Accelerated Weathering and Precision Spectral Ultraviolet Measurements Available to Purchase

The objective of accelerated exposure testing is the prediction of long-term weathering behavior by short-term tests. It is becoming increasingly evident that the timing of exposure tests, when measured on the basis of elapsed time only, is largely responsible for failures to achieve data correlation between exposures at the same site, between exposures at different sites, and, especially, between exposures in accelerated and realtime tests. It is these considerations that have led DSET Laboratories to begin reporting specific exposures not in terms of elapsed time, or even total langleys, but in terms of the total ultraviolet (UV) in a given wave band—for example, all the UV below 400 nm, the total UV between 298 and 310 nm, that between 310 and 320 nm, that between 320 and 340 nm, and so on. This analysis is being accomplished using the DSET solar scanning spectroradiometer, currently only one of two such devices in regular use in the United States. The spectroradiometer is briefly described, and pertinent spectra are presented as they relate to fundamental exposure considerations employed at this company. In this respect, the EMMAQUA test method is discussed and attention is devoted to the subject of rehabilitating “old” exposure data to provide correlation between EMMAQUA test data and conventional exposure results.