Steel strength outside, plastic corrosion resistance inside. Blue for potable water, red for fire, dual-resistant for mining, outer-PE inner-EP for cable conduits — to GB/T 28897, CJ/T 120 and MT 558.
Sanitary-grade epoxy inner wall, certified to GB/T 17219 for drinking water.
Municipal water supply, water plants, building risers · CJ/T 120
Red inner-outer coating, grooved joints, fast installation.
Sprinkler and standpipe systems · GB/T 5135.20 / GB 50974
Warning yellow coating for low-pressure gas and chemical lines.
Low-pressure gas mains, chemical transfer lines
Flame-retardant and anti-static coating certified to MT 558.
Mine gas drainage, water supply & compressed air underground
Weather-resistant PE outside, smooth epoxy inside — cables pull through fast.
Power cable protection, telecom ducts
Any RAL color from your card; black, grey and green are common for industry.
OEM projects, EPC contractors, brand-colored lines
The pipe is pre-heated, then epoxy or PE powder is electrostatically sprayed or fluid-bed fused onto the inner and outer walls, melting into a continuous layer that bonds mechanically and chemically to the steel. The result: steel strength outside, plastic corrosion resistance inside — no painting, no rust for decades.
Our self-developed large-diameter coating line takes DN up to 3800 — one of the largest in North China. Spiral, ERW, seamless and galvanized substrates can all be coated on the same line.
| Standards | GB/T 28897 · CJ/T 120 · CJ/T 136 · MT 558 · GB/T 5135.20 |
| Outside diameter | DN15 – DN3800（Φ21 – Φ3820 mm） |
| Coating types | Inner EP / PE, outer PE / EP — single or double coating |
| Coating thickness | Inner ≥ 0.3 mm · outer ≥ 0.5 mm (adjustable) |
| Substrate | Spiral · ERW/JCOE · seamless · galvanized |
| Colors | Blue · Red · Yellow · Green · White · Grey · Black (RAL on request) |
| Connections | Grooved · Flanged · Threaded · Bimetallic welded joint |
| Inspection | Adhesion (≥ grade 1) · flattening · hydrostatic test · sanitary report |
| Working temperature | EP: −30 ~ 110 °C · PE: −30 ~ 60 °C |
Hygienic approval, coal-safety certificate and third-party inspection (SGS / BV / TÜV) available on request.
Blue-coated trunk and branch lines with sanitary epoxy inner wall.
Red coated risers and sprinkler mains with grooved joints.
Dual-resistant green pipe for gas drainage, water and compressed air.
Outer-PE inner-EP conduit protects cables for decades.
Yellow warning-coated pipe for low-pressure gas and chemical media.
Corrosion-resistant inner wall handles aggressive wastewater.
Colors mainly mark the duty: blue for potable water (sanitary epoxy), red for fire fighting, yellow for gas and chemical warning, green for mining dual-resistant, white or grey for cable conduits. Custom RAL colors are available.
Yes — choose blue coated pipe whose sanitary-grade epoxy inner wall passes GB/T 17219 hygienic evaluation and comes with a potable-water approval document, to CJ/T 120 and GB/T 28897.
Grooves are pressed on the bare pipe end before coating or at the factory; the groove face is sealed with a gasketed coupling and repair paint keeps the coating continuous. Factory pre-fabricated grooves give the best protection.
Replace with our coating line: pre-heating furnace, powder booths, curing oven — the DN3800 line in North China.
Replace with coating thickness gauge readings, adhesion test and flattening samples.
Replace with a site photo of our coated pipe in service — water mains, fire risers or cable ducts.
Technical proposal and quotation within one working day.
