The importance of a national measurement system

04 May 2021

Dr Martin Hanton highlights the importance of flow measurement accuracy in the energy sector which makes traceability, along with supporting documentary standards and regulatory regimes vital.



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National Measurement Systems (NMS) are a network of laboratories and processes that provide measurement standards, traceable calibration and testing facilities. Usually covering a broad range of specialisms – including physics, engineering, chemistry and biology – they support many sectors, such as manufacturing, energy, environment, life and digital sciences. 

The constituent laboratories or organisations within an NMS are known as National Measurement Institutes (NMIs) and Designated Institutes (DIs), and they are crucial to supporting commerce within a nation and trade with the wider world. Essentially you cannot sell or trade, what you cannot measure accurately. Get measurements wrong and commerce is ultimately affected, alongside tax revenue of course.

An NMS is particularly interested in the production and refinement of technical standards. By ensuring proper procedure and technical excellence, while keeping a fair and unbiased approach. Techniques and procedures are clearly defined to allow a common level of quality, foster good practice, present a training structure, and guide users to maintain the growth of science and technology with metrology at its heart. When the technical aspects are combined with legal metrology, this leads to the foundation that underpins measurements for trade and market confidence.

Beyond the national boundaries of any NMS lies the international community of metrology organisations. For example, the Bureau International des Poids Mesures provides the basis for a coherent system of measurements and units throughout the world. NMIs are part of this international community, which expands their remit and influence. For regions of the world which do not support a common system, then a Mutual Recognition Agreement can be reached, whereby the different national standards are balanced, and equivalent merits are identified. Again, this facilitates international trade and universal standards. 

Measurement traceability plays a vital role in national infrastructure as it is the technical proof (normally through calibration records) that a measurement device has the appropriate pedigree and can be traced back to a national standard. This forms the pyramid of traceability. Note that the accuracy is improving, commonly by a factor of ten, through each level in the pyramid until the top is reached. If traceability is overlooked, then there is no impartial verification and the chain is broken. This results in measurement disputes, arguments or even conflicts. It is therefore the unbiased proof of measurement traceability which underpins agreement in transfer of products, boosts confidence and stabilises markets.  

A critical measurement
Flow is an example of a critical measurement which appears in many areas of any NMS. Understanding, monitoring and controlling flow rate, as part of industrial processes, are essential elements to the viable operation of production systems across numerous sectors. This can range from the infusion of medication to operation of oil and gas platforms.  

With decarbonisation now high on the agenda, flow measurement will be a critical technology to the use of hydrogen and carbon capture, utilisation and storage (CCUS). However, unlike basic measures, flow determination is a derived quantity. Several measurements are now required – mass, time, temperature, pressure, fluid properties, and others. Each of these quantities need their own calibration pedigree, so full traceability of a flow meter requires an extended family of pyramids. If a single term is mismeasured then the error propagates through to the final combined result. Flow metering tools and technology are therefore continually improved through application of a wide range of metrology considerations.

Flow measurement is an enabler of trade and commerce in many sectors, but most especially energy. With flow meters being viewed as the cash registers of the oil and gas industry today, they will equally be the cash registers of a decarbonised economy based on hydrogen and CCUS tomorrow. And reassuringly, European National Measurement Systems have been working behind the scenes for some years to ensure that the measurement traceability, along with supporting documentary standards and regulatory regimes, will be in place to support this.

Dr Martin Hanton is technical director at TÜV SÜD National Engineering Laboratory.


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