1.1 本规程描述了根据试验方法获得的光谱辐射透射率和反射率数据计算材料的发光（光度）透射率和反射率 E903 . 1.2 与使用太阳作为光源和光度计作为检测器的方法测量光度透射率相比，通过本实施规程确定光透射率更为可取，但透射不均匀、有图案或有波纹的板材除外。 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 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 建筑物中的玻璃孔通常用于将光能和太阳辐射热能控制进入结构中。其他装置也可用于将光和太阳辐射热反射到建筑物中。 5.1.1 以这种方式进入建筑物的大部分太阳辐射能的波长在300至2500纳米（3000至25纳米）之间 000 Å). 然而，只有380至760 nm之间的部分是可见辐射。因此，在采光应用中，重要的是将这些材料的太阳辐射能透射比和反射率与其发光（视觉或光度）透射比和反射率区分开来。 5.2 为了比较建筑窗系统的能量和照明性能，重要的是，窗系统中使用的材料的太阳辐射和光透射比和反射率的计算或测量或两者都使用相同的入射太阳光谱辐照度分布。 5.2.1 太阳光透射率和反射率是描述太阳照明系统（例如窗户、天窗、天窗、遮阳和反射装置）和其他允许日光和太阳能进入建筑物的窗户组件性能的重要属性。 5.3 本规程有助于测定采光系统中使用的玻璃材料和漫反射或准漫反射材料的透光率和反射率。为了使该实践的结果有意义，样品中的不均匀性或波纹不得过大。试验方法 E1175 （或试验方法 E972 )适用于不满足此标准的板材。

1.1 This practice describes the calculation of luminous (photometric) transmittance and reflectance of materials from spectral radiant transmittance and reflectance data obtained from Test Method E903 . 1.2 Determination of luminous transmittance by this practice is preferred over measurement of photometric transmittance by methods using the sun as a source and a photometer as detector except for transmitting sheet materials that are inhomogeneous, patterned, or corrugated. 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 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 Glazed apertures in buildings are commonly utilized for the controlled admission of both light and solar radiant heat energy into the structure. Other devices may also be used to reflect light and solar radiant heat into a building. 5.1.1 Most of the solar radiant energy entering a building in this manner possesses wavelengths that lie between 300 and 2500 nm (3000 to 25 000 Å). Only the portion between 380 and 760 nm is visible radiation, however. In daylighting applications, it is therefore important to distinguish the solar radiant energy transmittance and reflectance of these materials from their luminous (visual or photometric) transmittance and reflectance. 5.2 For comparisons of the energy and illumination performances of building fenestration systems it is important that the calculation or measurement, or both, of solar radiant and luminous transmittance and reflectance of materials used in fenestration systems use the same incident solar spectral irradiance distribution. 5.2.1 Solar luminous transmittance and reflectance are important properties in describing the performance of components of solar illumination systems (for example, windows, clerestories, skylights, shading and reflecting devices) and other fenestrations that permit the passage of daylight as well as solar energy into buildings. 5.3 This practice is useful for determining the luminous transmittance and reflectance of glazing materials and diffusely or quasi-diffusely reflecting materials used in daylighting systems. For the results of this practice to be meaningful, inhomogeneities or corrugations in the sample must not be large. Test Method E1175 (or Test Method E972 ) is available for sheet materials that do not satisfy this criterion.