Electromagnetic Testing (ET) and Eddy Current Testing (ECT) are methods of Non-Destructive Testing (NDT) used to provide a basis of material and component data, in order to establish an understanding of premature and/or preventative conditions that affect reliability and operation costs. This form of testing is performed on seamless and welded tube copper, copper alloy, and other non-ferromagnetic tubular products installed in commercial and industrial heat exchangers and chillers.
Eddy Current Testing provides information about:
1. “Background Noise” levels usually associated with Tube inside Diameter (ID).
2. Surface conditions, Rifling, Internal Enhancement, Swirling, Harmonics etc.
3. Volumetric support information, Land area tubes “Skip Finned” and / or Continuous Finned tubes and fin variations, Prime Seamless or Welded tube.
4. Geometric Information, Internal expansion at Tube Sheets and Supports
Tube Manufacturing, Inclusions, Lap Seams, Pits, Steel Tool Chips, Missed Lands, Deformed Lands, Cracks, Dents, Geometric Constrictions.
All equipment, personnel, and labor necessary for the performance of the Eddy Current testing procedure will be provided by Eddy Current USA, Inc. unless otherwise specified prior to the date of testing. All Equipment and Personnel requirements adhere to the standards specified by ASME sec. V, article 8 and ASNT CP-189-1995.
Testing Equipment will consist of suitable electronic devices that can energize the testing Coils/Probes with alternating currents at frequencies capable of sensing changes in the electromagnetic properties of the test specimen. Output data produced by the Testing Equipment will be both recorded and processed to a Signaling Instrument for visualization.
Test Coils and/or Probes will be capable of inducing alternating currents into the test material as well as sensing the changes in electromagnetic characteristics of the material. Test Coils and/or Probes will be selected so as to provide a minimum fill factor of 0.8, with respect to Unity (1.0). Maximum scanning speed of Test Coils and/or Probes shall not exceed a rate of 24 inches per second.
Reference Specimen (Standard)
Reference Specimen (Standard) material will be manufactured from a length of tubing in the same manner as the Test Subject; the same nominal size and material type (composition and form) as the tube being examined. This Standard is intended to establish and verify system response in the Signaling Instrument. Standard calibration discontinuities are distinguished as follows:
- 100 % Thru-wall Hole
A single hole drilled through 100% of the wall: a diameter of 0.052 in. (1.32 mm) for 0.750 in. (19 mm) O.D. tubing and smaller, and 0.067 in. (1.70 mm) for larger tubing.
- O.D. Notches
Four flat bottom holes 0.187 in. (4.8 mm) in diameter, spaced 90 deg. apart in a single plane around the tube circumference, 20% through the tube wall from the O.D.
- I.D. Notches
A single 0.062 in. (1.6 mm) wide, 360 deg. circumferential groove, 10% through the tube wall from the I.D.
Discontinuities of the Calibration Standard, at their center, will be accurate to within ±20% of the specified depth or ±0.003 in. (±0.08 mm), whichever is smaller. All other dimensions will be accurate to 0.010 in. (0.25 mm).
All Discontinuities of the Calibration Standard will be spaced in such a way that they are easily distinguishable from one another from each end of the tube.
Signaling Instrumentation will be inspected prior to each use and calibrated to the manufacturer specifications, so as to establish uniformity in the test data.
Data Capturing equipment will be inspected prior to each use and setup so as to allow for real-time data acquisition of signaling instrument, site and subject states, and Technician commentary.
All Personnel of Eddy Current USA, Inc. are certified and qualified in accordance with ASNT CP-189-1995 and ASNT SNT-TC-1A 1996 2nd ed.
All Personnel of Eddy Current USA, Inc. will have completed sufficient organized and documented training to become familiar with the principles of the method and practices of the test Technique. This training is conducted in accordance with a course outline provided by an ASNT certified, NDT Level III. Specifics of the training are available upon request.
Personnel not yet certified to any level are considered a Trainee. Trainees work with a certified person, under the direction of an NDT Level II or NDT Level III and will not independently conduct any Testing or write a report of testing Results.
Not less than thirty (30) days of experience directly under the supervision of a certified person not less than Level II.
Level I Personnel have demonstrated the skills and knowledge to properly perform specific Calibrations, specific Techniques, and, with prior written approval of an NDT Level III, perform specific Evaluations for acceptance or rejection to be Documented in the Report.
Not less than twelve (12) hours of training, sixty-five (65) hours specific to the Procedure, and one-hundred and thirty (130) hours in Non-Destructive Testing (NDT).
Level II Personnel have demonstrated the skills and knowledge to set up and Calibrate Equipment, conduct Testing, Evaluate, and Document data in accordance with the Procedure approved by an NDT Level III. Level II Personnel are thoroughly familiar with the scope and limitations of the Technique to which certified and are capable of directing the work of Trainees and Level I personnel. Level II Personnel are able to Evaluate and Document Testing data.
Not less than forty (40) hours of training, six-hundred (600) hours specific to the Procedure, and twelve-hundred (1200) hours in Non-Destructive Testing (NDT).
Level III Personnel have the skills and knowledge to establish Techniques; interpret codes, standards, and specifications; designate the particular Technique to be used; and to verify the adequacy of Procedures. Level III Personnel are capable of conducting or directing the training and examining of Personnel specific to the method(s) in which they are certified.
A current and valid ASNT NDT Level III certificate specific to the method of Non-Destructive Testing (NDT).