Thermography to survey pipe internal wall loss 3

What is the issue with using an ultrasonic device to measure wall thickness?

Given that the thermal conductivity of metal pipe is very high compared to many other materials, I can't see any temperature difference is going to be measurable in terms of temperature difference. You might notice it for a very accurate temp device, but its a new one on me. As bimr says, if you can see the outside, use a U/T probe. Far better and more accurate.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

The real issue is how would you calibrate?
How much hotter is too much?

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P.E. Metallurgy, consulting work welcomed

You'd have too many unknowns and like EdStainless suggests, unless you have some specific way to calibrate against a known standard, you're mostly going to be guessing.

Depending on the process fluid and temperature, wall profile radiography might give some useful results.

Not reliably, technically it could work, but the temp change is orders of magnitude lower than background noise levels (think issues like different surface colors, sun vs shade, and a whole host of other factors related to how thermal cameras work). But have seem it done extensively to locate scaled / blocked pipelines, vessels and tanks.

Andrew O'Neill
Specialist Mechanical Engineer
Australia