By Cori Sellars
Traditionally, vacuum excavators have been used by contractors for daylighting buried utilities, minimizing disruption to the impacted area, and leaving behind a negligible mess. Today, the benefits of soft digging â the process of using a combination of suction and high-pressure water and air to remove dirt and other materials from the ground â are gaining attention with crews working in non-traditional applications. For example, innovative maintenance professionals like David Willis, Plumbing Supervisor at Elon University â a private university with nearly 5,000 students located in Elon, North Carolina â are now using vacuum excavators to complete maintenance tasks around their facilities.
Two years ago, the university purchased a Vermeer Vac-Tron LP373SGT Vacuum Excavator, which Willis said his department uses frequently. âWe use it for everything, from potholing to find utilities for new construction to running it like a shop vac to pull water out of flooded buildings. We also have used it dig holes for new trees, signs, footings â we use it a lot.â
As an example, Willis knew that Vermeer made a good stump cutter, but taking stumps out for trees that have grown around utilities can be a real challenge. With their Vac-Tron LP373SGT Vacuum Excavator,when Willisâ team runs into this type of issue on campus, they employ their vacuum excavator to dig around the stump. This gives them a better visual of the root ball and utility lines, and from there, they are able to safely remove the stump without damaging nearby utilities.
Adding a Vacuum Excavator to Their Equipment Fleet
According to Willis, before the university invested in their own machine, a contractor working for the university had used a vacuum excavator while tunneling under a building to fix some utilities, and Willis was impressed with the results. Following that project, Willis contracted another vac crew to clean out vaults on campus. âThe college was built in 1889, and they’ve been burying stuff in the ground since then â and nobody knows where anything is,â said Willis. âVacuum excavation has been a great way of exposing whatâs down there, like poles, power lines, water lines or steam tunnels, without being intrusive.â
After using this excavation method successfully on multiple projects, he went to the universityâs administration and asked to purchase a vac for his departmentâs dedicated use. Willis said the universityâs administration had gotten tired of seeing his departmentâs backhoe around campus, and with their own vacuum excavator, his crew would be able to find utilities without tearing the university all to pieces, versus the mess made with a backhoe. âUpper management kept asking me, âWhat are you digging up now?â It seemed that every time we used the backhoe to dig around campus, it made a huge mess.â
He continued, âThey really appreciated that this method is a little softer and gentler. When it came time for allocating money for new machinery, they asked me what I wanted, and I told them a vac â they were so pleased with the results theyâd seen from our contracted units, that’s how I got ours.â
Equipped to Get the Job Done
When he had the funds to purchase the vacuum excavator approved, Willis reached out to his local Vermeer dealer,Â Vermeer Mid Atlantic in Colfax, North Carolina. âI had worked with Vermeer on different stuff, and I’d used their equipment before. Knowing that Vermeer owned the Vac-Tron and McLaughlin vacuum excavator brands, when I talked with them, they were âJohnny-on-the-spotâ to get the process going.â
Willis said they chose a Vac-Tron LP373SGT model because it was right sized to complete the work Elon University maintenance crew needed to do. And according to Willis, the new vacuum excavator came with everything he needed, but he did purchase additional hoses to increase the machineâs usage. âThe unit comes with 25 feet of hose, but because we bought additional hoses and the couplings, we can go out as far as the distance on our piping, about 70 feet.â
He mentioned that having this extra hose available had come in handy many times. âRecently, we had a pipe burst, flooding out a building. Water was running everywhere so we backed up the machine and ran the hose through a window,â he said. âBecause we had the hose and fittings to make it the right size for what we needed, we were able to use the vac to suck the water up out of the floor and straight into the tank â very similar to how restoration professionals use this type of equipment to suck the water out of the buildings.â
He added that they also bought additional accessories in order to maximize the machineâs use. âWe did buy a jetter,â he said, âas well as a hose reel that attaches to it, so we can jet and clean sewer lines at the same time.â
One Truck for Many Uses
Willis said that other departments on campus have also caught on to how useful the vacuum excavator is and are asking to use it more and more for other applications. âOur engineering group asks us to pothole for them frequently. They have a general idea where utility is, and we send our crew over to confirm the location and depth.â
For instance, Willis mentioned that as new buildings are being constructed, they’ve been trying to run sewers through older parts of the campus and have used the vacuum excavator for exposing the utilities before digging. He said that once the engineering team thought there was a gas line buried, but the locating people couldnât find it. Willis and his crew brought the vac out, potholed the ground and found the line â enabling the engineers to visibly check it.
