A containment system was set up to catch debris during removal of the old lead-based coating. Image courtesy of City of Virginia Beach Public Utilities Engineering Division. |
Because the tank needed to be stripped of its lead-based coating, applicators set up a containment system to catch any debris, ensuring public safety. The tank was prepped with a high-pressure water blaster, as well as a robotic Wheelabrator, which was used to complete multiple rounds of blasting due to mechanical issues.
Once the surface was prepped, applicators used an airless conventional spray method to apply the three-coat system, which included Sherwin-Williams' Corothane I GalvaPac Zinc Primer 1K, Acrolon 218 HS Acrylic Polyurethane semi-gloss intermediate coat, and the Fluorokem HS exterior gloss finish.
Corothane I GalvaPac Zinc Primer 1K is a single-component, VOC-compliant, moisture-curing urethane, zinc-rich primer designed for low-temperature application to blast-cleaned or power tool-cleaned steel surfaces. It is designed to provide cathodic and barrier-like protection, and begins the film build to fill the profile left by surface preparation. The intermediate coat then works to further build film thickness and supports additional color and gloss retention. The final coat provides the high gloss along with superior fade resistance to avoid chalking over the long term.
In addition to spray-applying the Fluorokem HS, applicators also used a backroll method to ensure complete coverage on the water tank. The team also applied a stripe coat to ensure the welds on the tank were completely protected.
"It is essential to have several coats to give you enough protection against corrosion," said John Williams, Sherwin-Williams Protective & Marine Division Sales Representative. "Applicators need to ensure that the coatings system completely covers the profile left on the tank by preparation efforts." Failure to do that, he explained, will result in the water tank or asset quickly rusting. "All the layers built into the coatings system are designed to build in terms of millage to ensure ultimate protection against Mother Nature, which is essential in this oceanfront and industrial environment."
According to Williams, most good urethanes will provide seven to ten years of service life when it comes to gloss; color retention, however, is closer to four to five years. And epoxies can begin chalking much earlier.
"With spending so much time and money on the last tank and having it chalk in just four years, we didn't want that to happen again," said Daniel Gibbens, manager at Spensieri Diversified. "The Fluorokem HS product seemed like the right solution, especially considering the 15-year warranty."
The Virginia Beach water tank project was one of the first applications of Fluorokem HS and the city is looking forward to the long-term solution the product has provided for the area's water structures.