How to Protect Against Corrosion Under Insulation (CUI)

Inspections and Maintenance will Protect Your Assets from CUI and Prolong its Lifecycle.


Routine inspection programmes need to be performed by certified inspectors who are trained to spot signs of CUI – which in most cases occurs out-of-sight.

Inspections should cover the whole insulation system; Insulation material, cladding, substructure, and ancillary materials, and any coatings system, not just the surface of the insulated asset.

For areas which are prone to CUI, such as bends, vertical rows, contaminated environments, and where fluctuations in temperate regularly occur, causing cyclic conditions, inspection procedures should be carried out at frequent intervals to help prevent CUI and stop it taking hold.

Any deterioration to the equipment should be reported and suitable maintenance actions prioritised to prevent further spreading of corrosion.

Inspections should also be carried out before the insulated equipment is put into service.  During the installation stage, inspecting the quality of work, materials applied and the overall specification of the system will confirm that the insulation system is fit for purpose, something which will help prevent localised corrosion.


Thermal Insulation operatives, inspections and maintenance



Maintenance of the insulation system and underlying equipment needs to be carried out proactively to enable to best chance of protecting against CUI.

Maintaining the integrity of the insulation system gives the best chance of protecting against CUI.  Rectifying damaged cladding will prevent moisture ingress, and replacing soaked insulation will help prevent corrosion occurring.

All on-site operatives should be encouraged to report any accidental damage or concerns related to the reliability of the insulation system, as soon as it occurs.  This will allow for immediate maintenance to be carried out, mitigating risk and reducing long-term impacts of untreated CUI.


If CUI is spotted early, it can be the difference between replacing a small patch of a pipe, rather than having to replace the whole pipeline.  Also, if not maintained, the insulation system and underlying assets integrity will become compromised, with the potential for a costly failure to occur.

Learn more about ways to protect your assets from CUI >>

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