1.1 本试验方法描述了测量反光膜反光性能的仪器。 1.2 本试验方法的用户必须指定要使用的入口和观察角度，并可以指定旋转角度。 1.3 本试验方法旨在作为实验室试验，需要能够充分变暗的设施，以便杂散光不会影响试验结果。测试设备必须能够实现共面几何形状。 1.4 便携式和台式反射测量设备可用于确定 R A. 使用根据本试验方法测量的几何形状和适当替代标准参考板提供的值。 在这种情况下，程序B的方法在实践中是可行的 E809 申请有关使用便携式回复反射计的更多信息，请参见试验方法 E1709 . 1.5 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。 1.6 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 通过本试验方法进行的测量与用钨丝光源（如机动车前照灯）照明时人眼看到的反光膜的视觉观察有关。 5.2 确定的值与试验方法用户指定的给定几何结构的视觉效果有关。该测试方法适用于0.1至2.0°之间的观察角（可通过仔细设计信源和接收器孔径配置实现0.1至0.2°之间的观察角），以及高达60°的入射角。它已用于确定低至0的逆反射系数值。 1 cd·lx −1. ·m −2. ，但对于小于1 cd·lx的值 −1. ·m −2. 必须特别注意接收器的响应度，并消除极少量的杂散光。

1.1 This test method describes an instrument measurement of the retroreflective performance of retroreflective sheeting. 1.2 The user of this test method must specify the entrance and observation angles to be used, and may specify the rotation angles. 1.3 This test method is intended as a laboratory test and requires a facility that can be darkened sufficiently so that stray light does not affect the test results. The testing apparatus must be able to achieve the coplanar geometry. 1.4 Portable and bench retroreflection measuring equipment may be used to determine R A values provided the geometry and appropriate substitution standard reference panels, measured in accordance with this test method, are utilized. In this case the methods of Procedure B in Practice E809 apply. Additional information on the use of portable retroreflectometers may be found in Test Method E1709 . 1.5 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. 1.6 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 Measurements made by this test method are related to visual observations of retroreflective sheeting as seen by the human eye when illuminated by tungsten-filament light sources such as a motor vehicle headlamp. 5.2 The values determined relate to the visual effects for a given geometric configuration as specified by the user of the test method. This test method has been found useful for tests at observation angles between 0.1 and 2.0° (observation angles between 0.1° and 0.2° may be achieved by careful design of source and receiver aperture configuration), and at entrance angles up to 60°. It has been used to determine coefficient of retroreflection values as low as 0.1 cd·lx −1 · m −2 , but for values less than 1 cd·lx −1 · m −2 special attention must be given to the responsivity of the receiver and to the elimination of very small amounts of stray light.