A Beginners Guide to Metrology
The very first thing that anyone should know when it comes to metrology is that it is not a typo of “meteorology,” the science of climates. Metrology is the science of measurements. Metrology began in France, as an outgrowth of the French Revolution’s desire to standardize units of measurement. Come 1795, the metric system came into existence. While several other countries felt that the metric system was worth transitioning to between 1795 and 1875, a central organization, the Bureau International des Poids et Mesures (BIPM) came into being. One century later, in 1960, the BIPM would help to establish the International System of Units (SI) which dictates the baseline measures for everything measurable, from temperature, to mass, to distance and so on.
The science of Metrology is broken up into three major sub-fields.
- Scientific (Fundamental) Metrology. This discipline is focused on defining what a unit of measurement is.
- Applied Metrology. This discipline is focused on applying agreed upon measurements in non-theoretical, actual uses. This sub-field is also known as Technical or Industrial Metrology.
- Legal Metrology. This discipline is focused on connecting measurements to their reference standards and ensuring that they are properly regulated.
Every country has a national measurement system of accredited labs and facilities to keep track of its metrology infrastructure. These systems discern how something is measured within the country and how those measurements are handled in countries beyond their own borders. While it may seem unimportant at first glance, metrology has a massive effect at all levels of a society, from economics and trade, to energy usage, the environment, manufacturing procedures and even health issues.
Two major elements to metrology are traceability and calibration. Both of these factors are of primary concern to legal metrologists.
- Traceability is the ability to find the source of a measurement in order to cite it for the purposes of calibrating instruments to that measurement. Traceability begins with industry and trade laboratories, travels up the “pyramid” to calibration labs for verification, then moves on to a nation’s metrology institute and stops at the international standard.
- Calibration is closely related to traceability and is concerned with ensuring that weights, scales and other devices are properly calibrated to assess the relevant measurement, such as how scales are used to gauge the weight of an object or thermometers are used to sense the temperature of something. Tracking calibration flows in the opposite direction to traceability, coming from the top of the metrology pyramid, the international standard and passing down through most nation’s measurement institutes, calibration labs and stopping at the many different industries and trades relevant to those particular measurement units.