EDDY CURRENT AND REMOTE FIELD TESTING (RFT)

The objective of this nondestructive testing method is to locate and evaluate abnormalities in electrically conductive material using an induced eddy current field in the test object. Changes in the electrical impedance caused by a variation in the eddy current field are detected and analyzed. RFT is a similar electromagnetic technique used on ferromagnetic materials.

Eddy Current can be successfully performed on non-ferromagnetic material (Copper, Brass, Stainless Steel, Titanium), while Remote Field Testing is utilized on ferromagnetic material (Carbon Steel, Duplex Stainless Steel).

Items commonly inspected by these methods include power boilers, recovery boilers, condensers, feedwater heaters, and air-cooled exchangers (chillers). Eddy Current and Remote Field Testing are efficient, accurate, and reliable nondestructive methods of assessing heat exchanger tube integrity. Typical tube discontinuities identified and evaluated include tube fretting, tubular cracking, corrosion/erosion and dimensional changes.

Successful Eddy Current and/or Remote Field Testing inspections:

• Are extremely dependent on operator proficiency.



• Require adequate access to the item to be inspected.



• Requires the tubes to be adequately cleaned prior to inspection (cleaning requirements are not as extensive as for other tubular inspection methods).

Inaccurate results are sometimes received due to the effects of tube sheets at the ends of the tubes.

The data from both Eddy Current and Remote Field Testing inspections is recorded and analyzed on site and a field report provided immediately for repairs if required. The analysis software provides tube sheet maps, which are correlated with the tube data for immediate reference and identification.