Page 40: of Offshore Engineer Magazine (May/Jun 2020)

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TECH TALK COATINGS • Exterior exposure at a 30-degree angle facing the Analyses. Finally, technicians analyzed the panels in four ocean in a warm environment ways. They frst looked for damage, corrosion, undercutting • Exterior exposure at a 45-degree angle facing south and degradation of color or gloss via a visual analysis. Second, in a light industrial environment they tested the coatings using electrochemical impedance • Exterior exposure at a 30-degree angle facing the spectroscopy. Third, they evaluated the coating’s permeability ocean in a cold environment before and after exposing the panels to the above conditions.

Finally, they used Fourier Transform Infrared Spectroscopy to analyze the coatings’ chemical properties and evaluate their health before and after the above exposures.

UNEXPECTED SYSTEMS DELIVER

BETTER PERFORMANCE

Following 24 months of the 36-month test protocol, select one- and two-coat systems are performing better than the tra- ditional three-coat systems used to protect offshore structures.

The best performing systems have featured Corothane® I – GalvaPac 1K Zinc Primer, an organic zinc-rich, moisture- cured urethane primer from Sherwin-Williams. This and other zinc-rich primer systems have demonstrated superior corrosion resistance and have exhibited no major breakdown at the 24-month mark.

Testing has also determined that a coating system’s flm thickness only helps prevent corrosion in offshore applica- tions if it is extremely high. In addition, testing showed that a thin flm of a high ultraviolet-resistant fuoropolymer coating impedes corrosion very well in offshore applications. These conclusions indicate that the ideal combination of a zinc-rich primer, a suitable coating thickness and a fuoropolymer top- coat will deliver the best performance compared to using al- ternate primers, thicknesses and topcoats.

As this test concludes and additional research and testing continues, the industry will know which systems offer the low- est corrosion potential and longest maintenance intervals. These developments will help owners, operators, specifers and coat- ings manufacturers alike optimize offshore asset coatings speci- fcations to enable better corrosion protection and outcomes.

New testing data shows that offshore platform owners are likely to experience better corrosion protection and longer maintenance intervals by specifying select one- and two- coat systems compared to the traditionally specified three-coat systems.

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