ASTM G155-13 pdf free download.Standard Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials.
4.3 Comparison of results obtained from specimens exposed in the same model of apparatus should not he made unless reproducibility has been established among devices for the material to he tested.
4.4 Comparison of results obtained from specimens exposed in different models of apparatus should not be made unless correlation has been established among devices for the material to be tested.
5. Significance and Use
5.1 The use of this apparatus is intended to induce properly changes associated with the end use conditions, including the effects of sunlight, moisture, and heat. 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 simulate the effects of sunlight through window glass. Typically, these exposures would include moisture in the form of humidity.
NOTE 2—Caution: Refer to Practice G 151 for full cautionary guidance applicable to all laboratory weathering devices.
5.2 Variation in results may be expected when operating conditions are varied within the accepted limits of this practice. Therefore, no reference shall be made to results from the use of this practice unless accompanied by a report detailing the specific operating conditions in conformance with the Report Section.
5.2.1 It is recommended that a similar material of known performance (a control) be exposed simultaneously with the test specimen to provide a standard thr comparative purposes. It is best practice to use control materials known to have relatively poor and good durability. It is recommended that at least three replicates of each material evaluated he exposed in each test to allow for statistical evaluation of results.
6. Apparatus
6.1 Laboratory Light Source—The light source shall be one or more quartz jacketed xenon arc lamps which emit radiation from below 270 nm in the ultraviolet through the visible spectrum and into the infrared. In order for xenon arcs to simulate terrestrial daylight, filters must be used to remove short wavelength UV radiation. Filters to reduce irradiance at wavelengths shorter than 310 nm must be used to simulate daylight filtered through window glass. In addition, filters to remove infrared radiation may be used to prevent unrealistic heating of test specimens that can cause thermal degradation not experienced during outdoor exposures.
6.1.1 The following factors can affect the spectral power distribution of filtered xenon arc light sources as used in these apparatus:
6.1.1.1 Differences in the composition and thickness of filters can have large effects on the amount of short wavelength UV radiation transmitted.ASTM G155 pdf download.ASTM G155 pdf download.