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Corrosion under insulation (CUI)

Corrosion under insulation (CUI), corrosion under fireproofing (CUF) and flow-accelerated corrosion (FAC) are key challenges for the petrochemical processing industries and the cost associated with mitigating them can be extremely high.

Despite the problem being well understood and documented, the corrosion process under insulation is one of the most difficult to prevent.

CUI occurs when moisture accumulates or is absorbed by insulation materials surrounding the external surfaces of steel equipment, particularly pipework. CUI can be extremely detrimental to the integrity of pipework, vessels and tanks leading to leaks or more serious incidents if not detected early on.

The most common inspection technique for CUI is to remove the insulation and perform a visual inspection. The removal and reinstatement of insulation is labour intensive, expensive and in many instances completely unnecessary, as the substrate can often be found to be in good condition.

JF NDT provide the pulsed eddy current (PEC) technique which is one of the most effective and efficient methods of determining the severity of CUI with minimal intervention, reducing the costly need for insulation removal and replacement in certain situations.

PEC inspection is an established and proven electromagnetic technique. It works by injecting an electrical current in the transmitting coil of the inspection probe, which induces a magnetic field into the underlying structure.

We use handheld Eddyfi Lyft™ PEC systems for rapid real-time inspection data of wall thickness with full traceability. This innovative system runs continuously, reducing the time required and significantly increasing the number of data points available, providing greater certainty of results.