The efficacy test of UV-rays stabilizer consists of the accelerated weathering test in the lab and outdoor exposure test.  The accelerated weathering resistant test can performed by selecting the environmental factors such as light, oxygen, humidity, Yong's modules, etc. Its results can be checked within a very short period of time. The test is regardless of regions, seasons, and weather conditions. The exposure outdoor test gives a high reliability because it is based on the usable conditions. However, it has a demerit of taking long period of time.
	Accelerated Weathering Test
	Equipment Development History
	The accelerated weathering test equipment was first developed by Lowell Technological Institute, who asked ATLAS to develop the equipment in order to improve the life cycle of product and the quality of dye. The fiber industry recognized the importance of the equipment because the color of dye changed suddenly during the use and the life cycle of product declined or ceased afterward. In fact, the history of equipment development matches with the development history of light source, which reproduce the sunlight. The sprinkler , temperature controller, time-program controller for the light source and sprinkler, and humidity-controller were added afterward and development of equipment.
	Types of light sources
	¨Í Enclosed Ultraviolet Carbon Arc As the earliest light source that ever developed, enclosed carbon arc has no energy at spectrum lower than 345 nm and between 400 and 800 nm, and it is very different from sun rays. ¨Î Sunshine Carbon Arc The sunshine carbon arc is a light source developed to supplement the deficit of the ultraviolet carbon arc. It has spectrum distribution similar to the sun rays, while it shows significant imbalance in energy at spectrum range between 350 and 450 nm. ¨Ï Xenon Arc The xenon arc is a light source with the most similar spectrum distribution to the sun rays. By combining filters, it is possible to control spectrum distribution. ¨Ð Fluorescent Ultra-Violet Lamp Fluorescent ultra-violet lamp is a light source developed mainly for the short-wavelength rays of the sunrays, and excellent in reproducibility in ultraviolet ray range. The most popular applications are UV-A lamp and UV-B lamp.
	Guidelines on Device Selection
	¿©Testing device for accelerated weather resistance developed by variety of light sources includes Weather-Ometer, Face-Ometer (Atlas Electrical Devices. Co.) and Xenotest (Original Hanu Quartzlampen GmbH) using carbon arc or xenon arc, and QUV (Q-Panel Lab Products) and UVCON (Atlas Electrical Devices Co.) using fluorescent ultraviolet lamps. Once a device is selected, the test is performed after setting humidity and cycles of day/night. ¡Ø ISO, DIN and ASTM standards for accelerated weather resistance using xenon arc lamps
	Major properties ISO 4892-1981 DIN 53387-1989 ASTM G26-88 Irradiation spectrum Total irradiation. Filtering through window glass is optional Total irradiation. Filtering through window glass is optional Total irradiation Optical flux density(W/§³) 1000¡¾100 550¡¾55 ¡Â1500 Blackboard temperature (?) 45¡¾35 5¡¾36 5¡¾3 63~67 63¡¾3 Relative humidity (%) 35¡¾35 0¡¾36 5¡¾39 0¡¾3 63~67 63¡¾3 Relative humidity (%) 5¡¾35 0¡¾36 5¡¾39 0¡¾3 40~60 60~80   30¡¾5   Cycle (min.) Water spray/Light irradiation  3/17 5/15 12/48 18/102 18/102 18/102 Measurement of irradiation Measuring devices of standard color fastness against sunray or irradiation Measuring device of irradiation
	Outdoor Exposure Test
	This test is the most ideal method for properties of a product for long-term outdoor exposure test. However, the use of this method is restricted due to significant difference in climate. The test is usually employed in areas of the most severe climate conditions such as Arizona with desert climate of strong sunray and high temperature and Florida with subtropical zone climate of strong sunray, high temperature and high moisture/humidity). ¨ç  Sample Preparation    The sample should be dry and flat material free of curve. Materials of high flexibility (e.g., fiber and paper) should not be bent, and free of contact with other sample. ¨è  Location Selection    The test location should be elected taking into account of natural features and climate. ¨é  How to expose the samples     Conditions of the test should be taken into account including direct exposure, exposure level under a sheet of glass, exposure angle, and other particular environments (moisture, salty atmosphere, underground burying and storage of warehouse, etc.). ¡Ø Accelerated Outdoor Exposure Test Measuring devices for this test include EMMA (Equatorial Mount with Mirrors for Acceleration), and EMMAQUA (EMMA in which the samples are sprayed with water for 8min during each hour of operation).