Corrosion Under Insulation (CUI) is recognized as a major corrosion problem, which costs the oil & gas, chemical & petrochemical and food processing industries millions of dollars a year in inspection, repair and replacement costs. CUI can be detrimental to the integrity of an insulated pipeline or vessel if not detected early on, causing leaks leading to possible catastrophic events.
Corrosion under insulation or cladding detection
CUI is a form of general and localized corrosion that may occur between the insulation and the outer surface of a thermally insulated and poorly coated pipeline or vessel. CUI can occur under the most common types of thermal insulation, foam rubber, polyurethane, calcium silicate, and fiberglass. Those insulation materials that have higher adsorption properties of water, oxygen and leachable chlorides are more likely to exacerbate or accelerate the corrosion process.
As the pipe surface is not normally accessible, detecting CUI may require the removal of the insulation and cladding. These include visual inspection, radiography, thermal imaging, moisture detectors, and moisture removal methods (eg. drain plug).