"Whether you have single samples or many samples we can conduct your testing."
Test Conditions & Durations
Clients often ask "how long should I expose my samples?". Both fluorescent tube type tests and Xenon arc type tests are accelerated laboratory tests. They expose the samples to a constant level of intense UV light combined with heat and moisture to produce an acceleration over normal outdoor exposure. Therefore any time tested in the laboratory will be equivalent to a much longer time outdoors.
The majority of test standards do not specify the test duration and this is often specified as part of the relevant product standards. You should check your product standards first for possible specified testing durations. In the absence of any defined periods our recommended minimum exposure duration is 500 hours. This is normally sufficient to distinguish poorly performing materials. However, longer durations may be necessary to determine which are the best performing materials. Typically, clients will test for 500, 1000, 1500, 2000 and 2500 hour durations with 500 and 1000 being the most common. In exceptional circumstances we may also test for periods of up to 5000 hours or longer.
In most cases we recommend including a control sample i.e. a material with some history or known outdoor performance that can also be used as a reference. This will help you to judge if your test material is better or worse than previous materials.
Ideally materials should be tested until a failure point is achieved, only then can the real improvement in the material be observed. However, often this is not practical. In all cases it is recommended that a key parameter such as colour, gloss or mechanical properties are measured with exposure duration as this will often signal the first changes in the material as it degrades. Measurement of mechanical properties, particularly elongation at break, is one of the most sensitive measures of UV degradation.
Cable Testing Durations
For many years the cable industry has conducted UV testing on their materials. However, there has been an absence of specific standards and recommendations for test durations. As a result, most cable manufacturers have found it useful to test at both 500 hours and 1000 hours exposure. They then look for a minimum retention of properties of 70% after 500 hours and 60% after 1000 hours. Throughout many years of testing this has proved to be a useful reference and has not resulted in any known outdoor failures. Note that standards in this area are currently under discussion and the most recent recommendations should be consulted.