Grading & Excavation Contractor

Advancements in Underground Detection Equipment

Hi-Tech goes underground

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Credit: GSSI GSSI’s UtilityScan DF system
Regulations and safety are the two primary driving factors in the use of underground detection technology picking up speed among contractors today.

As a result, more contractors are using GPS and three-dimensional mapping technology, says Cody Mecham, regional sales manager at McLaughlin Underground.

“There are a number of regulations being mandated by utility asset owners that utility contractors have to adopt using these technologies to work on these projects,” he says. “That trend will likely keep going which will lead to even more contractors utilizing the technology.”

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Underground detection—especially as it pertains to ground-penetrating radar (GPR)—is a fast-expanding market, notes Andrew Pronk, market manager, Sensors & Software.

“It’s safe to say that the utility locating and damage prevention industry is exploding,” he adds. “You can see billboards on the highway now with 811 logos and all of those really create large public awareness and awareness within the excavation industry.”

Pronk points out that the New Common Ground Alliance Damage Information Reporting Tool estimates $1.5 billion in damage had been done to buried utilities in 2016, a 20% increase from the previous year.

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The report summarizes data submitted anonymously and voluntarily by facility operators, utility locating companies, one-call centers, contractors, regulators, and others.

“There’s a huge liability there,” notes Pronk. “When there’s a hit and a gas leak and explosion, there’s a huge risk to the public, not to mention the workers on the site. It’s something we’re passionate about—it does come down to safety. This technology is quite literally saving lives.”

Entities such as the American Society of Civil Engineers and the National Utility Locating Contractors Association all have imaging contractors who are actively using GPR technology, points out Peter Masters, senior applications specialist, GSSI.

GPS tracking/pinpointing and data management are two hot topics right now in the industry, notes Mecham.

“The technology has been around for a while, but it is just now that we are seeing both of these underground detection advancements gaining widespread usage and acceptance,” adds Mecham.

Marker ball technology is another trend that is “really taking off,” says Mecham.

Marker balls are outfitted with a chip that can help supply information about the utilities underground such as when, why, and how a utility was previously repaired, he says, adding that using this type of technology gives future utility crews much more data with which to work.

The Vermeer Verifier G3 utility locator by McLaughlin is designed to combine precision with a user-friendly interface. Features include a combination peak and null screen, semiautomatic and manual gain adjustment, automatic depth and current measurement index, and compass icon.

“We recommend a toolbox approach to locating where multiple technologies are deployed,” notes Masters. “Each technology has its advantages and limitations, so it is best to use multiple methods that complement each other.”

The idea is to follow a mindset modeled after the concept of subsurface utility engineering, Masters suggests:

  • use drawings and existing documentation where available;
  • conduct a physical site inspection for visible clues;
  • use geophysical equipment such as electromagnetic locators, GPR, and metal detection for designating;
  • expose what you find for a final determination.

In developing GPR technologies, GSSI has utilized computer technology progress to improve the quality and ease of use for its GPR systems, including designing the systems with faster processors, more data storage, and higher-resolution displays, which are built into our latest systems to make GPR more effective.

GSSI recently released a new UtilityScan system bringing forward two primary enhancements, including a new HyperStacking antenna technology and combining its GPR antenna and LineTrac, an electromagnetic sensor, for electrical and electromagnetic locator signal.

HyperStacking refers to the use of a substantially larger GPR data set, notes Masters.

“By increasing the amount of data processed for an image, signal processing algorithms can more effectively filter noise, creating a better signal-to-noise ratio,” says Masters. “With a better signal to noise ratio, we can develop better resolution images and in many cases get better depth penetration. Because GPR is a ‘reading’ technology, better resolution and added depth is a real advantage.”

LineTrac adds the ability to detect AC power and induced RF energy present in buried utilities, notes Masters.

“It is designed to work with existing RD transmitters in the 20 hertz to 50 hertz active frequency band and seamlessly overlays the RF information onto the GPR data to greatly enhance survey efficiency,” adds Masters.

Credit: GSSI
Scanning with GSSI’s SIR-4000

Sensors & Software focuses on systems that are easy to use and fit into a contractor’s workload, notes Pronk, adding that many contractors who use the company’s systems “are not experts in geophysics by any stretch.”

GPRs can often be “confusing and difficult to use,” adds Pronk. Sensors & Software has endeavored to create systems that can be operated after a couple of days of experience, giving end-users what they need to begin to understand the interpretation and the answers that they want to achieve, he adds.

Of the offerings available from Sensors & Software, grading and excavation contractors will most benefit from GPR, notes Pronk.

“Perhaps they need to repair or they are doing a replacement of a component and they want to make sure they’re not going to hit something,” he says. “GPR is a great technology all around. 811 is the common way that excavators are getting their marks on the ground but it doesn’t promise to find everything.”

A post-811 survey may, for example, find abandoned infrastructure underground, enabling damage avoidance, says Pronk.

To that end, Sensors & Software offers the LMX100 and the LMX200. LMX is designed to locate and mark metallic and non-metallic underground utilities, utilities with broken tracer wires, undocumented utilities, disturbed soil often associated with utility burial, and unexpected obstacles and buried structures such as old foundations that can cause problems for excavations or construction.

