Ground penetrating radar services provided by GPRS aided in the safe excavation of a 24-mile-long pipeline in Monument, New Mexico.
GPRS Area Manager Ryan Dennis was called in to scan along 13 miles of the pipeline’s known path and verify the location and depths of multiple types of utility lines, including communication, irrigation, water, sewer, power, and natural gas.
GPRS primarily uses ground penetrating radar (GPR) when conducting utility locating services. GPR is a non-destructive detection and imaging method which identifies subsurface elements either underground or within a surface such as concrete.
GPR works by sending a radio signal into a structure and reading the interaction between the radio waves and subsurface objects they encounter, including both metallic and non-metallic materials. These interactions – sometimes referred to as “bounces” – are detected by the GPR unit and displayed in a readout of hyperbolas varying in size and shape depending on what type of material was located.
Properly trained utility locating professionals such as GPRS’ SIM-certified Project Managers (PMs) and Area Managers (AMs) can interpret the data in these readouts to determine what type of utilities or other obstructions were located and provide the estimated depth of these items.
When used properly, GPR scanning is a highly accurate method for conducting utility locates and/or precision concrete scanning and imaging. But while GPRS derives its name from GPR, we have become much more than just a GPR company. When locating utilities, that means employing complementary technology such as electromagnetic (EM) locating to compensate for GPR’s limitations and provide the most accurate infrastructure data possible.
Unlike with GPR scanning, EM locators do not locate buried pipes or cables – they detect the electromagnetic signals radiating from metallic pipes and cables.
These signals can be created by the locator’s transmitter applying current to the pipe, or from current flow in a live electrical cable. They can also result from a conductive pipe acting as an antenna and re-radiating signals from stray electrical fields (detected by the EM locator functioning in Power Mode) and communications transmissions (Radio Mode).
By utilizing both GPR and EM locating, Dennis verified the location of multiple known lines and located several previously unknown utilities along the pipeline’s path. This ensured no subsurface damage occurred during excavation of the pipeline, keeping the project on time, on budget, and safe.
This use of complementary technologies is in alignment with the teachings of SIM, or Subsurface Investigation Methodology. The industry-leading training program and specification for utility locating, concrete scanning and video pipe inspection, SIM teaches that the use of multiple locating technologies during these investigations ensures a redundant confirmation of results. And SIM’s step-by-step approach to collecting subsurface data ensures that the results of locates are repeatable and accurate.
Every member of GPRS’ field team is required to achieve SIM certification. To do this, they complete a minimum of 320 hours of field training, as well as 80 hours of classroom training at GPRS’ state-of-the-art training center in Sylvania, Ohio.
It’s GPRS’ adherence to SIM that has led to us achieving and maintaining a 99.8%+ rate of accuracy on the over 500,000 utility locating and concrete scanning projects that we’ve completed to date.
Some of the utilities that Dennis located were buried as far as 4 feet below the surface.
The data collected and provided by Dennis allowed the contractor to adjust their plans to avoid costly and potentially dangerous subsurface damage during excavation.
The client shared with Dennis that they originally believed they would only need to contact their state’s 811 one-call service prior to digging. 811 is the national call-before-you-dig number, which contractors and excavators are required by law to contact prior to breaking ground.
It’s important to remember, however, that 811 contractors only provide the approximate location of public utilities. They do not provide the estimated location of private utilities – those owned and operated by individuals and businesses – which make up 60% of all buried lines.
If the contractor had followed their initial plan of only contacting 811, they wouldn’t have known the location of private utilities along their planned excavation path and subsurface damage would have likely occurred.
This is why it’s vital to hire a private utility locator like GPRS prior to breaking ground. Our private utility locating services compliment the services provided by 811 to mitigate the risk of subsurface damage during excavation projects.
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Frequently Asked Questions
What type of informational output is provided when GPRS conducts a utility locate?
Our Project Managers flag and paint our findings directly on the surface. This method of communication is the most accurate form of marking when excavation is expected to commence within a few days of service.
GPRS also uses a global positioning system (GPS) to collect data points of findings. We use this data to generate a plan, KMZ file, satellite overlay, or CAD file to permanently preserve results for future use.
Finally, all GPRS clients receive a complimentary SiteMap® Personal subscription with every utility locate. SiteMap® (patent pending) is GPRS’ cloud-based infrastructure mapping software solution that provides secure, 24/7 access to the field-verified data collected by our SIM and NASSCO-certified Project Managers. Click here to learn more.
Can GPR scanning find PVC piping and other non-conductive utilities?
Yes, GPR scanning is exceptionally effective at locating all types of subsurface materials. There are times, however, when PVC pipes do not provide an adequate signal to ground penetrating radar (GPR) equipment and can’t be properly located by traditional methods.
When GPR isn’t the right tool for the job, GPRS utilizes complimentary technology such as electromagnetic (EM) locating.
Will I need to mark out the utilities that GPRS locates?
No, GPRS will locate and mark all utilities for you. We have a variety of tools and markers we can use to highlight the locations of utilities, underground storage tanks (USTs) and whatever else may be hiding beneath the surface.
