Ground penetrating radar (GPR) offers residential and commercial inspectors, plumbing and utility contractors and electricians a host of safety, efficiency and revenue benefits.
Image credit: Geophysical Survey Systems Inc.
Rather than solely relying on the national 811 call-before-you-dig hotline, to limit the risk of unintentionally digging into an underground utility line, general contractors, subcontractors and inspectors are including GPR units in their locating toolbox and using them in combination with other locating tools to improve accuracy in the workplace and on-site.
GPR Technology Addresses Wider Needs
In the past two decades, there has been an increasing adoption by surveyors and engineers of GPR utility locating equipment. Already employing electronic equipment throughout the construction process, surveyors and engineers successfully used GPR to modify the 811 process.
In recent years, engineers and project managers for subsurface utility engineering (SUE) contracts began to specify that contractors take additional measures to avoid unknown problems associated with buried underground utilities.
GPR service providers carved out a niche serving electricians, plumbers and contractors tasked with detecting utility locations.
Now, with the greater availability of numerous powerful, high quality and lower cost utility-locating GPR devices, inspectors, electricians, plumbing and utility contractors are asking why they are paying to use GPR equipment when they can simply purchase a unit for themselves.
Utility Locating Tools – 811 System, EM and GPR
Before contractors start a project, they use the 811 system to get the approximate details of all public utilities and indicate their location with spray paint or flags. Technically, just making that call satisfies a contractor’s legal responsibility.
However, many consider the 811 system to be insufficient – the safety risks and consequences of hitting a gas line and the cost of idling a workforce has compelled contractors to be more proactive in detecting exact locations of underground utility lines.
The majority of utility locators employ an electromagnetic (EM) line locator to search for active utilities. Electric lines are difficult to trace using GPR, this makes EM more reliable as it is much quicker and easier to use than GPR.
However, while EM is faster, its positioning accuracy is not as good as that of GPR, which can supply horizontal and vertical positioning information within a couple of inches.
These two methods supplement each other since GPR functions better for non-metallic objects and EM for metallic objects. If both tools determine the presence of a pipe, it instils a greater level of confidence.
Image credit: Geophysical Survey Systems Inc.
GPR Technology for Utility Location and Depth that Won’t Break Your Bank
Throughout the GPR utility world, trends have gravitated towards the use of small, portable and inexpensive units.
At the forefront of this standard is GSSI’s UtilityScan® system, released in 2017. UtilityScan was originally developed for municipalities, electrical contractors and utility installers. Since then, it has since been used in environmental and archaeology applications because of its convenient size and cost.
UtilityScan is easy to integrate with existing methods as it is the smallest utility locating GPR system available on the market.
Weighing only 34 pounds, the UtilityScan is constructed for rapid assembly, scanning and break down. When folded, the system can be stored in the back of a small vehicle. Its compact size makes it super portable and easy-to-maneuver around obstacles on busy streets and construction sites.
One of the main features of UtilityScan is the sturdy wireless antenna tested for harsh environments and job sites. UtilityScan integrates GSSI’s patented HyperStacking technology, which has been shown to increase depth penetration in complex soils while also offering high near surface data resolution.
UtilityScan is robust and built to endure on any job site anywhere in the world. This system is IP 65 rated, which makes it the perfect tool for handling rain, snow and muddy conditions.
Another key feature of UtilityScan is that it can be fitted with LineTrac®, which assists in the location of specific power sources buried underground, including AC power and induced RF energy present in conduits.
Combined with GPR radar into a single box, LineTrac has coils that can identify power radiating from electrical cables. This feature allows users to produce an overlay on the radar data that signifies the presence of AC power and/or induced RF energy present in conduits.
UtilityScan then combines the EM and GPR readings and generates the image on the screen. UtilityScan utilizes a wireless tablet-based system with a large screen, enhanced viewing experience and a simple Android app-based user interface (UI).
Perhaps the biggest shift into mass adoption has been the simple to use system. Utilizing an advanced, user-friendly interface means operators require less technical experience to gather and interpret data, charting the course to faster onboarding.
GPR offers contractors a boost in confidence, rather than relying on the 811 system. Now, GPR for utility locating is realistically accessible with small, portable and inexpensive systems readily available on the market.
This information has been sourced, reviewed and adapted from materials provided by Geophysical Survey Systems Inc.
For more information on this source, please visit Geophysical Survey Systems Inc.