The standard for 3LPE (Three-Layer Polyethylene) coating is primarily specified by ISO 21809-1 and DIN 30670. This coating process involves three layers: an epoxy primer for corrosion protection, a copolymer adhesive for binding, and an outer polyethylene layer for mechanical protection. 3LPE coating is widely used for pipelines exposed to harsh environments, as it provides excellent resistance to corrosion, impact, and abrasion. The standard outlines requirements for material composition, application procedures, and quality tests to ensure the coating's durability and effectiveness in various soil and environmental conditions.

The purpose of 3LPE (Three-Layer Polyethylene) coating is to provide pipelines with robust protection against corrosion, mechanical damage, and environmental wear, ensuring a longer service life and minimizing maintenance needs. The coating’s three-layer system consisting of an epoxy primer, an adhesive layer, and a polyethylene outer layer creates a strong barrier that resists moisture, chemicals, and physical impacts. This makes 3LPE coating ideal for pipelines buried underground or submerged, where it helps prevent rusting, cracking, and other damage, thus maintaining pipeline integrity in harsh conditions.

3-layer coating is a protective system typically applied to steel pipes to guard against corrosion, mechanical wear, and environmental damage. It consists of three layers: Epoxy Primer: The first layer, an epoxy coating, bonds directly to the steel surface to provide corrosion resistance and form a base layer. Adhesive Copolymer: The second layer, an adhesive, binds the epoxy primer to the top layer, ensuring strong adhesion and enhancing overall coating durability. Polyethylene (PE) Layer: The third, outer layer is a high-density polyethylene (HDPE) that provides mechanical protection, shielding the pipe from impacts, abrasion, and harsh environmental conditions. This three-layer system, commonly referred to as 3LPE or 3-layer polyethylene coating, is widely used in pipeline applications for its durability, corrosion resistance, and ability to withstand challenging conditions, especially in underground or underwater installations.

The main difference between 3LPE and FBE coatings is in their structure and protection capabilities: 3LPE consists of three layers an epoxy primer for corrosion resistance, a copolymer adhesive for bonding, and a polyethylene outer layer for mechanical protection, making it ideal for harsh, underground, or submerged environments due to its robust impact and abrasion resistance. In contrast, FBE is a single-layer fusion-bonded epoxy coating that provides strong corrosion protection but lacks the additional mechanical protection of 3LPE, making it more suitable for above-ground applications or environments where physical impact resistance is less critical.