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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A number in parentheses indicates the year of last reapproval. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. A number of exposure procedures g15-412 listed in an appendix; however, this practice does not specify the exposure g15-412 best suited for the material to be tested. NOTE 1—Practice G describes performance criteria for all exposure devices that use laboratory light sources.
This practice replaces Practice G53, which describes very speci? The apparatus described in Practice G53 is covered by this practice. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of ast, limitations prior to use.
Current edition approved Dec. Originally approved in Last previous edition approved in as G — No astmm reproductions authorized. Summary of Practice 4. These exposures may include a means to introduce moisture to the test specimen. Exposures are not intended to simulate the deterioration caused by localized weather phenomena, such as atmospheric pollution, biological attack, and saltwater exposure.
Alternatively, the exposure may asym the effects of sunlight through window glass. Typically, these exposures would include moisture in the form of condensing humidity. Refer to Practice G for full cautionary guidance applicable to all laboratory weathering devices.
Differences in lamp intensity or spectrum may cause signi? A detailed description of the type s of lamp s used should be stated in detail in the test report. The particular testing application determines which lamp should be used.
Accelerated Weathering (QUV) ASTM G154, ASTM D4329, ASTM D4587, ISO 4892
See Appendix X1 for lamp application guidelines. NOTE 3—Do not mix different types of lamps. Mixing different types of lamps in a? Consequently, the use of a radiometer to monitor and control the radiant energy is recommended. Aging of glass can result in a signi? The more common may be identi?
ASTM Ga 非金属材料的萤光UV灯曝晒_百度文库
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. Therefore, no reference shall be made to results from the use of this practice unless accompanied by a report detailing the speci? It is recommended that at least three replicates of each material evaluated be exposed in each test to allow for statistical evaluation of results.
The manufacturer is responsible for determining conformance to Table 1. Annex A1 states how to determine relative spectral irradiance. B The data in Table 1 are based on the rectangular integration of 65 spectral power distributions for?
The spectral power distribution data is for lamps within the aging recommendations of the device manufacturer. The minimum and maximum data are at least the three sigma limits from the mean for all measurements. Test results can be expected to differ between exposures using devices with?
Contact the manufacturer of the? D The benchmark solar radiation data is de? 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.
See Appendix X3 for more information comparing the solar radiation data used in this standard with that for CIE 85 Table 4.
F For the benchmark daylight spectrum, the UV irradiance to nm is 9. Because the primary emission of?
Use of this lamp is not recommended for sunlight simulation. A Data in Table 2 are the irradiance in the given bandpass expressed as a percentage of the total irradiance from g15-412 nm. B The data in Table 2 are based on the rectangular integration of 21 spectral power distributions for? Test results can be expected to differ between exposures using? D The window glass?
The glass transmission is the average for a series of single strength window glasses tested as part of a research study for ASTM Subcommittee G3. E Previous versions of this standard used window glass?
See Appendix X3 for more information comparing the solar radiation data used in the standard with that for CIE 85 Table 4. F For astn benchmark window glass? Atm 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. Whenever possible, calibration should be astmm to national or international standards.
If a radiometer is used, it shall comply with the requirements in Practice G The un-insulated thermometers may be made of either steel or aluminum. Thermometers shall conform to asym descriptions found in Practice G The manufacturer is responsible for determining conformance to Table 3. B The data in Table 3 are based on the rectangular integration of 44 spectral power distributions for?
For any individual UVB lamp, the calculated percentage in each bandpass must fall within the minimum and maximum limits of Table 3. Test results can be expected to differ between exposures conducted in?
This data is provided for comparison purposes only. F For the benchmark solar spectrum, the UV irradiance to nm is 9. Typically, water vapor shall be generated by heating water and? Such instruments shall be shielded sstm the lamp radiation. Corrosion resistant alloys of aluminium or stainless steel have been found acceptable.
Brass, steel, or copper shall not be used in the vicinity of the test specimens. Appendix X2 shows some representative exposure conditions. These are not necessarily preferred and no recommendation is implied. These conditions are provided for reference only. Prior to exposing the specimens, quantify the appropriate properties in accordance with recognized ASTM or international standards.
If required for example, destructive axtmuse unexposed?
See ISO for detailed guidance. To assure uniform exposure conditions,? 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.
Masking or shielding the face of test specimens with an opaque cover for the purpose of showing the effects of exposure on one panel is not recommended. Misleading results may be obtained by this method, since the masked asgm of the specimen is still exposed to temperature and humidity that in many cases will affect results.
Positioning and calibration of chamber air temperature sensors shall be in accordance with the descriptions found in Practice G NOTE 9—Typically, these devices control by black panel temperature only. The spray shall be uniformly distributed over the samples.
ASTM G154 and G155 Explained
The spray system shall be made from corrosion resistant materials that do not contaminate the water used. Very low levels of silica in spray water can cause signi? Care should be taken to keep silica levels below 0. In addition to distillation, a combination of deionization and reverse osmosis can effectively produce water of the required quality. The pH of the water used should be reported. See Practice G for detailed water quality instructions.
Maintain these conditions throughout the exposure. Interruptions to service the apparatus and to inspect specimens shall be minimized. Irradiance uniformity shall be determined in accordance with Practice G The repositioning schedule shall be agreed upon by all interested parties.
After inspection, the test specimen shall be returned to the test chamber with its test surface in the same orientation as previously tested. See Practice G for further guidance. Precision and Bias In round-robin studies conducted by Subcommittee G The round-robin shall be conducted according to Practice E or Practice D and shall include a statistically representative sample of all laboratories or organizations that would normally conduct the exposure and property measurement.
The design of the experiment used to determine the speci? 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 control specimens shall be exposed simultaneously with the test specimen s in the same device.
Expose replicates of the test specimen and the control specimen so axtm statistically signi? Manufacturers of equipment claiming conformance to this standard shall determine conformance to the spectral power distribution tables for all?