Class K8 DN600 ductile iron pipe features a nominal wall thickness of 9.6 mm, calculated per ISO 2531’s thickness formula e = K × (0.5 + 0.001 × DN) (K = 8, DN = 600) , and is rated PN 12.5 (1.25 MPa) for medium‑pressure water, sewage, irrigation, gas and fire‑protection mains . With an internal cement‑mortar lining and optional loose‑fit polyethylene sleeving (ISO 8180), its design life comfortably exceeds 100 years, reaching 110 years in aggressive soils. Installation is rapid and leak‑free via push‑on “Tyton” joints, AWWA C111 mechanical joints and ANSI B16.1 flanged connections . Within the K‑series, wall thickness increases from 8.4 mm (K7) to 9.6 mm (K8) to 10.8 mm (K9) to 14.4 mm (K12), with K8 pricing around $600 USD/ton on global markets . Life‑cycle analyses demonstrate a $47.68/ft cost advantage versus PVC and $17 million present‑value savings over 50 years in Huntsville, AL AMERICAN, and field tests in the Everglades show “excellent condition” after 10+ years.
Applications
Potable Water Distribution
Large‑diameter DN600 mains deliver stable hydraulic performance with minimal leakage, making K8 ideal for urban water networks .
Sewage & Drainage
Abrasion‑resistant iron core and smooth lining resist grit‑laden wastewater in gravity or force sewers .
Irrigation & Agriculture
Uniform flow under variable demands supports farm sprinklers and irrigation pivots .
Gas Distribution
When produced and externally coated per EN 969, DN600 K8 pipes safely convey medium‑pressure gas up to 16 bar .
Fire‑Protection Mains
High surge capacity and ductility ensure reliable hydrant loops and feeder mains for fire‑water delivery .
Service Life
Modern ductile iron pipe is engineered to exceed 100 years in benign soils, owing to its high‑strength matrix and durable linings . With loose polyethylene encasement per ISO 8180, life extends to 110 years even in aggressive soil conditions, as validated by Everglades City test sites . AWWA life‑cycle cost analysis reports a $47.68/ft advantage over PVC (24″ Class 200 vs DR 18) and a $17 million present‑value benefit over 50 years (3 % discount, reduced O&M) .
Installation & Connection
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Push‑On (“Tyton”) Joints use an elastomeric gasket in a spigot‑socket assembly for bolt‑free, rapid sealing per ISO 2531 dimensions.
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Mechanical Joints employ a gland‑and‑bolt design per AWWA C111, offering both restrained and unrestrained connections for valves and fittings .
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Flanged Joints conform to ANSI B16.1 / ASME B16.1 Class 125, enabling disassembly and high axial‑load resistance .
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Best Practices include 150 mm well‑graded trench bedding, ≤ 3 % deflection, hydrostatic testing and chlorination per ISO 2531/AWWA C600 guidelines .
K‑Series Comparison & Pricing
| Class | Nominal Wall Thickness<br>(e = K × (0.5+0.001×600)) | Pressure Rating | Price<sup>1</sup> (USD/ton) |
|---|---|---|---|
| K7 | 7×(0.5+0.001×600)=8.4 mm | PN 10 (1.0 MPa) | $400–500 |
| K8 | 9.6 mm | PN 12.5 (1.25 MPa) | $600 |
| K9 | 10.8 mm | PN 16 (1.6 MPa) | $650–750 |
| K12 | 14.4 mm | PN 25 (2.5 MPa) | $700–900 |
<sup>1</sup>Based on global supplier listings (Made‑in‑China, Alibaba) and market surveys .
International Standards
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ISO 2531:2009 – Ductile iron pipe dimensions, linings & joints.
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GB/T 13295‑2019 – Chinese standard for DIP, fittings & joints in water/gas systems.
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ISO 8180:2020 – Polyethylene sleeving for external corrosion protection.
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AWWA C111/A21.11 – Mechanical‑joint specifications for DN 80–600 mm.
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ANSI B16.1 / ASME B16.1 – Flanged joint dimensions & pressure classes.
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EN 969 – Gas‑pipeline ductile‑iron pipe, fittings & accessories (≤ 16 bar).
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ISO 1083 – Ductile iron material grades (tensile ≥ 350 MPa).
Advantages
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Outstanding Longevity: 100+ year service life minimizes replacements and downtime .
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High Strength & Toughness: Tensile ≥ 350 MPa per ISO 1083 grade JS I 350 RT ensures surge and load resistance .
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Superior Corrosion Control: Cement‑mortar lining (AWWA C104), zinc/bitumen coatings and LPS deliver comprehensive protection.
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Versatile Jointing: Push‑on, mechanical, flanged and restrained options suit diverse site needs .
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Sustainability: Recycled‐iron feedstock, fully recyclable with lower life‑cycle energy than thermoplastics .
FAQ
Q1: How do K classes differ?
They follow e = K·(0.5 + 0.001 DN)—for DN 600, K7=8.4 mm, K8=9.6 mm, K9=10.8 mm, K12=14.4 mm, corresponding to PN 10/12.5/16/25 .
Q2: Which joint type is best?
– Push‑On: Fast, bolt‑free installation
– Mechanical: Restrained/unrestrained versatility
– Flanged: Easy access for maintenance and high axial loads.
Q3: Is polyethylene sleeving necessary?
Recommended in aggressive soils for up to 110 years life extension; proven by DIPRA Logandale tests.
Q4: What sizes & lengths are available?
DN 80–2600 mm, standard 6 m laying lengths (5.7 m for container shipping), custom cuts on demand .
Q5: Can DIP be used in seismic areas?
Yes—restrained joints (tie‑rod, ball‑and‑socket) accommodate ground movement and axial loads for seismic resilience .
Case Studies
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Huntsville Utilities, AL: AWWA analysis shows $150.19 vs $197.87 net life‑cycle cost per foot for 24″ Class 200 DIP vs PVC DR 18, yielding $47.68/ft savings and $17 million PV benefit over 50 years .
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Everglades City, NV: DIP with loose HDCL polyethylene encasement remained in “excellent condition” after 10+ years in corrosive muck (140–240 Ω‑cm) at Logandale test site .
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Energy Savings Study: Journal AWWA reports utilities save millions in energy and maintenance by specifying ductile iron over alternate materials, due to larger inside diameters and smoother linings.
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 | ….. |
