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Sherwin-Williams Duraplate® UHS Epoxy Coating with Opti-Check Optically Active Pigment Technology Significantly Extends Ballast Tank Life
Fluorescing Formula Eliminates Guesswork, Enhances Visual Inspection, Clearly Identifying Holidays and Pinholes
CLEVELAND, Ohio (May 15, 2007) –Duraplate® UHS Ultra High Solids Epoxy with fluorescing Optically Active Pigments (OAP) from Sherwin-Williams Industrial & Marine Coatings allows shipboard tank lining applicators to efficiently address coatings application issues which can lead to significant increases in tank coating service life with a simple, low cost and extensive coating and inspection system.
Opti-Check fluorescing pigment was added to a proven Sherwin-Williams technology supplied to the U.S. Navy, and has effectively increased the service life of marine ballast storage tank coatings simply by illuminating insufficient film thickness, pinholes and holidays wherever they occur. The result: proper film thickness and uniform coverage can now be verified and corrected instantly, which in turn extends ballast tank service life.
“The U.S. Department of Defense recognized that the preservation of ballast tanks is at the top of fleet maintenance corrosion-related cost,” said W. Doni Riddle, Vice President, Sherwin-Williams Industrial & Marine Coatings. “Corrosion would be quite evident after only three years using standard coatings; by adding fluorescing Optically Active Pigments and visually inspecting the tank interior with a hand-held UV flashlight and non-line-of-sight mirror, holidays and pinholes are easily detected and corrected before returning the tank to service.”
Navy shipboard tanks can be confined spaces, with complex layouts sure to make any visual coating inspection difficult. Fluorescent inspection improves visual accuracy by enhancing the contrast of holidays, and easily identifying low film build applications.. Then, paired with using compact, lightweight inspection flashlights, tank lining applicators can observe small, hard to view spaces that before were unnoticed.
The coating uses Duraplate UHS Epoxy as the vehicle to hold the pigment, and is available as a single- or multi-coat application.
Traditional holiday detection methods as prescribed by NACE RP-0188 may identify bare substrate, but are not designed to pinpoint insufficient film thickness, Riddle said. How the system works depends on whether the application is single- or multi-coat. Viewed under LED light, a single-coat system with Opti-Check OAP pigments will fluoresce or glow even when still wet. Pinholes, holidays and improper film thickness will either appear black in contrast to the fluorescing coating, or not as bright due to insufficient film thickness.
The opposite is true for multi-coat systems. When the primer with OAP is used and the topcoat does not have OAP, pinholes will fluoresce under inspection of the topcoat. Pinholes as small as .25 mils can be identified and corrected before a tank is placed into service using an inexpensive ASTM E 2501-approved light source.
Riddle noted that the coating technology overcomes hurdles that contractor skill can’t plan for. “Multiple coat systems are typically specified in contrasting colors to make visual inspection easier,” he said, “but even then, holidays can be obscured by glossy coatings and poor lighting.”
Combining the OAP’s instant holiday detection with the three-day cure time of the Duraplate UHS line gives tanks a better coating application and faster return to service, Riddle said.
Sherwin-Williams Industrial and Marine Coatings group serves North America with a broad line of high-performance coatings, comprehensive technical service and the industry’s largest distribution network. Relying on more than 140 years of experience in formulating industrial coatings, the group provides cost-effective solutions for applications where extreme corrosion, abrasion and chemical attack are present.