By Joseph James
Measurements play a very important role in our day-to-day lives in trade, industry and scientific laboratories. Almost an infinite number of measurements are made every day globally. The objective of measurement is to find out the quantitative value of a physical parameter depending on the level of sophistication involved.
What is metrology?
Metrology is defined as a science of measurements and covers the following:
· The definition of internationally accepted units of measurement i.e. metre;
· Realization of units of measurement by scientific methods i.e. realization of metre through the use of lasers;
· Establishment of traceability and disseminating of that knowledge and documenting the value and accuracy of a measurement, i.e. documented relationship between the micrometer in a precision engineering workshop and primary laboratory of optical length metrology.
Importance of metrology
Metrology is very important due to the following reasons:
· Ensuring barrier-free trade through the concept of “once measured, accepted everywhere”;
· Raising productivity through improved process and quality control;
· Contributing to the development of existing and new products and processes;
· Confident compliance with statutory and regulatory requirements;
· Improving quality of life of citizens by promoting confidence in health and safety;
· Measurements are related to conformity assessment;
· Measurements are necessary in compliance with written standards and regulations;
· Wrong measurements can mean that goods can be rejected.
Industrial metrology ensures the adequate functioning of measurement instruments used in industry as well as production and testing process (quality in industrial activities). It is concerned with calibration, which determines the performance characteristics of an instrument or reference materials, achieved by means of direct comparison against measurement standards or certified reference materials.
Calibration is a set of operations which establish, under specific conditions, the relationship between values indicated by a measuring instrument and corresponding known values of the standard equipment.
Why perform calibration?
· To ensure readings from the instrument are consistent with other measurements;
· To determine the accuracy of the instrument readings;
· To establish reliability of the instrument.
The role of industrial metrology in global economy
• To make products that meet specifications, i.e. customer requirements and standards.
• To ensure compatibility. In manufacturing and assembly, different vessels such as cars and aircrafts can be manufactured from different countries and the assembling can be done in a different country. For example, the new Airbus A380 is manufactured in four countries and assembled in France. The wings are being made at Broughton in North Wales.
The issue of compatibility also helps with spares and repairs. We can find spares of our cars, TV, computers and different machines which are compatible to ours, which makes repairing easier.
• Compliance with regulations and requirement for exporting, e.g. home laws and the European Union legislation.
• Improve production process
• Reducing scrap and cutting costs
• Testing hypotheses and verifying theories
• Determining fundamental constants
• Establishing consistency of results
• Measurements should be traceable to the SI
• Growth of technical regulations (health, safety, trade and environment)
• A need for validation of test methods
• Appropriate methods, procedures and standards are needed
Metrology is very important to doctors during diagnosis of illness, monitoring patients and delivery of treatments. Measurements in medical laboratory need calibrated reference materials and equipment for accurate measurement of chemical concentrations of substances in, for example, blood and other fluids and fields like drugs, biological qualities, natural substances in blood such as cholesterol. It is also key in the treatment of cancer, heart disease, kidney functions, etc.
When do we need measurements?
When size matters or when we pay for quality
When we consult doctors or attend hospital
When our actions are subject to legislation
When we buy gasoline
When we pay our bills for electricity and water, etc.
Joseph James is a Metrologist in the TBS Metrology Laboratory.