1.1 本规程提供了一种将平板太阳能集热器的覆盖材料暴露在自然天气环境中的程序，温度升高至接近工作条件。 1.2 本规程适用于玻璃和塑料太阳能集热器盖材料的暴露。规定了单盖和双盖组件的暴露，以适应内外太阳能集热器盖材料的暴露需要。 1.3 本规程不适用于真空收集器或光伏电池的覆盖材料。 1.4 以国际单位制表示的数值应视为标准。 1.5 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和健康实践，并确定监管限制的适用性。 ====意义和用途====== 3.1 本规程描述了一种风化箱试验夹具，并提供了统一的暴露指南，以最小化室外暴露试验期间遇到的变量。 3.2 这种做法可能有助于比较不同材料在一个地点的性能，或相同材料在不同地点的性能，或两者兼而有之。 3.3 由于高温和太阳辐射的结合可能会导致一些太阳能集热器盖材料比单独使用任何一种材料降解更快，因此使用了一种提高盖材料温度的风化箱。 3.4 本规程旨在帮助评估运行模式下而非停滞模式下的太阳能集热器盖材料。没有足够的数据来获得根据本规程暴露的材料行为与实际情况之间的精确相关性- 服务性能。 3.5 实践中提供了评估风化影响的方法 E781 ，以及其他评估材料性能的ASTM试验方法。 3.6 本规程中所述类型的试验可用于评估太阳能集热器盖材料在户外暴露于包括天气在内的各种影响时的稳定性。暴露条件复杂多变。重要因素包括太阳辐射、温度、湿度、一年中的时间、污染物的存在等。这些因素因现场而异，在选择暴露位置时应予以考虑。风化试验中必须始终使用对照样品进行比较分析。需要在户外暴露至少两年才能做出明显的改变，例如在不使用精密分析设备的情况下表面退化。 3.7 使用该箱获得的温度条件可能与流体流动操作条件下发生的温度条件不完全相同。根据环境暴露条件，使用该箱获得的盖板温度可能高于或低于在操作条件下获得的温度。尽管本规程未涵盖，但应在停滞条件下进行额外测试。 注1: 研究表明，与在干旱气候下暴露相比，在湿度、太阳能和环境温度较高的场所暴露在室外，可能会导致一些聚合物覆盖材料更严重的降解（例如，紫外线辐射屏蔽添加剂的微裂纹和浸出）。 注2: 太阳能集热器通常会出现停滞状态，例如，在运行期间，当储能器充满电时；初次安装收集器时，系统启动前；或者当系统出于维护或季节性考虑（如夏季仅供暖系统）而关闭时。

1.1 This practice provides a procedure for the exposure of cover materials for flat-plate solar collectors to the natural weather environment at temperatures that are elevated to approximate operating conditions. 1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials. 1.3 This practice does not apply to cover materials for evacuated collectors or photovoltaics. 1.4 The values stated in SI units are to be regarded as the 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 3.1 This practice describes a weathering box test fixture and provides uniform exposure guidelines to minimize the variables encountered during outdoor exposure testing. 3.2 This practice may be useful in comparing the performance of different materials at one site or the performance of the same material at different sites, or both. 3.3 Since the combination of elevated temperature and solar radiation may cause some solar collector cover materials to degrade more rapidly than either alone, a weathering box that elevates the temperature of the cover materials is used. 3.4 This practice is intended to assist in the evaluation of solar collector cover materials in the operational, not stagnation mode. Insufficient data exist to obtain exact correlation between the behavior of materials exposed according to this practice and actual in-service performance. 3.5 Means of evaluation of effects of weathering are provided in Practice E781 , and in other ASTM test methods that evaluate material properties. 3.6 Tests of the type described in this practice may be used to evaluate the stability of solar collector cover materials when exposed outdoors to the varied influences which comprise weather. Exposure conditions are complex and changeable. Important factors are solar radiation, temperature, moisture, time of year, presence of pollutants, etc. These factors vary from site to site and should be considered in selecting locations for exposure. Control samples must always be used in weathering tests for comparative analysis. Outdoor exposure for at least two years is required to make evident changes, such as surface degradation without the use of sophisticated analytical equipment. 3.7 Temperature conditions attained with this box may not exactly duplicate those that occur under operational conditions with fluid flow. Dependent on environmental exposure conditions, the cover plate temperatures obtained with this box may be higher or lower than those obtained under operational conditions. Additional testing under stagnation conditions, although not covered by this practice should be conducted. Note 1: Research has shown that exposure outdoors at sites having the combination of high levels of humidity, solar energy, and ambient temperature can cause more severe degradation of some polymeric cover materials, (for example, microcracking and leaching of UV radiation screening additives) than exposure in arid climates. Note 2: Stagnation conditions are a normal occurrence for solar collectors, for example, during operation when the storage is fully charged; when the collectors are initially installed, before system start-up; or when the system is shut down for maintenance or seasonal considerations such as heating only systems in the summer.