Corrosion under insulation and high heat

Lowering maintenance requirements in the toughest conditions

Ready for anything

Corrosion under insulation (CUI) most often occurs in temperatures between 50°C and 175°C. But it can be found in lower temperatures in areas with high relative humidity – the so-called ‘sweating’ pipe syndrome. As many assets undergo temperature fluctuations, as a result of the process itself or before and after shutdowns, the most reliable CUI coatings are able to offer protection across a wide range of temperature.

Overcoming the challenge of traditional CUI systems

When it comes to high heat applications and the prevention of CUI, three coating types have historically been used:

  • Epoxy/epoxy phenolic coatings offer excellent performance when operating between -196°C and 175°C. However, when temperatures go higher, the coatings are more likely to crack.
  • Thin film silicone coatings are ideally suited to hot and dry conditions (up to 540°C). Outside these limits, such as during process cycling, their ability to protect against CUI is reduced. 
  • Zinc silicate systems can resist a wide temperature range – up to 400°C. However, as zinc silicates are ‘sacrificial’ in their defensive approach, they degrade rapidly when exposed to hot and wet CUI environments.

All these systems have pros and cons. With Hempel, our Inorganic copolymer coating has all the advantages and none of the drawbacks – Versiline CUI 56990.

Versiline CUI 56990

Protection and productivity in all conditions

Formulated to deliver optimal performance across a wide range of conditions, Versiline CUI 56990 gives you unrivalled protection against CUI, even if temperatures rise or fall above those predicted. It can withstand temperatures from -196°C to 650°C and delivers exceptional resistance to micro-cracking.

Versiline CUI 56990 is also extremely easy to apply and dries quickly to ensure high productivity onsite and in the yard. And it’s tough enough so it won’t get damaged easily during transportation or construction.

  • Designed and tested specifically for CUI conditions
  • Wide range of heat resistance from -196°C to 650°C
  • Meets the requirements of NACE SP0198 : 2017 SS-5, CS-6 and CS-8
  • Overcoatable within 6 hours at 20°C

Hempaprime CUI 275

Very high productivity and performance up to 275°C

Designed for use in severe corrosion environments, Hempaprime CUI 275 delivers excellent protection against CUI in temperatures from cryogenic to 275°C. 

Formulated for high productivity on new construction, maintenance and repair, it has an extremely short overcoating interval and ensures excellent crack resistance even if applied at high DFTs. This makes it ideal for projects where high productivity and predictable ISO-certified long-term performance are required.

  • Fast overcoating intervals: just 1.5 hours at 20°C 
  • Wide temperature resistance from cryogenic up to 275°C (527°F) 
  • Superior crack resistance to thermal cycling compared to traditional epoxy phenolic coatings
  • Can be applied in temperatures as low as -10°C and on hot surfaces up to 200°C  
  • Meets the requirements of ISO 19277:2018 for corrosion categories CUI-1, CUI-2, CUI-3 and their cryogenic extensions
  • Meets the requirements of ISO 12944 for corrosion categories C5-H and CX