UV Test Chamber

For simulations of direct solar UV radiation, the UVA-340 lamp is recommended. Because UVA-340 lamps typically have little or no UV output below 300 nm (that is considered the “cut-on” wavelength for terrestrial sunlight), they usually do not degrade materials as rapidly as UVB lamps, but they may allow enhanced correlation with actual outdoor weathering. Tests using UVA-340 lamps have been found useful for comparing different non-metallic materials such as polymers, textiles, and UV stabilizers.

The UVB region (280 to 315 nm) includes the shortest wavelengths found in sunlight at the earth’s surface and is responsible for considerable polymer damage. There are two commonly available types of UVB-313 lamps that meet the requirements of this document. These are known commercially as the UVB-313 and the FS-40. These lamps emit different amounts of total energy, but both peak at 313 nm and produce the same UV wavelengths in the same relative proportions. In tests using the same cycles and temperatures, shorter times to failure are typically observed when the lamp with higher UV irradiance is used. Furthermore, tests using the same cycles and temperatures with these two lamps may exhibit differences in ranking of materials due to the difference in the proportion of UV to moisture and temperature.

Any exposure conditions may be used, as long as the exact conditions are detailed in the report. Following are some representative exposure conditions. These conditions are provided for reference only.