ASTM D4364-13

4.1 This practice involves the concentration of sunlight by a system of plane mirrors, arranged to simulate a parabolic trough focused on an air-cooled target board on which the test specimens are mounted. Exposure cycles with and without water spray that are commonly used for this method are described in 4.1.1 Accelerated outdoor exposure tests performed using this practice in an absence of a programmed moisture cycle are intended to simulate conventional exposure testing on racks facing the equator in desert and arid regions.

4.1.2 Accelerated outdoor exposure tests performed using this practice with a programmed moisture cycle shall possess the feature of spraying high purity water on the specimens in a regular, periodic fashion that is intended to simulate the results of conventional exposure testing on fixed racks facing the equator in subtropical, semi-humid, and temperate regions. Water-spray cycles that are recommended by this practice are given in 4.2 The effectiveness of the Fresnel-reflector accelerated outdoor weathering test machines depends primarily on the amount and character of the UV in the direct-beam component of sunlight.

1.1 This practice covers the use of Fresnel-reflecting concentrators that use the sun as a source of ultraviolet (UV) and longer wavelength radiation. Such devices are used in the outdoor accelerated exposure testing of plastics.

1.2 This practice provides a procedure for performing outdoor accelerated exposure testing of plastics using a Fresnel-reflector outdoor accelerated weathering test machine. The apparatus is described herein and in Practice G90 more completely.

1.3 This practice is applicable to a range of plastic materials including, but not limited to, plastic films, sheets, laminates, and extruded and molded products in a variety of shapes and sizes, as specified in 8.2 and 8.3.

1.4 This practice describes test conditions that attempt to simulate plastics exposures in desert and subtropical climates. Specimen preparation, property testing procedures, and the evaluation of results are covered in existing test methods or specifications for specific materials.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 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 and health practices and determine the applicability of regulatory limitations prior to use.