Pressure drop along the pipeline is the main obstacle to transportation of unprocessed or
partly processed multiphase fluids over long distances. Several parameters contribute to pressure drop in
multiphase flow, e.g. liquid hold-up, precipitations, gas-liquid surface drag forces, liquid wetting of pipe
wall and surface roughness. Application of coatings inside the pipeline can reduce pressure drop by
preventing corrosion, preventing precipitations on the pipe wall and modify the pipe wall wetting
properties. Meso scale pressure drop tests have shown that pressure drop is significantly affected by
moderate corrosion, even in multiphase flow, demonstrating that application of internal coatings is
beneficial. However, the coating must have the same lifetime as the pipeline. In this work we have tried
to identify the most important coating degradation mechanisms and to find relevant test methods for
evaluation and qualification of coatings.