16 mm nominal wall thickness (ISO 2531 formula), PN 12.5 (1.25 MPa) rating, and a design life beyond 100 years when cement-mortar lined and optionally polyethylene-sleeved. It installs quickly via push-on (Tyton), mechanical (AWWA C111) or flanged (ANSI B16.1) joints, balancing strength and economy at US $410–560 / ton (global B2B surveys). Compared to K7/K9/K12 (9.8 / 17.6 mm), K8’s 13.6 mm provides a middle ground of cost and performance. Backed by ISO 2531, GB/T 13295, EN 969 and AWWA standards, DIPRA-verified longevity, and AWWA life-cycle savings (≈ $47.68/ft), this pipe supports water, sewage, irrigation, gas and fire mains with proven reliability.
Applications
Ductile iron pipe’s versatility spans:
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Potable Water Mains: Large-diameter DN1500 runs with minimal leakage and stable hydraulics.
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Sewage & Drainage: Abrasion-resistant lining conveys grit-laden flows in gravity/force systems .
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Irrigation Networks: Uniform flow and surge tolerance support agricultural distribution .
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Gas Distribution: BS EN 969–approved for combustible gases up to 16 bar .
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Fire-Protection Loops: High surge resilience ensures hydrant-feeder reliability .
Service Life
Modern DIP exceeds 100 years in benign soils and 110 years with polyethylene sleeving:
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Base Longevity: > 100 years per DIPRA’s durability studies .
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Polyethylene Sleeving: ISO 8180 encasement adds ~10 years in aggressive soils .
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Life-Cycle Savings: AWWA analysis shows net $47.68/ft advantage vs. PVC, yielding $17 million PV benefit over 50 years .
Installation & Connection
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Push-On (“Tyton”) Joints: Spigot-socket with elastomeric gasket per ISO 2531 ensures rapid, bolt-free sealing .
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Mechanical Joints: Gland-and-bolt restraint per AWWA C111 for both restrained/unrestrained connections .
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Flanged Joints: ANSI B16.1 flanges allow disassembly and high axial-load resistance .
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Best Practices: 150 mm well-graded bedding, ≤ 3 % deflection, hydro-testing & chlorination per ISO 2531/AWWA C600 .
Product Series Comparison & Pricing
| Class | Wall Thickness<sup>1</sup> (mm) | Pressure Rating | Price Range (USD/ton)<sup>2</sup> |
|---|---|---|---|
| K7 | 9.8 | PN 10 | $388 – 450 |
| K8 | 16.0 | PN 12.5 | $410 – 560 |
| K9 | 17.6 | PN 16 | $460 – 520 |
| K12 | 21.6 | PN 25 | $700 – 900 |
<sup>1</sup>e = K·(0.5 + 0.001·DN) per ISO 2531.
<sup>2</sup>Global B2B platform averages (Alibaba, Made-in-China).
International Standards
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ISO 2531:2009 – Dimensions, linings & joint performance.
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GB/T 13295-2019 – Chinese spec for DIP, fittings & joints .
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ISO 8180:2020 – Polyethylene sleeving for corrosion control.
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ANSI/AWWA C104 – Cement-mortar lining requirements.
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ANSI/AWWA C111/A21.11 – Mechanical joints for DN 80–600 mm (extendable) .
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ANSI B16.1 – Flanged joint dimensions & pressure classes .
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BS EN 969:2009 – Gas pipelines up to 16 bar (DIPRA, gas joints).
Advantages
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Outstanding Durability: > 100 year design life reduces replacements.
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High Strength & Toughness: Tensile ≥ 350 MPa withstands surges & loads .
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Comprehensive Corrosion Protection: CML, zinc/bitumen coatings & LPS.
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Joint Versatility: Push-on, mechanical, flanged & restrained systems.
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Sustainability: Recycled-iron, fully recyclable, lower life-cycle energy than PVC .
FAQ
Q1: How do K-series classes differ?
They follow e = K·(0.5 + 0.001·DN)—for DN1500, K7=9.8 mm, K8=16.0 mm, K9=17.6 mm, K12=21.6 mm, matching PN10/12.5/16/25 respectively .
Q2: Which joint type is best?
– Push-On for speed & simplicity; Mechanical for restraint; Flanged for maintenance/axial loads .
Q3: Is polyethylene sleeving necessary?
Recommended in aggressive soils for a ~10 year life extension to 110 years; DIPRA-validated .
Q4: What sizes & lengths are offered?
DN 80–2600 mm, standard 6 m laying lengths (5.7 m for containers), custom cuts on request.
Q5: Can DIP be used in seismic zones?
Yes—restrained joints (tie-rod, ball-and-socket) absorb ground movement, ensuring pipeline integrity .
Case Studies
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Huntsville Utilities, AL: AWWA life-cycle study shows $47.68/ft net savings and $17 million PV benefit over 50 years for DN1500 vs PVC mains .
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Everglades City, FL: Polyethylene-encased DIP remained in “excellent condition” after 10+ years in corrosive soils (140–240 Ω·cm).
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 | ….. |
