Reasons to Test

At Q-Lab, we often ask the question “Will Your Products Last Outdoors?” and respond with “Don’t Guess When You Can Test!” That said, what are the actual benefits of weathering and lightstability testing? Here are just a few:

Improve your product’s durability

Weathering testing has resulted in drastic increases in the lifetime of many important products. Take, for example, automotive coatings, where weathering testing has supported developments leading to over a 100% increase in product lifespan.

Save on material costs

The right materials selection can have a crucial impact on product performance – and your bottom line. How much would it save you if you bought raw materials that were 10% cheaper and your performance was unaffected? Proper materials selection can save hundreds of thousands of dollars in some cases, and weathering testing gives you the confidence to make the right choice.

Avoid catastrophic field failures

On the other hand, how much would it cost you if you bought 10% cheaper raw materials, but it made your product fail in service? Lawsuits and large-scale warranty claims can be very damaging to a company’s profits and reputation. Testing helps avoid such mistakes.

Many more!

Weathering and lightstability testing can help you meet customer specifications, enhance your marketplace reputation, verify supplier claims, expand your existing product lines, enter new markets, outpace the competition, and stay ahead of government regulations.

Test Types

It’s important to understand that not all weathering test types have the same goals. A test program should be developed with a clear understanding of what knowledge is critical to gain. The testing matrix below shows different categories of testing from simplest to most complex:

Most weathering testing, at least to begin with, is quality control testing – short, defined screening tests for fixed time intervals that generate pass/fail results. This is closely related to qualification or validation testing, where a customer’s specification needs to be met in a test in order to gain acceptance. Correlative and predictive testing require outdoor data and therefore are part of a broader test program. Correlative testing uses outdoor data as a reference to “rank order” specimens in lab testing – in other words, to determine which are the highest performers and which are less weathering-resistant. Predictive testing gives estimates of service life based on lab results, but is highly material-specific, test-specific, and failure mode-specific, and requires lots of outdoor test data.

Correlation

The most common question we receive at Q-Lab is some variation of “how many hours in an accelerated weathering tester corresponds to (5, 10, 20) years outdoors?”

The short answer is that there is no simple, general relationship between laboratory and accelerated weathering testing. The problem is not that we just haven’t developed the perfect weathering tester yet. No matter how sophisticated or expensive you make your weathering tester, you still won’t find the “magic number.” The biggest problem is the inherent variability and complexity of outdoor exposure situations, including geography, weather variability, service environment, test conditions, and many more. Reciprocity, the concept that an increase in irradiance intensity leads to a proportional decrease in test time, typically does not hold. Additionally, simply comparing tests by the amount of radiant dosage can lead to errors, especially for light sources with different spectral characteristics.

However, the rank-order data that can be generated by a comprehensive outdoor and accelerated weathering test plan is extremely valuable information that can tell you a lot about product durability. At Q–Lab, we’re here to help you get the most out of your testing program with the least possible hassle: it’s why we say that We Make Testing Simple.