1.1 This standard describes a guide for the methodology in using various weathering reference materials (WRMs) for outdoor and laboratory exposure tests. NOTE 1Examples of outdoor exposures where a weathering reference material could be used to monitor consistency are those conducted according to Practices G7, G24, or G90. Examples of exposure tests in which a weathering reference material could be used are described in Practices G152, G153, G154, and G155. Other standards in which tests conducted according to these standards are referenced would also apply. A reference material can also be used to monitor consistency of exposure or conditioning test that do not involve exposure to light. 1.2 This guide provides recommendations on specific uses of weathering reference materials to (1) monitor consistency (that is, repeatability, reproducibility, or both) of exposure tests, (2) determine uniformity at a location, on an exposure rack, or within a laboratory apparatus exposure area, (3) determine the time or radiant exposure at which test materials are evaluated, (4) as a reference material for comparing to test materials exposed at the same time. Weathering reference materials cannot be used to classify or characterize the relative severity of any exposure test because of the large variability in material responses to the effects of light, heat, and water. 1.3 This guide does not cover control materials which, by definition are selected to be of similar composition and construction to the test materials, and are exposed at the same time as test materials.
Keywordsweathering reference materials; outdoor exposure test; laboratory exposure tests; repeatability; reproducibility; uniformity; blue wool; polystyrene chip;
The scope of ASTM G156 was written to select and characterize weathering reference materials for use with exposure tests, but it does not provide any detailed information on how to then actually use these materials to determine performance of laboratory exposure testing apparatus or monitor consistency of outdoor tests. This standard will provide that information.
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development