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3LPP is a three-layer external anticorrosion system for steel pipe used in qualified buried or submerged pipeline projects. The system combines an epoxy primer, an adhesive layer and a polypropylene outer layer.
Layer 1: Fusion-bonded epoxy (FBE) primer provides adhesion to the prepared steel surface and corrosion protection.
Layer 2: Adhesive bonds the epoxy primer to the polypropylene outer layer.
Layer 3: Polypropylene provides mechanical protection and performance for the specified service and installation conditions.
| Base pipe | Standard, grade, manufacturing route, OD, wall thickness and length |
| Coating | Standard and edition, coating class, minimum thickness and design temperature |
| Pipe ends | Cutback length and tolerance, bevel protection and field-joint interface |
| Inspection | Surface preparation, thickness, holiday, adhesion and project-specific tests |
| Documents | ITP, base-pipe MTC, coating reports, traceability and third-party witness points |
3LPP and 3LPE are not interchangeable coating names. Final coating selection and acceptance criteria should follow the project environment, operating temperature, installation method, field-joint system and governing design documents.
The final supply range is confirmed against the base-pipe specification and the complete coating purchase requirements.
| Coating system | FBE primer + adhesive + polypropylene outer layer |
| Base pipe | SMLS, ERW/HFW, LSAW or SSAW as specified |
| Outside diameter | 219 mm–2020 mm, subject to base-pipe and coating-line capability |
| Wall thickness | 5 mm–25 mm or project-specified range, confirmed at quotation |
| Length | 5.8 m–12 m or agreed project length |
| Coating thickness | 2.0 mm–4.5 mm or purchaser-specified minimum thickness |
| Ends | Plain or beveled with specified coating cutback and end protection |
| Testing | Thickness, holiday and adhesion tests plus agreed project requirements |
| Documents | Base-pipe MTC, coating records, ITP and release documents as agreed |
| Handling and packing | Padded handling, separators and transport protection matched to the coating system |
Coating class, minimum total thickness, cutback geometry, repair limits and inspection acceptance criteria must be stated in the RFQ or project specification. Values are not assumed from the product name alone.
ISO 21809-1 addresses plant-applied three-layer polyethylene and polypropylene external coatings for buried or submerged pipeline transportation systems. The required edition, coating class and project deviations should be identified in the purchase documents.
DIN 30678-1 covers requirements and testing for factory-applied extruded polypropylene coatings. DIN 30678-2 addresses different polypropylene application systems and should not be assumed for an extruded 3LPP order.
The RFQ or PO should state the governing standard and edition, base-pipe specification, design temperature, coating class and thickness, cutback, test plan, repair criteria and required documentation. Project specifications take precedence where additional requirements are defined.
The typical plant sequence starts with base-pipe acceptance and finishes with coating inspection, traceability marking and protected handling for shipment.
Base-pipe inspection → cleaning and abrasive blasting → dust removal → preheating → FBE primer application → adhesive extrusion → polypropylene extrusion → water cooling → end cutback → thickness, holiday and adhesion testing → marking and packing.
Process controls and acceptance criteria follow the agreed coating specification, project ITP and approved repair procedure.
The system uses an FBE primer on the prepared steel surface, an adhesive bonding layer and a polypropylene outer layer.
No. 3LPP uses polypropylene as the outer layer, while 3LPE uses polyethylene. Selection should consider service temperature, installation conditions, mechanical loads and the governing project specification.
Key inputs include base-pipe dimensions, coating standard and class, minimum thickness, cutback, quantity, inspection plan, document package, destination and delivery requirement.
The agreed plan can include surface-preparation checks, total thickness, holiday detection, adhesion, impact and other qualification or production tests required by the governing specification.
The field-joint system must be compatible with the mainline coating and pipeline design. It should be selected or approved by the purchaser or project engineer and stated in the project documents.
The final supply range is confirmed against the base-pipe specification and the complete coating purchase requirements.
| Coating system | FBE primer + adhesive + polypropylene outer layer |
| Base pipe | SMLS, ERW/HFW, LSAW or SSAW as specified |
| Outside diameter | 219 mm–2020 mm, subject to base-pipe and coating-line capability |
| Wall thickness | 5 mm–25 mm or project-specified range, confirmed at quotation |
| Length | 5.8 m–12 m or agreed project length |
| Coating thickness | 2.0 mm–4.5 mm or purchaser-specified minimum thickness |
| Ends | Plain or beveled with specified coating cutback and end protection |
| Testing | Thickness, holiday and adhesion tests plus agreed project requirements |
| Documents | Base-pipe MTC, coating records, ITP and release documents as agreed |
| Handling and packing | Padded handling, separators and transport protection matched to the coating system |
Coating class, minimum total thickness, cutback geometry, repair limits and inspection acceptance criteria must be stated in the RFQ or project specification. Values are not assumed from the product name alone.
ISO 21809-1 addresses plant-applied three-layer polyethylene and polypropylene external coatings for buried or submerged pipeline transportation systems. The required edition, coating class and project deviations should be identified in the purchase documents.
DIN 30678-1 covers requirements and testing for factory-applied extruded polypropylene coatings. DIN 30678-2 addresses different polypropylene application systems and should not be assumed for an extruded 3LPP order.
The RFQ or PO should state the governing standard and edition, base-pipe specification, design temperature, coating class and thickness, cutback, test plan, repair criteria and required documentation. Project specifications take precedence where additional requirements are defined.
The typical plant sequence starts with base-pipe acceptance and finishes with coating inspection, traceability marking and protected handling for shipment.
Base-pipe inspection → cleaning and abrasive blasting → dust removal → preheating → FBE primer application → adhesive extrusion → polypropylene extrusion → water cooling → end cutback → thickness, holiday and adhesion testing → marking and packing.
Process controls and acceptance criteria follow the agreed coating specification, project ITP and approved repair procedure.
The system uses an FBE primer on the prepared steel surface, an adhesive bonding layer and a polypropylene outer layer.
No. 3LPP uses polypropylene as the outer layer, while 3LPE uses polyethylene. Selection should consider service temperature, installation conditions, mechanical loads and the governing project specification.
Key inputs include base-pipe dimensions, coating standard and class, minimum thickness, cutback, quantity, inspection plan, document package, destination and delivery requirement.
The agreed plan can include surface-preparation checks, total thickness, holiday detection, adhesion, impact and other qualification or production tests required by the governing specification.
The field-joint system must be compatible with the mainline coating and pipeline design. It should be selected or approved by the purchaser or project engineer and stated in the project documents.
