Application status of external coating of pipeline and its development trend in HDD project

This paper analyzes the application status of various global external coatings, including single-layer fusion bonded epoxy powder coating, dual-layer fusion bonded epoxy powder coating, fusion bonded epoxy powder coating+polyurethane top coating, epoxy coating+polyepoxy concrete surface layer, multi-layer powder coating and polyethylene anti-corrosion coating, in horizontal directional drilling (HDD) project, and points out that dual-layer epoxy coating is usually adopted for international HDD pipelines, but SLPE with a simple structure is often chosen for the domestic HDD pipelines. Due to the increasing pipeline construction projects and pipeline routing limitations, more and more pipelines will adopt HDD technique in the construction, and the future coating development trend is focused on multi-layer powder coating, fusion bonded epoxy powder coating+polyurethane top coating, epoxy coating polyepoxy concrete surface layer. The proper selection of pipeline coatings can reduce coating damages and maintain high economy.