Metrological map of a fleet of equipment a metrology laboratory: application of weight method according to FDX-07-014

Metrology is the science of measurement. It is applied in several fields where quantitative measurements are made. In fact, in any industrial activity (food processing, electrical energy, chemistry, mechanics, aeronautics, space, defense, agriculture, electronics) various measuring instruments are used. After a certain period of operation, their indications will be erroneous, which leads to major risks for the safety of people and industrial installations. Thus all equipment drifts over time, it is a well known phenomenon. A measuring instrument that is "accurate" today will not be so tomorrow because it will have drifted! The causes of drift are multiple and varied (mechanical origin: shocks and vibrations, oxidation, wear, conditions of use, aging...). This calibration interval or drift is determined either by the manufacturer or by the needs of the company or the laboratory. Historically, the periodicity is 12 months in metrology for all the instruments, this drift allows to have a management of periodicity of the equipments but sometimes the calibration will be with a high cost. Therefore, to avoid costly periodic calibrations, methods have been created to adjust and optimize calibration costs according to the criticality and use of the measuring instrument. The optimization and justification of periodicity are increasingly crucial problems over time, they are now the subject of strict guides defining the methods of calculating periodicity such as the method of max drift, the method of weight and the method OPPERET. In this paper, we will demonstrate the adequate method for a special laboratory that has a limited number of equipments according to the ISO/CEI 17025 version 2017.