Defining accelerated weathering for outdoor fabric
Compiled by Juli Case
The sales literature on the boat cover fabric I’m thinking of using has information on something called accelerated weathering. What’s that, and how does it relate to how long the fabric will last?
Assessing how a fabric is going to perform outdoors is a tricky business. Not only is there sunlight damage to consider, but also potential damage from rain, atmospheric pollutants and other environmental factors. If you’ve been in the trade for a while, you probably have a feel for how the fabrics you primarily use are going to weather. If you’re considering a new fabric, however, you’ll have to rely on information provided by the manufacturer, or have the material tested yourself.
There are two basic ways to test the weatherability of fabric—direct weathering and accelerated weathering. Direct weathering is real time testing. As the name implies, a fabric is placed outside under very specific conditions, and its performance is measured. This type of testing uses real world conditions, but it also takes time. Years, even.
Accelerated weathering takes place in equipment that has been designed to simulate outdoor conditions, but at a much faster pace. Accelerated weathering is much faster than direct weathering, but the conditions are simulated, rather than real. To make the matter more complicated, different types of equipment use different light sources—carbon arc, xenon arc and fluorescent UV—and have different ways of simulating rain. These can affect the outcome of the test. In the United States, ASTM and the American Association of Textile Chemists and Colorists (AATCC) are the primary writers of weathering testing.
What does this mean to you, as a fabricator? It can be difficult to correlate an accelerated weathering test to an anticipated lifetime of a fabric, although that’s something you can get a feel for as you work more with the various testing methods. Be assured, though, that this is something your supplier is aware of and is likely factoring in to the warranty for their product. Large shops that are OEM suppliers might be involved in actual testing. For most shops, however, it should be enough to be aware that there are different types of accelerated weathering tests; and to make the most accurate evaluation, make sure that the fabrics you are comparing have used the same kind of test.
