UNCERTAINTY IN RADIOGRAPHY

Uncertainty in measured results is an integral part of measurement. Th e ISO Guide 25 (1990), the applicable ISO standard for testing and cal ibrating laboratories, requires one to specify the uncertainty of each measurement, in order to give additional information about the measur and and the quality of the measurement. It is well understood how to c alculate the uncertainty for quantitative measurements such as length, temperature and so on, but not for test results as in radiography or other NDT testing methods. This paper describes a study undertaken to calculate uncertainty and to estimate the real sizes of discontinuitie s observed in radiography.