GPRS’ precision leak detection services helped a municipality in California mitigate an early-morning leak emergency.
GPRS Project Manager Rolando Medina was called to a neighborhood in the Golden State just after 6 a.m. on December 30, when the client was alerted to water surfacing between the asphalt road and sidewalks.
The problem area spanned approximately 300 linear feet (LF), and there was no evidence indicating a precise location for the leak within that area.
Municipal water distribution systems consist of extensive networks of pipes buried underground. These pipes are subject to various stressors, including ground movement, corrosion, temperature changes, and external pressure from construction activities. Over time, these issues can lead to the formation of leaks.
Detecting these leaks early is crucial to preventing non-revenue water (NRW) loss, soil erosion, contamination of drinking water, and other problems that can endanger a community, lead to increased repair costs, and more.
Medina deployed both acoustic leak detection and leak detection correlators to find the leak in the municipal system.
Acoustic leak detection is among the oldest and most commonly employed techniques for locating leaks in buried water pipes. It operates on the principle that pressurized water escaping from a pipe generates a characteristic sound. These leak noises travel through the pipe material and the surrounding soil, where they can be identified using specialized tools.
When conducting acoustic leak detection, GPRS Project Managers use sensitive listening devices, such as ground microphones or acoustic sensors, to detect the sound of water escaping from a pipe. These devices can pick up the vibrations and noises caused by the leak, even when they are not audible to the human ear.
The detected sounds are analyzed to distinguish between typical background noise and specific frequencies associated with leaks. Factors such as the type of pipe material, soil conditions, and the size of the leak can affect the sound’s characteristics.
By moving the sensors along the pipeline and comparing the intensity and frequency of the sounds, GPRS Project Managers can estimate the leak’s location with a high degree of accuracy.
Leak detection, or leak noise correlators represent a more advanced and precise evolution of acoustic leak detection. These devices use sophisticated algorithms and sensors to pinpoint the exact location of leaks with greater accuracy, even in challenging conditions.
Correlators use two more sensors placed at different points along the pipe. These sensors detect the sound of the leak as it travels through the pipe. The sensors transmit the detected sound signals to a central unit, which records the time it takes for the sound to reach each sensor.
The central unit uses cross-correlation analysis to compare the signals from the sensors. By calculating the difference in the time it takes for the leak noise to reach each sensor, the correlator can determine the leak’s precise location. The correlator displays the results on a digital interface, showing the leak’s estimated position along the pipeline. Some advanced correlators also provide information about the leak’s size and the condition of the pipe.
GPRS’ ability to rapidly mobilize to any job site anywhere in the U.S., combined with our Project Managers’ advanced knowledge and training, allowed us to use acoustic leak detection and leak detection correlators to pinpoint the neighborhood’s leak so it could be quickly repaired.
“We swiftly pinpointed the precise locations for our clients to commence excavation and repair the line,” Medina said. “Upon [the excavation crew] removing the asphalt and delving into the base, a pool of water became evident. After draining the water from the cavity, minimal digging revealed the source of the leak.”
Medina said that the surfacing water was the result of a service line which had been leaking for some time until it eventually broke off from the water main connection. Without GPRS’ leak detection services pinpointing the source of the leak, repair crews would have had to conduct exploratory excavation that would have torn up a large portion of the neighborhood’s street and sidewalks, inconveniencing residents and leading to costly and time-consuming repairs.
Instead, the leaking pipe was quickly repaired with minimal surface damage.
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Frequently Asked Questions
Can GPRS determine the size of a located leak?
After reviewing thousands of previously detected leaks, we requested clients to share photos of the remediation process. This information has allowed us to compare the final leak signals detected with the actual leak outcomes. We estimate the size of the leak based on how far the leak signal travels between contact points and the pitch of the tone received. However, we do not provide formal leak size estimations.
Why does GPRS often perform leak detection services in the early hours of the morning?
Our acoustic listening equipment is extremely sensitive, amplifying both leak signals and other noises that can obscure them during the day. In urban environments, ambient noise is often substantial, including sounds from airplanes, traffic, lawnmowers, machinery, and, most critically, water usage by residents. It falls to the Leak Detector to decide whether nighttime work is necessary to reduce background noise and focus solely on detecting the leak signal.
How confident is GPRS in the results of their leak detection investigations?
We have established a robust leak detection methodology and are confident in the accuracy of our leak location markings when all criteria are satisfied using our available technologies.
How many miles of water pipe can GPRS test in one day?
The length of pipe we can test largely depends on the Leak Detector's experience. Team members with extensive expertise can inspect up to 10 miles of metallic pipe (Cast Iron/Ductile) in a single day. Skilled Leak Detectors can assess a contact point, such as a hydrant or valve, in under a minute before proceeding to the next. Their efficiency comes from specialized training that enables them to distinguish the unique tone of a leak from the myriad of noises in the surrounding environment.
Why don’t I see any water at the location where GPRS has pinpointed as the leak?
Water naturally follows the path of least resistance, often flowing through cracks in subsurface rock or entering storm, sanitary, and conduit piping. In areas with a high sand content, it tends to travel even farther. In over 99% of the leaks we identify, no water is visible on the surface.
