This Technical Specification is established to consider and define discontinuities-types to be exhibited in test specimens for use in practical Non Destructive Testing examinations. According to EN 473:2000, Clause 7.1.3.3, the discontinuities contains in the test specimens may be natural, artificial or implanted.
Acoustic Emission Testing, Infrared Thermography Testing and Leak Testing need not define discontinuity-type, due to their specific approach (e.g. replaced in AT by artificial sources).