ASNT NDT III ET study guide
ASNT NDT III ET · Work through your exam, one topic at a time.
The ASNT NDT Level III certification in Electromagnetic Testing (ET) is an advanced, method-specific credential offered through ASNT's NDT certification program, which ASNT describes as comprehensive, two-part certifications recognized internationally as validation of competence. Candidates sit an NDT General computer-based exam plus specific computer-based exams for one or more methods; the ET exam is the method-specific portion for electromagnetic testing. The credential is aimed at experienced practitioners ready to move into Level III responsibilities such as writing inspection procedures, designing processes, auditing and updating documentation, supervising and training teams, and managing operations or internal certification programs. ASNT states that its NDT Level III Basic, ET, MT, PT, RT, UT, and VT exams are accredited by the ANSI National Accreditation Board (ANAB) in accordance with ISO/IEC 17024:2012. Topics on this exam: NDT General (Basic) and Electromagnetic Testing (ET) Method Specific. The ASNT NDT III ET study guide has 2 sections and about 710 words.
01NDT General (Basic): Principles, Personnel, and Documentation
A Level III is tested less on trivia than on judgment: why a method is chosen, how a technique is validated, and how results are documented and defended. You must be fluent in the standard NDT methods (VT, PT, MT, ET, RT, UT, LT, AE), their energy forms, and their relative strengths and blind spots. Know the difference between a discontinuity and a defect, and between detection and rejection - a defect is only a discontinuity that exceeds an acceptance criterion. Understand the certification ladder (Trainee, Level I, II, III) and what each may do: Level I performs calibrated, standardized tests under supervision; Level II sets up, calibrates, interprets, and reports; Level III selects methods, establishes techniques, interprets codes, and trains/certifies.
381 words, about 2 min02Electromagnetic Testing (ET): Physics, Probes, and Signal Interpretation
ET relies on Faraday's law and eddy currents induced in a conductive test object by a time-varying coil field. The currents concentrate near the surface; standard depth of penetration (the depth where current density falls to about 37%, or 1/e) is δ ≈ 1/√(π f μ σ). Increasing frequency, permeability, or conductivity reduces penetration. This single relationship drives most ET questions.
329 words, about 2 min