GPRS recently provided utility locating services to ensure safe trenching and excavation at a private residence in Maine.
GPRS helps commercial construction, AEC, and facility management customers Intelligently Visualize The Built World® to mitigate subsurface damage and create existing condition documentation on commercial projects.
However, the general contractor for this project had worked with GPRS on several large-scale projects across the United States and contacted us to locate and map buried utilities on the quarter-acre private property after discovering that existing as-built documentation was out of date and likely inaccurate.
While federal law requires that you contact your state’s 811 one-call service prior to excavating to obtain the estimated location of all public utilities on your job site, it’s important to remember that 811 contractors do not locate private utilities – which make up roughly 60% of all subsurface infrastructure in the U.S.
To ensure that you are safe to dig, it’s vital to hire a professional private utility locating company like GPRS in addition to calling 811.
In Maine, Senior Project Manager Peter Kessinger utilized ground penetrating radar (GPR) and electromagnetic (EM) locating to locate and map all utilities on the property.
GPR scanners emit radio waves into the ground or a concrete slab, and those waves interact with any buried objects hidden within. The scanner detects these interactions and displays them in a readout as a series of hyperbolas that vary in size and shape depending on the type of material located. GPRS Project Managers are specially trained to interpret these readouts to tell you the precise location of the buried objects and provide their depth within the ground or concrete.
EM locators detect the electromagnetic signals radiating from metallic pipes and cables. These signals can emanate from current flow in a live electrical cable, or a conductive pipe acting as an antenna and re-radiating signals from stray electrical fields and communications transmissions. Your Project Manager can also create a signal by applying current to a known pipe, allowing them to map that utility’s path through your property.
GPRS Project Managers typically use both GPR scanners and EM locators when mapping underground utilities. The technologies compensate for each other’s limitations and create a redundant confirmation when designating subsurface elements – a key component of Subsurface Investigation Methodology (SIM), the industry-leading training program that we use to educate our field team members.
Kessinger located and annotated the depth of multiple previously unknown buried utilities, and he also identified the location and depth of an existing septic leach field on the property.
Also known as a septic tank drain field or a leach drain, this component of a septic system acts as a disposal filter for organic material and consists of an underground system of perforated pipes adjacent to the septic tank. After contaminants and liquid waste have been broken down by bacteria in the tank, the material then flows into the leach field through underground pipes. As liquid travels through the leach field pipes, it will seep into the ground below and be naturally filtered by the soil.
Had the contractor struck a component of the leach field during excavation, they could have caused costly damage and contaminated the property’s soil with untreated wastewater. Fortunately, the accurate utility maps created using Kessinger’s field-verified data prevented this from happening.
All utilities on the property were marked with paint and flags on the ground so that the contractor had a visual guide to reference while excavating. Additionally, our PMs use a global positioning system (GPS) to collect data points of findings that are used to generate a plan, KMZ file, satellite overlay, or CAD file to permanently preserve results for future use.
All this data is at your fingertips 24/7 courtesy of SiteMap® (patent pending), GPRS’ cloud-based infrastructure mapping software solution that provides accurate existing condition documentation to protect your assets & people.
You receive a complimentary SiteMap® Personal subscription whenever you hire GPRS to conduct a utility locate, allowing you to securely review that data whenever and wherever you need it.
From skyscrapers to sewer lines, GPRS Intelligently Visualizes The Built World® to keep your projects on time, on budget, and safe.
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GPRS’ SiteMap® team members are currently scheduling live, personal SiteMap® demos. Click below to schedule your demo and see how SiteMap® can help you plan, design, manage, dig, and build better today!
Frequently Asked Questions
Can GPRS find PVC piping and other non-conductive utilities?
GPRS scanning is exceptionally effective at locating all types of subsurface materials. There are times when PVC pipes do not provide an adequate signal to ground penetrating radar equipment and can’t be properly located by traditional methods. However, GPRS Project Managers are expertly trained at multiple methods of utility locating and can easily find PVC.
Can GPR be used to verify known measurements?
We can use ground penetrating radar (GPR) to cross-check the measured depth and location of a buried utility with existing as-built plans to verify the accuracy of plans.
Is GPRS able to distinguish between each type of underground utility that’s located?
In most situations, we can identify the utility in question without any problems, although it is not always possible to determine what type of utility is present. When this happens, we attempt to trace the utility to a valve, meter, control box, or other signifying markers to determine the type of utility buried.