Class K8 DN1200 ductile iron pipe features a nominal wall thickness of 13.6 mm, calculated per ISO 2531’s formula e = K × (0.5 + 0.001 × DN) (K = 8, DN = 1200 mm) . It is rated PN 12.5 (1.25 MPa) for medium-pressure water, sewage, irrigation, gas and fire-protection mains . With cement-mortar lining (ANSI/AWWA C104) and optional loose-fit polyethylene sleeving (ISO 8180), its design life exceeds 100 years, extending to 110 years under aggressive soil conditions . Installation uses push-on (“Tyton”), AWWA C111 mechanical and ANSI B16.1 flanged joints for rapid, leak-free assembly . Among the K-series, wall thickness increases from 9.8 mm (K7) → 13.6 mm (K8) → 14.8 mm (K9) → 19.6 mm (K12), with K8 pricing around US $800–1,200 / ton at FOB from China and $470–570 / ton on global B2B platforms .
Applications
Potable Water Distribution
DN1200 mains deliver stable hydraulics and minimal leakage in large municipal networks .
Sewage & Drainage
Abrasion-resistant iron core and smooth mortar lining handle grit-laden wastewater in gravity or force mains .
Irrigation Systems
Uniform flow under variable pressures supports large-scale agricultural supply lines .
Gas Distribution
When produced per BS EN 969 and coated, DN1200 K8 pipes safely convey natural gas up to 16 bar .
Fire-Protection Mains
High ductility and surge resilience ensure reliable hydrant loops and feeder mains for fire-water delivery .
Service Life
Modern ductile iron pipe is engineered to last 100 + years in benign soils, owing to its recycled-iron matrix and proven linings .
Cement-mortar lining (ANSI/AWWA C104) provides internal corrosion protection exceeding a century .
Loose-fit polyethylene sleeving per ISO 8180 adds ~10 years in aggressive soils, validated by DIPRA research .
Life-cycle cost analyses by the University of Michigan show PVC’s 50-year design life vs. ductile iron’s 100+ years yields a significantly lower total cost for ductile iron over a full century .
Installation & Connection
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Push-On (“Tyton”) Joints: Spigot-socket with elastomeric gasket for bolt-free, rapid, leak-tight assembly per ISO 2531 .
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Mechanical Joints: Gland-and-bolt restraint conforming to AWWA C111 for DN 80–600 mm (extendable designs up to 1600 mm) .
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Flanged Joints: ANSI B16.1 (Class 125) or EN 1092 flanges enable easy disassembly and high axial-load resistance .
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Best Practices: 150 mm well-graded trench bedding, ≤ 3 % deflection, hydrostatic testing and chlorination per ISO 2531/AWWA C600 maximize joint performance and longevity .
K-Series Comparison & Pricing
| Class | Wall Thickness<br>(e=K·(0.5+0.001·1200)) | PN Rating | Price (USD/ton) |
|---|---|---|---|
| K7 | 9.8 mm | PN 10 (1.0 MPa) | $470 – 570 |
| K8 | 13.6 mm | PN 12.5 (1.25 MPa) | $800 – 1,200 |
| K9 | 14.8 mm | PN 16 (1.6 MPa) | $900 – 1,000 |
| K12 | 19.6 mm | PN 25 (2.5 MPa) | $1,100 – 1,300 |
International Standards
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ISO 2531:2009 / EN 545:2006 / EN 598:2007 – Pipe dimensions, linings & joint performance .
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GB/T 13295-2019 – Chinese standard for DIP, fittings & joints in water/gas systems .
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ANSI/AWWA C104/A21.4 – Cement-mortar lining requirements.
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ANSI/AWWA C111/A21.11 – Rubber-gasket joints for DI pressure pipe & fittings.
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ANSI B16.1 / ASME B16.1 – Flanged joint dimensions & pressure ratings.
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ISO 8180:2020 – Polyethylene sleeving for external corrosion control.
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BS EN 969:2009 – Gas-pipeline DI pipe, fittings & accessories requirements.
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ISO 1083 – Ductile iron material grades (tensile ≥ 350 MPa).
Advantages
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Exceptional Longevity: 100+ year service life minimizes replacements.
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High Strength & Toughness: Tensile ≥ 350 MPa resists surge and external loads .
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Comprehensive Corrosion Control: CML, zinc/bitumen coatings & LPS ensure internal/external protection.
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Jointing Flexibility: Push-on, mechanical, flanged & restrained options suit diverse field needs.
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Sustainability: High recycled content, fully recyclable with low life-cycle energy vs. thermoplastics.
FAQ
Q1: How do K-series classes differ?
They follow e=K·(0.5+0.001·DN)—for DN 1200, K7=9.8 mm, K8=13.6 mm, K9=14.8 mm, K12=19.6 mm, matching PN 10/12.5/16/25 respectively.
Q2: Which joint type is best?
– Tyton push-on for speed & simplicity; Mechanical for restrained connections; Flanged for maintenance access & axial loads .
Q3: Is polyethylene sleeving necessary?
Recommended in aggressive soils for up to 110 years life extension; proven by DIPRA research .
Q4: What sizes & laying lengths are offered?
DN 80–2600 mm, standard 6 m (5.7 m for containers), custom cuts on request .
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: Over 50 years, ductile iron mains delivered a present-value savings of $17 million, plus 9 % lower operating energy vs. alternatives .
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University of Michigan LCCA: PVC’s 50-year design life vs. ductile iron’s 100+ years yields a significantly lower total cost when all lifecycle phases are considered
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 | ….. |
