Around the world, leaking water pipelines represent a major resource and financial loss for utilities. It is estimated that in some places, Non-Revenue Water exceeds 50 percent. In terms of financial losses, the World Bank estimates that NRW costs utilities worldwide about US$14 billion annually. By reducing these losses by half in areas with the highest NRW, it is estimated that US$2.9 billion in cash would be generated and an additional 90 million people could have access to water.
In Spain, Mancomunidad Comarca de Pamplona (MCP) is very dedicated to controlling water loss and completing regular leak detection; they have a permanent internal group with the unique goal of finding leaks.
Typically, the group uses an advanced SCADA system to identify an area with a leak and then experienced technicians use geophones to establish the exact location of the leak. Using this procedure, MCP has reached a Non-Revenue Water (NRW) level of roughly 10 percent of in their entire network. However, the Impulsión de Gorraiz pipeline had a known leak that could not be pinpointed precisely by leakage unit. MCP knew its elevation coordinates but couldn’t identify its exact location using traditional methods.
MCP uses inline tool to locate known leak
To locate the known leak on the 400 millimeter ductile iron (DI) pipeline, Pure Technologies and MCP completed am inline leak detection survey in March 2014. The inspected pipeline is part of the MCP water supply network and was constructed 20 years ago. It transports water from the Olaz – El Cano Pump Station to the Gorraiz Reservoir for 2.4 kilometers.
The purpose of this trunk main is to keep water supply to the town of Egües, which features a hotel and golf course. The pipeline has an operating pressure of 12bar and is pump operated with 50 liters per second during winter months and 100 liters per second during summer season because of increased demand. The inspection was performed in two runs to proactively address water loss on the transmission main.
To supplement its internal leak detection team and SCADA system, MCP wanted to test the validity of an inline leak detection tool to locate the known leak on this pipeline. With a philosophy of continuous improvement, MCP and Pure performed a leak detection survey with SmartBall® technology.
The importance of locating small leaks
MCP places equal importance on identifying both large and small leaks. While large leaks leak at a much higher rate, identifying them only eliminates a leak at the tail end of its life. In terms of reducing NRW, locating small leaks may actually represent the best opportunity for long-term water loss reduction. Catching a leak while it is very small prevents the decades of sustained water loss that would occur as it grows into a large leak. While large leaks are important to locate, using technology that can find small leaks on large-diameter pipelines can prevent the development of large leaks and play a vital role in the safe management of a pipeline network.
How inline leak detection works
The SmartBall tool is a free-flowing leak detection platform that operates while the pipeline remains in service. It is capable of completing long inspections in a single deployment and is equipped with an acoustic sensor that identifies acoustic anomalies associated with leaks; the acoustic signature is then analyzed to determine if it is a leak, air pocket, or an external noise.
To track the tool as it traverses the pipeline, SmartBall receivers (SBR) are placed strategically throughout the planned inspection route. As the tool traverses, it makes a sound that is recorded by the receivers to determine its position on the pipeline; this system allows leak locations to be estimated typically within 10-feet (3-meters) of the actual leak location.
Due to a 12 bar pressure at the pump station a new high pressure insertion cap was designed and fabricated to assist with insertion procedure together with a pulley system that allowed the SmartBall insertion claw to be pushed into the pipeline.
In order to ensure the highest level of accuracy, additional SBR points were mounted to track the tool closely and a mobile SBR unit was used. At the reservoir, a small-diameter net was used to retrieve the tool after the inspection was completed.
Inspection Results – MCP and Pure locate 4 leaks
Upon completion of the inspection, data analysis revealed four acoustic anomalies resembling leaks despite MCP expecting one leak along the main. Using updated client estimates and the SmartBall tool’s joint detection feature, Pure identified the exact location of the leaks with an accuracy of less than 0.5 meters. The close location accuracy was confirmed after MCP excavated the leak locations.
In addition to the accuracy, the inspection was also successful in identifying very small leaks. The leaks confirmed through excavation were as small as ~0.1 liters per minute.
Based on the inspection, MCP was very satisfied with the technology and information that will be used for future management of their water supply network.