In this Supply Insights article, we’ll explore the resources, history, processes, and equipment municipalities and contractors use for pipe locating and leak detection.
Why Do Municipalities Need Locators?
Pipe Locating and leak detection is an important process for any municipality or contractor to utilize before installing new or making a repair to existing infrastructure.
Magnetic locators and pipe and cable Locators detect underground utilities, including sewer and water lines, pipes and cables. Ferrous materials can be picked up by a magnetic locator, while non-magnetic materials use a pipe and cable locator. A sonde can also be employed to help mark the location of underground utilities.
A sonde is a battery-powered transmitter that omits a specific frequency that pipe and cable locators can find. Sondes are fed through the pipe via a stand-alone unit or attached to a camera that is used to trace unmarked pipes or find blockages.
This video from Schonstedt® showcases the basic principles of magnetic locators.
Understanding the basic principles of our natural electromagnetic field helps professionals with locating and marking on the job. The earth acts like a large magnet, with charged north and south poles. Magnetic locators like the MAGGIE® utilize this field to passively detect and pinpoint the location of magnetic objects. The larger the object, the easier the locator will find it underground.
Differences between Pipe/Cable and Magnetic Locators
At first glance, a pipe and cable locator and magnetic locator might look the same. These high-tech tools allow operators to find and identify utilities underground, but there are significant differences in how they work.
Magnetic Locators utilize the naturally occurring magnetic field in ferrous metals to pinpoint the location. These locators can only detect the magnetic field from iron-based objects and do not interact directly with the object. Because of physics, magnetic locators can only detect ferrous metals like iron or steel. Magnetic locators are useful for locating ferrous materials near the surface, like an overgrown steel or iron septic cover or partially exposed iron pipe.
Pipe and Cable Locators utilize active and passive locating techniques to find metals and currents that are underground. An active locating technique means that operators locate pipes by introducing an electromagnetic field to existing infrastructure. Alternatively, if a pipe already carries and electromagnetic field generated by "live" cables, the locator will passively detect and find the infrastructure.
Pipe and cable locating can be more involved than magnetic pipe locating, but it still extremely important for underground infrastructure damage prevention. The video below showcases how pipe and cable locators are used and the three types of active locating.
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The direct mode introduces a strong current directly to the pipe.
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Inductive clamping introduces a weaker current by clamping the outside of the pipe.
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Inductive mode produces the weakest current and does not directly connect with the pipe. A transmitting box sends out a strong electronic signal to interact with the pipe below. This mode should only be used if direct or inductive clamp methods are not available.
Municipalities use locators to help prevent costly repairs to underground infrastructure. It’s estimated that an underground facility is damaged every 6 minutes and that annual digging damages exceed $30 billion (Common Ground Alliance). For every $1 of direct damage to a wastewater pipeline, remediating the indirect costs to the environment, worker or community health, or other affected parties can cost upwards of $29.
With this in mind, in addition to investing in the right equipment to quickly and accurately identify underground utilities, a strong public outreach message to utilize the 811-dig hotline is essential.
What are dig laws and the 811 hotline?
In 2005, '811’ became the nationally recognized number assigned by the Federal Communications Commision to allow homeowners and excavators to dial a regional call center and connect with local participating utilities. Before this, many states and local governments worked with utilities and set-up local lines to help protect electric, water and gas investments. These early call lines helped mark the start of ensuring that any excavation effort first had a municipality or utility survey the ground for existing utilities.
In 2019, local 811 call centers received over 265-million collective calls. Despite the large number, a failure to call or notify 811 is listed as the largest individual contributor to damages sustained from excavation or digging.
‘Water & Sewer’ reported the fewest incidents compared to electric, telecom and natural gas utilities. The water and wastewater field’s dedication to keeping existing infrastructure visible to locators and mitigating risk by properly locating utilities saves communities time and money while protecting infrastructure.
Considering having an on-hand supply of marking paint, flags and accessories to keep important underground utilities visible and avoid having to make an incident report.
Leak Detection Equipment
Multiple types of leak detection are employed in the field, including acoustic detection, thermal, pressure testing and video inspection. These methods vary in cost and level of invasiveness, and
depending on the pipe being inspected, they are commonly used in conjunction.
Acoustic detection uses sound to identify leaks and is the least invasive of leak detection techniques. Specialized equipment from Fisher Research Labs and Subsuface Instruments uses sensors and microphones listen to waves emitted by leaks in a pipeline and can alert technicians to the location of potential problem areas.
Thermal imaging uses infrared cameras to detect temperature differences along a pipe. Seeing a distinct heat variance on or around a pipe can quickly identify a small and slow leak.
Pressure testing is done by isolating a section of pipe and checking for leaks using pressure recording equipment. If the pressure drops unexpectedly, this is a sign of a pipe or valve infrastructure leak.
Smoke testing is a valuable method used in water and wastewater applications to identify leaks or problems in sewer systems. By introducing non-toxic smoke into the system, technicians can visually trace where the smoke escapes, pinpointing areas that need repair or maintenance. Specialized equipment is available from Superior® and Cherne®.
Video inspection involves using a camera, often equipped with a sonde, to help record location data and move it down the pipe to look for obvious defects or leaks. This method allows operators to quickly identify leaks or blockages in the system without digging up the pipeline or causing utility disruption.
Reducing Risk in Locate and Leak Detection
Investing in pipe locating and leak detection technologies is important for protecting existing infrastructure and reducing potential repair costs.
Services like the 811-dig hotline ensure safe excavation practices and prevent utility damage. Methods like acoustic detection, thermal imaging, and tracer gas allow for quick leak identification, minimizing environmental and financial risks.
These technologies enhance efficiency, safety, and sustainability, offering long-term value. By prioritizing leak detection and proper utility locating, municipalities can protect resources, reduce repair costs, and maintain the reliability of essential utility systems for their communities.
Curious about what products and programs can help with effective pipe locating or leak detection? Start a conversation with your local Supply account manager.
Isaac Ketteman - Regional Account Manager
Sources:
2020 DIRT REPORT (Common Ground Alliance)