Class K8 DN300 ductile iron pipe has a nominal wall thickness of 6.4 mm, calculated per ISO 2531’s formula e = K·(0.5 + 0.001 × DN) with K = 8 and DN = 300 mm. It is rated for PN 12.5 (1.25 MPa) working pressure in medium‑pressure water and gas networks . With cement‑mortar lining and optional loose polyethylene sleeving, its design life exceeds 100 years—up to 110 years under optimal corrosion control . Installation employs push‑on “Tyton”, mechanical and flanged joints per ISO 2531, AWWA C111 and ANSI B16.1 standards . In the K‑series, wall thickness rises from 5.6 mm (K7) to 6.4 mm (K8) to 7.2 mm (K9) to 9.6 mm (K12), with market prices roughly $480–900 USD/ton depending on class and coating . Real‑world studies report $17 million PV savings over 50 years in Huntsville, AL, and “excellent” corrosion performance in Everglades muck .
Applications
Potable Water Distribution
Designed for leak‑tight, large‑diameter mains in urban networks, K8 DN300 maintains stable hydraulics and water quality .
Sewage & Drainage
Its abrasion‑resistant core and robust lining handle grit‑laden wastewater in gravity or force mains .
Irrigation Systems
Stable hydraulic performance under variable flows supports agricultural supply and farm sprinklers.
Gas Distribution
When manufactured and tested per EN 969 with external coatings, it safely conveys natural gas in medium‑pressure networks .
Fire‑Protection Mains
High surge resilience and ductility ensure reliable fire‑water delivery in hydrant loops and feeder mains .
Service Life
Modern ductile iron pipe is engineered to last 100 + years in benign soils, thanks to its inherent toughness and recycled‑iron matrix .
With external polyethylene sleeving meeting ISO 8180, life expectancy extends to 110 years even in aggressive soils .
A Black & Veatch life‑cycle analysis for Huntsville Utilities showed annual pumping‑cost savings of $666,999, yielding $17 million PV benefit over 50 years compared to PVC mains .
At Everglades test sites, polyethylene‑encased pipes remained in “excellent condition” after 10+ years buried in corrosive muck .
Installation & Connection
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Push‑On (“Tyton”) Joints use a rubber gasket in a spigot‑socket assembly for fast, bolt‑free sealing per ISO 2531 socket dimensions .
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Mechanical Joints employ a gland‑and‑bolt system for restrained or unrestrained connections, as defined in AWWA C111 (DN 80–600 mm) .
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Flanged Joints conform to ANSI B16.1 or EN 1092, allowing easy disassembly and high axial‑load resistance .
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Best Practices—including well‑graded bedding, ≤ 3 % deflection limits, hydrostatic testing and disinfection—follow ISO 2531 and AWWA C600 guidelines .
K‑Series Comparison & Pricing
| Class | Wall Thickness (mm)1 | Pressure Rating | Price (USD/ton)2 |
|---|---|---|---|
| K7 | 5.6 = 7×(0.5+0.001×300) | PN10 (1.0 MPa) | $480 – 530 |
| K8 | 6.4 = 8×(0.5+0.001×300) | PN12.5 (1.25 MPa) | $500 – 600 |
| K9 | 7.2 = 9×(0.5+0.001×300) | PN16 (1.6 MPa) | $545 – 645 |
| K12 | 9.6 = 12×(0.5+0.001×300) | PN25 (2.5 MPa) | $750 – 900 |
1.Per ISO 2531 nominal‑thickness formula.
2.Based on industry price lists and market surveys.
International Standards
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ISO 2531:2009 / EN 545:2006 – 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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ISO 8180:2020 – Polyethylene sleeving for external corrosion control.
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AWWA C111/A21.11 – Mechanical‑joint specs for DN 80–600 mm.
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ANSI B16.1 – Flanged joint dimensions & ratings.
Advantages
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Exceptional Longevity: 100+ year design life minimizes replacement cycles .
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High Strength & Toughness: Tensile ≥ 420 MPa resists surge and external loads .
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Comprehensive Corrosion Control: Cement‑mortar lining (ANSI/AWWA C104), zinc/bitumen coatings, LPS .
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Versatile Jointing: Push‑on, mechanical, flanged and restrained options for any site condition.
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Sustainability: Recyclable iron with lower life‑cycle energy than thermoplastics.
FAQ
Q1: How do K classes differ?
They follow e=K·(0.5+0.001×DN)—for DN300, K7=5.6 mm, K8=6.4 mm, K9=7.2 mm, K12=9.6 mm, matching PN10/12.5/16/25 respectively.
Q2: What lining & coating options are available?
Internal cement‑mortar (ANSI/AWWA C104), epoxy or ceramic; external bitumen, zinc, or polyethylene sleeving per ISO 8180.
Q3: Can DIP be used in corrosive soils?
Yes—LPS or cathodic protection enable 100+ year life even in aggressive environments, as proven at Everglades test sites.
Q4: What sizes & lengths are offered?
DN 80–2600 mm in standard 6 m laying lengths (5.7 m for container loads), with custom cuts on demand.
Q5: Is DIP suitable for seismic zones?
Restrained joints (tie‑rod, ball‑and‑socket) absorb ground movement, ensuring pipeline integrity in seismic areas.
Case Studies
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Huntsville Utilities, AL: $666,999/year in pumping‑cost savings; $17 million PV benefit over 50 years by choosing DIP over PVC mains.
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Everglades City, FL: LPS‑encased DIP remained in “excellent condition” after 10+ years in corrosive muck (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 | ….. |
