Piping internal coating inspection

[arcpro]

Have there been proven non-intrusive techniques now available to perform inspection of internal coating for piping?
Share some reference, if available.

[ben]

Non-intrusive inspection for internally coated piping and pipelines is challenging.
They key is to perform an opportunity inspection with specified frequency, and obtain the data in terms of visual condition, thickness, and the damages incurred. More the data we have, more are the chances that an acceptable offline opportunity inspection is planned, performed, and recorded.

[irish]

First you need to assess that how challenging, and damaging would be any failure or an unscheduled inspection of the piping system in question before you apply any kind of internal coating inspection non-intrusively. This because that it has to be an advanced NDT, most probably scanning to start with picking up metallic defects (coating damages would anyway not be picked with whatsoever technique you apply externally - while you have process conditions). Further on, to locate the exact area of damage would call for localized flaw detection, separate inspection technique, inspection planning and manhours. And what I understand, you would still not be providing 100% assurance or getting the right inspection confidence.
Now let us see what are the techniques available:
1. Ultrasonic Guided Wave
2. Magnetic Eddy Current

Check them out and see what can actually help.

We employed GW but with a lot of limitations and data repeatability issues.
Like ben said, we restricted our focus to whatever shutdown window was made available and gave call for 2-3 years to offer us piping coating internal inspection.
This for business critical cooling water loops with internal coating.