To measure weathering, manufacturers currently either set their product in the sun and watch what happens or use an indoor weathering chamber. The outdoor method often requires multiyear iterations before a marketable product is developed. While laboratory testing is quicker, no one has been able to link field and laboratory exposure results, and neither approach is very repeatable or reproducible.
The NIST SPHERE, which can accommodate more than 500 samples, distributes UV radiation uniformly into as many as 32 specimen chambers with independently and precisely controlled temperature and humidity ensuring repeatability and reproducibility of test results. The device accelerates weathering by generating controlled temperature, humidity and UV exposure environments up to 50 times faster than outdoor weathering. Materials exposed to the SPHERE's UV light for one day receive the equivalent of 50 days of sunlight. The SPHERE is designed to allow rapid testing of the same material under a wide variety of weathering environments at the same time. For example, this device can generate exposures similar to a Texas summer dawn, a North Dakota winter night, a mid-summer Florida afternoon and a California sunset, plus up to 28 other environments all at the same time.
The National Association of Home Builders estimates that Americans spend between $65 billion and $75 billion annually on maintenance, repair and replacement, often due to the premature failure of a material exposed to outdoor weathering. The NIST SPHERE will make it possible for manufacturers to rapidly develop innovative products tailored for specific environments and will enable consumers to choose a product based not only on cost but also on its performance life.
Among NIST's partners with Cooperative Research and Development Agreements in this project: Atlas Electric Devices, DAP Products Inc., Degussa Construction Systems-Americas, Dow Corning, Sika Corporation, Solvay and Wacker. NIST's partners directly supporting this work include: Department of Housing and Urban Development/ Partnership for Advancing Technology in Housing; U.S. Department of Agriculture/Forest Products Laboratory (Madison); Air Force Research Laboratory; Federal Highway Administration; and the Smithsonian Environmental Research Center.
The NIST SPHERE is the centerpiece of NIST's Service Life Prediction program to develop repeatable and reproducible methods for predicting the performance of construction materials. For further information, see http://slp.nist.gov/coatings/cslpmain.html.
As a non-regulatory agency of the U.S. Department of Commerce's Technology Administration, NIST develops and promotes measurements, standards and technology to enhance productivity, facilitate trade and improve the quality of life.
Website: http://slp.nist.gov/coatings/cslpmain.html
Video: http://www.nist.gov/public_affairs/releases/weathering.htm