Trunk and Interceptor Assessment

Critical Pipelines, Critical Decisions

Often times, asset managers and asset owners will identify larger diameter trunks and interceptors among their most critical sewer pipes.  Critical sewer lines often present the highest risk in a system due to the inherently high consequence of failure associated with these pipes.  Decisions regarding rehabilitation and maintenance of large pipes are accompanied with exponentially higher costs relative to performing the same activities in smaller diameter lines.

The Challenge:  Insufficient Information

Given the importance of these pipes and the decisions made to manage them, asset managers require the most useful information to make informed decisions.  Unfortunately, CCTV and other technologies commonly used for smaller diameter pipe assessments can be limited in their ability to provide useful information in larger pipes.  CCTV is of limited value in assessing large diameter pipes for two main reasons: 1) Most CCTV cameras and crawlers were designed to inspect smaller diameter lines rather larger diameter trunks and interceptors, and 2) CCTV video is of limited value in diagnosing the problems that most commonly affect critical trunks and interceptors.

• Deployment Challenges:  Trunks and interceptors often provide much harsher conditions than typically encountered in smaller diameter pipelines.  High or fast flows, large amounts of sediment or debris, inspections performed deep underground, or inspections with long distances between access points are all conditions that can thwart conventional CCTV crawlers when attempting to inspect large diameter pipes.  To address this shortcoming, RedZone has developed a complete suite of multi-sensor inspection platforms specifically designed for capturing quality data in large diameter trunks and interceptors.  By using a variety of platforms (floating, tracked, submersible), the right tool can be used to match encountered field conditions and reliably collect the required data.
• Limited Value of Visible Assessment:  CCTV video is a useful tool for assessing smaller diameter pipes, often made from materials like vitrified clay.  CCTV can adequately assess visible defects such as cracks and fractures that are likely to occur, and most CCTV crawlers can adequately light these smaller diameter pipes to capture clear video. However, larger diameter pipes are frequently constructed of materials such as concrete or brick, and asset managers are often concerned with completely different types of problems.  Corrosion of concrete pipes is a major concern, and CCTV can pick-up clues that corrosion may be occurring  but it is extremely limited in accurately diagnosing the extent of the corrosion and allowing asset managers to prioritize which areas of the system are corroding the most severely.  Quantitative techniques like multi-sensor assessment complement CCTV by providing true measurements of conditions like corrosion, sediment and debris accumulation, deformation, missing bricks, and hydrogen sulfide gas.  This allows asset managers to make fact based prioritization decisions based on objective measurements than trying to define a pipe’s condition by looking at pictures alone.  Especially when it comes to the most expensive decisions in the most critical pipes, asset managers should have no reason to guess based only on qualitative information.
  

Multi-Sensor Inspection:  Complete, Quantitative Assessment

Multi-Sensor Inspection (MSI) was developed to detect and quantify conditions that affect trunks and interceptors, but often go unnoticed by CCTV inspection.  An EPA study evaluating condition assessment technologies for large diameter pipe compared Multi-Sensor Inspection to other techniques like CCTV-only and pole cameras, inspecting a set of lines with multiple inspection technologies.  CCTV found a handful of defects, also detected during the Multi-Sensor Inspection, but it completely failed to detect or quantify the corrosion that was affecting portions of pipe.  The EPA report states:

“The laser data revealed and quantified corrosion above the water line that the conventional CCTV did not. Seven of the eighteen segments had maximum corrosion depths of greater than 1.0-in.  For areas below the water surface, the sonar data provided additional information on changes in the wall material (i.e., gain or loss) resulting from corrosion, siltation, or deformation (ovality and deflection). Evaluation of pipe below the water surface was not possible by CCTV or the other technologies evaluated.”

Multi-Sensor Information becomes even more valuable when it is accompanied with viewing tools that allow an asset manager or consultant to easily view, sort, query, and make decisions based on the data.

 

Proven Track Record

RedZone has been developing and deploying multi-sensor inspection technologies for trunks and interceptors since 2004.  Many cities and engineering consultants have relied on RedZone to inspect difficult pipes that they were unable to inspect with conventional equipment.  Still more have come to value multi-sensor information and have incorporated the objective measurements of corrosion and debris levels into their decision making processes.  Our customers frequently return to us with stories of failures that were averted or savings that have been realized by understanding their pipes in a way that CCTV only inspection cannot provide.

Contact RedZone to learn more about our trunk and interceptor assessment capabilities and discuss if our capabilities may be a fit to provide the information that you’re looking for.

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