Eddy Current
AGR Inspection Inc.
P.O. Box 608
Burleson, TX 76097
1-866-339-2768
agr@eddy-test.com

Eddy Current Testing Can Detect Tube Damage Before It’s To Late.
Eddy current testing is a nondestructive method of locating discontinuities in
tubing made of materials that conduct electricity. The test will identify
common problems that cause tube leaks, resulting in major repair costs and
extended down time. One of the most important things you can do to
minimize equipment failure and prevent unscheduled downtime is eddy
current tube testing. It is a test that should be performed on chiller heat
exchanger tubes at least every three to five years. If you think this kind of test
is unnecessary, remember that the single most costly failure in a water
chiller is a tube failure.

How Eddy Current Works.
A test probe is inserted the length of the tube. The probe is energized with
alternating currents at the appropriate frequencies. The electrical
impedance of the test probe is modified by the proximity of the tube, the
tube dimensions, electrical conductivity, magnetic permeability and
metallurgical or mechanical discontinuities in the tube. Each discontinuity
produces an electromagnetic response unique to the anomaly detected.
These responses are processed electronically and displayed on the test
instrument for interpretation. Our analyst interprets the data to identify
problems and to recommend corrective action.

Eddy Current Is Not A Leak Detector.
The test is designed to aid in assessing the likelihood of failure during
service. It is not possible to specify an all inclusive reject level that would
acknowledge all of the possible combinations of heat exchanger design,
environmental factors, type and amount of use and acceptable level of
operational shutdowns. The purpose of this test is to detect defects normally
encountered in industrial air conditioning. Calibration standards are
designed to simulate these types of defects. When other types of defects
are suspected different calibration standards, test frequencies and even
test probes may be required. Not all defects are of a sufficient size to
disrupt current flow enough to be detectable. This is particularly true were
irrelevant signals caused by metallurgical or mechanical variations
generated during manufacturing occur. These irrelevant indications can
mask lesser relevant discontinuities. Discontinuities adjacent to tube ends
may not produce signals capable of detection due to end effect.

Technician Qualification.
Technicians are trained and certified in accordance with guidelines
established by the American Society for Nondestructive Testing. Our
technicians are further certified by an outside agency. A Level III analyst with
over 15 years experience reviews reports.