Pure Technologies : FOR CITY OF LYON, SUEZ INSPECTS CRITICAL TRANSMISSION MAINS WITH SMARTBALL™ TOOL

With a population of nearly 500,000, Lyon is the third largest city in France, a vibrant metropolis known for its modern Confluence district as well as Renaissance palaces and Roman ruins that date back more than 2,000 years.

While Lyon's historic architecture has aged well, the same cannot be said for its buried infrastructure. In June of 2016, Suez retained the services of Pure Technologies (Pure) to perform a SmartBall inspection of two critical water mains, the Grigny Water Main and Les Halles Water Main, both located near Lyon. The inspections, conducted over two days, were part of a long-term condition assessment program for the city.

As an industrial services and solutions company specialising in securing and recovering resources, Suez provides its customers (local authorities, industry and consumers) with concrete solutions to address new resource management challenges.

Pipelines constructed of ductile iron and cast iron

The Grigny Water Main is a 500mm (20-inch) cast iron pipeline that transfers Water from the Grigny Pump Station to Saint Romain en Gier. The SmartBall inspection started at a previously installed 150mm (6-inch) tap and ended at a previously installed 150mm tap in Saint Romain en Gier, and covered a distance of approximately 8.6 kilometers (5.3 miles).

The following day Pure deployed a second SmartBall inspection, this time on the Les Halles Water Main, a 400mm (16-inch) ductile iron pipeline that transfers water from Les Halles to Saint Laurent D Chamousset. The purpose of the inspection was to locate and identify leaks and pockets of trapped gas along the 2.9 kilometer (1.8 mile) section of pipeline.

SmartBall tool chosen for ease of use and sensitivity to gas pockets and 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 its ability to inspect long distances in a single deployment. The free-swimming, acoustic-based SmartBall tool is inserted into the pipeline flow, and after traversing the inspection length, the tool is captured and extracted at a point downstream.

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.

For this project, 13 surface-mounted acoustic sensors (SMS) were placed along the Grigny pipeline to track the SmartBall tool during the inspection. For the Les Halles inspection, five (5) SMS were used to track the tool. SmartBall receivers were connected to the sensors on the pipeline at locations to track the tool during inspection.

An extraction net was used to extract the SmartBall tool once it traversed the entire length of both pipelines, and the data was evaluated by Pure analysts to identify acoustic anomalies associated with leaks and pockets of trapped gas.

SmartBall survey detects two leaks and zero (0) gas pockets

The acoustic data recorded by the SmartBall tool was analyzed and cross-referenced with the position data from each SmartBall Receiver (SBR) to determine a location for each acoustic anomaly.

From the results conducted on the Grigny Water Main, Pure detected a total of two (2) acoustic anomalies characteristic of leaks and zero (0) anomalies consistent with pockets of trapped gas. Pure analysts classified one leak as a small leak. The anomaly confidence for this leak was designated as 'low' due to the fact that it does not have all of the characteristics of a conventional leak. It is thought to be perhaps a leaking feature, such as a branch with a leaking valve or leaking air valve.

Pure classified a second leak as a large leak, and because it was a good distance away from any reference points, Pure suggested using conventional ground microphones to locate it from above ground.

For the survey of the Les Halles Water Main, Pure detected zero (0) anomalies characteristic of leaks and zero (0) acoustic anomalies characteristic of pockets of trapped gas.

The results gave Suez actionable data regarding the condition of the pipelines, and the confidence to move forward on fixing the leaks. It's a great example of a water authority taking proactive efforts at keeping its network in healthy shape.