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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Originally approved in F For the benchmark solar spectrum, the UV irradiance to nm is 9. For determining conformance to the relative spectral irradiance requirements for a?
Typically, these exposures would g14-12 moisture in the form of condensing humidity. Active view current version of standard. Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards.
To assure uniform exposure conditions,?
Accelerated Weathering (QUV) ASTM G, ASTM D, ASTM D, ISO
Ordinary glass is essentially transparent to light above about nm. This allows for accurate comparison.
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. Very low levels of silica in spray water can cause signi? 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.
Irradiance uniformity shall be determined in accordance with Practice G It is recommended that at least three replicates of each material evaluated be exposed in each test to allow for statistical evaluation of results. Control samples and multiple material samples produce the best comparative data. Element has been helping companies make Certain for over years. The apparatus described in Practice G53 is covered by this practice.
If the aim of testing is to boost color fastness, UV-A bulbs are ideal. These cycles would be continued for extended periods of time – up to thousands of hours – simulating even longer periods of time in the real world. Send us a request Need help or have a question?
Standards can be obtained from appropriate standard authorities. If the actual operating conditions do not agree with the machine settings after the equipment has stabilized, discontinue the test and correct the cause of the disagreement before continuing. Cycles 3 and 4 have been used for exterior asrm materials.
A QUV test chamber uses fluorescent lamps to provide a radiation spectrum centered in the ultraviolet wavelengths. Consequently, in testers without feed-back-loop control of irradiance, the lamp output will decrease with increasing chamber temperature.
Accelerated Weathering (QUV) ASTM G154, ASTM D4329, ASTM D4587, ISO 4892
The total irradiance in each wavelength bandpass is then summed and divided by the speci? E Previous versions of this standard used window glass? Weatherometers used in the G and G tests approximate performance via intense exposure to the damaging elements in sunlight. A detailed description of the type s of lamp s used shall be stated in detail in the test report. Contact the manufacturer of the? If required for example, destructive testinguse unexposed?
Moisture takes its own toll on surfaces, and the combination of sunlight and moisture can amplify damage, costing millions of dollars of depreciation each year.
Positioning and calibration of chamber air temperature sensors shall be in accordance with the descriptions found in Practice G Due to time constraints, however, many producers employ the G and G laboratory chamber tests for reliable exposure results in shorter time periods. For instance, asttm exposure with no temperature cycling fails to recreate the expansion and contraction stress that materials face in outdoor locations.
The specimen temperature permissible for the accelerated test depends on the material to be tested and on the aging criterion under consideration. The pH of the water used should be reported. Certification Formally confirming that your products and services meet all trusted external and internal standards.
The actual g514-12 emissions are at and nm, respectively. A number in parentheses indicates the year of last reapproval.
ASTM Ga 非金属材料的萤光UV灯曝晒_百度文库
Accelerated weathering simulates damaging effects of long term outdoor exposure of materials and coatings. Corrosion resistant alloys of aluminium or stainless steel have been found acceptable. These lamps emit different amounts of total energy, but both peak at nm and produce the same UV wavelengths in the same relative proportions.
These exposures may include a means to introduce moisture to the test specimen. Manufacturers of equipment claiming conformance to this standard shall determine conformance to the spectral power distribution tables for all?
This data is provided for asgm purposes only. Whenever possible, calibration should be traceable to national or international standards.
Prior to exposing the specimens, quantify the appropriate properties in accordance with y154-12 ASTM or international standards. Maintain these conditions throughout the exposure. Typically, water vapor shall be generated by heating water and? Typically, flat plaques or disks are g54-12 for accelerated weathering studies. Accelerated weathering provides exposed samples for comparison to unexposed control samples.
Different UV bulbs are useful for different testing purposes. Such instruments shall be shielded from the lamp radiation. Misleading results may be obtained by this method, since the masked portion of the specimen is still exposed to temperature and humidity that in many cases will affect results. Moisture is provided by forced condensation, and temperature is controlled by heaters.