By Karen Hall
In just a few months our measurement system, the International System of Units, the SI, will be changing to remove the last physical artefact and redefine the base units with respect to the fixed values of reference constants – thereby improving our knowledge of fundamental constants and in turn making lower uncertainties available in new measurement opportunities.
This was the overall message from Georgette MacDonald of the NRC, Canada in her keynote address – The Revised SI: A Change That’s Worth the Weight, presented at the annual T&M (Test and Measurement) Conference, which took place in Somerset West in the Western Cape, South Africa, from 8-10 October 2018.
With the theme ‘Out with the old, in with the new’ – turning a new leaf in science measurement and quality assurance, the T&M Conference, hosted by the National Laboratory Association of South Africa (NLA-SA), presented a wide diversity of papers, including international speakers from the NRC, Canada, the National Laboratory for Civil Engineering/EUROLAB, Portugal, the NCSL International/Fluke of the USA and IFMQS Pty Ltd, Australia. The conference was structured around dedicated streams on the revised SI, testing (water, food, civils materials and stack emission), calibration, and the changes that have been made to SANS 17025:2005.
Elaborating further on the revised SI, Ms MacDonald explained that the original SI had three base units – kilogram, meter and second, all of which were based on physical artefacts suitable for that time. But the SI has evolved, added more base units, namely the ampere, kelvin and candela, and incorporated several fundamental constants such as the speed of light, the Avogadro constant and the atomic mass unit.
The changes to the SI, which are expected to be implemented on World Metrology Day, 20 May 2019, are focused on the first four reference constants introduced, the kilogram, ampere, kelvin and mole. The new definitions will be based on fixed numerical values of the Planck constant (h), the elementary charge (e), the Boltzmann constant (kB), and the Avogadro constant (NA), respectively. Further, the definitions of all seven base units of the SI will be uniformly expressed using the explicit-constant formulation, and specific mises en pratique will be drawn up to explain the realization of the definitions of each of the base units in a practical way.
A further highlight of this year’s conference was the representation by EUROLAB (European Federation of National Associations of Measurement, Testing and Analytical Laboratories) with the president, Álvaro Silvo Ribeiro, outlining the foundation of the Federation in 1990. Quoting the first EUROLAB President, Mr Ribeiro noted that: “ When a group of Directors of eminent public and private laboratories took the initiative to create EUROLAB back in 1990, they shared a common vision: the European harmonised internal market could only prosper based on improving the quality and safety of products, goods and the environment, both to serve the European Citizens and to improve the competitiveness of European companies and services on world market.”
EUROLAB‘s general objective is to promote cost-effective testing, calibration and measurement, services, for which the accuracy and quality assurance requirements are adjusted to the actual needs. The Federation today has 21 full members, three associated members, one observer member and two international affiliates, and numbers over 3 000 conformity assessment bodies representing over 150 000 technical experts and laboratory practitioners.
“As highlighted by Mr Ribeiro, we are proud of our special relationship, with the NLA-SA being the first organisation to have established an MoU with EUROLAB, a partnership we are looking to build on even more if we are to jointly advance the science of metrology in a rapidly changing and challenging world,” commented NLA-SA Director, Steve Sidney. “It is only through global scientific and technical cooperation that we will ensure that the required high-quality data continues to be available.”
As a result of this forward thinking, the NLA-SA also established an MoU with NCSL INTERNATIONAL, represented at the T&M Conference by Mr Jeff Gust, Chief Corporate Metrologist, Fluke, United States. In his presentation, he noted that the NCSL International as one of the leading professional organisations for metrology since its inception in 1961. Initially formed to be an organization to serve U.S. interests, NCSL International collaborates with other related organisations around the world, such as the NLA.
The NLA-SA is extremely proud of its relationship over many years with both these organisations and is looking to cooperate further in the future to the benefit of its members.
The NLA-SA is the representative association for accredited and non-accredited laboratories in South Africa. This includes measuring, testing, calibration, verification and other bodies, as well as laboratories which operate in well-defined areas of R&D in the natural and applied sciences.