UV Testing, or Solar radiation testing exposes the product to an intense ultra-violet spectrum to stimulate fatigue, aging and weathering. Products that are exposed to sunshine throughout their life will exhibit failure modes brought about by UV exposure. These failure modes can be screened and recognised during development by applying UV Testing.
UV Testing Vs Solar Radiation
Solar radiation consists, in addition to UV radiation, of visible light and thermal radiation. In fact, only 5 % of all radiation is UV radiation. UV radiation is the most significant factor in fading colours and mechanical weathering. However, other effects of solar radiation are left out from bare UV test.
UV Testing is typically conducted using a Xenon arc test chamber, these chambers typically are made for testing material samples rather than products. The sample size is stipulated at 150mm x 75mm x < 10mm thick and typically you would aim to test at least 5 samples in one lot.
UV tests durations are wide-ranging, for an indoor used product approximately 10 hours of exposure may be sufficient. For a building material you’ll want to make sure the samples attain at least 1,000 hours of exposure.
Solar radiation chambers on the other hand are made to accomodate larger samples, and have a slightly different light spectrum and temperature control than xenon arc chambers.
MIL-STD-810 is a common test standard used when applying solar radiation. There are two test methods – cyclic exposure and constant exposure. The duration of the test is determined by the client, we can help to provide advice and benchmarking information if needed.
Typical test durations for MIL-STD-810 solar radiation range from 48 – 500 hours and beyond.
How many samples should we test?
For UV testing you’ll want at least 5, for solar radiation it really depends on sample availability, as always more is better. One thing to note about both UV and Solar radiation testing is there is no accurate means to calculate field life from the exposure period. MIL-STD-810 attempts to provide guidelines for such a calculation, but in practice the unknowns of the end-use environment tend to derail any attempt to quantify UV or solar radiation damage.
For UV testing the following list summarises some of the available test standards you can apply:
- ASTM G155
- ASTM D2565
- ASTM D4459
- ISO 11341
- ISO 4892
For Solar Radiation refer to this list:
- DIN 75220
- IEC 60068-2-5
- EN 60079-0, Clause 26.10
- EN 60945
For further information, or if you have any questions, please contact us here.