Archive for July, 2015

Accelerated weathering correlation statements – A risky marketing strategy.

An initial enquiry for UV testing goes something like this:

Dear Accelerated Weathering Laboratory Ltd.

Our marketing department has requested our literature should state that our product is capable of withstanding 2 years outside exposure without significant fade. We believe our products are photo-stable over this period so we require an accelerated weathering test programme to prove this.

As 500 hours exposure is equivalent to 1 year outside, please would you quote us for 1000 hours exposure in accordance with BS EN ISO 4892 part 2. Your test report should state that our mouldings are photo-stable over a min period of 2 years if they have a dE shift less than 2.


Fudgit and Bodge Mouldings UK Ltd.


Now………. There are no short answers to this one without going into ‘geek mode’ so please accept my apologises and find the actual reply from AWL by return email below:


FAO Mr Fudge and Mr Bodge.

Thank you for your enquiry concerning accelerated weathering testing.

I am concerned you have made a definitive correlation statement regarding accelerated weathering tests and real time correlation.

At the set point irradiance level, BP temperatures and humidity levels of ISO 4892-2 I do not agree with the 500 hours = 1 year statement. Our experience with many different materials suggests correlation to be in the region of 1000 – 1500 hours depending on geographical location and local climatic conditions.

Please be aware that correlation statements in marketing literature should be used with extreme caution and that AWL Ltd would NEVER underwrite such a statement. If you do decide to take this route, please ensure you include a robust disclaimer!!

 It is our view that colourfast / photo-stability performance statements should be based on the test cycle, the exposure period and acceptance criteria usually based on dE shift and / or ISO 105 grey scale assessments.

 For example, Product X – Weathering performance standard is: BS EN ISO 4892-2 : 2012 – Cycle 1 – Method A – 1000 hours – dE shift <2 / ISO 105 A02 = 4 max. These are preferred ‘Performance Standard Statements’ recommended by AWL Ltd and similar is required from the BBA.

 AWL can provide a full explanation / interpretation of the above statement if required.

We can quote you for a 1000 hour test, but we cannot make any statements within the test report regarding +2 years of guaranteed photo-stability.

Sorry to be so negative, but I would not be doing my job properly if I do not make you aware of the complexities of accelerated weathering and the dangers of litigation using real time weathering correlation statements for products going into the marketplace during this contract review discussion.


Kind regards,

Paul Edwards.

Technical Director

Accelerated Weathering Laboratory Ltd



My response was a bit ‘War & Peace’ but hopefully it will educate those new to accelerated weathering in terms of its limitations and how best data can be used.

It is our view that any test house making correlation statements should only be doing so as a guide for costing advice and NEVER FOR warrantees or marketing literature statements.


Disclaimer: Although our email response was real, the recipient company name and personnel are fictitious to protect the innocent (just to show that although I can turn into a geek I still have a sense of humour which is important in this business). Any similarity to a company called Fudgit and Bodge Mouldings UK Ltd is by unfortunate coincidence only. No plastic mouldings or marketing people were harmed during the publication of this newsletter. Smile PJE.


Taber abrasion data from AWL Ltd verifies improved wear resistance of new flooring lacquer.

You know what it’s like. A lacquer manufacturer provides marketing literature or statements over the phone suggesting their product is harder wearing than the competition.

The question that should be asked is ‘On what data do you base that statement?’ Upton Wood Flooring based in Oxfordshire showed due diligence by asking AWL Ltd to provide independent testing to establish the relative wear resistance of 3 lacquers from different manufacturers on their wood flooring samples and they were in a desperate hurry for results!

Upton contacted AWL Ltd on a Monday for initial contract review discussions and it was clear test protocols were not available and a starting point needed to be established by AWL Ltd.

Despite this lack of information, they needed to be going into production with the best lacquer by the end of that week!!

To that aim it was agreed that prepared samples were to be delivered by hand to AWL on the Tuesday.

Testing was carried out on the Wednesday using our experience to provide the correct choice of abrasive wheel, load and number to cycles to prevent wearing through the lacquer during the test.

Results were completed, reviewed and reported in accordance with ASTM D4060 on the Thursday and the data was conclusive.

Production of flooring protected by the best lacquer took place on the Friday as scheduled with added confidence the correct choice had been made.

Upton Flooring were happy to say the least, and AWL Ltd were pleased to have helped.


Accelerated Weathering Laboratory Ltd celebrates its 10th year of Materials Testing

As AWL Ltd celebrates its 10th year in business with year on year steady growth in terms of turnover and profits, I would like to take this opportunity to thank all of our clients, both UK and overseas for their continuous business and support.

I would also like to thank our small team of dedicated staff who have provided the efforts required to maintain this growth by response to demand in a timely and efficient manor in accordance with our ISO 17025 / ISO 9001 quality systems and policies.

I would also like to thank our key suppliers for their support over the past 10 years.

Paul Edwards, Technical Director, Accelerated Weathering Laboratory (AWL) Ltd.


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