1.1 本规程涵盖了试验条件和程序的具体变化，这些变化应在实践中适用 G151页 加上任何一种做法 G152页 , G153页 , G154页 或 G155页 用于硫化橡胶化合物的暴露。它还包括试样的制备和结果的评估。 1.2 以国际单位制表示的数值应视为标准值。括号中给出的值仅供参考。 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====== 3.1 本实施规程描述了用于确定明火碳弧光源、封闭碳弧光源、氙弧光源或荧光紫外线光源以及热量和水分对夹具或支架中固定的橡胶试样（有或无规定应变）的影响的程序。其目的是试图加速自然环境中光、热和水分产生的影响。暴露不是为了模拟局部天气现象引起的恶化，例如大气污染、生物攻击和盐水暴露。实践中的意义和使用部分 G151页 以及适当仪器的标准，即实践 G152页 , G153页 , G154页 或 G155页 有关暴露试验的重要性和使用的更多信息，请咨询。 3.2 评估耐候性的主要标准是抗拉强度和断裂伸长率的下降百分比。 评估耐候性的一个补充标准是观察到的表面龟裂和开裂程度。 3.3 使用这些试验程序获得的结果不应表示为等同于任何自然暴露试验的结果，直到确定了相关材料的定量相关性程度。 3.4 由于不同类型的实验室风化试验中暴露源的光谱功率分布以及其他条件的差异，不同的程序可能不会导致相同的性能等级或材料的失效模式类型。不得对暴露在不同类型仪器中的材料的相对稳定性进行比较。 3.5 在使用实验室光源的设备中进行曝光时，重要的是要考虑人工风化条件将在多大程度上再现被测材料的最终使用环境引起的性能变化和故障模式。 3.6 实践 G151页 , G152页 , G153页 , G154页 和 G155页 建议与试样同时暴露具有已知性能的类似材料（对照），以提供用于比较目的的标准。优选地，应使用已知耐久性较差以及具有良好耐久性的控制材料。使用对照的原因是，排序稳定性的再现性通常优于绝对变化的再现性。因此，当测试材料没有相互比较时，控制的使用尤为重要。

1.1 This practice covers specific variations in the test conditions and procedures that shall be applicable when Practice G151 plus either Practice G152 , G153 , G154 , or G155 are employed for exposure of vulcanized rubber compounds. It also covers the preparation of test specimens and the evaluation of results. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 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 ====== 3.1 This practice describes procedures to use in determining the effects of an open-flame carbon-arc light source, an enclosed carbon-arc light source, a xenon-arc light source, or a fluorescent UV source along with heat and moisture on rubber specimens held in a jig or holder with or without a specified strain. The purpose is to attempt to accelerate the effects produced by light, heat, and moisture in the natural environment. Exposures are not intended to simulate the deterioration caused by localized weather phenomena, such as atmospheric pollution, biological attack, and saltwater exposure. The Significance and Use section in Practice G151 and the standard for the appropriate apparatus, that is, Practices G152 , G153 , G154 , or G155 should be consulted for additional information on significance and use of the exposure tests. 3.2 The primary criterion used in estimating resistance to weathering is the percentage decrease in tensile strength and in elongation at break. A supplementary criterion for estimating resistance to weathering is the observed extent of surface crazing and cracking. 3.3 Results obtained by use of these test procedures should not be represented as equivalent to those of any natural exposure test until the degree of quantitative correlation has been established for the material in question. 3.4 Because of differences in the spectral power distributions of the exposure sources as well as the other conditions in the different types of laboratory weathering tests, the different procedures may not result in the same performance rankings or types of failure modes of the materials. Comparisons shall not be made of relative stabilities of materials exposed in different types of apparatus. 3.5 When conducting exposures in devices that use laboratory light sources, it is important to consider how well the artificial weathering conditions will reproduce property changes and failure modes caused by end-use environments on the materials being tested. 3.6 Practices G151 , G152 , G153 , G154 , and G155 recommend that a similar material of known performance (a control) be exposed simultaneously with the test specimen to provide a standard for comparative purposes. Preferably, a control material known to have poor durability as well as one that has good durability should be used. The reason for using a control is that reproducibility in ranking stabilities is usually better than reproducibility of absolute changes. Therefore, the use of controls is particularly important when test materials are not being compared with one another.