How to prevent corrosion under insulation

We’ve previously discussed the basics of high temp coatings, which are often used in process facilities such as refineries, oil and gas, and petrochemical plants. These coatings protect pipe systems that transport various materials at high heat.

These hot pipes are usually covered with a layer of insulation to increase efficiency, protect personnel and capitalize on energy savings. Unfortunately, it also helps create one of the most vexing corrosion problems in the industry: corrosion under insulation.

Corrosion under insulation of steel pipes

What causes corrosion under insulation?

Corrosion under insulation, or CUI, occurs when moisture enters through holes or cracks in the insulation and becomes trapped against the hot pipe. Prolonged moisture exposure can cause rapid rusting and corrosion on the pipe’s surface.

Since the layer of insulation completely surrounds the pipe, corrosion under insulation often goes unnoticed. When the insulation is finally stripped from the pipe, either to investigate a problem or as part of a scheduled replacement, facility managers sometimes find the pipe to be completely ruined.

What to do about corrosion under insulation?

The insulation surrounding a pipe must be completely enclosed to prevent CUI. Joints, terminations and other irregularities along the length of the pipe should be carefully sealed. However, moisture can still penetrate insulating layers.

There isn’t a perfect solution for corrosion under insulation, but it can be mitigated by regularly checking the piping under insulation often as a part of a scheduled coatings maintenance plan, sealing insulation with care, and most importantly, choosing a top quality high temp CUI coating.

It’s important to verify that the coating you choose has been specifically designed to stand up to high temperatures and to defend against corrosion under insulation. Also, that it is designed to withstand the range of temperatures the substrate will subject it to.

When chosen to match these criteria, high temp CUI coatings are the most effective method for fighting corrosion under insulation in process facilities.

Contact US Coatings for help in creating a system to protect your insulated assets for the long haul.



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