{"id":973,"date":"2016-11-23T23:25:13","date_gmt":"2016-11-23T23:25:13","guid":{"rendered":"https:\/\/spiperformancecoatings.com\/?p=973"},"modified":"2018-03-25T22:29:37","modified_gmt":"2018-03-25T21:29:37","slug":"corrosion-insulation-treat-prevent-repair-corrosion-properly","status":"publish","type":"post","link":"https:\/\/spiperformancecoatings.com\/corrosion-insulation-treat-prevent-repair-corrosion-properly\/","title":{"rendered":"Corrosion Under Insulation: how to treat, prevent and repair corrosion properly"},"content":{"rendered":"

\u201eI spy CUI\u201d<\/h4>\n

Wrapping thermal insulation around pipes and other temperature sensitive assets is common practice in many industries and yes, maintaining the right temperature across vital processing or storage vessels and equipment can save money on energy bills.<\/i><\/p>\n

But what about the hidden threat beneath that all-important insulation? Corrosion Under Insulation<\/strong> (CUI<\/em>) is one of the biggest problems facing industries such as the petrochemical, oil and gas<\/a>, commercial heating and industrial sectors and left untreated or worse, ignored, the cost of correcting CUI damage can easily outweigh the savings you\u2019ve made on your utility bills.<\/p>\n

What exactly is CUI<\/strong> and why is it such a problem?<\/h4>\n

Well the clue is in the name; CUI is the name given to corrosion which occurs under insulation. Why is it such an issue? Because it remains largely hidden, even in the presence of observation ports, which on a typical application will only represent around 1% of the total surface area.<\/p>\n

In most environments, insulation is removed from carbon steel (or other types of stainless steel) assets around every 15 to 20 years, often revealing considerable corrosive damage beneath. If the surface was coated before the insulation was applied, then of course the damage will be less, but the presence of insulation can magnify the corrosive environment causing many coatings to fail prematurely \u2013 especially in particularly moist environments.<\/p>\n

Where does this moisture come from?<\/h4>\n

It doesn\u2019t matter what sort of insulation you use, whether it is calcium silicate, man-made mineral fibres, organic foams or expanded perlite, there will always be seams, gaps or other discontinuities \u2013 it\u2019s simply the nature of the product.<\/p>\n

Because insulation is neither seamless nor vapor-tight, it will allow moisture (liquid or vapor) to infiltrate beneath the cover, collecting either inside the annular space between the insulation and the coated surface, or within the insulation itself.<\/p>\n

This moisture can come from a variety of sources including:<\/p>\n