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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There is no easy exposure formula. Cycle 6 has been used for high irradiance exposures of coatings and plastics.
Inspection Validating the specifications, value and safety of your raw materials, products and assets. A number in parentheses indicates g15412 year of last reapproval.
Element can provide you with critically important data on your product or part’s performance in response to typical or extreme environmental stresses and conditions. These numbers represent the characteristic nominal wavelength in nm of peak emission for each of these lamp types.
The actual peak emissions are at and nm, respectively. When rays of sunlight—particularly UV rays—bombard a surface, they degrade smaller pigment particles, changing the surface color and creating a chalky effect. NOTE 3—Do not mix different types of lamps.
This practice replaces Practice G53which describes very specific designs for devices used for fluorescent UV exposures. The standard sample holders can hold one sample 3 x 12 inches 75 x mm or two samples 3 x 6 inches 75 x mm.
ASTM G154 and G155 Explained
Active view current version of standard. Cycle 5 has been used for roo? Cycle 7 has been used for thermal shock and for erosion testing of coatings for wood.
Ashm 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.
B The data in Table 1 are based on the rectangular integration of 65 spectral power distributions for? Moisture takes its own toll on surfaces, and the combination of sunlight and moisture can amplify awtm, costing millions of dollars of depreciation each year. Moisture is provided by forced condensation, and temperature is controlled by heaters.
The minimum and maximum data are at least the three sigma limits from the mean for all measurements. Consequently, the use of a radiometer to monitor and control the radiant energy is recommended. For instance, a slight shift in formula may produce twice as much resistance to weathering.
Send us a request Need help or have a question? Appendix X2 shows some representative exposure conditions. 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. While this data is provided for comparison purposes only, it is desirable for the laboratory accelerated light source to provide a spectrum that is a close match to the benchmark solar spectrum.
Hemispherical on 37 Tilted Surface. Following are some representative exposure conditions.
ASTM Ga 非金属材料的萤光UV灯曝晒_百度文库
Brass, steel, or copper shall not be used in the vicinity of the test specimens. Ultimately, the most realistic way to test for weathering is to allow the product to degrade in real time, with outdoor testing panels.
D The window glass? Cycle 2 has been widely used for coatings. After aztm, the test specimen shall be returned to the test chamber with its test surface in the same orientation as previously tested. These cycles would be continued for extended periods of time – up to thousands of hours – simulating even g1554-12 periods of time in the real world.
Typically, this is done at 2 nm increments. Manufacturers of equipment claiming conformance to this standard shall determine conformance to the spectral power distribution tables for all? Different types of fluorescent UV light sources are described. NOTE 10—Evaluation of color and appearance changes of exposed materials shall be made based on comparisons to unexposed specimens of the same material which have been stored in the dark.
F For the benchmark solar spectrum, the UV irradiance to nm is 9. The specimen temperature permissible for the accelerated test depends on the material to be tested and on the aging criterion under consideration.