A smart Q standard

F or us consumers, it is now taken for granted that a kilo of potatoes weighs the same in the farm shop and in the wholesaler, and that every time I see 20 litres at the petrol pump, 20 litres have also gone into my tank. As blameless citizens, we rely on the fact that foodstuffs comply with the permissible values and, if we are stopped by the police for exceeding the speed limit, the corresponding measurement is correct and lawful. However, it cannot be taken for granted that measurements and readings are correct and comparable with other readings on the same thing. This is because there is a complex, and above all political, process behind this.

Regulatory environment

In the 18th century, for example, the cubit was a common measure of length, which varied in effective length according to region and dominion. According to today's unit of measurement, a cubit was approx. 60 cm. These approx. 60 cm were, for example, 597 mm in Zofingen, 548 mm in Rheinfelden and 628 mm in Lucerne. The basis for the fact that for us today 1 metre in Zurich, New York or Tokyo is exactly 1000 millimetres was laid in 1875 with the Metre Convention. This is also when the International Bureau of Weights and Measures (BIPM - Bureau International des Poids et Mesures, in Sèvres near Paris) came into being. This is the place,

Einheitensystemgeschaffen

where the original kilogram is still kept today and used for comparison purposes with national copies of the kilogram. (Image 1)

It finally took until 1960 for the system of units (SI) valid today to be created and seven units of measurement to be defined: Meter, kilogram, second, ampere, kelvin, mole and candela. The traceability of measurements to the SI units and, for example, to the original kilogram in Paris, is the task of the national weights and measures offices. Their work can be seen, for example, in the calibration marks affixed to petrol pumps at petrol stations or to the vegetable scales at retailers. (Figure 2)

We owe the latest historic step to increasingly global trade. The need for testing of cross-border trade products has grown extremely. With the aim of dismantling corresponding technical barriers to trade and the signing of a corresponding treaty under international law (GATT/WTO Agreement), accreditation gained worldwide significance. The foundation stone for the Swiss accreditation system was laid in 1985. The start was made in what was then the Federal Accreditation Council.

Accreditation - a proof of quality

the German Office of Metrology. The bodies accredited in the second half of the 1980s received recognition primarily for safety tests within the framework of CE marking. For the consumer, this process is particularly visible in electronic products. (Figure 3)

ISO 17025 and accreditation

Accreditation is a legally defined procedure. Bodies and in particular calibration and testing bodies are checked on the basis of defined criteria and, if all criteria are met, receive official recognition. The corresponding criteria for testing and calibration bodies are defined in SN EN ISO/IEC 17025.

This means that a procedure is now available which enables a large number of competitors to participate in legally defined tests on the basis of officially recognised competence. Currently, around 440 testing bodies and around 90 calibration bodies are accredited by the Swiss accreditation body in Switzerland. Interestingly, the recognition procedure is used mainly by bodies in the non-regulated area, i.e. it is used voluntarily, so to speak. An accredited body is authorised to refer to the special recognition in its reports with a protected label.

Management content of the standard

A first central element is that accredited facilities are managed in accordance with ISO 17025. This refers to the systematic structuring of work processes and the equally structured assurance that these processes are effective and that those concerned perform good work within these structures.

The element of management is a function independent of execution and administration. A very clever feature of this ISO 17025 is that it has built in the structured assurance of the procedures and also requires it as mandatory. Thus, it should be self-evident for an accredited institution that it regularly checks itself whether it also follows the specially established work procedures. This is called internal auditing. And it should also be ensured that following one's own rules also has the desired effect on the market, on customers, on employees, etc. This process is called a management review.

A second central element is that an accredited institution maintains a formalised management system. This system represents the guidelines of the management in the form of orientations, directives, regulations, etc. in words, pictures and symbols. An explicit function is designated for the maintenance of this system: the quality manager. The holder of this function ensures that the guidelines are entered into the system in an orderly manner, that they can be found again in the system, that they do not contradict each other, and that they are coherent and up-to-date, which is also called document monitoring and control. As a rule, the quality manager also has the special knowledge to assess conformity with ISO 17025 and can therefore also ensure that the internal specifications also cover the standard requirements. With such a system, everyone can orientate themselves according to their function, at any time and with the certainty that the information and the specifications are well thought out and up-to-date.

