What Is The Relationship Between Equipment Exposure And Outdoor Exposure
September 23, 2020
The test time of the aging test chamber equipment cannot be accurately calculated as the equivalent outdoor actual exposure time. This is not because there is no perfect aging test chamber equipment, but no matter how complex and sophisticated the test equipment is, how high-end and precise the configuration is, there is still no way to calculate the equipment exposure and outdoor exposure. The inherent variable characteristics and complexity of the outdoor exposure environment are The biggest consideration. The relationship between test chamber equipment exposure and outdoor exposure depends on many variable factors, such as:
· Geographical latitude of the exposure field (the closer to the equator, the stronger the ultraviolet).
· Altitude (the higher the sea waves, the stronger the ultraviolet rays).
· Test local geographical features, such as wind-dried test samples, or near water sources are prone to forming dew.
· The weather changes year by year, and the degree of aging caused by the same location for several years will also change 2:1.
· Seasonal changes (winter exposure may only damage one-seventh of summer exposure).
· The sample placement angle (5° south or true north).
· Sample insulation (usually, outdoor samples with insulated sample holders age 50% faster than non-insulated samples).
· Tester operation cycle (light time and humidity time).
· Tester working temperature (the higher the temperature, the faster the aging).
· Specific materials tested.
· Laboratory light source spectral power distribution.
Obviously, it makes no logical sense to discuss the conversion between accelerated weathering test hours and outdoor exposure months. Because of these two factors, one is constant and the other changes. It is no meaningless to looking for a conversion factor between the two in test data.
In other words, the aging data is relative data. Although we can still use the accelerated aging test chamber to obtain accurate durability data, you must realize that the data obtained is relative data, not absolute data. The most tests from laboratory weathering are reliable prediction of the relative ranking of the durability of the material relative to other materials. It is possible to compare the test results of the test piece exposed in the "black box" outdoors for one year and indoors or in the car for one year in a 5° southerly position. No one knows, even the outdoor test results It is a relative forecast of actual service life.