This paper describes experimental work investigating the influence of steel surface roughness on the adhesion performance of fusion bonded epoxy (FBE) pipeline coatings. The paper begins with a summary of the standards and methods that can be used to measure surface roughness. Several parameters are used to characterize the roughness of a blast cleaned steel including profile peak height and peak count. Tortuosity and rugosity indicate the proportional increase in steel surface area developed by roughening the surface. Normal pipeline coating industry practice is to specify and control a single roughness parameter termed “surface profile”. It is measured with replica tape and corresponds to the maximum peak-to-valley height.In the experimental work steel panels were abrasive blast cleaned with various steel shot and grit abrasives and the roughness characteristics of the blast cleaned surface were measured with stylus profilometers conventional replica tape and 3D imaging of replica tape.A FBE pipeline coating was applied to the prepared steel panels. The adhesion performance of the FBE coating was evaluated using the following test methods.<ul><li>Hot water immersion adhesion rating per CSA Z245.20 section 12.14 </li><li>Pull-off adhesion strength after hot water soak exposure per ASTM 4541 </li><li>Cathodic disbondment radius at 65 and 80 °C per CSA Z245.20 section 12.8 </li><li>Time before blisters were observed in Atlas Cell per NACE TM0174 modified </li><li>Average blister diameter in Atlas Cell </li><li>Pull-off adhesion strength after Atlas Cell exposure per ASTM 4541 </li></ul>The experimental data were analyzed using statistical techniques to investigate the relationship between the measured surface roughness and the adhesion test results. The adhesion results were found to be positively and linearly correlated with substrate tortuosity and rugosity. Profile peak height and peak count were found to contribute to tortuosity.

This paper introduces the available technology of chemical coating removal as an alternative to mechanical coating removal by comparing and contrasting the advantages and disadvantages of each chemical coating removal technology. Due to the high cost and environmental drawbacks of mechanical methods of coating removal, chemical coating removal systems have advanced as a cost effective and environmentally friendly way to remove coatings that are highly cost effective on a per square foot basis cost comparison. The presentation will discuss all chemical coating removal technology, features and benefits.

Surface preparation techniques have evolved with the acceptance of UHP waterjetting (UHP WJ). The new technique has proven to provide benefits in not only workflow, but also in the overall project’s pocketbook as well. With quality requirements rising and budgets for maintenance activities decreasing, UHP WJ has become the ideal surface preparation solution.