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.