3LPE Field Joint Coating System
Complete Solution: Epoxy Primer + Heat Shrink Sleeves
Product Overview
Our 3LPE Field Joint Coating System is a fully integrated, three-layer corrosion protection solution designed for the welded joints of three-layer polyethylene (3LPE) coated pipelines. The system combines a two-component epoxy primer and a heat shrink sleeve to reconstruct the factory-applied 3LPE coating at every field joint, delivering performance equivalent to the mainline coating.
This product introduction covers the complete system: the epoxy primer (Part A + Part B) as the first layer, and the heat shrink sleeve as the second and third layers (adhesive + PE backing).
System Overview
| Layer |
Product |
Function |
| First Layer |
Epoxy Primer (A+B) |
Bonds to blast-cleaned steel; provides cathodic disbondment resistance and primary corrosion barrier |
| Second Layer |
Heat Shrink Sleeve – Adhesive |
Bonds to the epoxy primer and adjacent 3LPE plant coating; seals the joint |
| Third Layer |
Heat Shrink Sleeve – PE Backing |
Mechanical protection, moisture barrier, UV resistance |
The epoxy primer is applied to the prepared steel surface, followed by installation of the heat-shrinkable sleeve. Heat application causes the sleeve to shrink and the adhesive to flow, forming a continuous bond to the steel and the adjacent 3LPE coating.
Epoxy Primer (A+B)
| Parameter |
Specification |
| Type |
Two-component, solvent-free or high-solids epoxy |
| Components |
Part A (resin) + Part B (curing agent) |
| Color |
Black, grey, or as specified |
| Recommended Dry Film Thickness |
150–200 μm |
| Pot Life (23°C) |
Approx. 20–30 minutes |
| Application Temperature |
≥ 10°C surface temperature |
| Curing |
Ambient or heat-assisted force cure |
| Compatibility |
3LPE, 3LPP, FBE plant coatings |
The epoxy primer provides the critical bond between the steel substrate and the heat shrink sleeve adhesive, while delivering cathodic disbondment resistance at the joint.
Heat Shrink Sleeves
| Parameter |
Specification |
| Type |
Heat shrinkable wraparound sleeve |
| Backing Material |
Radiation cross-linked polyethylene (PE) |
| Adhesive Type |
High-performance hot-melt adhesive |
| Backing Thickness |
0.8 – 1.5 mm (product-dependent) |
| Total Thickness |
2.0 – 3.0 mm (product-dependent) |
| Width |
Customized to joint length and pipe diameter |
| Service Temperature |
60°C / 80°C / 110°C (grade-dependent) |
| Configuration |
Wraparound with closure patch |
The heat shrink sleeve reconstructs the 3LPE coating structure at the field joint, providing the same mechanical protection and moisture barrier as the factory-applied coating.
Key Features & Benefits
| Feature |
Benefit |
| Complete 3LPE System |
Epoxy primer + heat shrink sleeve supplied as an integrated solution |
| Mainline-Coating Equivalent |
Reconstructs the 3LPE structure at the joint for monolithic corrosion protection |
| Epoxy Primer A+B |
Two-component system provides superior adhesion and cathodic disbondment resistance |
| Heat Shrink Sleeve |
Cross-linked PE backing and hot-melt adhesive deliver mechanical protection and moisture sealing |
| ISO 21809-3 Compliant |
Meets international requirements for 3LPE field joint coatings |
| Temperature Grades Available |
60°C, 80°C, and 110°C options to match pipeline design temperature |
| Field-Proven |
Suitable for buried, submerged, and above-ground pipeline service |
Typical System Performance (Reference)
| Property |
Test Reference |
Typical Value |
| Peel Strength to Steel (23°C) |
ISO 21809-3 |
≥ 5 N/mm |
| Peel Strength to Steel (Tmax) |
ISO 21809-3 |
≥ 1.5 N/mm |
| Cathodic Disbondment |
ISO 21809-3 |
≤ 10 mm radius (28 days) |
| Impact Resistance |
ISO 21809-3 |
≥ 5 J/mm |
| Indentation Resistance |
ISO 21809-3 |
Pass at Tmax |
| Hot Water Immersion |
ISO 21809-3 |
Adhesion retained |
Values are indicative and shall be confirmed against the specific CNPetro product data sheet and project specification.
Compliance with ISO 21809-3
ISO 21809-3 specifies requirements for field-joint coatings on buried and submerged pipelines. The complete 3LPE system—epoxy primer + heat shrink sleeve—is qualified to the applicable Type 14 classification for heat-shrinkable coatings on 3LPE mainline pipelines. The standard requires testing of the complete applied system, including peel strength, cathodic disbondment, impact resistance, indentation resistance, and thermal ageing.
Primary Applications
3LPE-coated pipeline field joints – Girth welds, tie-ins, and repair areas
Buried and submerged pipelines – Onshore and offshore environments
Oil and gas transmission lines – External corrosion protection
Water and sewerage pipelines – Joint protection and sealing
Pipeline rehabilitation – Restoration of damaged field-joint coatings on 3LPE lines
Quotation Scope
For a complete 3LPE field joint coating quotation, please provide:
| Information Required |
Details |
| Pipeline size |
Pipe OD and wall thickness |
| Joint length |
Weld cutback width and required sleeve width |
| Design temperature |
To select appropriate sleeve grade (60°C / 80°C / 110°C) |
| Quantity |
Number of joints or total length of pipeline |
| Plant coating |
3LPE specification (standard or project-specific) |
We will provide a detailed quotation covering:
Epoxy Primer A+B (volume calculated per joint)
Heat Shrink Sleeves (dimensions per pipe size and joint length)
Closure patches and installation accessories
Technical documentation and compliance certificates
Packaging and Availability
| Item |
Details |
| Epoxy Primer |
A+B kit, volume per joint requirement |
| Heat Shrink Sleeves |
Wraparound configuration with closure patch |
| Customization |
Sleeve dimensions, temperature grade, and primer volume customized per project |
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