Decision rules for metrological confirmation of EMC measurement equipment

In the forthcoming edition of the standard ISO/IEC 17025 emphasis is placed on the “decision rules” according to which conformity to a specified requirement is stated taking measurement uncertainty into account. Decision rules shall be defined in particular for metrological confirmation, i.e. to confirm that a measuring instrument is adequate to its intended use. The level of risk associated with false acceptance and false rejection and inherent with the adopted decision rule shall be calculated. In this work three decision rules are proposed that apply to the case where: a) calibration uncertainty is comparable with the tolerance set by standards, as frequently occurs in the case of electromagnetic compatibility measuring equipment; b) the specification to be met is expressed in terms of a coverage interval corresponding to a given coverage probability; c) no specification or requirement is available and confirmation has to be obtained by comparison with previous calibration data. The three decision rules proposed here are not, and cannot be, exhaustive. Further investigation is underway.