Construction process, features, and quality inspection of 3PE coated pipelines

3-Layer Polyethylene (3PE) coated pipelines are widely used in the transportation of oil, gas, and water due to their superior corrosion resistance, durability, and mechanical strength. This article explores the construction process, key features, and quality inspection measures associated with 3PE-coated pipelines.

API 5L Grade B 3PE Coated Bends

Construction Process

1.Surface Preparation:

The pipeline surface is cleaned using shot blasting or sandblasting to remove rust, scale, and contaminants.

Achieving the desired surface roughness and cleanliness level (typically Sa 2.5 according to ISO 8501-1) ensures strong adhesion of the coating.

2.Application of 3PE Coating:

First Layer: A fusion-bonded epoxy (FBE) coating is applied to provide excellent anti-corrosion properties and enhance adhesion.

Second Layer: An adhesive polymer layer is applied to bond the FBE and polyethylene layers.

Third Layer: A high-density polyethylene (HDPE) layer is applied to provide mechanical protection and resistance to external damage.

Each layer is applied under controlled conditions to ensure uniformity and thickness as per specifications.

3.Inspection and Testing:

After coating, the pipeline undergoes various tests to ensure coating integrity and adherence to quality standards.

4.Transportation and Installation:

Coated pipelines are carefully transported to avoid damage to the coating.

During installation, proper handling techniques, such as using soft slings and padded supports, are employed.

After installation, field joint coating is applied to weld areas to maintain continuity of protection.

3PE anti corrosion coated steel pipes

Key Features of 3PE Coated Pipelines

1.Superior Corrosion Resistance:

The FBE layer provides excellent protection against chemical reactions and prevents corrosion in aggressive environments.

2.Mechanical Strength:

The HDPE outer layer offers strong resistance to impact, abrasion, and soil stress, making it suitable for buried pipelines.

3.Long Lifespan:

With proper installation and maintenance, 3PE-coated pipelines can last over 50 years, reducing replacement and repair costs.

4.Thermal Stability:

The coating maintains its properties across a wide temperature range, ensuring performance under extreme conditions.

5.Adherence to Standards:

The coating complies with international standards such as DIN 30670, EN 10204, and ISO 21809-1.

3PE-coated B36.10M pipe BE A53 Gr.B ERW SCH40 with end caps

Quality Inspection Measures

To ensure the coating meets project specifications, rigorous quality control is implemented:

1.Thickness Measurement:

The thickness of each layer is measured using ultrasonic or magnetic testing equipment to ensure it meets design requirements.

2.Adhesion Testing:

Pull-off tests are conducted to verify the adhesion strength between the coating layers and the pipeline surface.

3.Holiday Testing:

A high-voltage detector is used to identify any discontinuities or pinholes in the coating.

4.Impact Testing:

The coating’s ability to withstand mechanical impact is evaluated to ensure durability during handling and installation.

5.Peel Strength Test:

This test measures the bond strength of the adhesive layer to the epoxy and polyethylene layers.

6.Visual Inspection:

A thorough inspection ensures the coating is free from defects such as cracks, bubbles, or irregularities.

7.Cathodic Disbondment Test:

This test evaluates the coating’s resistance to disbondment under simulated cathodic protection conditions.

3PE-coated pipelines are the industry standard for high-performance, long-lasting pipeline solutions. By following a meticulous construction process, leveraging the unique features of 3PE coatings, and implementing rigorous quality inspection measures, pipeline operators can ensure reliable and efficient operations in diverse environments.

Haihao Group is committed to delivering top-quality 3PE-coated pipelines tailored to meet your project needs. Contact us for more information about our pipeline solutions. Email:sales@haihaogroup.com