Choosing a test laboratory

Some of the basic criteria to consider when choosing a laboratory.

by Austin Simmons

Footwear and leather goods technologists often rely on test reports to help them assess whether products meet appropriate specifications. It is, therefore, essential that the test house used operates to a high level of quality assurance and has members of staff who are capable of understanding the nuances of specifications and test reports.

Conducting appropriate tests on a product is an important step in demonstrating compliance with a specification or safety standard. In many cases, retailers, distributers and sourcing companies rely on their suppliers to provide results from third-party laboratories. While many purchasers will designate the laboratory to be used via an approved list, others will accept the supplier’s own preference.

It goes without saying that a good test house must be competent, accurate, efficient, customer-focused and competitive. While some of these attributes become apparent relatively quickly, the quality and accuracy of testing and the provision of correct results may not be so obvious.

In terms of routine testing, most commercial laboratories today will have some form of third-party accreditation. Laboratories engaged in more specialist or non-routine testing do not always follow this route, and there are a number of highly competent organisations that do not follow the formal accreditation route.

However, for technologists looking for simple pass/fail routine testing, confirming that their prospective supplier is ISO 17025-accredited should be a prerequisite before submitting any samples. Equally important is to confirm that the actual tests required also fall within the accredited scope.

International quality standard for laboratories

So, what is ISO 17025? Its full title is ‘EN ISO/IEC 17025:2005: General requirements for the competence of testing and calibration laboratories’, and it is the internationally-accepted quality standard for testing and calibration laboratories. ISO 17025 can be considered as the laboratory equivalent of ISO 9001 – the international quality management system applicable to manufacturing and service industries.

First published in 1999, the ISO 17025 standard was revised in 2005 to provide an increased emphasis on the responsibilities of senior management. The revision also included explicit requirements for continual improvement of the management system itself, and particularly customer service.

As expected, the standard concentrates on the operation and effectiveness of the quality management system, as well as the reliability and correctness of the results. Competency and impartiality are to the fore.

Stringent standards

ISO 17025 is the latest in a series of standards designed to help testing laboratories operate to high standards of accuracy, reliability and consistency by ensuring that the following main aspects are covered:

• fully documented systems (see figure 1)
• clearly defined responsibilities
• a controlled laboratory environment
• comprehensive training of personnel
• test method control
• equipment maintenance and calibration
• control of reference materials
• action in respect of suspect test results
• traceability of testing work (see figure 2)
• accurate reporting procedures
• retention of work records and test samples
• regular review of laboratory operation
• regularly-sought feedback from customers
• continual improvement.

All these aspects must be subject to regular audit – both internally by the company running the laboratory and externally by an independent and authoritative body. Only by this means can the laboratory demonstrate its commitment to ensuring that the quality of the testing operation is of the highest possible standard.

Accreditation

Accreditation to ISO 17025 by a reputable accreditation provider demonstrates competence and independence. Many companies in the supply chain will accept test reports only from an organisation with this status.

SATRA's own testing laboratories have been accredited to this standard for many years by the United Kingdom Accreditation Service (UKAS), which acts on behalf of (but is independent from) the UK government. However, members will be aware that prior to the publication of ISO 17025, SATRA’s testing laboratories had been accredited for 20 years to EN 45001 – the forerunner of this standard.

SATRA's current schedule of tests covered by ISO 17025 accreditation can be found on the UKAS website. SATRA can, of course, also carry out many non-standard tests, and is continually developing unique test methods for the footwear and leather goods industries – many of which are unavailable anywhere else.

The International infrastructure

UKAS accreditation is recognised throughout the world via the international accreditation infrastructure. The global accreditation system operates through regional blocks. In Europe, this is the European Cooperation for Accreditation (EA).

