1.1 本试验方法涵盖了在实验室或现场使用商用便携式太阳反射率计测定平板不透明材料太阳反射率的技术。试验方法的目的是提供评估暴露于太阳辐射的表面温度和热流所需的太阳反射率数据。 1.2 本试验方法不能取代试验方法 E903型 测量波长范围为250的太阳反射率 nm至2500 nm，使用积分球。便携式太阳反射率计使用已知太阳反射率的样品进行校准，以根据太阳光谱中四个波长的测量结果确定太阳反射率:380 nm、500 nm、650 nm和1220 nm。通过比较反射计测量值和使用测试方法获得的测量值，可以支持该技术 E903型 本试验方法适用于具有镜面和漫反射光学特性的材料试样。它特别适合测量不透明材料的太阳反射率。 1.3 以国际单位表示的数值视为标准值。本标准不包括其他计量单位。 1.4 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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 暴露于太阳辐射下的不透明表面的温度通常高于相邻的空气温度。在屋顶或墙壁封闭空调空间的情况下，会导致向内热流增加。如果设备或存储容器暴露在阳光下，通常会导致工作温度升高。太阳辐射影响表面温度的程度取决于暴露表面的太阳反射率。太阳反射率为1.0（100 % 反射）意味着对表面温度没有影响，而太阳反射率为0（无反射，全部吸收）将产生最大影响。特定太阳反射率的涂层用于改变暴露于阳光下的表面温度。涂层和表面光洁度通常根据太阳反射率进行规定。 在涂层或饰面的使用寿命期间，必须保持初始（清洁）太阳反射率，以达到预期的热性能。 5.2 该试验方法提供了一种在现场或实验室对表面进行定期试验的方法。使用此测试方法，监测因老化和/或曝露引起的太阳反射率变化。 5.3 本试验方法用于测量平面不透明表面的太阳反射率。多次测量平均值的精度通常取决于被测表面反射率的可变性。 5.4 使用此方法确定的太阳反射率计算不透明表面吸收的太阳能，如所示 等式1 . 5.4.1 将吸收的太阳能与传导、对流和其他辐射项相结合，以构建元素周围的热平衡，或计算实践中讨论的太阳反射率指数 E1980型 .

1.1 This test method covers a technique for determining the solar reflectance of flat opaque materials in a laboratory or in the field using a commercial portable solar reflectometer. The purpose of the test method is to provide solar reflectance data required to evaluate temperatures and heat flows across surfaces exposed to solar radiation. 1.2 This test method does not supplant Test Method E903 which measures solar reflectance over the wavelength range 250 nm to 2500 nm using integrating spheres. The portable solar reflectometer is calibrated using specimens of known solar reflectance to determine solar reflectance from measurements at four wavelengths in the solar spectrum: 380 nm, 500 nm, 650 nm, and 1220 nm. This technique is supported by comparison of reflectometer measurements with measurements obtained using Test Method E903 . This test method is applicable to specimens of materials having both specular and diffuse optical properties. It is particularly suited to the measurement of the solar reflectance of opaque materials. 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 The temperatures of opaque surfaces exposed to solar radiation are generally higher than the adjacent air temperatures. In the case of roofs or walls enclosing conditioned spaces, increased inward heat flows result. In the case of equipment or storage containers exposed to the sun, increased operating temperatures usually result. The extent to which solar radiation affects surface temperatures depends on the solar reflectance of the exposed surface. A solar reflectance of 1.0 (100 % reflected) would mean no effect on surface temperature while a solar reflectance of 0 (none reflected, all absorbed) would result in the maximum effect. Coatings of specific solar reflectance are used to change the temperature of surfaces exposed to sunlight. Coatings and surface finishes are commonly specified in terms of solar reflectance. The initial (clean) solar reflectance must be maintained during the life of the coating or finish to have the expected thermal performance. 5.2 The test method provides a means for periodic testing of surfaces in the field or in the laboratory. Monitor changes in solar reflectance due to aging and exposure, or both, with this test method. 5.3 This test method is used to measure the solar reflectance of a flat opaque surface. The precision of the average of several measurements is usually governed by the variability of reflectances on the surface being tested. 5.4 Use the solar reflectance that is determined by this method to calculate the solar energy absorbed by an opaque surface as shown in Eq 1 . 5.4.1 Combine the absorbed solar energy with conductive, convective and other radiative terms to construct a heat balance around an element or calculate a Solar Reflectance Index such as that discussed in Practice E1980 .