Polyethylenes are often used as pipeline coatings due to their excellent properties and suitability for the task. Here are some reasons why polyethylenes are considered good pipeline coatings:
Corrosion resistance: Polyethylenes exhibit excellent resistance to corrosion. They are non-reactive to most chemicals and can withstand exposure to harsh environments, including soil, moisture, and various chemicals present in the ground. This corrosion resistance helps protect the pipeline from deterioration, extending its lifespan.
Impermeability: Polyethylenes are highly impermeable to gases and liquids. This property prevents the diffusion of water, oxygen, and other corrosive substances into the pipeline, reducing the risk of corrosion and maintaining the integrity of the pipeline system.
Toughness and durability: Polyethylenes have high impact resistance and toughness, making them suitable for protecting pipelines against mechanical damage during installation, operation, and maintenance. They can withstand soil movement, rock impingement, and other external stresses that may occur over time.
Flexibility: Polyethylenes have good flexibility, allowing them to accommodate the natural movement and expansion/contraction of the pipeline due to temperature changes. This flexibility helps prevent cracking or delamination of the coating, maintaining its protective barrier.
Ease of application: Polyethylenes can be applied as coatings through various methods, such as extrusion, spraying, or wrapping. This versatility makes them easier to apply on pipelines of different sizes and shapes. Additionally, polyethylene coatings can be factory-applied or field-applied, providing flexibility during installation.
Cost-effectiveness: Polyethylene coatings are generally cost-effective compared to other types of pipeline coatings. Their availability, ease of application, and long-term durability contribute to lower installation and maintenance costs over the life of the pipeline.
Environmental considerations: Polyethylenes are considered environmentally friendly coatings. They are non-toxic, do not contain heavy metals or volatile organic compounds (VOCs), and have minimal impact on soil and water quality.
It's worth noting that there are different types of polyethylenes used for pipeline coatings, including high-density polyethylene (HDPE) and three-layer polyethylene (3LPE) or fusion-bonded epoxy (FBE) with a polyethylene topcoat. The specific type of polyethylene coating chosen depends on factors such as pipeline location, operating conditions, and project requirements.