3PE Coated Steel Pipe
Three-layer polyethylene coated steel pipes with superior corrosion resistance for oil & gas transmission, water supply, and industrial applications.
3PE Coated Steel Pipe
Three-layer polyethylene (3PE) coating provides the ultimate protection for steel pipes in corrosive environments. The three-layer system combines an epoxy primer (FBE), adhesive layer, and polyethylene outer layer to deliver exceptional corrosion resistance and mechanical strength.
This advanced coating technology extends pipeline service life to over 50 years, making it the preferred choice for oil & gas transmission, water supply systems, and industrial applications worldwide.
FBE layer ensures excellent adhesion to steel surface
Polymer adhesive bonds epoxy to PE outer layer
High-density polyethylene protects against mechanical damage
50+ years service life in harsh conditions
Stable performance under sunlight exposure
Operating temperature from -40C to +80C
Technical Specifications & Performance
| Standard | Scope | Region |
|---|---|---|
| DIN 30670 | Polyethylene coatings of steel pipes and fittings | Germany / Europe |
| ISO 21809-1 | Polyolefin coatings (3-layer PE and 3-layer PP) for pipelines | International |
| CAN/CSA Z245.21 | External polyethylene coating systems for pipe | Canada |
| GB/T 23257 | Polyethylene coating (2PE / 3PE) for buried steel pipelines | China |
| API 5L / ISO 3183 | Base line pipe specification | International |
| Parameter | Specification |
|---|---|
| Outside Diameter | 33.4 mm – 1820 mm (1″ – 72″) |
| Wall Thickness | 2.0 – 40 mm |
| Pipe Length | 6 m / 12 m / up to 18 m custom |
| Total Coating Thickness | 1.8 – 4.5 mm (by diameter class, see Thickness tab) |
| Pipe Types | Seamless, ERW, LSAW, SSAW |
| Steel Grades | API 5L Gr.B – X80 PSL1/PSL2, ASTM A53/A106, ISO 3183 |
| Surface Preparation | Grit-blast to Sa 2½ (ISO 8501-1), anchor profile 50–100 μm |
| Operating Temperature | -40°C to +80°C (continuous service) |
| Layer | Material | Typical Thickness | Function |
|---|---|---|---|
| Layer 1 | Fusion-Bonded Epoxy (FBE) | 150–250 μm | Primary anti-corrosion barrier, chemical bond to steel |
| Layer 2 | Copolymer Adhesive | 170–250 μm | Bonds the FBE primer to the PE outer layer |
| Layer 3 | High-Density Polyethylene (PE) | 1.5–3.7 mm | Mechanical protection, water barrier, soil-stress resistance |
Application Process Parameters
| Parameter | Value |
|---|---|
| Pipe preheat temperature | 180–220°C (medium-frequency induction) |
| FBE application | Electrostatic powder spray |
| Adhesive & PE application | Side extrusion, within ~15 s of FBE spray |
| Quench | Water cooling after PE layer consolidation |
The three layers are applied in one continuous pass before the FBE gels, ensuring a true chemical bond between layers.
| Pipe Diameter | Normal Type (min) | Reinforced Type (min) |
|---|---|---|
| DN ≤ 100 (≤ 114.3 mm) | 1.8 mm | 2.5 mm |
| 100 < DN ≤ 250 (114.3–323.9 mm) | 2.0 mm | 2.7 mm |
| 250 < DN ≤ 500 (323.9–508 mm) | 2.2 mm | 2.9 mm |
| 500 < DN ≤ 800 (508–762 mm) | 2.5 mm | 3.2 mm |
| DN > 800 (> 762 mm) | 3.0 mm | 3.7 mm |
Thickness classes per DIN 30670 / GB/T 23257. Reinforced type is specified for rocky terrain and high soil-stress service.
| Property | Requirement | Test Method |
|---|---|---|
| Cathodic Disbondment | Acceptance per standard, typically ≤ 8 mm radius after 28 days @ 65°C | ISO 21809-1 / DIN 30670 |
| Peel Strength (20°C) | ≥ 70 N/cm | GB/T 23257 / DIN 30670 |
| Peel Strength (50°C) | ≥ 25 N/cm | GB/T 23257 / DIN 30670 |
| Impact Resistance | No coating damage to steel at specified impact energy (commonly ≥ 15 J at 23°C) | ISO 21809-1 |
| Bend / Flexibility | No cracking at 2.5° per pipe diameter | ISO 21809-1 |
| Heat Aging | No degradation after 1000 h @ 95°C (laboratory type test) | ISO 21809-1 |
| Operating Temperature | -40°C to +80°C (continuous) | Design based |
| Holiday Detection | 100% of pipe length, 5–25 kV DC by thickness class | Spark test |
100% Production Testing (every joint)
| Test | Frequency |
|---|---|
| Holiday (spark) test | 100% of length |
| Coating thickness | Multiple points per joint |
| Visual & dimensional inspection | Every joint |
Batch / Type Testing
| Test | Frequency |
|---|---|
| Peel strength, cathodic disbondment, impact, bend | Per qualification / agreed lot schedule |
| Laboratory type tests (heat aging, hot water, UV) | Coating system qualification |
Manufacturing Process
Advanced three-layer polyethylene coating process ensuring consistent quality and maximum corrosion protection.
