Description
High-strength ductile iron pipes and fittings manufactured strictly per Chinese national standard GB/T26081. Ideal for municipal water supply, sewage transmission, and gravity flow drainage systems with proven reliability.
Key Technical Specifications
| Item | Specification | GB/T26081 Requirement |
|---|---|---|
| Pipe Type | Ductile Iron Pipe for Sewage | Centrifugally cast |
| Size Range | DN80 – DN2000 | Full range covered |
| Pressure Rating | PN10 / PN16 / PN25 | For pressure sewers |
| Ring Stiffness | SN4000 / SN8000 / SN16000 | For gravity sewers |
| Wall Thickness | Standard (K9) / Thickened (K12) | Per GB/T26081 table |
| Base Material | Ductile Iron (EN-GJS-400-15 equivalent) | Tensile ≥ 420 MPa |
| Inner Coating | High-alumina cement mortar / Epoxy / PU | Sewage grade required |
| Outer Coating | Zinc + bitumen / Epoxy / Polyethylene sleeving | Enhanced for corrosion |
| Joint Type | Push-on rubber ring (T-type) / Flanged | Restricted joint design |
| Gasket Material | EPDM (sewage grade) / NBR | Acid & alkali resistant |
| Standard Compliance | GB/T26081 | Full certification |
Product Features
Dedicated Sewage Standard, Not Just Water Pipe
GB/T26081 focuses specifically on sewage and wastewater conditions. The standard requires higher corrosion resistance than water pipe standards. You get pipes designed for hydrogen sulfide, acids, and aggressive sewage chemicals.
Enhanced Inner Coating for Sewage
High-alumina cement mortar lining resists sulfuric acid attack. This prevents biogenic corrosion from sewer gases. Standard cement mortar would fail in sewage environments. Our GB/T26081 pipes include the right coating.
Superior Ring Stiffness for Deep Burial
Sewer pipes often go deeper than water lines. GB/T26081 requires high ring stiffness grades. Choose SN4000, SN8000, or SN16000 based on your burial depth. The pipe will not collapse under soil load.
Ductile Iron Strength with Sewage Protection
The ductile iron base material gives 420 MPa minimum tensile strength. This handles heavy traffic loads above buried pipes. The material also resists impact during installation. No cracking from dropped pipes or backfill stones.
Application & Scope
Municipal Sewage Collection Networks – Gravity mains and force mains. Standard meets all Chinese municipal requirements. International sewer projects also accept GB/T26081.
Industrial Effluent Lines – Factories discharge aggressive wastewater. GB/T26081 pipes resist chemicals. High-alumina lining stands up to hot effluents.
Stormwater Drainage Systems – Large diameter pipes for rainwater. Ring stiffness handles depth and traffic loads.
Interceptor Sewers – Trunk lines along rivers or coasts. Restricted joints prevent leakage into water bodies.
Pump Station Force Mains – Pressurized sewage lines from lift stations. PN16 and PN25 ratings available.
Outfall Pipelines – Sewage discharge to treatment plants. Long lengths reduce joints. Corrosion protection for tidal zones.
Landfill Leachate Collection – Aggressive liquid from waste. GB/T26081 pipes resist chemical attack.
Reclaimed Water Pipelines – Treated sewage for irrigation or industry. Standard covers non-potable water too.
Materials & Standards Compliance
| Component | GB/T26081 Requirement | Our Supply | Notes |
|---|---|---|---|
| Base iron | Ductile iron grade | EN-GJS-400-15 equivalent | Tensile ≥ 420 MPa |
| Chemical composition | C, Si, Mn, P, S controlled | Certified mill report | Full traceability |
| Microstructure | Nodular graphite ≥ 80% | Yes | Per GB/T9441 |
| Inner coating | High-alumina cement mortar | C2 grade | Sulfuric acid resistant |
| Outer coating | Zinc + bitumen min 200 g/m² | 200 g/m² zinc + bitumen | Standard for GB/T26081 |
| Gasket | EPDM (sewage grade) | EPDM 70 Shore A | Resists H2S and acids |
| Gasket test | GB/T21873 | Passed | 24h compression set |
Accessories
Rubber Gaskets (GB/T21873) – EPDM sewage grade. Resists hydrogen sulfide and acids. Temperature range -20°C to 80°C. Two gaskets included per joint for restricted design.
Pipe Fittings – Bends (11.25°, 22.5°, 45°, 90°), tees, reducers, and adapters. All fittings comply with GB/T26081. Same coating as pipes.
Polyethylene Sleeving – For aggressive soil conditions. Encases the pipe after installation. Stops corrosion from chlorides and low resistivity soil.
Epoxy External Coating – Fusion bonded epoxy. Resists acid soil and industrial waste. Coating thickness 300-400 microns. Meets GB/T34202.
Polyurethane Inner Lining – For highly abrasive sewage. Resists sand and grit wear. Superior to cement mortar for slurry lines.
Flanged Adapters – Connect ductile iron pipe to pumps or valves. Steel or ductile iron construction. Drilled to PN10 or PN16 standards.
Performance Testing
Hydrostatic Pressure Test – Every pipe tested to 1.5x working pressure. Hold pressure for 10 seconds minimum. No leakage allowed. Test pressure recorded per pipe.
Tensile Test – Sample from each batch tested. Minimum tensile strength 420 MPa. Minimum elongation 10%. Test report provided.
Hardness Test – Brinell hardness maximum 230 HBW. Ensures ductile iron quality. Not too hard, not too soft.
Microstructure Examination – Nodularity minimum 80%. Graphite spheroidization grade 1-3. Per GB/T9441.
Coating Thickness Test – Zinc layer minimum 200 g/m² measured by magnetic gauge. Bitumen coating thickness measured. High-alumina cement lining thickness checked.
Coating Adhesion Test – Cross-cut test for cement lining. No flaking allowed. Pull-off test for epoxy coatings.
Ring Stiffness Test – For gravity sewer pipes per GB/T26081. Load applied until deflection reaches 3% of diameter. Strength verified.
Rubber Gasket Test – Per GB/T21873. Hardness, tensile strength, elongation, compression set all tested.
Optional Quality Services
Third-party inspection (SGS, BV, TUV) – Witness all factory tests. Provide independent report.
Mill certificate for each heat number – Full chemistry and mechanicals.
Dimensional inspection report – OD, ID, wall thickness, length.
Photographic record – Pipe marking, coating application, testing.
GB/T26081 Advantages
Proven in China's Massive Sewer Infrastructure
China builds thousands of kilometers of sewers every year. GB/T26081 is the standard they trust. The requirements are battle-tested in real conditions.
More Cost-Effective Than European Standards
EN 598 pipes cost more for the same performance. GB/T26081 achieves equivalent quality with optimized manufacturing. You get European-level protection at lower cost.
Widely Accepted for International Projects
Many African, Middle Eastern, and Southeast Asian projects accept GB/T26081. The standard aligns with ISO 7186. Mutual recognition saves you certification work.
Comprehensive Corrosion Protection
The standard requires high-alumina cement lining. This resists biogenic sulfuric acid from sewer gases. Standard cement mortar would fail within years. GB/T26081 pipes last decades.
