ASTM C1900-20

4.1 Tests conducted in accordance with this practice are used to evaluate the stability of laminated glazing materials when they are exposed outdoors or used indoors. The relative durability of glazing in outdoor use can be very different depending on the location of the exposure because of differences in ultraviolet (UV) radiation, time of wetness, temperature, pollutants, and other factors. It cannot be assumed, therefore, that results from one exposure in a single location will be useful for determining relative durability in a different location. When comparing exposure results, at a minimum, the locations of exposure are to be as similar as possible with regard to critical factors such as the amount and rate of solar radiation deposited on the specimens, temperature and humidity levels during exposure. Exposures in several locations with different climates that represent a broad range of anticipated service conditions may be necessary.

4.2 Because of year-to-year climatological variations, results from a single exposure test cannot be used to predict the absolute rate at which a material degrades. Several years of repeat exposures are needed to get an average test result for a given location.

4.3 The results of short-term natural and accelerated exposure tests can provide an indication of relative outdoor performance, but they should not be used to predict the absolute long-term performance of a material. The results of tests conducted under natural exposure for less than twelve months will depend on the particular season of the year in which they begin.

1.1 This practice is intended to cover procedures for the exposure of laminated glass materials to natural and accelerated weather.

1.2 This practice is limited to the method by which the material is to be exposed and the general procedure to be followed. It is intended for use with finished articles of commerce as well as with all sizes and shapes of test specimens.

1.3 Means of evaluation of the effects of weathering will depend on the intended use for the test material.

1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.