2.1 To develop a ASTM/NCSLI standard guide on determining the need metrological traceability and then establishing metrological traceability. Where measurement is impacts the validity of test results, metrological traceability provides assurance that the measurements are reliable. This standard will provide guidance on how to determine the impact of measurements on the validity of test results and so when metrological traceability is needed. Laboratories, regulators, users of test results, accreditors and ASTM committees can use the guide to their needs for metrological traceability, for example, identifying critical measurements or critical measurement equipment. It will describe the components of metrological traceability: realization of SI units, calibration hierarchy, calibration intervals, measurement uncertainty, measurement procedures, measurement assurance, accredited technical competence and documentation. Their relationship with the other aspects of test method development and validation.
Metrological Traceability; International System of Units; Reference materials :
International vocabulary of metrology - Basic and general concepts and associated terms (VIM) defines metrological traceability as the property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty. Just the quantity without reference makes the quality virtually meaningless. The same as entering a grocery shop and requesting 7, the result would be a confused grocer ask 7 of what? Measurement units are the way for us to reference quantities and the relationships between quantities. Metrological traceability as a whole, is how we continually assure our understanding of measurement results relative globally accepted references. For some tests and measurements this understanding is important for example, in trade where payment is based on qualities or medical treatments where dosage is a critical factor. It is not the case for every measurement within testing. For example the evaluation of characteristics due to weathering. In these cases the uncertainty contributors related to measurement instruments are insignificant, when compared to the other contributing elements. This guide is necessary to assure that users make informed decisions related to metrological traceability.
The title and scope are in draft form and are under development within this ASTM Committee.
Developed by Subcommittee: E11.50
Staff Manager: Kelly Paul
Date Initiated: 05-20-2019
Technical Contact: Andrew Oldershaw