1.1 本规程涵盖了使用透射声学评估重力供水下水管道堵塞的程序，目的是优先考虑下水管道清洁操作。 2. 该评估基于声学接收器，该声学接收器测量通过被测管段传输的声学平面波，以评估整个管段的堵塞情况，并对管段内的堵塞情况进行现场评估。( 1. ， 2. ， 3. ， 4. ， 5. ) 3. 1.2 本规程的范围包括使用透射声学检查作为筛查工具。声学检查提供的堵塞评估应用于识别需要进一步维护（如清洁或目视检查）的管段并确定其优先级。 因此，还可以识别足够清洁且不需要额外维护操作的管段。 1.3 本标准做法不涉及管壁的结构问题。 1.4 检查过程需要从地面进入检修孔（MH）。它不需要设备或操作员对下水道进行物理访问。 1.5 本标准实施规程适用于所有类型的管道材料。 1.6 检查过程需要进入下水道，并沿道路或其他存在安全隐患的位置进行作业。本标准未描述在这些危险环境中操作时可能遇到的危险或必须执行的安全程序。 1.7 以英寸-磅为单位的数值应视为标准。括号中给出的值是国际单位制的数学转换，仅供参考，不被视为标准。 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）。本标准的使用者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》中确立的国际公认的标准化原则制定的。 ===意义和用途====== 4.1 意义: 4.1.1 收集系统维护需要在系统故障（下水道溢流、主线堵塞和建筑物备份）之前将清洁资源分配到正确的位置。透射声学检查提供了一种工具，通过根据管道段的堵塞评估对其进行优先级排序来帮助分配清洁资源，从而促进高效的清洁资源分配。 4.1.2 本标准实施规程提供了关于重力供水下水道管道堵塞评估的透射声学检查的最低要求和建议实施规程，以满足维护人员、工程师、承包商、当局、监管机构和金融机构的需求。 4.2 限制和适当用途: 4.2.1 透射声学检查提供的堵塞评估可能无法解决管段内堵塞的类型，也无法解决管节内堵塞的位置。 4.2.2 由于与透射声学检查相关的物理特性，堵塞评估可能会因以下原因而混淆: （1） 导致差的声学耦合的结构设计， （2） 完全充满水的管段，例如，完全管道下垂或倒虹吸管，以及 （3） 管道内的瞬态条件，例如主动横向排放或临时流量附加费。 这些问题作为中指定的性能标准的一部分进行了解决 X1.5 。 4.2.3 由于与声学和贸易相关的物理学- 在进行透射声学检测的设备设计中，存在基于以下管段属性的限制: （1） 管道直径， （2） 管段长度， （3） MH深度，以及 （4） 流量水平。 在这些管段属性的制造商建议范围之外进行的检查可能会导致透射声堵塞评估偏离中规定的性能标准 X1.5 。 4.2.4 在非相邻MH之间进行的检查，例如，跳过中间MH，可能导致透射声阻塞评估偏离中规定的性能标准 X1.5 。

1.1 This practice covers procedures for assessing the blockage within gravity-fed sewer pipes using transmissive acoustics for the purpose of prioritizing sewer pipe cleaning operations. 2 The assessment is based on an acoustic receiver measuring the acoustic plane wave transmitted through the pipe segment under test in order to evaluate the blockage condition of an entire segment and to provide an onsite assessment of the blockage within the pipe segment. ( 1 , 2 , 3 , 4 , 5 ) 3 1.2 The scope of this practice covers the use of the transmissive acoustic inspection as a screening tool. The blockage assessment provided by the acoustic inspection should be used to identify and prioritize pipe segments requiring further maintenance action such as cleaning or visual inspection, or both. Thereby, also identifying the pipe segments which are sufficiently clean and do not require additional maintenance action. 1.3 This standard practice does not address structural issues with the pipe wall. 1.4 The inspection process requires access to the manhole (MH) from ground level. It does not require physical access to the sewer line by either the equipment or the operator. 1.5 This standard practice applies to all types of pipe material. 1.6 The inspection process requires access to sewers and operations along roadways or other locations that are safety hazards. This standard does not describe the hazards likely to be encountered or the safety procedures that must be carried out when operating in these hazardous environments. 1.7 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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 ====== 4.1 Significance: 4.1.1 Collection system maintenance requires allocating cleaning resources to the right place prior to system failure (sanitary sewer overflows, mainline blockages, and building backups). Transmissive acoustic inspection provides a tool to assist in allocating cleaning resources by prioritizing pipe segments based on their blockage assessment and thereby facilitating efficient cleaning resource allocation. 4.1.2 This standard practice provides minimum requirements and suggested practices regarding the transmissive acoustic inspection of gravity-fed sewer line blockage assessment to meet the needs of maintenance personnel, engineers, contractors, authorities, regulatory agencies, and financing institutions. 4.2 Limitations and Appropriate Uses: 4.2.1 The blockage assessment provided by the transmissive acoustic inspection may not resolve the type of blockage(s) within the pipe segment nor resolve the location(s) of the blockage(s) within the pipe segment. 4.2.2 Due to the physics associated with transmissive acoustic inspection, the blockage assessment may be confounded due to: (1) Structural designs resulting in poor acoustic coupling, (2) Pipe segments completely filled with water, for example, full pipe sag or inverted siphon, and (3) Transient conditions within the pipe, for example, active lateral discharge or temporary flow surcharges. These issues are addressed as part of the performance criteria specified in X1.5 . 4.2.3 Due to physics associated with acoustics and trade-offs in equipment design for conducting transmissive acoustic inspection, there are limitations based on the following pipe segment attributes: (1) Pipe diameter, (2) Pipe segment length, (3) MH depth, and (4) Flow levels. Inspections conducted outside the manufacturer’s recommended ranges for these pipe segment attributes may result in the transmissive acoustic blockage assessment deviating from the performance criteria specified in X1.5 . 4.2.4 Inspections conducted between non-adjacent MHs, for example, skipping an intermediate MH, may result in the transmissive acoustic blockage assessment deviating from the performance criteria specified in X1.5 .