Industry News

Sherwin-Williams Unveils New Epoxy Coating to Resist CUI

Paints and coatings manufacturer Sherwin-Williams Protective & Marine is introducing new ways to mitigate the dangerous conditions of corrosion under insulation (CUI) with a new line of Heat-Flex CUI-mitigation coatings. 

The line includes Heat-Flex ACE (advanced CUI epoxy), which is an ultra-high-solids epoxy novolac developed with a functional chemical enhancement for CUI mitigation. According to the manufacturer, the coating performs the best at mitigating CUI of any available formulation. 

In addition, three coatings featuring a high concentration of micaceous iron oxide (MIO) pigment round out the lineup. These include the Heat-Flex 750, Heat-Flex 1200 Plus, and Heat-Flex 650. According to the company, these MIO-enhanced coatings offer significantly improved CUI-mitigation performance compared to similar formulations on the market.

The Battle Against CUI

“The battle against CUI is never-ending, as coated steel encapsulated in insulation will inevitably corrode over time. Our goal is to mitigate that corrosion process for as long as possible, and we’ve developed some high-performance coatings that enable just that,” said Mark Rubio, energy business manager. 

“For example, Heat-Flex ACE is the best product we’ve tested for long-term CUI mitigation,” Rubio added. “We anticipate it becoming a preferred specification solution as the industry gains experience with this enhanced CUI-mitigation system. We have also boosted the market’s CUI-mitigation capabilities for existing specifications with the three MIO-enhanced Heat-Flex coatings.”

Extensive Lab Testing

All four Heat-Flex coatings have passed extensive lab testing, showing good to excellent performance in a variety of tests, according to the manufacturer. These tests included various heat cycling, simulated CUI, and BS EN 927-6:2016 erosion and dry film thickness (DFT) tolerance testing for thermal resistivity performed on all coatings. Cryogenic testing was performed on the MIO-enhanced coatings.

According to the company, Heat-Flex 750, Heat-Flex 1200 Plus, and Heat-Flex ACE ashowed excellent results following ISO 12944-9 CX cyclic anticorrosion testing. In addition, Heat-Flex ACE showed exceptional results in a series of CUI simulation tests performed in accordance with ISO TM21442 in excess of 204 °C (400 °F).

More details are available at the manufacturer’s website.

For more information, contact: Sherwin-Williams,