Testing Times With Bonkers Conkers

Finishing Articles - Testing and the Finishing Industry

Malcolm Griffiths looks at how testing is becoming more important in the finishing industry. Since joining the paint industry in 1963, Malcolm has worked for several leading coating manufacturers. He is a graduate in chemistry, Fellow of the Institute of Metal Finishing and a Chartered Member of the Institute of Occupational Safety and Health. He now runs the independent coatings advisory service Ad Qual Castech

We have been heavily involved in testing recently; from VOC concentrations in paint waste, environmental stack emissions or fugitive losses to evaluating product performance, process parameters and analysis of coatings. There are a wide range of tests out there to chose from – many of them overlapping and duplicating (or perhaps almost duplicating) each other. The International Standards Organisation is instrumental in developing universal standards but it can take a long time before those replace the national and industry versions.

Test methods are important because they allow us to measure and compare the properties and performance of samples, to evaluate new materials offered to us and to compare them with proven ones. They also allow us to assess our raw materials and end-products for quality and performance, against preset values, and to use that data to underwrite claims we might wish to make for the performance of our products.

Hand-made products can be inspected for faults on an individual basis but mass-production allows us to make things (including scrap) at a very fast rate. To minimise scrap and maximise production, we need to be sure of our equipment, our materials and the techniques we use. Standards are what help us to keep the products rolling off the line. But have you ever wondered how the standards came about?

When I first started in a coatings laboratory, we used to carry out tests on every batch of raw material that arrived. Those tests may have been developed by a particular company to suit its own needs but a good test soon spreads, usually via the supplier, who would then begin to use it to monitor their own products. Trade associations would often rationalise these tests so that eventually they became industry standards.

To be of any use, a standard test needs to satisfy certain basic criteria. It must be repeatable – i.e. if I do the same test several times, I can achieve a reasonable correlation between the results. It must be reproducible – i.e. if someone else does it on the same or a similar sample elsewhere, they must be able to achieve a similar result. Obviously, tests must also be relevant to the case in hand and should not be prohibitively expensive to carry out.

There are a few points that would-be users often miss. Many of the performance standards only describe a controlled method of testing. They do not necessarily define pass / fail levels. Usually it is left up to the interested parties to decide what the acceptable level is for their particular product and end-use. Further, it is not always possible to relate test results to performance in service. Useful examples of this are the various types of accelerated weathering tests and the pull-off adhesion test.

We are often asked how long a product would last outside, if it had survived (say) 240 hours in neutral 5% aqueous salt mist without significant corrosion. It is not possible to directly relate these test conditions to the various and varying conditions encountered by a product during service. The only way is to already have sufficient experience of the real-time performance of similar products to be able to extrapolate the test results. Similarly, with the pull-off test, is a pull-off force of 3 Mpa good or bad in a given system? One has to have carried out a large number of similar tests to be able to give a rational decision.

There are a few standards that actually relate levels of test performance to durability in the field. For example ISO12944 describes categories of corrosion resistant coatings and is very useful when considering steel structures.

A specification may need to cover aesthetic factors such as colour and appearance, and in-house processing requirements as well as service conditions.

We recommend that tests are carried out in triplicate and preferably with a ‘benchmark’ of some sort – i.e. a product about which we already have a good knowledge of its performance in the test and / or in service. The use of a benchmark is hopefully obvious but some may question ‘why three samples?’ A single sample may be a random result. If all three samples pass, we would naturally assume all is well. In general, if only two out of three samples passed, we would consider that the product was okay but that there may be a potential processing problem. After all, you can always make a good system fail but it is far more difficult to make a poor system pass.

Bonkers Conkers

You may have noticed that, although this edition of Finishing has highlighted Health & Safety issues, in this article I did not immediately jump into the topic. I thought I would save this till last. The Health & Safety Executive (HSE) and the Commission (HSC) have linked up with the Institution of Occupational Safety and Health (IOSH) in an attempt to counter the more wacky health and safety stories that appear in the media from time to time and so undermine their strategies. They refer to these stories as ‘Bonkers Conkers’ because of a particular incident in which, I understand, a headmaster (fearful that his school might be sued if anyone were to be injured) insisted that all children playing conkers must wear goggles ‘for health and safety reasons’. Well, it was silly, wasn’t it?

The people who use health and safety as an excuse for their administrative decisions do us no favours at all. In fact, they bring safety into disrepute; they make it a laughing-stock when it is actually one of the most important factors - if not THE most important - at work.

In their counter campaign to ‘set the record straight’, the HSC and IOSH push the view that it is risk aversion that is the real problem and that insurance companies, the media and a general lack of knowledge are the real cause of that. They may have a point but could it also be aggravated by the way in which the HSC has extended employers’ responsibilities under the Act to include what many consider to be social ills, such as obesity and stress. The HSE publish statistics showing that, when asked, company directors agree with the laws. Would you tell them you disagree?

The HSC and IOSH have a good point in many ways, since too many people use the excuse of health and safety as the reason for banning something or other. I read a nice example of that about two years ago, when a police chief in Kingswinford, Staffordshire decided on ‘health and safety grounds’ that a troop of old soldiers from WWII could not march the half a kilometre from the local British Legion to the war memorial. It was interesting to see that Chief Inspector of Constabulary, Sir Ronnie Flanagan, this week issued a report that the Police were too risk-averse and bogged down with tick-box forms and bean-counting. Sounds familiar. The trouble is that, although HSE suggest safety is not about paperwork, the insurers want written records, to prove that companies have taken reasonably practicable steps.

Most people look aghast at the awards arising from claims on health and safety grounds. For example, a recent case involved an award of nearly £500,000 to a typist who had suffered a muscular skeletal disorder (‘a strain’ to you and me) to her thumb as a result of typing. Some managers to throw up their hands in horror and could then end up making silly, over cautious, defensive decisions.

However, even though it is 33 years since the Health & Safety at Work Act came into force, few companies have managed to engender a real safety culture. Many haven’t produced a coherent policy, let alone risk assessments. Employees are often duplicitous in their approach to safety. They may agree that it is a very good thing to have the protection of the Act but actually obeying the rules? Well, that’s a different matter.

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