Optimized Calibration Plan based on Gray Model GM(1,1) applied in Physical-Photometric and Chemical Laboratories Accredited by ISO/IEC 17025

Abstract

The competence of laboratories to perform testing and calibration services for the industry is assured by the ISO/IEC 17025 accreditation. To comply with this standard, it is imperative to ensure metrological traceability through the regular calibration of laboratory equipment at defined schedules, which is time-consuming and demands significant financial resources. The present work applies first-order gray models GM(1,1) using calibration uncertainties to establish an optimized calibration plan that considers different natural characteristics of laboratory activities, thus providing technical support to ensure metrological traceability for a wide range of laboratory tests. A luminous intensity distribution test on LED luminaires and a fire assay method for determining gold were considered. Applying the proposed approach, the outcoming times between calibrations were longer than previously established, reducing 11% of the financial resources for the physical-photometric laboratory and 54% for the chemical laboratory. Therefore, it also increases the availability of calibrated pieces of equipment. Moreover, results showed that this method suits physical and chemical laboratory tests. In conclusion, this methodology could increase the time between calibrations and reduce the financial resources needed while maintaining technical competence or confidence in laboratory results.

Keywords

• fire assay
• gray model
• iso/iec 17025 accreditation
• luminous intensity
• uncertainties