本文件规定了一种实验室替代方法，用于确定管道消音器（主要是吸收式、圆形和矩形消音器）以及通风和空调系统中使用的其他管道元件的无流动插入损失。 注:ISO 7235[5]中描述了叠加流管道消音器的实验室测量程序。 本文件适用于设计速度不超过15 m/s的消音器。由于该方法不包括自产生的流动噪声，因此本文件不适用于消音器测试，因为这种类型的噪声对于消音器性能的评估非常重要。由于大多数消音器，尤其是办公室和住宅中的消音器，其设计速度低于15 m/s，因此本文件通常是ISO 7235[5]的经济高效的替代方案。根据本文档在实验室中确定的插入损耗不一定与在现场安装中获得的插入损耗相同。管道中不同的声场和流场产生不同的结果。在本文中，声场以平面波模式为主。由于使用常规测试管道，结果可以包括经由管道壁中的结构振动的一些侧翼传输，这设置了可以确定的插入损耗的上限。 本文件旨在用于直径为80 mm至2 000 mm的圆形消音器或横截面积在相同范围内的矩形消音器。

This document specifies a laboratory substitution method to determine the insertion loss without flow of ducted, mainly absorbent, circular and rectangular silencers, as well as other duct elements for use in ventilating and air-conditioning systems. NOTE Laboratory measurement procedures for ducted silencers with superimposed flow are described in ISO 7235^[5]. This document is applicable to silencers where the design velocity does not exceed 15 m/s. As the method does not include self-generated flow noise, this document is not suitable for tests on silencers where this type of noise is of great importance for the evaluation of the silencer performance. As most silencers, particularly in offices and dwelling, have design velocities below 15 m/s, this document can often be a cost-efficient alternative to ISO 7235^[5]. The insertion loss determined according to this document in a laboratory is not necessarily the same as the insertion loss obtained in an installation in the field. Different sound and flow fields in the duct yield different results. In this document, the sound field is dominated by plane wave modes. Due to the use of regular test ducts, the results can include some flanking transmission via structural vibrations in the duct walls that sets an upper limit to the insertion loss that can be determined. This document is intended to be used for circular silencers with diameters of 80 mm to 2 000 mm or for rectangular silencers with cross-sectional areas within the same range.