The ingress of moisture into the insulation system and the consequential concentration of chlorides in the insulation enhance the corrosion of insulated parts of the installation. Moisture may even lead to the concentration of corrosive substances from the atmosphere in the insulation system. Therefore consideration must be given to how corrosion of the object can be prevented through appropriate anti-corrosion applications and/or design of the insulation system. Where pipelines are insulated or lagged, such as ammonia and steam lines, the damage of the insulation is certainly a sure event with much more probability. Corrosion under Insulation (CUI) is a multi-billion dollar problem that destroys expensive industrial infrastructure. It is difficult to detect due to the insulation that covers the location of the corrosion or erosion. Corrosion under insulation measurement in process equipment and piping is necessary required to determine corrosion rates, Wall thickness, and remaining life and will be used for Risk Based Inspection (RBI), environmental safety and for insurance purposes. So, there are much more methods to be practicable in this respect but the most probable in this regard will be Computerized reporting, is possible with comparison to previous results for the determination of rate of material loss and the remaining life of the pipeline.
Profile Radiography
A comprehensive explanation of this technique, also called "Profile Radiography" or "Tangential Radiography" and Wall-thickness measurement of insulated piping is a typical NDT-application in the chemical and petrochemical industry
The Radiographic source could be a X-Ray machine or a radioactive isotope. The greatest contrast is usually obtained with X-Rays then Gamma-rays, such as produced by Selenium-75 and Iridium-192.Tangential imaging is