19,521
That's the number of utility strikes in 2021 alone due to the utilization of trenchless technology for directional boring – better known as directional drilling.
While directional drilling technology can provide quick installation of utility lines with less environmental impact compared to traditional trenching for installation of new underground utility lines (water, gas, electric, telecommunication, and sewer) it can have catastrophic effects on existing underground infrastructure and bring a huge hit to your projects bottom line if proper procedures are not first put into place.
There are dangerous crossings of utilities from directional boring projects near you and you would not even know it. These unintentional breaches, known as cross bores, can occur if private and public utility lines are not first located on site before directional boring begins. These intersections of underground infrastructure can cost over $150,000 to repair once damage has occurred and have been known in the construction industry as ticking time bombs... Because it's not if something bad will happen when a cross bore occurs, it's when.
Whether it's a damaged communications line, leaving a neighborhood unable to call 911 or other emergency services, or a potentially explosive meeting of gas and sewer pipes, these crossings can cause major property damage, injury, and in some cases, death.
When gas lines are ruptured within an existing sewer line, methane gas can leak into homes overtop of the cross bore, and the flip of a switch is all it could take to cause the horrific catastrophes shown in the images below. According to the Cross Bore Safety Association, the most expensive cross bore explosion ever on record added up to $30,000,000 in damages and resulted in 2 girls being burned. While the results of such crossed utilities can be devastating, certain companies have become proactive to reduce the risk of cross bores from trenchless technology.
To mitigate the high risks involved with directional boring and to prevent damages to existing underground infrastructure, general contractor FET Construction Services out of Sylvania, Ohio, contacted GPRS to locate all private underground utility lines prior to conducting a project they would be performing directional drilling work on.
How Do I Know If There Is Directional Boring Near Me?
Directional boring is defined by trenchlesspedia.com as "a trenchless construction technique used to install underground piping, conduits, and cables along a pre-determined bore path using a surface launched drilling rig."
Before performing any horizontal bore shots in the quaint downtown district of West Unity, Ohio, FET Construction Services scheduled GPRS Project Manager Michael Garcia for a week’s worth of work to complete this project and ensure that the horizontal bore drilling would not occur until after all underground utility lines were accurately mapped and marked.
With only a week to map all the utilities on site, Garcia went to work. FET Construction needed to install new utility lines before new streetlights were installed. With over 1,800 feet of directional boring required before the new utility lines could be installed, Garcia concentrated on the accurate assessment, location, and marking of all underground utility lines on site to ensure no damage occurred during the horizontal bore shots.
Why Avoiding Cross Bores When Directional Drilling Matters.
Locating private and public utility lines on every job site where directional boring takes place to avoid cross bores is extremely important. According to the Cross Bore Safety Association, there are an estimated 1 million cross bores that currently exist along Americas underground utility highways. When all underground utility lines are accurately located, marked, and mapped, directional drillers have the information they need to effectively complete their job without the risk of damage to the current underground infrastructure. The result of ineffective locates before directional bore projects take place has resulted in some of the most significant utility line damages annually in the United States. According to the Common Ground Alliance’s 2021 Dirt Report, Boring/Directional Drilling was the 3rd third most prominent cause of underground utility strikes nationally. That figure alone speaks to the importance of both a proper public and private utility locate before the completion of a directional boring project.
With the goal of 100% subsurface damage prevention on his mind, Garcia proceeded strategically, taking pride in his duty to protect GPRS’ client’s reputation, budget, and timeline, while also ensuring the safety of the entire Village of West Unity and its inhabitants through accurate mark outs, which help directional drillers avoid cross bores.
Challenges Faced by Our Underground Pipe Locator
Prior to GPRS being contacted to complete the private utility locating on the job site, an up to date 811 locate had not yet been performed on any of the contractor’s proposed drilling routes. This gave Garcia limited information to begin his initial inspection of the property because 95% of the utilities on site were deemed as public. He talks about the challenges in his interview below.
To add another twist to the scope of the project, sewer utilities - which often are the victims of dangerous cross bore intersections caused by directional drilling - were left unmarked. Sewers are often excluded from 811 marking requirements. The unmarked pipes increased the risk to crossed utilities during directional boring.
To combat the limited information available, Garcia and his team moved forward with a proactive response to go above and beyond the required scope of work to the benefit of both the GC and the general public. They accomplished this by marking both private and public underground utilities in the proposed work area, including sewer, utilizing the industry leading standard for all utility mapping companies, the SIM Specification (Subsurface Investigation Methodology). The extra mark-outs ensured the contractor that they could re-calculate their bore path to avoid damaging any existing underground lines.
Simplicity is in the details of a safe, accurate, and industry leading process
Through Garcia's use of the SIM specification, he ensured accuracy of the locates. He shared:
“I do the same thing every time, I get out of the truck, I look at my visuals, I hook up to everything with the EM [Electromagnetic Locator], I do my passive sweeps, I do the GPR [Ground Penetrating Radar], I write down depths, and then I finally map it out. And I do it on every job from start to finish. I don't care if it's a five-foot job, one soil boring, or five miles of utilities, it's all the same, and that's what we need to stick with so that we have huge success with the SIM's process."
As shared by Garcia in his interview, part of the difference between GPRS and 811 Call Before You Dig services is that GPRS provides the depths of utilities located when applicable, where 811 locates do not. Providing depths in the utility markings helps excavators and General Contractors know how far they are able to dig or drill within a certain range before they will come into contact with subsurface utility lines. Thus, depth location helps prevent damages while keeping workers safe, projects on time, and budgets intact.
A nearly foolproof way GPRS Project Managers help clients mitigate the damages of cross bores when directional boring or digging is through our Video Pipe Inspection (VPI) services. Conducting Pre and Post Cross Bore Inspections before and after all directional drilling work is complete can help inform contractors where sewer lines are, as well as any damages caused by post drill operations. While VPI was not conducted on this specific jobsite, it is the standard that NASSCO certified VPI Project Managers at GPRS recommend when directional boring takes place.
A Pleasant Surprise
Throughout Michael's investigation of West Unity's downtown, he identified that all the five main utilities including, power, sewer, water, communication, and gas were all being fed from behind the buildings and not on the main street where the work was being completed. This allowed Garcia to focus on the accurate mapping and marking of the current streetlight utilities on the sidewalk.
Before he could be certain, however, Garcia had to do his homework by completing step one of the pre-job check points of the SIM process: performing a site walk while checking for visual representations on the ground such as manhole covers, water taps, and sewer grates. Utilizing step two of the SIM pre-job process, Garcia performed his pre-scan duties, including calibrating his GPR unit to the conditions at the site, and performing several test scans through the scan area to determine the maximum depth of penetration GPR would have. Once this was all complete, he used multiple forms of technology with his Electromagnetic locator to trace all known utilities, which was followed by using his GPR PinPointR unit to locate any unidentified known utilities. To ensure accuracy, Garcia followed this with a final GPR scan across all previous located utility lines to confirm locations and approximate depth of the lines so that FET could know where the lines would be with certainty.
Peace of Mind & a Job Well Done:
Due to Garcia’s safe practice of marking both private and public lines where necessary, as well as providing depths for lines being located when applicable, FET was able to complete directional boring with the peace of mind that their project would remain on time, on budget, and safe from cross bores.
FET Construction Services was delivered the findings of their site through their own complimentary personal SiteMap® subscription, so that they could have easy access and control of the data collected on their jobsite by GPRS.
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