Making Some Surprising Discoveries
Willis said that the vac has not only been useful in uncovering utilities but also in locating other materials buried underground. âMany times, we thought stuff was at a certain depth, or hoped something was here, so weâve used the vac to pothole to know whether or not we could run a line. We know from maps generally what’s what, but weâve dug down and found stuff we werenât expecting. Sometimes, itâs an old utility line that we know has to be inactive because the building it would attach to isnât there anymore.â
Other times, he said that the crews have been surprised at what theyâve found. Once, he said, his crews dug down and found a parking lot. âBack in the 1960s, there was a building and parking lot that the college wanted to make a natural area,â he said. âBasically, the crews at the time just put dirt down to cover the area, graded and landscaped it, and then everyone forgot about the parking lot. Fast forward 50 years, now we want to bury a sewer line across the area â when we dug down about 3 feet, we hit asphalt. Sure enough, the curbing and everything from the parking lot was still under there.â
Estimating that their Vac-Tron LP373SGT vac is used about 70 percent of the time in plumbing applications, Willis said that the rest of the time itâs supporting other campus services. One thing is for sure, though, there isnât much idle time for the universityâs vacuum excavator. âIt’s been a good machine, and it’s really been helpful,â Willis said, mentioning that the universityâs maintenance departments continue to find more and more uses for the machine.
Vacuum Excavation Applications â Going Beyond Utility Work
Since the introduction of hydro and air vacuum excavation equipment, utility applications like potholing and cleaning up horizontal directional drilling (HDD) slurry have been a natural fit for these machines. However, there are many industries using vacuum excavators to replace more labor-intensive and inefficient methods of working. Vacuum excavators arenât just for utility work anymore.
Vacuum excavators have a wide range of applications, many of which donât even involve excavating, such as cleaning to reshaping sand traps at golf courses. Hereâs a look at a few of the industries using hydro and air vacuum excavator equipment.
Many cities employ large vac trucks to maintain networks of sewer systems, but public works departments sometimes need smaller and more nimble vacuum excavators to help out and allow crews to work in more places at one time. Municipalities are adding hydro and air vac systems to excavate for poles and signs, aid with water line repairs, exercise water valves, and jet sewer pipes.
Cities, counties, and state entities are always discovering new ways to use vac systems. Beyond some of the traditional applications, workers employ vacuum excavators to remove roots and debris around water meters and valves, and remove waste from storm drains, catch basins, and culverts. High-pressure water wands help them with digging and cleaning. Air vacuum excavators are also excellent for pressure testing sewer lines.
Industry plants are investing in vacuum excavators to help clean around the facility. Facility managers used to have to employ service companies with big trucks to work during scheduled shutdowns. With smaller vacuum excavators, they can now make cleaning an ongoing effort, which has helped extend the intervals between scheduled shutdowns.
Vac systems are also widely used to remove debris from drains in wash bays and car washes. These drains tend to get plugged up with mud, grease and waste oil while cleaning dirty equipment, and doing the work with a shovel is a job no one wants. Vacuum excavators do a better job in a fraction of the time.
There are also a few niche landscaping applications that vacuum excavators are being used for. Contractors are renting them to remove old mulch or rock around flowerbeds, parks and around buildings, as well as to dig holes for fence posts and footings for signs. Vacs are also being used at large cemeteries for setting headstones.
Itâs also worth noting that vacuum excavators arenât just being used to do utility work in the construction industry. Utility strikes are a common concern for every contractor working near buried lines. And anytime new subdivisions are being constructed, vacuum excavators are an excellent addition to help with sewer and drainage work.
There are a ton of applications where using a vacuum excavator can improve efficiencies while maintaining a safe working environment.Â
This material appears in the February 2021 issues of the ACP Magazines:
CaliforniaÂ Builder &Â Engineer,Â Construction,Â ConstructionÂ Digest,Â Construction News,Â Constructioneer,DixieÂ Contractor,Â MichiganÂ Contractor & Builder,Â Midwest Contractor,Â NewÂ EnglandÂ Construction,Â Pacific Builder &Â Engineer,Â Rocky MountainÂ Construction,Â TexasÂ Contractor,Â Western Builder