Bridging the Gap between Lab Testing and Field Reliability in CUI Coating Systems

Abstract Corrosion under insulation (CUI) remains a persistent and costly integrity issue in the oil and gas industry, affecting assets across upstream, midstream, and downstream operations. Protective coatings play a crucial role in mitigating CUI, but their performance under insulation must be validated through rigorous laboratory testing that reflects real operating conditions. This paper presents a comparative analysis of several commercially available coatings, including epoxy phenolics, silicone-aluminum systems, and modified novolac epoxies, tested under controlled laboratory conditions following NACE SP0198 and ISO 19277 protocols. Simulated exposure to cyclic temperatures, immersion, salt spray, and thermal shock allowed for detailed evaluation of coating degradation, blistering, corrosion creep, and adhesion loss. The results demonstrate significant performance differences between coating types, highlighting the limitations of relying solely on product datasheets or field experience for specification. Case studies from recent oil and gas facility maintenance programs further underscore how laboratory-tested coatings have extended asset life and reduced unplanned downtime. These findings support a shift toward evidence based coating selection and standardized testing as essential components of a CUI prevention strategy in high-risk environments.