At the global level, accreditation is divided into two groups: the International Laboratory Accreditation Cooperation (ILAC), and the International Accreditation Forum (IAF). The decisions of these organisations determine the nature of the accreditation that UKAS and its equivalent bodies in other countries offer. The ILAC and IAF have established international arrangements, based on the mutual recognition of certificates and reports issued by conformity assessment bodies. These arrangements facilitate trade and create a platform on which ‘accredited once, accepted everywhere’ is realised.

UKAS is a signatory to the EA Multi-Lateral Agreement (MLA), which is recognised at international level by the ILAC and IAF. This means that a test report or certificate accredited by UKAS is also recognised by the signatories to the IAF MLA and ILAC MLA. In this way, the EA MLA acts as an international passport to trade.

Benefits

Bringing a laboratory’s systems up to the standards required in ISO 17025 is not without considerable investment in staff, equipment and buildings. What benefits can this bring? There are many – including better accuracy, more consistency and improved customer focus to mention but a few. However, the major benefit is the ability to demonstrate to customers that the laboratory can provide them with a high degree of confidence that they are working with a credible, quality conscious organisation which provides correct test results.

In today's world, it is becoming increasingly difficult for any supply company to compete without demonstrating a commitment to providing a consistent, quality product. Testing laboratories are no exception. The product they supply is testing services, and the way they can demonstrate that their testing is a high quality product is to have independent accreditation to the known standard of quality – namely, ISO 17025. Just as manufacturing companies now find it more difficult to sell their product without an ISO 9001 quality system, so commercial testing laboratories will experience great difficulty in competing without recognition of their ISO 17025 capabilities.

Consistency of testing

In theory, all ISO 17025 laboratories with footwear- and leathergoods-related tests on their respective schedules are competent to test to those methods. A large part of the accreditation authority’s work involves trying to ensure that test laboratories across the world provide similar results.

This is easier said than done, and there are a number of important issues that mean that high-minded ideals do not always follow through in practice. Many tests must be carried out under tight environmental conditions – usually conditioning to set temperatures and humidities with close tolerances on variations. Prospective customers should always check that a laboratory is capable of meeting these conditions for both conditioning (where applicable) and testing – and should expect this to be detailed on the report.

While conditions may well be the same, there is considerable variety in the test equipment available to laboratories. SATRA makes a comprehensive range of test equipment which has been specifically designed to operate with SATRA test methods, and has been thoroughly assessed by its technologists and scientists within our laboratories. However, not everyone uses SATRA equipment and, while some other manufacturers supply reasonable equivalents, there are machines in use that fail to take account of all the detailed test method specifications. This immediately leads to variations in results that might not be noticeable to accreditation authorities, which often do not employ auditors with specific footwear testing experience. Rather, they usually rely on their more general laboratory testing experience on which to base their conclusions. This is before the calibre of staff members conducting the tests or the amount of training undertaken are considered. A number of commercial laboratories conduct SATRA test methods, but few have actually been trained by SATRA. This may not be essential for the simpler tests, but some of the whole shoe tests are more complicated and, moreover, it is often the interpretation of the result that requires considerable knowledge and experience.

Regardless of the equipment or staff skills available, all tests have an 'uncertainty of measurement' (UoM). This is often a difficult concept to understand and even more complicated to calculate accurately. 'Uncertainty' is introduced due to small changes in equipment performance when repeatedly testing the same sample, coupled with differences in the way the operator conducts the tests. A mathematical calculation is then carried out to estimate the ‘band’ in which the result is likely to be correct (on a probability of 95 per cent).

For instance, if a 'pass' is ≥4 and the indicated result of the test is exactly four, then due to the UoM it is not possible to be entirely sure if the sample passes the test. This is because the actual test result will always have to be 4 ± something, taking into account the previously-calculated small errors relating to machines and staff (see the article 'Why physical test results may differ between laboratories'). For safety-related tests, SATRA expects the result to be 4+UoM value to be absolutely sure it passes. In the past, court cases have been won and lost on exactly these very subtle points. A reputable laboratory will indicate its uncertainty values either on the report or on request.

