Class K7 DN800 ductile iron pipe features an 800 mm nominal diameter and a working pressure rating of 7 bar with a minimum tensile strength of 420 MPa. It boasts an anticipated service life of over 100 years under typical operating environments. Installation options include push‑on (Tyton®), mechanical and flange joints, providing leak‑tight and flexible assemblies for both buried and above‑ground applications.
Application Scenarios
Municipal Water Distribution
Large‑diameter mains (DN800) form the backbone of city water networks, delivering high‑volume flows with minimal leakage and maintaining stable pressure for potable supply.
Sewage & Wastewater
Its robust cement‑mortar lining and external coatings withstand abrasive and chemically aggressive effluents in sanitary sewers and stormwater systems.
Industrial Process Lines
Power plants, chemical and manufacturing facilities employ DN800 DI pipe for raw‑water intake, cooling‑water loops and process pipelines, trusting its high mechanical strength and corrosion resistance.
Agricultural Irrigation
Large‑bore mains transport irrigation flows across vast farmlands, and ductile iron’s inherent flexibility copes with soil movement and thermal cycles without cracking.
Service Life
Modern ductile iron mains routinely exceed 100 years of service in potable‑water service, thanks to durable cement‑mortar linings and protective exterior coatings. Even in corrosive soils, properly encased DI pipelines maintain integrity for a century or more, minimizing maintenance and replacement costs over multiple decades.
Installation & Connection
Push‑On (Tyton®) Joint
A gasket‑sealed bell and spigot system allows rapid, tool‑free assembly; the Tyton® joint provides up to 5° of angular deflection and a permanent water‑tight seal.
Mechanical Joint
Mechanical couplings (bell, gland, bolts) deliver restrained connections ideal where thrust blocks are impractical; SBR rubber gaskets handle service temperatures up to 120 °F.
Flange Joint
Flat or raised‑face flanges (ANSI B16.1 / EN 1092 / AS/NZS 4087) offer rigid, dismantlable connections—preferred for above‑ground runs and sections requiring frequent access.
Trenching & Encasement
Pipes rest on well‑graded granular bedding; backfill is compacted in layers. In highly corrosive soils, loose polyethylene sleeving (LPS) encasement adds an external corrosion barrier.
International Standards
-
ISO 2531:2009 — materials, dimensions, tolerances, linings and coatings for DN 80–DN 2600 mm pressure pipelines.
-
EN 545 / EN 598 — European standards for water and sewerage pipelines.
-
ANSI/AWWA C151/A21.51 — American specifications for DI pipes, fittings, coatings and joint types.
-
Other ISO: ISO 7186 (sewage fittings), ISO 8179 (external zinc coating), ISO 4633 (rubber seals), ISO 7005‑2 (flanges).
Price Comparison with Other Classes
| Class | Pressure (bar) | Price (USD/ton) |
|---|---|---|
| K7 | 7 bar | 500 – 530 |
| K8 | 8 bar | 450 – 550 |
| K9 | 9 bar | 545 – 645 |
Based on an average weight of ~213 kg/m, these translate to approximate meter‑prices of USD 106–113 for K7, USD 101–124 for K8, and USD 116–138 for K9.
Advantages
-
Corrosion Resistance: Cement‑mortar lining virtually eliminates tuberculation; external epoxy, bitumen or zinc‑aluminum coatings protect against soil corrosion.
-
High Impact Strength: ANSI/AWWA C151 tests confirm resilience to water hammer, traffic loads and handling shocks.
-
Structural Flexibility: Ductile cast iron with nodular graphite tolerates soil shifts and seismic movement without fracturing.
-
Sustainability: Contains high recycled‑content iron and is 100% recyclable at end‑of‑life.
FAQs
-
What does DN800 mean?
Nominal Diameter of 800 mm; actual internal diameter varies slightly by lining and thickness class. -
What is Class K7?
A pressure‑class designation indicating 7 bar working pressure, minimum tensile strength 420 MPa and ≥ 10% elongation. -
How long will the pipe last?
Modern DI mains exceed 100 years in potable and raw water service, per DIPRA research. -
Which joint types are available?
Push‑on (Tyton®), mechanical and flange joints—select based on thrust, accessibility and installation conditions. -
Is ductile iron pipe eco‑friendly?
Yes—high recycled content, energy‑efficient service, and fully recyclable at end‑of‑life.
Case Studies
-
Nîmes Métropole Mains Upgrade (France): Viking Johnson supplied UltraGrip® DN800 flange adaptors to retrofit 39 municipalities’ network, improving leak‑free connectivity for 260 000 residents.
-
Global Municipal Projects (DIPRA): Case studies across varied climates demonstrate DI mains’ easy installation, low maintenance and predictable lifecycle costs in cities worldwide.
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 | ….. |
