A great majority of us drive our cars down busy city streets or take leisurely strolls on the sidewalks of our neighborhoods and seldom give much thought to the elaborate maze of utility lines situated directly below. The often-forgotten infrastructure of pipe, wire and cable that provides us with the basic services we rely on every day is also largely underappreciated — we seldom give thought to what we cannot see. That is, of course, until something happens to disrupt the flow of water required for us to shower and flush or the transmission of gas or electricity needed to light, cool or heat our homes and businesses.
Utility contractors — the conscientious professionals responsible for installing the intricate underground network that allows us to enjoy so many basic services — are keenly aware of what’s at stake. Since the introduction of horizontal directional drilling (HDD) and related trenchless methods, the volume of utilities installed using trenchless technology has exploded. Yet, thanks in large part to the capabilities of a lightweight, easy-to-operate handheld locating device, the frequency of accidents — severed lines, punctured pipes, cut cables — and subsequent disruption of services, is rare.
The critical importance of locating devices simply cannot be overstated. Each year, electromagnetic (a.k.a. utility locator) and radiolocation (ground-penetrating radar) equipment saves utility, oil and gas companies, municipalities and installation contractors millions of dollars by avoiding damage to existing utility infrastructures. But aside from the expense of repairing a severed cable or punctured pipeline, costs related to lost sales revenue and production downtime for affected businesses would be astronomical. Costs and inconveniences aside, however, the more important benefit is that locating equipment saves lives.
According to Chris Workman, Kentucky Supervisor with DPS (a.k.a. Damage Prevention Specialists Inc. in Greenville, S.C.), the safety of its employees and residents living near dig areas is the company’s No.1 priority.
“Keeping anybody who’s out there on or near the job safe comes first,” says Workman. “While costs and inconveniences resulting from a damaged underground utility line are certainly impactful, the damage can be repaired. Loss of life or a disabling injury cannot be reversed. We want everybody to go home safe at the end of a day.”
Founded in 2003 by Jacqueline and James McCarter, DPS is a leading utility locating service specializing in locating natural gas lines. Prior to starting DPS, McCarter’s father, Rob, along with business partner Austin Evans, formed E&M Pipeline in 1987, installing natural gas lines for several natural gas companies in South Carolina. In 1992, E&M Pipeline started a locate division, E&M Services. This division would be the foundation for the eventual origination of DPS Inc.
The company started with 12 employees, working primarily in the upstate region of South Carolina, and has since grown to more than 50 on staff, along with expanding their trade territory to include all of South Carolina, North Carolina and Kentucky. DPS specializes in locating natural gas pipelines. Using the GX locator, manufactured by McLaughlin, DPS offers 100 percent dedicated service to utility companies — based on a single locate service approach.
“The DPS single-utility locate approach is somewhat unique, but extremely effective,” says Workman. “The ability to concentrate on locating just one utility, vs. five separate locates, allows our guys to focus on just one thing. The dedicated single-utility locate approach provides greater attention to detail. This is the fundamental difference between DPS and most locating companies. They are likely to contract for locating multiple utilities at one site, using only one locater. If DPS contracts to locate more than one utility, we send a dedicated locater for each.”
“Basically, locating underground lines is similar to tuning into your favorite radio station,” says Matt Manning, Locating Equipment Product Manager for McLaughlin. “Each station transmits a different signal and locators are like a radio designed to pick up those signals. These signals help identify the exact location of an underground utility.”
Many utility lines give off a charge or transmit a signal, and in most cases, each line has a different charge or signal just like a radio station. However, some lines do not give off a charge or transmit a signal. In these cases, a transmitter can be used to induce a signal onto a metal line, which allows the locator to pick up the signal.
Single-frequency locators have been around for decades. These systems consist of a transmitter you place on the ground that induces a single high-frequency signal. The signal is picked up by the underground line and then radiated back up to the receiver. Single-frequency systems work well on lines and pipes in uncongested easements, but putting a high frequency into the ground has the tendency to “light up” everything underground and may produce a distorted signal. In other words, you cannot distinguish whether it is a power, gas or communications line. The other limitation is that most single-frequency locators cannot determine the depth of the line.
Multi-frequency systems (some offer up to five frequencies) allow you to tune the frequency you are putting into the ground to the type of line or pipe you are trying to locate. The lower the frequency, the better it will stay on the line you are trying to locate, thus making the job of distinguishing a gas from a water line easier.
Innovations in Locator Technology
In the earlier days of locator technology, the vast, complicated and aging utility infrastructure often challenged the capabilities and accuracy of locating technology at that time. But in just the past several years alone, advancements in transmitter technology, along with improved noise reduction, have resulted in locators with the ability to achieve better accuracy — even in the presence of multiple utilities.
Virtually all locator manufacturers have put more power into their utility locators, as well as updating receiver software to help filter out the extra noise in the ground and air. These innovations have helped to provide a more accurate filtering of the signal.
Another trend occurring in the industry is linking the locator with GPS devices and mapping the utility line with latitude and longitude coordinates, thus providing an accurate location of the line for future reference.
“A lot of the utility lines were installed in the late 1960s and early 1970s without tracer wire or may have been installed with tracer wire that has since corroded,” says Workman. “Depth can also be a challenge. DPS is often challenged with locating pipelines installed very deep; pipelines that go beneath rivers, highways and rail crossing.”
Yet despite much advancement in locator technology, there’s a tried-and-true method that Workman employs in situations where a locator signal cannot be established or a locator fails to transmit, or as is the case with many older lines, there is corroded tracer wire or none at all.
“We have a lot of problems here with lines that were installed with no tracer wire,” says Workman. “There’s really nothing you can do about that. One of our gas utility customers has an established relationship with a subcontractor with vacuum capabilities. They will come out and vac the lines up, allowing us to hook into the tracer wire, provided one exists, or if not, verify the locations of the pipeline so we can notify contractors before they ever go out to dig. It’s more work, but sometimes it can’t be avoided. The alternative, e.g., damaging a line during excavation, or worse yet, provoking an explosion, is a situation that should be avoided at all costs.”
Lucinda Rinzel is a Marketing Coordinator at McLaughlin.