Technical contents of ISO 17025

The third central element of the standard content concerns the technical

BindingTransactions

execution. According to ISO 17025, the accuracy and comparability of a measurement are based on competent personnel, validated measurement procedures and reliable facilities/equipment. Competent personnel know what they are doing, work in a comprehensible manner and, as a rule, according to standardized procedures. Of particular importance is the traceable and in this sense also reproducible work. This is the only way to ensure that the quality level is recognisable and can be sustainably adjusted to the required level.

A measurement procedure is considered validated when there is practical and written evidence that the procedure actually measures what it is intended to measure. Such evidence provides information, for example, on how accurate the method is in its application. If, for example, the aim is to determine the proportion of gold in a precious metal alloy, much higher demands are placed on the accuracy of the method than if the aim is to measure cadmium in industrial waste water. In the case of the gold alloy, a measurement inaccuracy of 0.5 per mil can be tolerated; in the case of the wastewater, a good ten percent can be tolerated - i.e. a tolerance greater by a factor of 200.

Providing experimental evidence that a procedure has the accuracy required by the customer is very demanding and is part of the core competence of an accredited facility. Facilities and equipment are reliable if the users understand their operation and they are maintained according to the assigned purpose. The maintenance specifications include, in particular, calibration and the traceability of the measured values of instruments to the internationally defined measurement standards (SI), which ultimately brings us back to the starting point. Accredited testing and calibration laboratories trace their measurement results back to the internationally recognised standards using appropriate reference means, i.e. to the original kilogram, for example.

Effect of the standard - two examples

Bachema AG in Schlieren is a private laboratory for chemical and microbiological analyses of environmental samples (water, soils and recyclables). (Fig. 4) Bachema was first accredited in 1994, and since then the laboratory has been continuously working on ISO 17025. Microbiologist Dr. Annette Rust explains what this long-term involvement has brought about: "Thanks to the initial accreditation, we have written down our analytical procedures as standard operating procedures (SOPs) and thus structured and secured this knowledge. In the second accreditation period, all methods were revalidated, which provided broader support for technical expertise. In the third five-year period, we worked on the traceability of all actions from the client order to the results report. This strengthens trust and makes it possible to learn from small mistakes. The 'paperwork' (document management, updates in subordinate regulations, plans, etc.) was sometimes perceived as tedious. However, once a practical, tailor-made system of control and approval had been developed, the gain in quality and efficiency quickly became apparent. Today we can say that our company has benefited from a comprehensive management system, which has been designed for the developments of the

Sophisticated and competent

last few years has been and will continue to be a valuable tool."

The Biomechanics Group of the Institute of Mechanical Systems (IMES) at the Zurich University of Applied Sciences (ZHAW) in Winterthur received its recognition in January 2010 and is comparatively young as an accredited body. It specialises in developing and testing physiological implants (colloquially: body replacement parts). The fact that corresponding tests can be used by customers for their CE marking of products has prompted the Biomechanics Group to seek accreditation according to SN EN ISO/IEC 17025.

According to Prof. Maja Bürgi, the laboratory has developed from a "tinkerer's standard" to a professional test laboratory in which a standardised development process leads to high-quality test methods. It was thus able to massively increase the reproducibility and repeatability of investigations. The planning of examinations and their execution became more efficient and of better quality, which greatly reduced the number of failures and faulty examinations. This professionalism is also reflected in the education of the students. Their project, bachelor and master theses now reach a completely different level, which in turn benefits future employers. (Figure 5)

Appreciation

With SN EN ISO 17025, in conjunction with the state-regulated recognition procedure, it has been possible to extend confidence in testing far beyond the state verification bodies. Moreover, if one considers the effect of the discussion of the standard at accredited bodies, the confidence that has arisen is also fully justified: SN EN ISO 17025 is a truly smart standard.