Raw Material Inspection
Steel pipes are inspected for surface defects, dimensional tolerances, and mill test certificates
Shot Blasting
Pipe surface is grit-blasted to Sa 2.5 cleanliness with a 50–100 μm anchor profile for optimum adhesion
Surface Inspection & Preheating
Blasted surface is checked for cleanliness and dust, then pipes are induction-heated to 180–220°C
FBE Epoxy Primer Application
Fusion-bonded epoxy powder is electrostatically sprayed and melt-cured onto the hot steel surface
Adhesive Layer Extrusion
A copolymer adhesive is side-extruded to bond the FBE primer to the outer polyethylene layer
PE Outer Layer Extrusion
High-density polyethylene is extruded and roll-pressed into a dense, watertight protective shell
Water Quenching
The coated pipe passes through water cooling to solidify the three-layer structure and stabilize thickness
Cutback & End Preparation
Pipe ends are trimmed to the specified cutback length and beveled ready for field welding
Holiday Detection
100% electrical holiday testing detects any pinholes or discontinuities in the coating film
Thickness & Visual Inspection
Coating thickness and appearance are inspected for uniformity, bubbles, and surface defects
Performance Testing
Peel strength, cathodic disbondment, impact, and bending tests verify long-term coating performance
Marking, Packing & Dispatch
Pipes are marked, end-capped, strapped, and dispatched with complete QC documentation
FBE vs 3PE vs 3PP: Which Coating Do You Need?
All three systems protect steel pipes against corrosion — but they differ in structure, temperature capability, and mechanical performance. Here is how FBE, 3PE and 3PP compare:
| Criteria | FBE (Single-Layer) | 3PE (3-Layer PE) | 3PP (3-Layer PP) |
|---|---|---|---|
| Layer Structure | Fusion-bonded epoxy powder only | FBE + adhesive + polyethylene | FBE + adhesive + polypropylene |
| Standard Thickness | 125–400 μm | 0.5–3.8 mm | 0.6–3.8 mm |
| Max Operating Temp. | Up to 100°C (limited moisture barrier) | Up to 80°C | 80–110°C (peaks to 140°C) |
| Corrosion Resistance | Good chemical resistance | Excellent | Excellent |
| Mechanical Strength | Hard but brittle; prone to impact damage | High flexibility, good damping | Highest hardness & abrasion resistance |
| UV / Weathering | Needs care in storage | Moderate | Excellent (UV stabilizers) |
| Typical Standards | CSA Z245.20 / AWWA C213 | DIN 30670 / ISO 21809-1 | DIN 30678 / ISO 21809-1 & -3 / CSA Z245.21 |
| Best For | Water lines, injection, light oil & gas | Onshore buried oil & gas pipelines | Offshore, subsea, HPHT & high-temp lines |
| Relative Cost | $ (most economical) | $$ | $$$ |
Fusion Bonded Epoxy
A single thermofused epoxy layer applied electrostatically to the heated pipe. Excellent adhesion and chemical resistance at the lowest cost, but thin and vulnerable to mechanical damage — best for water injection and light hydrocarbon service.
Three-Layer Polyethylene
FBE primer + copolymer adhesive + PE outer layer. The industry standard for buried onshore pipelines: outstanding corrosion protection, flexibility and soil-stress resistance for service temperatures up to 80°C.
Three-Layer Polypropylene
Same structure as 3PE but with a polypropylene outer layer. Higher melting point, harder surface and better UV stability make it the choice for offshore, subsea and high-temperature (up to 110°C) pipelines.
Applications
The industry-standard three-layer system for buried pipelines — proven across oil & gas, water, and utility networks worldwide.
Long-Distance Oil & Gas Transmission
The industry benchmark for buried trunk lines. The FBE primer delivers corrosion protection while the PE outer shell resists soil stress, moisture, and handling damage across thousands of kilometers of right-of-way.
✓ DIN 30670 / ISO 21809-1 / GB/T 23257
Urban Gas & Utility Networks
3PE coated ERW and SSAW pipe serves medium- and low-pressure city gas distribution, district heating outfalls, and utility corridors, where tough field handling and long maintenance-free life are decisive.
✓ Full size range DN 15 – DN 1200+
Water Transmission & Distribution
Large-diameter 3PE pipe is used for raw water intake, long-distance water transfer, and irrigation schemes, combining cathodic protection compatibility with an almost impermeable moisture barrier.
✓ Potable-water-grade outer layer options
Sliplining & Pipeline Rehabilitation
High abrasion resistance and smooth external surface make 3PE pipe well suited to sliplining inside aging mains and to microtunneling drives where the coating must survive jacking loads.
✓ Reinforced (heavy-duty) thickness class
Industrial & Chemical Plant Piping
Refineries, petrochemical complexes, and power stations use 3PE for cooling water, firewater, and buried process lines exposed to aggressive soils and intermittent chemical contact.
✓ Custom thicknesses to 3.7 mm+
Shallow-Buried Marine & Swamp Lines
With cathodic protection, 3PE performs reliably in swamps, tidal zones, and shallow-buried marine approaches where 3PP or concrete weight coating takes over for deeper or hotter service.
✓ CP-compatible, low current demand
Frequently Asked Questions
Ready to Order 3PE Coated Pipes?
Get a competitive quote within 24 hours. Our coating specialists are ready to help you select the right 3PE solution for your project.
[email protected] | 
+86 15602135951 | 
WhatsApp Available