Pipe coatings, fusion-bonded epoxy

Recent trends in protective coatings used on buried pipelines have been away from reinforced hot applied coal tar and asphalt enamels and butyl rubber laminate tapes, particularly where applied over-the-ditch . The more recently developed coatings based on fusion bonded epoxies, extruded poly-ethylenes, liquid-applied epoxies and polyurethanes, require factory application where superior levels of pipe preparation and quality control of the application process can be achieved. 

Omori, K., Watanabe, U. and Takeda, T., Improvement of Fusion Bonded Epoxy Coating, 5lh International Conference on the Internal and External Protection of Pipes, Innsbruck Austria, pp. 67-79, BHRA, London (1983)... 

A specific example for epoxy is fusion bonded epoxy (FEE) coating [8]. It is widely used to protect steel pipes. In this case, the resin and hardener components of a dry powder stock of FEE do not react until the coating application temperature is reached. Then the powder contents melt and form a liquid which flows onto a steel surface where it becomes a solid coating by chemical crosslinking and the use of heat. This is known as fusion bonding and the chemical crosslinking reaction is not reversible. 

Coatings based on bituminous compositions offer excellent service but are now being supplemented by others—for example, fusion-bonded epoxy resin typically 1 mm thick applied at the pipe mill. 

Internal Coating of Line Pipe for Non-Corrosive Gas Transmission Service Unprimed Internal Fusion Bonded Epoxy Coating of Line Pipe... 

Application, Performance and Quality Control of Paint-Applied, Fusion-Bonded Epoxy External Pipe Coating... 

Corrosion Protection. Although steel underground transmission lines are often protected by coal tar or fusion bonded epoxy coatings, a large volume of polyethylene tapes as well as some vinyl-backed tapes are used for corrosion protection. Pipes of large diameter, such as oil line pipes, are usually machine-wrapped in the field just prior to placement in the ground. The tapes are unusual in that the backing is from 12 to 15 mils thick and the butyl-based adhesive is approximately of the same thickness. For the pipeline industry the rolls are 18 in. wide and contain up to 800 feet of tape. There is a reduction currently in domestic pipeline construction but appreciable amounts of pipewrap are exported. 

Two types of underground piping are commonly used in industry (1) two-layer extruded polyethylene coatings (yellow jacket) and (2) fusion-bonded epoxy coating (FEE). 

External Fusion-bonded Epoxy Coating for Still Pipes, Australian/New Zealand Standaid AS/NZS 3862 2002. 

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