Assessing the competence of laboratories - Accreditation and alternatives

Historians remind us that it's by looking back that we should see the future more clearly and better understand the present. Nature tells us that without healthy, well-established roots, plants cannot produce flowers, and therefore fruit. That's why we've included a few reminders in this article.

Guaranteeing measurement accuracy is essential for quality control in industrial companies, as well as for conformity assessment of products and services exported or covered by European directives. Over the years, industrialized nations have developed a metrological infrastructure to support their trade and industry, as well as accreditation structures working within the framework of market surveillance.

To provide customers with a guarantee of measurement accuracy, it is necessary to demonstrate the laboratory's technical capability. To achieve this goal, many nations set up reference laboratories (NMI – National Metrology Institute) at the beginning of the 20th century, backed up by national accreditation systems for calibration laboratories, which ensure the traceability of industry's measurement standards to the International System of Units (SI).

The aim of traceability to the International System of Units (SI) is to ensure that a measurement result obtained at one point on the globe, under known conditions, is unambiguously comparable with another measurement result obtained under similar conditions at another geographical location, at another time, to within the measurement uncertainties. Measurement equipment, whether simple or complex, drifts over time. Their indications can only be reliable if the suitability of this measuring equipment for its intended use is mastered.

As a result, all measuring, control or test equipment having a significant effect on the accuracy or validity of the measurement result, including instruments used for ancillary measurements (e.g. of ambient conditions), must be traceable to the International System of Units (SI). This influence, assessed by the user of the measurement result, may be different for the same type of equipment, depending on the processes in which the equipment is used.

The most widely recognized mechanism for facilitating the acceptance of measurement results between countries seems to be mutual recognition between accreditation systems.

To accredit means "to officially recognize, sanction, authorize, attest or guarantee that the requirements of a standard have been met".

To accredit implies a certain "recognized level of authority, competence or excellence" (definition taken from the Collins English dictionary). The Larousse dictionary tells us that it means to make something likely, to make...