1.1 本规程涵盖了根据规程进行氙弧暴露的试验条件和程序 G151页 和 G155页 用于沥青屋面和防水材料。（参见术语 G113页 .) 1.2 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.3 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。 1.4 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 根据本规程进行的试验用于比较沥青材料与具有已知室外耐久性的对照材料的风化特性。在根据本规程进行的加速试验时间和自然风化时间之间，不可能建立适用于所有材料的单一关系，因为( 1. )存在地理气候变化、当地天气变化和当地污染物变化，以及( 2. )加速风化和自然风化之间的关系取决于材料之间以及同一材料的不同配方的加速系数差异。指导 G141页 提供关于室外和加速风化试验的可变性以及关于控制材料使用的指导。 注1: 建议使用室外风化来验证实验室加速试验的性能排名。 注2: 本规程可用于沥青材料以外的材料，但其意义和用途尚未评估。

1.1 This practice covers test conditions and procedures for xenon-arc exposures according to Practices G151 and G155 for bituminous roofing and waterproofing materials. (See Terminology G113 .) 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.3 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. 1.4 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 Tests conducted according to this practice are used to compare the weathering characteristics of bituminous materials versus a control material of known outdoor durability. It is not possible to establish a single relationship that is applicable to all materials between time in accelerated tests conducted according to this practice and time in natural weathering because ( 1 ) there are geographical climatic variations, local weather variations, and variations in local pollutants, and ( 2 ) the relation between accelerated and natural weathering is material dependent with differences in acceleration factors between materials as well as for different formulations of the same material. Guide G141 provides guidance regarding variability in outdoor and accelerated weathering tests and about the use of control materials. Note 1: It is recommended that outdoor weathering be used to validate the laboratory accelerated test in terms of performance ranking. Note 2: This practice can be used for other than bituminous materials, but the significance and use have not been evaluated.