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Avoiding the 'over-testing' trap

25 June 2013

The benefits of testing products are obvious, but tests are often duplicated unnecessarily just to ‘cover all bases’.

This 'over-testing' may reflect customers' poor understanding of the intended environment and the specifications used to qualify a need for testing. Jean-Louis Evans offers some guidance to those about to embark on a product testing programme.

It is a fact that many designers and manufacturers err on the side of caution and often over test their products due to a lack of understanding of the conditions under which the product will be used and uncertainty as to the specifications used to qualify the need for testing in the first place. This not only wastes money through unnecessary testing costs, but occasionally slows the process for launching new products into a competitive market. 

Contractual requirements often mean that the designer or supplier of a product is obliged by their customer to undertake particular tests. However, always bear in mind that this does not mean that those demands should not be refined or challenged as there are many considerations that should first be taken into account before embarking on a set of expensive tests.

Firstly, it is important to check whether the product in question has been tested to another specification. As there are a huge variety of tests and standards that have very similar specifications, taking a ‘read across’ approach may be appropriate. This is where test specialists compare two standards, identify where they differ and create an argument for partial testing or not testing at all. 

It is also vital to consider if the product in question is very similar to others that have already been tested, as a qualification by similarity may also be possible in this situation. If there is much similarity between the current and a previous product, it may also be possible to ‘read across’ from the previous product’s test results to avoid some re-testing. For example, this would apply to product upgrades where it is the same product but with some additions. 

Also, if an existing product is sold into a new market, do not ignore the value of good field evidence of where it is currently used. While it may not satisfy a very particular requirement in a completely new market, such as a significant change in temperature from its current use, it may have some value and a new customer may even be willing to accept that record as proof.

Even if a product is vastly different from a previous model there may be constructional similarities which could reduce the requirement for embarking on specific tests such as contamination. This could be the case where the materials used are the same as those on previous products. If this is the situation there will be no need to run the very specific requirements of contamination testing again.

Likewise, if the material’s performance characteristics are already known and are intrinsically resistant to the known contaminants and their conformance can be proven, there may be no reason to test. An example would be the fact that we know plastics do not rust when they get wet!

It is also important to consider if combined tests satisfy two requirements. For example, an altitude test may satisfy both an altitude and a temperature requirement, thus significantly reducing test times and laboratory costs. Where there is already confidence that the product is sufficiently robust, storage and operational tests may be combined as a sequence, offering a reduction in time over the tests performed individually.

If it transpires that your product does require testing, very often the duration of tests can also be cut to reduce costs. Historically, climatic tests were run overnight starting at 5pm and ending at 9am, so a 16 hour dwell time soon became the standard. If a product stabilises more quickly why would you pay for unnecessary laboratory time? A stabilisation time of two hours is now accepted and is the commonsense approach unless the sample is large or bulky.

Product testing passport
Often, manufacturers test their products repeatedly to similar, but slightly different, standards in order to meet country specific requirements. The CB Scheme is the world's first international system for the mutual acceptance of test reports and certificates for electrical and electronic components, equipment and products. It does not completely eliminate the need for additional ‘in-country’ approval or testing, but will get manufacturers 85 percent of the way there. 

The CB Scheme reduces significantly the need for duplicate testing, is operational in over 50 countries, and is being used by more than 15,000 manufacturers worldwide. Many countries will now accept CB Test reports and certificates without the need for local certification.

The ability to carry out one test programme, in effect to gain many national marks faster and at a lower cost, surely means that more should be taking advantage of it. Frequently, initial testing requirements can be flawed because of:

Poorly understood environment – while the customer is aware of the intended environment, they do not necessarily capture all of the environments for every possible use, often concentrating on operational environments and neglecting transportation.

Poorly defined test requirements – the test standards and methods that are defined by the customer show a misunderstanding and tests are incorrectly specified. 

Exaggerated test parameters – there is always a temptation to be ‘safe’ with test parameters, involving rounding up and adding safety margins. Be sure that this has only happened once, not once for each person involved!

When a customer for your product demands that certain tests are done, it is advantageous to reassess if they are required, or determine if they can be reduced. Most importantly, first check that the standards relating to the product have been interpreted correctly.

Also, do some research in order to assess what testing has already been performed, and look for similarities with other products. If you do have to test, you can often save time and money by investigating ways to combine tests and reduce test durations wherever possible. 

By making an investment in time and thought at the outset of a testing programme, and considering some of the advice outlined above, you could find that you will make significant long-term cost savings, as well as being in a position to release products more quickly into the marketplace, thereby staying one step ahead of the competition.

Jean-Louis Evans is managing director of TÜV SÜD Product Service and at its sister company, TÜV SÜD BABT, a radio and telecommunications certification body




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