Corrosion Under Insulation (CUI) is the corrosion of piping and vessels that occurs beneath insulation as a result of the vapour seal being breached allowing moisture ingress, with the effects often hidden from view and not discovered until it is too late.
There are a number of key focus areas, which should be inspected. In order of priority they are:
- Nozzles, as they have the thinnest walls and if water enters the insulation, these are the most likely sites for CUI to occur.
- Areas of highest shell stress. These are usually nozzle/shell boundaries and therefore should be inspected at least 1m around the nozzles.
- Skirt (corrosion behind fire-bricks), especially the base in the vicinity of hold-down bolts.
- Shell.
- Horizontal head.
Tcorr Inspection staff are experienced in CUI surveying and can address your complete solution needs. Inspections can be performed with the system still online and the cladding removed utilising the KOOLKUNA work enclosure system. This innovative solution allows CUI inspection, maintenance and insulation replacement on pipework operating at temperatures as low as -30 °C without moisture intrusion.
