1.1 该表提供了标准的紫外光谱辐照度分布，该分布可作为在应用于室内暴露试验时判断人造紫外光源的依据。该表为与自然阳光紫外线光谱数据进行比较提供了参考。紫外线参考光谱辐照度适用于280至400 nm的波长范围。所选波长区域由320至400 nm的UV-A光谱区域和280至320 nm的UV-B区域组成。 1.2 该表定义了单个紫外线太阳光谱辐照度分布: 1.2.1 入射到太阳上的半球形紫外线太阳光谱总辐照度（由直接和漫反射分量组成）- 根据1976年美国标准大气廓线（USSA 1976），在海拔2 km（2000 m）处，面对波长范围为280至400 nm的37°倾斜表面，气团1.05，臭氧含量规定为0.30大气厘米（atm-cm）等效厚度。 1.3 这些表中包含的数据是使用Gueymard开发的SMARTS2 2.9.2版大气传输模型生成的 ( 1. , 2. ) . 1.4 选择的气候、大气和几何参数反映了在典型晴空条件下提供真实最大紫外线照射的条件。 1.5 SMARTS2型号的可用性（作为附件（ADJG173CD 3. )用于生成标准光谱的）允许用户评估相对于此处指定光谱的光谱差异。 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。 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====== 5.1 本标准无意解决材料在其使用寿命期间将受到的太阳紫外线光谱辐照度的平均水平。 选择光谱辐照度分布来代表自然太阳紫外线辐射的合理上限，在评估材料在各种暴露条件下的行为时应考虑该上限。 5.2 太阳能的吸收率、反射率和透射率是材料降解研究中的重要因素。这些特性通常是波长的函数，在计算太阳加权特性之前，需要知道太阳通量的光谱分布。 5.3 要解释暴露于自然太阳辐射或人工光源紫外线辐射的材料的行为，需要了解所采用的光谱能量分布。 为了比较竞争产品的相对性能，或比较产品在经受风化或其他暴露条件前后的性能，需要参考标准太阳光谱分布。 5.4 37°朝南倾斜表面上参考半球紫外线辐射的SMARTS2模型输出图如所示 图1 . SMARTS2在规定条件下生成频谱所需的输入如所示 表1 . 5.5 需要使用SMARTS2 2.9.2版来生成AM 1.05 UV参考光谱。 5.6 辅助标准计算机软件（ADJG173CD）的可用性 5. )对于SMARTS2，用户可以( 1. )使用上述输入参数再现参考光谱； ( 2. )计算测试光谱，尝试在指定的半高宽下匹配测量数据，并评估大气条件；和( 3. )计算代表相对于任何一个或所有参考光谱进行分析的特定条件的测试光谱。

1.1 The table provides a standard ultraviolet spectral irradiance distribution that maybe employed as a guide against which manufactured ultraviolet light sources may be judged when applied to indoor exposure testing. The table provides a reference for comparison with natural sunlight ultraviolet spectral data. The ultraviolet reference spectral irradiance is provided for the wavelength range from 280 to 400 nm. The wavelength region selected is comprised of the UV-A spectral region from 320 to 400 nm and the UV-B region from 280 to 320 nm. 1.2 The table defines a single ultraviolet solar spectral irradiance distribution: 1.2.1 Total hemispherical ultraviolet solar spectral irradiance (consisting of combined direct and diffuse components) incident on a sun-facing, 37° tilted surface in the wavelength region from 280 to 400 nm for air mass 1.05, at an elevation of 2 km (2000 m) above sea level for the United States Standard Atmosphere profile for 1976 (USSA 1976), excepting for the ozone content which is specified as 0.30 atmosphere-centimeters (atm-cm) equivalent thickness. 1.3 The data contained in these tables were generated using the SMARTS2 Version 2.9.2 atmospheric transmission model developed by Gueymard ( 1 , 2 ) . 1.4 The climatic, atmospheric and geometric parameters selected reflect the conditions to provide a realistic maximum ultraviolet exposure under representative clear sky conditions. 1.5 The availability of the SMARTS2 model (as an adjunct (ADJG173CD 3 ) to this standard) used to generate the standard spectra allows users to evaluate spectral differences relative to the spectra specified here. 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. 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 ====== 5.1 This standard does not purport to address the mean level of solar ultraviolet spectral irradiance to which materials will be subjected during their useful life. The spectral irradiance distributions have been chosen to represent a reasonable upper limit for natural solar ultraviolet radiation that ought to be considered when evaluating the behavior of materials under various exposure conditions. 5.2 Absorptance, reflectance, and transmittance of solar energy are important factors in material degradation studies. These properties are normally functions of wavelength, which require that the spectral distribution of the solar flux be known before the solar-weighted property can be calculated. 5.3 The interpretation of the behavior of materials exposed to either natural solar radiation or ultraviolet radiation from artificial light sources requires an understanding of the spectral energy distribution employed. To compare the relative performance of competitive products, or to compare the performance of products before and after being subjected to weathering or other exposure conditions, a reference standard solar spectral distribution is desirable. 5.4 A plot of the SMARTS2 model output for the reference hemispherical UV radiation on a 37° south facing tilted surface is shown in Fig. 1 . The input needed by SMARTS2 to generate the spectrum for the prescribed conditions are shown in Table 1 . 5.5 SMARTS2 Version 2.9.2 is required to generate AM 1.05 UV reference spectra. 5.6 The availability of the adjunct standard computer software (ADJG173CD 5 ) for SMARTS2 allows one to ( 1 ) reproduce the reference spectra, using the above input parameters; ( 2 ) compute test spectra to attempt to match measured data at a specified FWHM, and evaluate atmospheric conditions; and ( 3 ) compute test spectra representing specific conditions for analysis vis-à-vis any one or all of the reference spectra.