What is Corrosion Under Insulation?​

Corrosion under insulation (CUI) is corrosion that develops on carbon and alloyed steel substrates which have been insulated. ​This type of corrosion often arises when moisture is absorbed by or trapped in the insulation.

The Key Challenges and Causes of Corrosion Under Insulation​

Environmental impact:​

  • Temperature change – hot/cold, condensation formation​
  • High humidity​
  • Rainfall​
  • Fire-fighting system tests (seawater in offshore)​
  • Pressure relief valves for overspray/steam​

Functional impact:​

  • Poor sealing of cladding​
  • Poor sealing of insulation​
  • Damage to insulation due to foot traffic​
  • Corrosion of cladding (electrochemical)​

​Usually, it is difficult to inspect and detect due to the multiple layers of coating, insulation and cladding covering the steel surface. If insulation gets wet and traps in moisture, it has an extremely detrimental effect on the working efficiency, leading to excess use of heat trace and creation of steam, essentially creating a constant climate chamber.​

Prevent Corrosion Under Insulation With SFL Solutions

STOPAQ: a permanent corrosion protection and water sealing solution. Based on Polyisobutene (PIB), the coating mimics the natural behaviour of tree sap, with self-adhering, self-sealing and self-healing properties. ​This coating forms an impervious layer to oxygen, water and MIC, helping protect corroding materials such as steel. STOPAQ’s advanced corrosion under insulation coatings and sealing solutions can be applied directly to hot surfaces without the need for a shutdown and offer: excellent water vapour barrier properties, good puncture and tear resistance, resistance to low temperatures and temperature cycling without getting brittle or deteriorating performance and UV resistant protection. ​

Mascoat DTI: offers thermal insulation, reducing surface temperatures and heat loss while preventing corrosion under insulation (CUI). Extending asset life, it also keeps people safe, minimising the occurrence of burns upon contact with hot-touch surfaces, as well as saving energy through improved efficiency of the asset protected. DTI’s thermal insulating ability remains constant from the day it is installed onward, with a track record of protecting against CUI for 25+ years!

Highland International: specially engineered corrosion under insulation coatings that can withstand extreme temperatures ranging from -300°F to 1200°F.  Furthermore, they offer superior resistance to boiling water and thermal shock. Additionally, our CUI coatings can be applied directly to hot steel surfaces up to 750°F. All of this adds up to easier applications and maximum service life even in the harshest environments. 

Our corrosion solutions offer vital protection without the need for a shutdown, minimal surface preparation and minimal waste. Asset lifetime is extended, and very little maintenance is required.