1.1 本试验方法描述了根据规范生产的交联聚乙烯（PEX）管的暴露程序 F876 并评估暴露的影响。本试验方法概述了试样尺寸和制备、暴露方向、最小紫外线暴露能量、暴露后测试和报告的要求。 注1: 虽然其他实验室紫外线暴露系统可用，但本试验方法依赖自然阳光作为紫外线辐射源。如果测试证实自然阳光与实验室暴露之间存在相关性，则未来可能会添加实验室方法。 1.2 PEX管道不是为室外使用而设计的。根据本试验方法进行的短期暴露试验的数据可用于判断在安装之前在室外短期存放的PEX管的相对性能，该PEX管完全遮挡阳光。 1.3 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。 1.4 以下预防性警告仅适用于本试验方法第8节和第9节中的试验方法和暴露后试验部分。 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。 1.5 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====== 5.1 在装运、储存和安装过程中，PEX管道可能会暴露在紫外线辐射下，然后在安装后进行防护，以避免进一步暴露。使用本试验方法确定紫外线照射对PEX管的影响。通过首先将样品暴露于太阳紫外线辐射，然后测试样品的抗氧化性或稳定剂功能，可以评估由于太阳紫外线辐射暴露而引起的变化。该信息可用于在安装提供永久屏蔽之前确定最大允许总紫外线暴露量。 5.2 短期暴露试验的结果可以提供相对室外性能的指示，但不应用于预测绝对长期性能- 材料的长期性能。不到12个月的测试结果将取决于测试开始的特定季节。

1.1 This test method describes the procedure for exposing crosslinked polyethylene (PEX) tubing produced in accordance with Specification F876 to natural (sunlight) ultraviolet (UV) radiation and evaluating the effects of the exposure. This test method outlines the requirements for specimen size and preparation, exposure orientation, minimum UV exposure energy, post exposure testing and reporting. Note 1: While other laboratory UV exposure systems are available, this test method relies on natural sunlight as the UV radiation source. Laboratory methods may be added in the future if testing confirms a correlation between natural sunlight and laboratory exposure. 1.2 PEX tubing is not designed for outdoor use. Data from short-term exposure testing per this test method can be used to judge the relative performance of PEX tubing stored outdoors for short periods of time prior to installation completely shielded from sunlight. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 The following precautionary caveat pertains only to the test method and post exposure testing portions, Sections 8 and 9 of this test method. 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. 1.5 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 ====== 5.1 During shipment, storage and installation, PEX tubing may be exposed to UV radiation prior to being shielded from further exposure after installation. The effects of UV exposure on PEX tubing is determined by use of this test method. By first exposing specimens to solar UV radiation and subsequently testing specimens for oxidative resistance or stabilizer functionality, changes as a result of solar UV radiation exposure can be evaluated. This information can be used to determine the maximum allowable total UV exposure prior to permanent shielding provided by installation. 5.2 The results of short-term 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 for less than twelve months will depend on the particular season of the year in which they begin.