General NDT / Method Fundamentals: Qualification, Standards, and Safety
The framework a Level III must command
This domain tests judgment beyond technique: personnel qualification, written procedures, standards hierarchy, and radiation safety. Know the roles of employer certification versus central certification, the meaning of Level I, II, and III responsibilities, and why the employer-not the certifying body-authorizes work. Understand that a written procedure must be qualified and that technique sheets implement, not replace, the procedure.
Standards and acceptance criteria
Distinguish between referencing standards (how to test) and acceptance criteria (what is acceptable). A frequent trap is applying an acceptance criterion from the wrong code or revision. Know that discontinuities are not defects until judged against criteria, and that indications require interpretation before sizing or sentencing.
Safety fundamentals
Radiation safety questions favor ALARA and time-distance-shielding. Recall that dose rate follows the inverse-square law, that shielding effectiveness depends on energy and material, and that personal dosimetry and area surveys are mandatory controls. Traps include confusing exposure rate with dose, and forgetting that collimation reduces both scatter and personnel dose.
Worked rule of thumb
If dose rate at 2 m is 40 mR/h, at 4 m it falls to 40/2² = 10 mR/h. Doubling distance quarters the rate-use this to check any safety answer quickly. When in doubt, choose the option that reduces time, increases distance, or adds shielding.