1.1 本规程涵盖菲涅耳反射聚光器的使用，该聚光器使用太阳作为紫外线（UV）和长波辐射源。此类装置用于塑料的室外加速暴露试验。 1.2 本规程提供了使用菲涅耳反射镜室外加速老化试验机进行塑料室外加速暴露试验的程序。本文和实践中描述了该装置 G90 更完整。 1.3 本规程适用于一系列塑料材料，包括但不限于塑料薄膜、薄板、层压板以及各种形状和尺寸的挤压和模压产品，如 8.2和 8.3 . 1.4 本规程描述了试图模拟沙漠和亚热带气候中塑料暴露的试验条件。特定材料的现有测试方法或规范涵盖了样本制备、性能测试程序和结果评估。 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 第节给出了具体的预防说明 7. . 注1: 本标准等同于ISO 877-3:2009。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 该实践涉及通过平面镜系统对阳光进行浓缩，平面镜的布置旨在模拟抛物线槽，抛物线槽聚焦在安装试样的风冷靶板上。本方法中常用的有喷雾和无喷雾的暴露周期如所述 表1 . 中未列出的其他暴露周期 表1 经相关方协商一致，可使用。 （A） 这是实践程序C中规定的循环 D4141/D4141米 . 4.1.1 在没有程序化水分循环的情况下，使用本规程进行的加速室外暴露试验旨在模拟沙漠和干旱地区面向赤道机架上的常规暴露试验。 4.1.2 使用本规程和程序化水分循环进行的加速室外暴露试验应具有定期向试样喷洒高纯度水的特点，旨在模拟亚热带半干旱地区面向赤道的固定架上的常规暴露试验结果- 潮湿和温带地区。本规程推荐的喷水循环见 表1 . 4.2 菲涅耳反射器加速室外风化试验机的有效性主要取决于阳光直射光束成分中紫外线的数量和特征。 注2: 在中到高漫射辐照度区域使用仪器将大大降低试验机在目标（样品）区域提供集中紫外线的有效性。 4.3 建议测试特定水平（数量）的太阳紫外线辐射暴露。经过时间的暴露水平测定不得用于本规程的测试。测试特定的紫外线辐射水平，无论是总紫外线还是在选定的波段内，都是提高菲涅耳薄膜冬季和夏季测试一致性的有效方法- 反射镜风化试验机。温度和湿润时间等其他季节性因素可能会显著影响试样的风化。 4.4 所述风化机提供样品冷却，减少大多数材料的热问题。建议每月对热敏塑料进行温度测量，以记录典型的每月试样温度。 注3: 与自然风化相比，热敏塑料材料和自绝缘厚试样可能表现出不现实的热诱导降解。因此，不建议使用本规程测试透明薄膜光降解塑料。 4.5 由于自然环境随时间、地理和地形而变化，因此可以预计自然暴露的影响将相应变化。此外，所有材料都不会受到辐照度和温度增加的同等影响。因此，根据本规程进行的暴露与在规定的自然暴露条件下进行的暴露之间的定量相关性将因材料的类型和成分而异。 4.6 而根据本惯例和惯例测试的标准物质 G7/G7M 和 D1435 对于提供加速试验和实时试验之间关系的信息很有用，为参考材料找到的加速因子不能用于推断加速试验的结果，以预测自然暴露下的寿命，但已建立关系的特定材料除外。

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 7 . Note 1: This standard is equivalent to ISO 877-3: 2009. 1.7 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. ====== Significance And Use ====== 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 Table 1 . Other exposure cycles not listed in Table 1 can be used, upon consensual agreement between interested parties. (A) This is the cycle specified in Procedure C of Practice D4141/D4141M . 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 Table 1 . 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. Note 2: Use of the apparatus in regions of moderate- to high-diffuse irradiance will reduce the test machine's effectiveness substantially for providing concentrated UV in the target (specimen) area. 4.3 Testing to specific levels (quantities) of solar ultraviolet radiant exposure is recommended. Elapsed time exposure-level determinations shall not be used for testing with this practice. Testing to specific levels of UV irradiation, whether to total UV or within selected wavebands, is an effective method for improving agreement between wintertime and summertime testing on the Fresnel-reflector weathering-test machines. Other seasonal factors such as temperature and time of wetness can affect the weathering of test specimens significantly. 4.4 The weathering machines described provide for specimen cooling that reduces thermal problems in most materials. It is recommended that monthly temperature measurements be performed on heat-sensitive plastics to record the typical monthly test specimen temperatures. Note 3: It is possible for heat-sensitive plastic materials and thick specimens that are self-insulating to exhibit thermal-induced degradation that is unrealistic compared to natural weathering. Clear, thin-film photodegradable plastics are not recommended for testing with this practice for this reason. 4.5 Since the natural environment varies with respect to time, geography, and topography, it can be expected that the effects of natural exposure will vary accordingly. Furthermore, all materials are not affected equally by increased irradiance and temperature. The quantitative correlation between exposures conducted in accordance with this practice and those conducted under specified natural exposure conditions will therefore vary with the type and composition of the material. 4.6 While reference materials tested in accordance with this practice and Practices G7/G7M and D1435 are useful for providing information on the relationship between accelerated and real-time tests, the acceleration factor found for the reference material cannot be used to extrapolate results of the accelerated test to predict lifetimes under natural exposure except for the specific material for which the relationship has been established.