Water Supply Plastic-Coated Composite Steel Pipe
Product Overview
Water supply plastic-Coated composite steel pipe is a high-performance piping system engineered for potable water distribution networks, featuring a seamless fusion-bonded thermoplastic lining and coating over a robust steel substrate. The composite structure combines the mechanical strength and pressure-bearing capacity of steel with the corrosion resistance, hygienic properties, and smooth flow characteristics of food-grade plastics—typically epoxy resin (EP) for interior lining and polyethylene (PE) or polypropylene (PP) for exterior protection. Designed to comply with stringent drinking water standards, this pipe delivers safe, clean, and efficient water conveyance for municipal utilities, building services, industrial plants, and agricultural irrigation systems.
Key Features
Hygienic Potable Water Conveyance
The fusion-bonded epoxy (FBE) inner lining creates an ultra-smooth, non-porous surface (Ra ≤ 0.4 μm) that prevents bacterial adhesion, biofilm formation, and scale accumulation. The coating is certified to NSF/ANSI 61, WRAS, and GB/T 17219 for direct potable water contact, with zero leaching of heavy metals, plasticizers, or volatile organic compounds.
Superior Corrosion Resistance
The dual-layer coating system provides comprehensive protection: the inner epoxy barrier prevents water-induced internal corrosion and tuberculation, while the outer PE/PP jacket shields against soil corrosion, atmospheric oxidation, and galvanic degradation. Service life exceeds 50 years in typical buried applications, 3-5 times longer than galvanized or bare steel alternatives.
Optimized Hydraulic Performance
The mirror-smooth plastic lining achieves a Hazen-Williams C-factor of 150 and a Manning's n-value of 0.009, significantly reducing friction losses compared to uncoated steel (C-120), ductile iron (C-100), or concrete (C-110). This translates to lower pumping energy costs, higher flow capacity, and reduced pressure drop over long distribution runs.
Mechanical Robustness
Manufactured from Q235B, Q345B, or 20# quality carbon steel with wall thicknesses from 2.0 mm to 12.0 mm. The steel substrate withstands internal pressures up to 2.5 MPa (360 psi), external soil loads, and traffic-induced stresses, while the flexible coating accommodates minor ground settlement without cracking.
Thermal & Chemical Stability
Standard epoxy linings operate continuously from -30°C to +80°C, with high-temperature grades extending to +120°C. The coating resists chlorine residuals up to 5 mg/L, pH variations from 6.0 to 9.0, and typical water treatment chemicals, ensuring integrity across diverse water chemistries.
Environmentally Sustainable
The steel core is 100% recyclable, and the thermoplastic coatings can be mechanically separated for material recovery at end-of-life. The extended service life reduces replacement frequency, minimizing embodied carbon and construction disruption over the infrastructure lifecycle.
Technical Specifications
| Parameter | Specification |
|---|---|
| Substrate Material | Q235B / Q345B / 20# Carbon Steel |
| Inner Lining | Fusion-Bonded Epoxy (FBE), 250-500 μm |
| Outer Coating | Polyethylene (PE) or Polypropylene (PP), 400-800 μm |
| Nominal Diameter | DN15 - DN1200 (1/2" - 48") |
| Wall Thickness | 2.0 mm - 12.0 mm (Sch 10 - Sch 80) |
| Pressure Rating | 1.0 MPa - 2.5 MPa (150 - 360 psi) |
| Operating Temperature | -30°C to +80°C (standard), up to +120°C (high-temp grade) |
| Coating Adhesion | ≥8 MPa (pull-off test, ASTM D4541) |
| Cathodic Disbondment | ≤8 mm radius (30-day test, ASTM G8) |
| Impact Resistance | ≥2.0 J/mm (ASTM G14) |
| Bend Performance | No cracking at 2.5° per diameter |
| Potable Water Certifications | NSF/ANSI 61, WRAS, ACS, DVGW W270, GB/T 17219 |
| Standards | GB/T 3091, GB/T 28897, AWWA C213, EN 10255, ISO 21809-2 |
Applications
Municipal Water Distribution
Primary transmission mains, distribution networks, and service connections in urban and rural water supply systems. The corrosion-resistant coating eliminates red water complaints and reduces leakage rates associated with pipe deterioration.
Building Plumbing Systems
Risers, horizontal distribution lines, and branch connections in high-rise residential, commercial, and institutional buildings. The lightweight design reduces structural load compared to ductile iron, while the smooth bore minimizes pump energy in booster systems.
Industrial Process Water
Cooling water circuits, boiler feed lines, and process water distribution in power plants, chemical facilities, and manufacturing plants. Chemical-resistant coating grades handle treated cooling tower water and demineralized water applications.
Agricultural Irrigation
Pivot irrigation systems, drip irrigation mains, and canal siphons. The UV-stable exterior coating withstands prolonged sun exposure, while the smooth interior prevents sediment accumulation in low-flow conditions.
Seawater & Brackish Water
Desalination plant intake and product water lines, aquaculture systems, and coastal infrastructure. Special marine-grade epoxy formulations resist chloride-induced coating degradation.
Mining & Remote Sites
Camp water supply, dewatering systems, and process water lines in remote mining and oilfield operations. The robust steel construction withstands rough handling and transportation, while the coating prevents internal corrosion in aggressive groundwater.
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