Variability in technical and legal metrological control

Abstract

Introduction. The variety  of instruments available today for specific uses in of science and the technology tasks, due to the demand of products and services for an increasingly conspicuous and global consumerist market, demanded a review of the  conditions with measurements should be performed and the way result validity should be guaranteed, in order to unify the new and modified methods in previous and novel metrology applications.

Method. Joint Committee for Guides in Metrology ( JCGM) issued the third edition of the international metrology vocabulary (VIM), in which a new  approach  for  measurement reliability evaluation (uncertainty
budget)  and result validity (measurement  uncertainty).  With  this  new approach a measurement is characterized in terms of its conditions and properties as a strategy for measurement design and evaluation in different applications while making the fulfillment of technical recommendations and legal requests, as mandated by the Bureau International des Poids et Mesures (BIPM) and the Organisation Internationale de Métrologie Légale (OIML) in what could be defined as the World Metrology System.

Result. To achieve this goal, the conditions and properties of a measurement on industrial and medical applications have been expressed in terms of the short and the long term variability to demonstrate the validity  of measurement to perform technical and legal metrological control.

Conclusion. The sufficient and necessary information that establishes future measurements conditions for the same process is documented in a uncertainty budget and the accuracy is assesed with uncertainty measurement. When part of the process is modified or some of his components changes, it is necessary to update the budget and hence to correct the uncertainty statement.