Made to measure - the NSAI metrology service to industry Print this article

Paul Hetherington on the vital statistics upon which modern technology depends

We all make measurements, every day of our lives: think how often you glance at your watch or your car’s speedometer. And we are surrounded by the outputs of measurement devices too, from the wind speeds on weather forecasts to the figures on gas bills.

Then there are all those behind-the scenes measurements needed to ensure that pills contain the doses they should, to prepare and package food and to check whether our environment is safe. Many of the measurements on which modern life depends are hidden. For instance, although the precise dimensions and electrical properties of the many components of your car or computer are of no interest to you, they make all the difference between functioning and failure. As a result of its importance, measurement has a science of its own, called metrology, from the Greek words metron (‘measure’) and logos (‘study’).

Main groups
Metrology can be sub-divided into three main groups: scientific metrology – the science of measurement, including the development and provision of measurement standards; industrial metrology – the application of measurement science to manufacturing and other processes; and, legal metrology – measurement activity underpinning fair trade and consumer protection.

For a very long time, we used units that were based on familiar things like feet. If everyone’s feet were the same size, this would be an extremely simple and convenient system. As they aren’t, a foot of a particular length had to be defined as a standard. Other units were treated in the same way until there were accepted values, used throughout the country, all of common unit.

A problem with this approach was that other countries also had units based on familiar things in their own country. This led to difficulties when these countries began to trade with each other. It became clear that it was essential that a set of units should be established that could be based on stable phenomena and that would be agreed internationally.

In 1960, the world agreed to adopt a single primary system of units, called the International System of Units, or SI for short. The System established a set of seven base units (metre, kilogramme, second, ampere, kelvin, candela and mole) and a number of derived units.

National measurement systems
As modern economies become more technologically advanced, they must rely more and more on the measurement systems that underpin their technologies.

A reliable national measurement system is required as part of the technical infrastructure. Such a system directly underpins manufacturing processes, facilitates innovation and supports international trading and exporting. It is widely recognised that a national metrology institute is a necessary part of the technical infrastructure of a developed economy.

A precise and reliable measurement system is of fundamental importance to industry, government and society. In Ireland, the body with responsibility for the national measurement system is the National Standards Authority of Ireland (NSAI). NSAI National Metrology Laboratory (NML) is the national metrology institute for Ireland and is responsible for the maintenance and development of the national standards for physical units and their dissemination to Irish users. It is located in a purpose-built laboratory, located off Griffith Avenue in Glasnevin, Dublin.

The measurement standards maintained by NSAI NML are the most accurate representations of the SI units available in Ireland and provide the gateway by which measurement results can be traced to the International System of Units (SI). Characterised reference standards, experienced staff and a carefully controlled environment ensure that low measurement uncertainties, suitable for calibrating the highest quality measuring instruments, are achieved.

NSAI NML provides measurement-related services in a range of quantities including: acoustics, electricity, length, mass, force, pressure, mass, temperature and humidity, time and frequency, and torque. In all of these areas, NSAI NML provides critical traceability to a wide range of industrial companies. The primary industrial sectors that use NSAI NML regularly include commercial calibration labs, testing labs, the medical device sector, pharmaceuticals and the food and drink sector.

Paul Hetherington is the manager of the Irish National Metrology Laboratory, NSAI – a position he has held since 1991. He is a member of the NSAI executive committee. He has previously served as EURAMET chair, and he is currently on the EURAMET board of directors. He has also served as a member of the board of INAB, the Irish national accreditation body. A physics graduate, Paul has worked in the field of metrology for over 25 years.