Designation: G? 12a Standard Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic Materials1. ASTM CommiKee E44 intends to address these concerns by creaIng a standard on meeIng the ASTM G‐ Standard PracIce for. OperaIng Fluorescent. Engaged Expert Terry Candlish discusses ASTM G and G tests which are used to evaluate sunlight and moisture exposure. ASTM.
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This practice replaces Practice G53, which describes very speci? Cycle 6 has been used for high irradiance exposures of coatings and plastics. This may lead to anomalous results. Note that glass transmission characteristics will vary due to manufacturer, production lot, thickness, or other factors.
ASTM G and G Explained | Element
When comparing relative spectral power distribution data to the spectral power distribution requirements of this standard, use the rectangular integration technique.
It g1554-12 be tempting to assume that shorter wavelengths, continuous exposure, high temperatures, and other variables can result in more intense acceleration.
Practice G53 indicated that a cycle of 8 hours UV and 4 hours condensation is widely used. Test results can be expected to differ between exposures conducted in? The spectral power distribution data is for lamps within the aging recommendations of the device manufacturer. Ultimately, the most realistic way to test for weathering is to allow the product to degrade in real time, with outdoor testing panels. The specimen temperature permissible for the accelerated test depends on the material to be tested and on the aging criterion under consideration.
Brass, steel, or copper shall not be used in the vicinity of the test specimens. While this data is provided for comparison purposes wstm, it is desirable for the laboratory accelerated light source to provide a spectrum that is a close match to the benchmark solar spectrum.
When required, provision shall be made for the spraying of water on the test specimen for the formation of condensate on the exposed face of the specimen or for the immersion of the test specimen in water.
Other lamps, or combinations of lamps, may be used. B The data in Table 2 are based on the rectangular integration of 21 spectral power distributions for? Remember, these accelerated weatherization tests cannot exactly reproduce outdoor conditions, as they cannot account for altitude, seasonal variations, local geographical features, and other variables.
Send us a request Wilton UK: A number in parentheses indicates the year of last reapproval. The lamps discussed in this G1541-2 differ in the total amount of UV energy emitted and their wavelength spectrum. UV-B light accelerates the brittleness that materials, particularly polymers, may suffer as they age indoors. B The data in Table 1 are based on the rectangular integration of 65 spectral power distributions for?
The spray shall be uniformly distributed over the samples. Often several exposure times such as, and hours also will be compared to each other.
ASTM G154 and G155 Explained
These conditions are provided for reference only See Table X2. The particular application determines which lamp g154-1 be used. Whether your business is local or global, we can ensure your products meet quality, health, environmental, safety, and social accountability standards for virtually any market around the world.
As such, the ASTM G and Sstm tests produce comparative, not absolute data, but these comparative evaluations can still prove extremely valuable to designers. This is because the UVA has asttm special power distribution in the short wave UV region that is similar to sunlight that has already been?
As shown in Fig. Expose replicates of the test specimen and the control specimen so that statistically signi? Following are some representative exposure conditions. However, there is no simple equation for calculating exposure.
Appendix X2 shows some representative exposure conditions. NOTE 3—Do not mix different types of lamps.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. The pH of the water used should be reported. These lamps emit different amounts of total energy, but both peak at nm and produce the same UV wavelengths in the same relative proportions.
Therefore, these bulbs are useful for testing interior applications. In the ASTM G test, xenon arc lamps simulate full-spectrum sunlight within a controlled test chamber. When rays of sunlight—particularly UV rays—bombard a surface, they degrade smaller pigment particles, changing the surface color and creating a chalky effect.
Testing Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. See Appendix X3 for more information comparing the solar radiation data used in the standard with that for CIE 85 Table 4. Because xenon arc light is most similar to natural sunlight, we generally use the ASTM G test for outdoor weatherization testing.
ASTM Ga 非金属材料的萤光UV灯曝晒_百度文库
Misleading results may be obtained by this method, since the masked portion of the specimen is still exposed to temperature and humidity that ast many cases will affect results. Active view current version of standard. When reproducibility in results from an exposure test conducted according to this practice have not been established through round-robin testing, performance requirements for materials shall be speci?
The UVA is used for these applications because the low end cut-on of this lamp is similar to that of direct sunlight which has been? See Practice G for further guidance. Aging axtm glass can result in a signi?