ASTM G is an accelerated UV ageing test using a Xenon arc to simulate the impact of sun exposure on coatings and other carbon based materials. 14 Sep Engaged Expert Terry Candlish discusses ASTM G and G tests which are used to evaluate sunlight and moisture exposure. ASTM. ASTM G – 00 Standard Practice for Operating Xenon Arc. Light Apparatus for Exposure of Non-Metallic Materials. View on Information Provider website.
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Include a control, to act as a weatherization standard.
In the ASTM G test, xenon arc lamps simulate full-spectrum sunlight within a controlled test chamber. Without testing in a specific location over a number of years, it is impossible to perfectly predict product response. Historical Version s – view previous versions of standard. More specific information about methods for determining the change in properties after exposure and reporting these results is described in ISO Cracking, peeling, de-glossing, oxidation, and tensile weakening are additional outcomes of exposure; sometimes such deterioration can even occur through window glass.
Different types of xenon arc light sources and different filter combinations are described. Overall, this test involves 21 days of exposure.
Our Engaged Experts can help you select the best UV bulbs for your testing purposes. It is impossible to recreate nature in the lab. For instance, constant exposure with no temperature cycling fails to recreate the expansion and contraction stress that materials face in outdoor locations.
Every location on the globe has its own unique combination of damaging elements, such as pollution, salt spray, and biological attack. Weatherometers used in g155 G and G tests approximate performance via intense exposure to the damaging elements asstm sunlight. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
ASTM G154 and G155 Explained
This practice replaces Practice G26which describes very specific designs for devices used for xenon-arc exposures. Because xenon arc light is most similar to natural sunlight, we generally use the ASTM G test for outdoor weatherization testing. Note Practice G describes performance criteria for all exposure devices that use laboratory light sources. A number of exposure procedures are listed in an appendix; however, this practice does not specify the exposure conditions best suited for the material to be tested.
If the aim of testing is to boost color fastness, UV-A bulbs are ideal. Control samples and multiple material samples produce the best comparative data. Xenon Arc Testing Weatherometers used in the G and G tests approximate performance via intense exposure to the damaging elements in sunlight. However, there is no astn equation for calculating exposure.
In ASTM G testing, UVA bulbs create the best correlation with outdoor exposure, as they have the closest wavelengths to damaging natural light from to nm. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. In contrast, UV-A bulbs have a propensity for accelerating color fading and yellowing.
As a general guide, hours under UV-B bulbs is equivalent to 1 year of exposure in South Florida, while hours under UV-A bulbs can create the same exposure effects. Note 1 — Practice G describes performance criteria for all exposure devices that use laboratory light sources. A number of exposure procedures are listed in an appendix; however, this practice does not specify the exposure conditions best suited for the material to be tested.
More specific information about methods for determining the change in properties after exposure and reporting these results is described in Practice D Recreate specialized conditions with filters.