Data is collected in the Locate and Mark mode to provide a real-time image in the field to identify utilities and mark their locations. LMX also is available with a high-resolution screen. Additional features include a touchscreen that can be used wearing gloves, markers, Wi-Fi mini-reports, internal GPS for geotagging, export usage report, USB for data transfer, full collection review of digital hyperbola calibration, data markers to highlight features, horizontal scaling to optimize target visibility, and bright, high-contrast color display for data visibility in all lighting conditions.

Subsurface utility engineering is a prequel to the planning process, notes Pronk.

“A utility locator is going to be paid to go in and find all of the services to a certain level of quality. GPR is an excellent tool to process and allow them to achieve the process by providing them with even more information, more accuracy, and more confidence that what they’re finding is correct,” says Pronk.

The GPR data can help the contractor mark a spot that enables a vacuum excavator truck to be positioned in the exact location the first time, thus saving money, says Pronk.

In data management, GPR with GPS enables contractors to have a record of where the objects are found, providing those in utility engineering the ability to manage the information, he adds.

To that end, Sensors & Software offers Noggin GPR systems in four standard configurations, designed to collect data in any environment, temperature, and weather conditions for any application, spanning the depths and resolutions required for subsurface investigations.

Noggin features ultra-wideband GPR antennas; a digital video logger; flexible data collection; and a high resolution, sunlight visible, resistive touchscreen with Wi-Fi and USB data transfer. It is ground-coupled for maximum signal penetration and data quality.

The GPR parameters can be changed to optimize the survey by adjusting depth, step size, stacking, time window, grid size, and triggering.

Noggin offers Wi-Fi mini-reports of a line, depth slice, or map view. Depth slicing enables users to collect grids of data and view depth slices in the field. Using external GPS, users can display a plan map view of survey path, grids, field interpretations, and flags.

Field interpretations can be color-coded with field flags included. An optional GPS can be integrated for post-processing and export to Google Earth, CAD drawings, and GIS databases.

Custom settings allow users to collect data with extreme values.

The use of EKKO Project software enables users to transfer the data to a computer to be organized, edited, processed, and plotted with GPR data. EKKO Project’s reporting capability outputs interpretations and other information into PDF, spreadsheet, Google Earth, and CAD files.

“Noggin provides the contractors with the ability to deploy the system depending on the situation,” notes Pronk. “They can tow it behind a vehicle, run it in a cart, survey in very tight areas. It also gives them the right ultra-wideband antennae option in order to get the depth of penetration they need to get the resolution so they can find those small surface lines, particularly on the telecom side of things.

“It’s really important to find fiber optics when they’re doing subsurface utility engineering because some of these lines cost millions of dollars for an excavator if they were to cut those.”

Many operators run GPR in real time, notes Masters.

“However, there seems to be a recent push towards subsurface utility engineering practices in mainstream utility locating—a trend with big data,” says Masters. “The use of GPS, network level surveys, and virtual reality are becoming common topics in the underground utility locating industry. The net benefit in all of this is transparency. The more transparent the data is, the better we are at communicating what’s under and above ground.”

Using GPS and 3D mapping can save a tremendous amount of labor expenses, Mecham points out.

Presently, a locator must mark utilities before every underground construction project. As more locators use GPS locating and utility crews verify exact locations through potholing, the collective data can be used in the future to help reduce the labor involved with marking utilities, he points out.

Going forward, “the goal would be that there is enough collected data that utility contractors could simply request a locale, plug the information into their equipment, and pinpoint the location of everything buried underground,” says Mecham.

While having big data to leverage can be advantageous, “making sure you have the right information is even more important,” says Pronk.

Sensors & Software focuses on a user-friendly system with easy to interpret data processing software “so that they have the background of this big data, but in the foreground, they find the things they need to find,” he says.

Pronk says he likes to emphasize GPS integration with GPR.

“We’re seeing people move into this realm in order to be able to map,” he adds. “Traditionally, whenever you’re mapping with GPR, you’re measuring lines and trying to position things and that takes a long time.”

Sensor & Software’s system is designed to identify the utilities “and with the touch of a finger, they can put little dots or interpretations into the data of where the utilities are and when they take that back to the office and put that on their computer, it can be processed immediately.”

While underground detection equipment is becoming more common on the job site, it’s not quite widespread yet because of its associated costs.

“The best GPS locator requires a more significant upfront investment which is why it’s taking a bit of time for GPS technology to gain widespread acceptance,” says Mecham. “We see cost begin to decline. However, it is still not at a point where small municipalities are willing to invest in using it yet.”

Data storage costs are another factor, says Mecham.

“As more data is collected, storage fees grow, and over time there could be thousands of terabytes of information in a nationwide database,” he adds.

Associated costs for ground penetrating radar systems can run from $10,000 to $100,000, notes Masters, adding that costs depend on the manufacturer and amount of data needed.

“Beyond that, some manufacturers charge for training, and the company will always have costs with onboarding new employees if this is a new service offering,” says Masters.

Pronk notes that costs associated with underground detection are based on a company’s size and the type of work they’re doing, be it post-811 locates or subsurface utility engineering work.

“Often a GPR operator charges out at $250 an hour, so when you look at that over the course of a day or a week, that adds up very quickly,” he says. “Bringing the technology in-house allows people to save on those costs.”

Sensors & Software offers a lease-to-own program which is ideal for those who don’t have the upfront capital, notes Pronk, adding that it provides contractors the ability to obtain a GPR system and after a few months of usage, start seeing a return on investment. GX_bug_web

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