Inspection of internal non-metallic coating online

[Dlew]

What are the successful stories of performing non-intrusive in-operation inspection of internal non-metallic coating for piping?
Please support with recognized publications, if any.

[novice123]

Would recommend you this one:
https://link.springer.com/article/10.10 ... 26-06595-0

[ben]

Very informative one, thanks for sharing novice123

[octane]

GWT ring arrays are clamped externally around the pipe while it remains in service. Low-frequency ultrasonic guided waves propagate axially over long distances, making it possible to screen unpiggable or coated pipe sections (Lyu et al., 2024). While sticky or highly bonded coatings can cause wave attenuation, changes in wave propagation modes help identify debonding, thinning, or internal corrosion behind the liner.

PEC is widely utilized for non-intrusive evaluation of insulated or internally lined ferromagnetic pipes. Because PEC measures changes in a transient magnetic field, it evaluates underlying steel wall thickness from the exterior without requiring direct physical contact with the fluid or removal of internal barriers. Similarly, EMAT technologies generate acoustic waves directly inside the metallic pipe wall via electromagnetic induction, bypassing the need for liquid couplants or direct access to the internal coating surface.