Accredited laboratories are expected to undertake correlation exercises (often called 'round robin' testing). These are intended to provide confidence that individual laboratory organisations are achieving similar and consistent results. To be meaningful, the process needs to be well managed and tightly controlled. Correlation exercises are usually conducted at the laboratory’s own expense, and therefore the amount carried out and the quality of these can vary considerably between laboratories. Prospective customers can ask if the laboratory they are considering using for their testing is a regular correlation exercise contributor.

A further factor that affects consistency is interpretation of the test requirements. While most test methods are well written, there can be areas of ambiguity that need interpreting. Some regions have specific forums for laboratories to meet and discuss these problems, with a view to providing a common approach. However, this is not global and the less integrated in the standards-making process a laboratory is, the less likely it is to know about (let alone apply) any agreed clarifications. Probably the best example of organised forums is the European Union Notified Body (NB) Vertical Group and Horizontal Group committees. At these forums, groups of Notified Bodies agree and approve how to interpret a standard requirement, which eventually filters into the European standards body (CEN) standards revision process.

While some Vertical Groups publish details, others do not, so for European safety-related standards, SATRA would always recommend using only test houses with close links to Notified Bodies or who themselves are represented at these meetings. SATRA itself is a Notified Body and is represented on all the VGs and HGs associated with its accredited scope.

Technologists also need to ensure that the tests have been conducted exactly in accordance with the specification and standard. For instance, that all the required conditioning has been carried out, and that the correct quantities of specimens have been tested. Many tests should be carried out in triplicate or specimens taken from both shoes in a pair. Particularly for restricted substances testing, the sampling process can be critical to obtaining the correct result. If the report is not clear on any of these points, technologists should check with the provider.

Where do SATRA Accredited Laboratories fit in?

SATRA test methods are widely employed throughout the footwear and leathergoods industries. In addition, many manufacturers have in-house laboratories that have been provided with comprehensive training and assessment from SATRA though our SATRA laboratory accreditation programme.

While ISO 17025 is of most benefit to independent testing laboratories wishing to sell their services in a highly competitive market, it also has applications and benefits for in-factory quality control laboratories.

For smaller facilities dedicated to one production site and existing only to check the quality of incoming raw materials and the final product, the extra investment required to be fully ISO 17025 compliant may not be cost effective. For such laboratories, SATRA accreditation, based on the key ISO 17025 requirements but using our own quality standards, is seen as the most economic method with which to achieve a recognised quality level.

There are currently over 170 SATRA-accredited laboratories around the world. The full list, together with their schedules of accredited tests, is available to view by clicking here.

Comparatively few commercial laboratories have been accredited by SATRA. Therefore, most commercial laboratories offering SATRA test methods will not have benefitted from any in-depth SATRA training or explanation of the standards.

In conclusion

While there are a number of industries with specific quality standards and programmes such as the SATRA laboratory accreditation programme, ISO 17025 is the benchmark which most commercial laboratories use to demonstrate their competency. However, this must be backed up by accreditation from an official national body. SATRA has one of the largest UKAS accredited ISO 17025 scopes.

Although accreditation authorities work hard at providing a framework of consistency around the world, this does not guarantee that every laboratory will produce the correct results every time, and there can be a wide variation due to differences in equipment, training and interpretation. SATRA is confident in its knowledge and ability gained over nearly 100 years of testing footwear and leathergoods. However, members considering using other test providers are recommended to check their competency by confirming a particular test is on their respective national body accreditation schedule, and also visit the facility and meet the staff involved in the testing in order to make a personal assessment of competence. There is no substitute to seeing facilities first hand and checking that members of the technical staff have in-depth knowledge of footwear testing and requirements. After all, you may well be making significant commercial decisions based on the quality and accuracy of the results.

Publishing Data

This article was originally published on page 38 of the October 2016 issue of SATRA Bulletin.

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