ASME PTC 19.1-2018

The scope of this Standard is to specify procedures for
(a) evaluation of uncertainties in test measurements, parameters, and methods
(b) propagation of those uncertainties into the uncertainty of a test result

Depending on the application, uncertainty sources may be classified either by the presumed effect (systematic or random) on the measurement or test result, or by the process in which they may be quantified or their pedigree (Type A or Type B).