Standard Practice for Prioritizing Sewer Pipe Cleaning Operations by Using Transmissive Acoustic Inspection

Importancia y uso:

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.

Subcomité:

F36.20

Volúmen:

04.12

Número ICS:

93.030 (External sewage systems)

Palabras clave:

acoustic inspection; blockage assessment; cleaning operations; combined sewer; condition assessment; maintenance operation; prioritizing cleaning; sanitary sewer; wastewater collection system;