1.1 本试验方法利用实验室空间，其布置方式可以模拟一对水平相邻的小办公室或房间，这些办公室或房间由隔墙隔开，并共享一个公共阻燃空间。隔板要么延伸到公共增压空间的底面，要么穿过它。在规定的配置中，设施的特殊设计特征确保唯一有效的声音传输路径是通过天花板和增压空间。 1.2 在重要性声明中概述的限制范围内，通过本试验方法测量的主要量是安装在实验室环境中的吊顶的天花板衰减。 通过考虑接收室吸声，可以确定归一化天花板衰减。 1.3 该试验方法也可用于评估由天花板材料和其他部件（如灯具和通风系统）组成的复合天花板系统的衰减。 1.4 天花板系统的现场性能可能与通过该试验方法获得的结果存在显著差异（见第节） 5. ，意义和用途，以及测试方法 E336页 ). 1.5 这些程序也可用于研究其他衰减措施可能实现的额外隔声。这包括用作增压屏障或用作全部或部分天花板的背衬的材料。 1.6 该设施还可用于研究由增压室、天花板和隔板组成的集成系统的性能，并作为单个组件进行测试。 1.7 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.8 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。 1.9 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 现代办公室和其他多用途建筑通常在房间分隔隔板上安装有吊顶吸声天花板。本测试方法中规定的测试设施有助于提供相关天花板/隔墙元件和系统的天花板衰减数据，以确保通过天花板和增压空间或通过天花板、增压空间和隔墙系统的组合进行的声音传输提供适当的隔音度。 5.2 本试验方法有助于在标准化条件下，对安装在指定悬挂系统中的天花板材料的声音衰减性能进行评级和规定。 5.3 该测试方法可用于选择可能符合房间间整体隔声性能规范的墙-天花板系统。然而，实际现场性能可能会有显著差异，特别是如果现场静压箱深度不在本试验方法规定的限制范围内，或者如果静压箱空间包含大型管道、梁等，或者两者都包含。（见试验方法 E336页 .) 5.4 测试设施固有的灵活性可以评估贯穿件、诱导泄漏路径、灯具和空气扩散器安装的影响以及隔墙线处天花板悬挂系统中的不连续性，包括隔墙渗透到天花板静压箱的影响。 还可以研究在分隔线处安装增压屏障的效果。 5.5 由于安装在房间中的悬吊吸声天花板提供的吸声区域的浓度，不可能获得该房间中漫反射声场的良好近似值。静压箱尺寸防止在试样上方维持漫射声场。这些因素会影响测得的天花板声衰减值，因此测量值不是天花板的基本特性。该测试方法测量在规定的测试条件下可达到的声学特性，这些条件是任意选择的。 每个测试设施都必须遵守这些条件，以便测量结果保持一致。获取的两种方法 A. ，接收室吸收，无需优先考虑。一种称为稳态方法的方法已用于获得 A. 在AMA 1-II-1967标准中。另一种方法遵循试验方法中使用的程序 E90 和 C423 ; 可在参考文献中找到使用该方法的理由 ( 1. ) 5. . 建议希望进一步调查本试验方法限制的人员阅读参考文献 ( 2. ) , ( 3. ) , ( 4. ) 和 ( 5. ) . 5.6 尽管存在上述限制，多年来，这种类型的测试方法已成功用于对商用天花板系统进行排序，测试结果通常用于此目的。

1.1 This test method utilizes a laboratory space so arranged that it simulates a pair of horizontally adjacent small offices or rooms separated by a partition and sharing a common plenum space. The partition either extends to the underside of a common plenum space or penetrates through it. In the prescribed configuration, special design features of the facility ensure that the only significant sound transmission path is by way of the ceiling and the plenum space. 1.2 Within the limitations outlined in the significance statement, the primary quantity measured by this test method is the ceiling attenuation of a suspended ceiling installed in a laboratory environment. By accounting for receiving room sound absorption, the normalized ceiling attenuation may be determined. 1.3 The test method may also be used to evaluate the attenuation of composite ceiling systems comprised of the ceiling material and other components such as luminaires and ventilating systems. 1.4 The field performance of a ceiling system may differ significantly from the results obtained by this test method (see Section 5 , Significance and Use, and Test Method E336 ). 1.5 The procedures may also be used to study the additional sound insulation that may be achieved by other attenuation measures. This would include materials used either as plenum barriers or as backing for all or part of the ceiling. 1.6 The facility may also be used to study the performance of an integrated system comprising plenum, ceiling, and partition, tested as a single assembly. 1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.8 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. 1.9 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 Modern offices and other multipurpose buildings commonly have suspended acoustical ceilings installed over room dividing partitions. The test facility prescribed in this test method is useful for providing ceiling attenuation data on the relevant ceiling/partition elements and systems, to ensure that the transmission of sound through the ceiling and plenum space, or through the combination of ceiling, plenum space, and partition systems, provides a suitable degree of acoustical isolation. 5.2 This test method is useful for rating and specifying, under standardized conditions, the sound attenuation performance of ceiling materials when mounted in a specified suspension system. 5.3 This test method may be useful for selecting a wall-ceiling system for probable compliance with a performance specification for overall sound isolation between rooms. However, the actual field performance may differ significantly, particularly if the field plenum depth is not within the limits specified in this test method or if the plenum space contains large ducts, beams, etc., or both. (See Test Method E336 .) 5.4 The flexibility inherent in the test facility enables evaluation of the effects of penetrations, induced leakage paths, luminaire, and air diffuser installations and discontinuities in the ceiling suspension system at the partition line, including penetration of the partition into the ceiling plenum. The effect of installing plenum barriers at the partition line may also be investigated. 5.5 With the concentration of sound absorbent area offered by a suspended sound absorbent ceiling installed in a room, it is not possible to obtain a good approximation to a diffuse sound field in that room. The plenum dimensions prevent the maintenance of a diffuse sound field above the test specimen. These factors affect the values of the measured ceiling sound attenuation and thus the measurements are not a fundamental property of the ceiling. The test method measures the acoustical properties attainable under the prescribed test conditions, which have been arbitrarily selected. The conditions must be adhered to in every test facility so that the measured results will be consistent. Two methods for obtaining A , the receiving room absorption, are given without preference. One method, known as the steady state method, has been used to obtain an estimate for A in the AMA 1-II-1967 standard. The other method follows the procedures used in Test Methods E90 and C423 ; justification for the use of this method may be found in reference ( 1 ) 5 . Persons wishing to further investigate the limitations imposed by this test method are advised to read references ( 2 ) , ( 3 ) , ( 4 ) and ( 5 ) . 5.6 Notwithstanding the above limitations, this type of test method has been used successfully for a number of years to rank order commercial ceiling systems and the test results are commonly used for this purpose.