What is CUI?
CUI stands for Corrosion Under Insulation and is caused mostly by water condensation on the inside and/or outside of piping equipment. This water intrusion can lead to chloride and galvanic, or acidic and alkaline corrosion. Understanding what can occur under insulation can prevent further damage to the jacketing, insulation hardware, or the underlying piping or equipment.
Galvanic corrosion results from the presence of electrolytes or salt in the water, which interferes with the insulated metal surface and the outer jacket or accessories causing a flow between dissimilar metals.
Acidic or alkaline corrosion results when alkali or acid is present in certain fibrous or granular insulations, and the water vapor dissolves into the chemicals. This can cause corrosion of the steel or aluminum jacketing.
How to Prevent CUI
CUI can be prevented by protective paint and coating; appropriate insulation; insulation quality; equipment design; correct weather barriers, and proper maintenance practices of the equipment. It is important to consider the humidity of the location and if there are any water spills constantly present in the area where the equipment is situated.
Why Paint Matters
Paint has a large part in preventing corrosion under insulation by regulating the external and internal temperature, and preventing moisture from being trapped inside. Water-based micro-porous coatings may allow for water to escape, creating a more breathable pipe. Paints such as Heat-Flex 3500 can minimize radiant solar heat and condensation with an ability to insulate and be applied to equipment operating at over 350°F.
We believe that what’s on the inside is just as important as what is on the outside. That’s why we use only the best industrial paints for industrial jobs.