1.1 这些规程涵盖了根据试验方法进行吸声试验期间使用的试样安装 第423页 . 1.2 以国际单位制表示的值应视为标准值。括号中给出的值是英寸-磅单位的数学转换，仅供参考，不被视为标准值。 1.3 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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 覆盖平面的材料的吸声不仅取决于材料的物理财产，还取决于材料在表面上的安装方式。 这些规程中规定的安装旨在模拟正常使用中存在的实验室条件。 4.2 某些指定的安装需要特殊的固定装置或与常规做法的微小偏差。这些夹具或偏差仅在实验室测试期间使用，不应指定用于实际安装。在所述安装件的规范中，它们标注为“仅用于实验室测试” 4.3 测试报告可通过类型名称引用这些安装件，而不是提供所用安装件的详细说明。

1.1 These practices cover test specimen mountings to be used during sound absorption tests performed in accordance with Test Method C423 . 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard. 1.3 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 ====== 4.1 The sound absorption of a material that covers a flat surface depends not only on the physical properties of the material but also on the way in which the material is mounted over the surface. The mountings specified in these practices are intended to simulate in the laboratory conditions that exist in normal use. 4.2 Some of the specified mountings require special fixtures or minor deviations from normal practice. These fixtures or deviations are to be used only during laboratory tests and should not be specified for practical installations. They are noted in the specifications for the mountings in question by the phrase “for laboratory testing only.” 4.3 Test reports may refer to these mountings by type designation instead of providing a detailed description of the mounting used.