Corrosion is a pesky problem. In fact, it costs about $2.2 trillion for industries around the world to address it, according to the World Corrosion Organization. But once you notice them, many measures are available to prevent their spread. What’s more challenging to fix is corrosion that goes unseen. Corrosion under insulation (CUI) refers to a condition that occurs when moisture penetrates a structure protected by insulation material. This is why when insulating surfaces or you’re ordering a Storage tank insulation, make sure that you choose a solution specifically formulated to prevent CUI.

The Causes and Consequences of CUI

CUI is a problem affecting many industries, including marine, chemical, and petrochemical. Typically, it can be caused by:


Improperly installed ductwork, pipes, and vents that can create leaks

Poor maintenance of equipment, machinery, tanks, and terminals

Harsh environments where the structure is located

Intermittent/extreme wet-dry climate conditions

Insulation type (For instance, your storage tank insulation doesn’t have CUI-preventing properties)

As stated, CUI occurs when moisture penetrates through the insulation materials into the structure. This can lead to corrosion of metal components and degradation of the insulation material. If not adequately addressed, it can also lead to mold and mildew growth and, in worse cases, it can cause structural failure.

CUI is often overlooked until it’s too late, but if caught early enough, repair costs are much less than replacement.

How Can You Prevent CUI

As it always has been, prevention is better — and more cost-effective — than repairing or replacing CUI-affected structures. To prevent CUI from eating away your structures, here are essential tips to follow:

Choose proper insulation. When choosing an insulating coating, make sure that they are particularly capable of preventing corrosion under insulation. It means that your solution must be capable of blocking off or holding moisture. Also keep in mind that kind of surface that you’re insulating. If it’s a marine structure, for instance, apart from being a CUI protector, your coating must also be able to withstand unique and often harsh marine environments. Or if you need to protect a surface from fire, you have to ensure that your coating is also fire-resistant.

Schedule periodic inspection and maintenance. Even if you have the best insulating coatings to protect your surfaces against CUI, you must never be complacent. Experts recommend devising a maintenance plan that is unique to your specific needs and situation. For instance, if your structure is located in a more corrosion-prone area, the more frequent you should conduct your inspection and maintenance.

Recoat and reinsulate when needed. Even the most durable insulation solutions (including your storage tank insulation) have a limited lifespan. If you choose more reliable brands, you can be fortunate enough to enjoy CUI protection for up to two decades or more. As coatings age, their capacity to prevent moisture penetration wanes. This is why once your coatings reach the lifespan indicated or estimated by their manufacturer, you must be quick to cover your surfaces with a new one.