ASTM G141-09 (R2021) pdf free download.Standard Guide for Addressing Variability in Exposure Testing of Nonmetallic Materials.
1.1 This guide covers information on sources of variability and strategies for its reduction in exposure testing. and for taking variability into consideration in the design, execution, and data analysis of both exterior and laboratory accelerated exposure tests.
1.2 The values stated in SI units are to be regarded separately as the standard. The inch-pound values given in parentheses are for information only.
4. Significance and Use
4.1 Many standards and specifications reference exposure tests performed according to standards that are the responsibility of Committee G03 on Durability of Nonmetallic Materials. In many cases, use of the data generated in these tests fails to consider the ramifications of variability in the exposure test practices. This variability can have a profound efléct on the interpretation of results from the exposure tests, and if not taken into consideration in test design and data analysis, can lead to erroneous or misleading conclusions. This guide lists some of the sources for test variability and recommends strategies for executing successful weathering studies. Not all sources of variability in weathering testing are addressed in this guide. Specific materials, sampling procedures. specimen preparation, specimen conditioning, and material property measurernenLs can contribute significantly to variability in weathering test results. Many of these concerns are addressed in Guide G 147. To reduce the contribution of an instrumental method to test variability, ills essential to follow appropriate calibration procedures and ASTM standards associated with the particular property measurement. Additional sources of variability in test results are listed in Guide D4853, along with methods for identifying probable causes.
5. Variability in Outdoor Exposure Tests
5. 1 Variability Due to Climate—Climate at the test site location can significantly affect the material failure rates and modes. Typical climatological categories are: arctic, temperate, subtropical, and tropical (that are primarily functions of latitude). Subcategories may be of more importance as being dictated by geographic, meteorological, terrain, ecological, and land-use factors, and include such categories as desert, forested, (numerous classifications), open. marine, industrial, and so forth.ASTM G141 pdf download.