1.1 本试验方法包括隔声罩降噪的混响室测量。 1.2 可根据根据本试验方法测量的降噪来确定噪声隔离等级。 1.3 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建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《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 外壳的降噪取决于外壳的特性、用于测量降噪的声源的位置以及外壳所在的空间。它不仅仅是外壳的特性，在不同条件下的测量可以得到不同的结果。当根据本试验方法测量降噪时，声源位于外壳外，外壳外的声场近似于扩散声场。根据本试验方法进行的测量可以在实验室间重现。 5.2 根据本试验方法测量的降噪可用于以下目的: 5.2.1 根据噪声隔离等级NIC对隔音外壳的顺序进行排序。 5.2.2 估计外壳外可能出现的最高三分之一倍频程声压级，而不超过外壳内规定的声压级。 5.2.3 估计外壳内部出现的三分之一倍频程声压级和外壳外部指定的声压级。 5.3 根据本测试方法测量的降噪可能无法准确估计外壳用于将内部噪声源与外部空间隔离时将提供的隔离。当使用本测试方法测量的降噪来评估用于封闭噪声源的外壳时，用户应谨慎。 5.4 隔音外壳通常由预制模块化面板制成。本试验方法测得的降噪适用于整个外壳，而不适用于制造外壳的单个面板，且不能用于推断单个面板的声音传输损失。 5.5 隔音外壳的规范可包括根据本试验方法测量的降噪和隔音等级。

1.1 This test method covers the reverberation room measurement of the noise reduction of sound-isolating enclosures. 1.2 The noise isolation class may be determined from the noise reduction measured in accordance with this test method. 1.3 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. 1.4 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 noise reduction of an enclosure is a property of the enclosure, the location of the sound source used to measure noise reduction, and the space in which the enclosure is placed. It is not a property of the enclosure alone, and its measurement under different conditions can be expected to give different results. When the noise reduction is measured in accordance with this test method, the sound source is outside the enclosure and the sound field outside the enclosure approximates a diffuse sound field. Measurements made in accordance with this test method can be expected to be reproducible from one laboratory to another. 5.2 The noise reduction measured in accordance with this test method may be used for the following purposes: 5.2.1 To rank the order of sound-isolating enclosures according to noise isolation class, NIC. 5.2.2 To estimate the highest one-third octave band sound pressure levels that can occur outside the enclosure without exceeding specified sound pressure levels inside the enclosure. 5.2.3 To estimate the one-third octave band sound pressure levels that will occur inside the enclosure with specified sound pressure levels outside. 5.3 The noise reduction measured in accordance with this test method may not estimate accurately the isolation that the enclosure will provide when it is used to isolate a noise source inside it from the space outside. The user should be cautious when using noise reductions measured by this test method to evaluate enclosures used to enclose noise sources. 5.4 Sound-isolating enclosures are frequently made from prefabricated modular panels. The noise reduction measured by this test method applies to the complete enclosure and not to individual panels from which it is made and cannot be used to infer the sound transmission loss of the individual panels. 5.5 Specifications for sound-isolating enclosures may include reference to noise reduction and noise isolation class measured in accordance with this test method.