Article

Seven Georgia communities jump at opportunity to assess potable water network

Georgia Road Sign

Unlike many large, well-funded municipalities, smaller mid-sized communities often lack the financial resources to conduct proactive inspections on their buried infrastructure. Generally it’s a common situation prevalent across much of the United States.

For this reason, when several medium-sized Georgia communities were provided state funding for an inspection and condition assessment on critical sections of their water pipelines, they jumped at the opportunity to have actionable information about their actual pipeline condition.

A baseline condition inspection helps operators make defensible decisions

The Georgia Environmental Finance Authority (GEFA) facilitates programs that conserve and protect Georgia’s energy, land and water resources. In this instance, GEFA provided technical assistance funding for seven mid-sized communities to perform condition assessment on large diameter lines, which for these communities, ranged from 8-inch polyvinyl chloride (PVC) to 24-inch ductile iron pipes.

Pure Technologies was retained to perform condition assessment work for seven (7) Georgia communities, which included Marietta Board of Lights and Water, Paulding County, Haralson County, City of Dublin, City of Valdosta, Spalding County, and Coweta County—whose populations ranged from 10,000 to 100,000.

For the most part, Pure performed a SmartBall® leak and gas pocket inspection and Transient Pressure Monitoring with Fatigue Analysis on the potable water pipelines for the subject communities.

In addition, Pure was also retained to deploy a SmartBall® Pipe Wall Assessment (PWA) on the ductile iron mains for the City of Valdosta Utilities Department and the Marietta Board of Lights and Water.

PWA data

SmartBall PWA technology is used to evaluate metallic pipelines by detecting and measuring the changing levels of the magnetic field, which is related to the stress in the pipe wall. As a screening tool, PWA technology provides an indication of pipe sections exhibiting higher levels of stress, which can be used as a first stage of pipeline condition assessment to help make informed decisions on higher resolution investigations, inspection, data collection and subsequent management or rehabilitation.

SmartBall tool chosen for its ease of use and sensitivity to small leaks

The SmartBall tool was chosen as an inspection platform for its sensitivity to small leaks, minimal pipeline modifications required for insertion and extraction and ability to inspect long distances in one deployment. The free-swimming, acoustic-based SmartBall tool is inserted into the flow of a pipeline, traverses the pipeline, and is captured and extracted at a point downstream.

SmartBall inside a pipe with a net

During inspection, the SmartBall tool’s location is tracked at known points along the alignment to correlate the inspection data with specific locations. As the SmartBall tool approaches a leak, the acoustic signal will increase and crescendo at the point when the tool passes the leak.

Deploying the SmartBall tool allowed each inspection to take place while the mains remained in service, a benefit much appreciated by the communities.

“This was an excellent opportunity to offer mid-sized communities in Georgia with a non-destructive internal inspection of critical pipes within areas where traditional methods may not able to collect this important information. Pure provided very professional service to work with the Utilities and help develop a specific plan to acquire this valuable data.”

Larry Lewison, NRW Analyst, Consultant

Inspection not without its challenges

In general, for most of these smaller communities, condition assessment was a novel concept, which meant lots of communication between Pure and the utilities. Mid-sized utilities, understandably, are often hamstrung by a lack of as-built drawings, geographic information systems (GIS) or other connection and appurtenances information on their pipeline network.

In the end, based on Pure’s many years of inline inspection experience and expertise, obstacles were overcome and the overall inspection program was a positive learning experience for all.

Results from cumulative 11.7 miles of inspection

Immediately after each inspection, the data was downloaded from the SmartBall tool, verified for quality and sent to Pure Technologies for review by the analysis team.

Based on the acoustic results of all the SmartBall inspections, three (3) true leaks and zero (0) acoustic anomalies characteristic of gas pockets were found on a cumulative distance of 11.73 miles of pipe inspected. For the city of Valdosta, which included a PWA inspection, Pure identified 30 specific pipes as having anomalies indicative of stress. For the Marietta Board of Lights and Water, Pure detected 61 stress anomalies along the pipe wall. This indicates a 22 percent anomaly rate, which is average compared to historical data on similar pipelines.

In addition, Pure also performed fatigue analysis for all PVC pipes, and no immediate concerns were noted.

The results indicate that the assessed mains are generally in serviceable condition, and gave the Georgia communities confidence in the overall health their systems, with no need for immediate rehabilitation, except for the three leaks that warranted attention. This process allows the communities to develop a sustainable long-term strategy for managing their critical buried assets.

Insertion and extraction sites