As Marc Grenier discussed in The Corrosion Under Insulation Plague: What You Need to Know, corrosion under insulation (CUI) is one of the most difficult corrosion processes to prevent. The reason for that is, by and large, no matter the precautions taken, water invariably seeps into the insulation and begins its dirty work—sometimes unseen until process leakage occurs. Data shows that about 60% of pipe leaks are caused by CUI. That’s not good.
CUI is difficult to find because the insulation covers the corrosion problem until it is too late. Removing insulation, inspecting, and then reinstating the insulation after inspection is an expensive process. Inspecting without removing insulation and weather jackets greatly reduces the cost of inspections. Non-destructive testing methods to detect CUI in such a way is therefore a major benefit to the industry.
There are a number of methods used today to inspect for CUI. No one method is ever used by itself—several methods complement each other for optimal results, but that’s not the object of this article. Click here to read more about methods you can use to inspect for corrosion.