4. Field joint coatings

4.1 Different types of coating

When a pipeline is constructed, sections measuring between 12 m and 18 m in length are welded together. Figure 6 shows a welded joint following surface preparation. At the cut-backs, protection needs to be restored that is equivalent to the factory-applied coating, but under site conditions, which can sometimes be sub-optimal (poor weather, temperature, workspace). The application of coatings perpendicular to welded joints is thus a sensitive operation, requiring rigorous product selection and mastery of the application methods.