NONDESTRUCTIVE EQUIPMENTS ARE NOT CLASSIFIED AS METROLOGICAL INSTRUMENT

The question if nondestructive flaw detectors are metrological instrument is discussed. On the basis of the physical principles and characters of nondestructive testing(NDT) methods, as well as the metrological law and the definition of metrological instrument, it is concluded that nondestructive flaw detectors are not metrological instrument. The limitations of radiographic, ultrasonic and magnetic particle testing methods and the errors in measuring results should be recognized. It should not be considered that NDT equipments are metrological instrument.