1.1 本试验方法包括在实验室条件下测量管道保温系统的插入损耗。 1.2 本试验方法的实验室认证程序见 附件A1 . 1.3 以国际单位制表示的值应视为标准值。括号中给出的值仅供参考，不视为标准值。 1.4 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。 1.5 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====== 5.1 管道保温系统的插入损耗取决于保温系统材料、使用材料的方法、管壁厚度、裸管和保温管的尺寸和形状以及造成管道噪声辐射的机制。使用该测试方法测量的插入损耗应谨慎使用。在实验室中，必须在可重复的条件下进行测量，但在现场的实际使用中，确定有效插入损耗的条件很难预测，它们可能会导致略有不同的结果。用这种测试方法测量的插入损耗可以成功地用于声学设计目的。用这种测试方法测量的插入损耗对于与实验室配置中使用的管道和滞后系统最为有用。 5.2 该测试方法可用于根据插入损失对管道隔热系统进行排序，或用于估计现场安装的管道隔热系统的现场插入损失。 5.3 该试验方法假设实验室中支撑试验管的不同方法产生的管壁应力对测量的插入损失没有显著影响。 5.4 在低于500Hz的频率下，管道滞后系统通常具有较小的插入损耗，有时为负插入损耗。在低于500Hz的频率下获得的结果可能有些不稳定。本试验方法中使用的声源通常具有300至500 Hz范围内的低频限值。由于这些原因，需要结果的最低频率带以500Hz为中心。

1.1 This test method covers the measurement of the insertion loss of pipe lagging systems under laboratory conditions. 1.2 A procedure for accrediting a laboratory for purposes of this test method is given in Annex A1 . 1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard. 1.4 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. 1.5 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 insertion loss of a pipe lagging system depends upon the lagging system materials, the method used to apply the materials, the pipe wall thickness, the size and shape of the bare and lagged pipe, and the mechanisms causing noise radiation from the pipe. Insertion losses measured using this test method should be used with some caution. In the laboratory, measurements must be made under reproducible conditions, but in practical usage in the field, the conditions that determine the effective insertion loss are difficult to predict and they may lead to slightly different results. Insertion losses measured with this test method can be used successfully for acoustical design purposes. Insertion losses measured with this test method are most useful for pipes and lagging systems which are similar to those used in the laboratory configuration. 5.2 This test method may be used to rank-order pipe lagging systems according to insertion loss or to estimate the field insertion loss of pipe lagging systems installed in the field. 5.3 This test method assumes that pipe wall stresses resulting from different methods of supporting the test pipe in the laboratory do not have a significant effect upon the measured insertion loss. 5.4 Pipe lagging systems typically have small insertion loss, and sometimes negative insertion loss, at frequencies below 500 Hz. The results obtained at frequencies below 500 Hz may be somewhat erratic. Sound sources used with this test method normally have a low frequency limit in the range from 300 to 500 Hz. For these reasons, the lowest band of frequencies for which results are required is centered at 500 Hz.