The Safest Way to Dig

April 14, 2020
The advantages of using hydro excavators and vacuum trucks

Excavation has always been laborious work that involves an element of surprise. Perhaps a large boulder will appear. Maybe the water table is higher than expected in your area, and you find yourself in Mud City. Possibly, you find yourself dealing with soil that insists on collapsing in on a hidden hole.

What would you do if the job site included abandoned, corroded, crisscrossing pipes that were never properly recorded with the proper municipality? What about live broadband piping, gas lines, and other utilities? A backhoe loader’s bucket could certainly hit one of these hidden pipes, damage your machine, and potentially create a dangerous and/or expensive headache.

Experts say the answer is clear when it comes to this level of uncertainty: Bring a hydro or vacuum excavator.

Hydro excavators and vacuum excavators are soil and debris removal machines that use suction to remove soil and are often accompanied by high-pressure water guns (in the case of hydro excavation) or high-pressure air (air excavation). Vacuum excavation can be done without the aid of high-pressure water or air, but it can help speed up jobs since it is used to break up dirt, clay, rocks, and other debris so the vacuum tube can more efficiently suck up that debris.

Vacuum excavation is best used for digging jobs that require precision or a careful approach since the excavator can dig several feet deep within a relatively small hole. Also, the dirt or sludge collected has to be carefully dumped later on.

Some laws mandate the use of hydro excavation to find utility lines before the beginning of any construction project so digging of a foundation, embankment, or another project won’t accidentally damage existing lines, says Benjamen Schmitt, general manager of Federal Signal, an equipment manufacturing company which is headquartered in Oak Brook, IL.

“Laws and best practices state that mechanical digging within a tolerance zone of a utility is illegal and must be completed by hand digging methods or hydro excavation,” says Schmitt. “Hydro excavation is faster and has far less potential to damage a utility than hand-digging methods.”

To decide beyond this whether an excavation job requires you to bring a vacuum or hydro excavator, it’s important to consider a variety of factors, says Marshall McMaster, general manager at Cusco Fabricators Inc., a Wastequip company based in Ontario, Canada, that manufactures hydro and vacuum excavators.

He says the variables of the job in question will play a role.

“Consider how much material needs to be moved, what type of material needs to be moved, and whether the material needs to be transported away,” he says. “Hydro excavators are well-suited for use with heavy, wet, or extremely fine material and are ideal for easily removing and transporting material.”

It’s also important to factor in whether you’re working with limited space. Is there a nearby dump site for removed dirt? Is the area where you’re digging accessible for large machinery? Do you have enough room for the housing of a large excavator to drive up to the dig site, or should a hydro excavator with a long boom be brought in?

“Because of their long boom systems, hydro excavators can easily reach and fit into tight spaces, making them a better choice in crowded urban areas or to avoid tying up traffic on an entire roadway,” says McMaster.

He says hydro excavation should be considered for jobs that meet the other criteria and also have a tight timeline because they can save considerable man-hours when compared to traditional equipment used for these sorts of jobs, which range in scope but which sometimes required workers to break out shovels for the precision required for these jobs.

Also, the terrain you’re digging in plays a significant role when evaluating whether to use a hydro or vacuum excavator, McMaster says. Areas with significant numbers of trees will likely have tree roots that could cause damage, or the excavation of a backhoe loader could damage these tree roots and potentially kill the tree. This, in turn, could cause the tree to topple at a later time, opening up the possibility of bystander injury, property damage, and habitat loss—not to mention the loss of a previously healthy tree. With hydro or air excavation, the roots stay in place while the dirt around them is blown away, and once the job is complete, the removed soil is replaced.

“Hydro excavators play a critical role in minimizing disruption, increasing efficiency, saving time, and protecting the environment,” says McMaster.

Another essential consideration is whether the job requires seeking out utility lines or working in an area with unmarked or imprecisely marked utilities. Michael Reis, Vice President of Industrial Sales at Super Products LLC, which manufactures truck-mounted vacuum excavation equipment, says municipal water lines, power lines, gas lines, private fiber optic cables for internet, and other utilities are known to have some margin of error with their recorded location.

“With our technologies—especially as old as our cities are getting—we know roughly where (a utility) is, but we don’t know the exact depth. It can be a foot sometimes to the left, a foot to the right,” he says.

Reis says with a backhoe loader or other types of excavators, breaking one of these pipes could cause a small-scale emergency or a disastrously expensive break.

“If that line isn’t right where you think it’s supposed to be…if it’s a gas line, there’s a gas leak. If it’s a fiber optic line, that can be an expensive break. It can be several thousand to hundreds of thousands for fiber optics. It could be a million. It’s an expensive investment that’s put in the ground.”

Schmitt says while utility location is a job where the vacuum and hydro excavation is a go-to option, there are a wide array of jobs that a vacuum or hydro excavator would be able to be useful and efficient, such as vacuum drilling mud while directional drilling.

“It’s quite surprising how versatile a vacuum excavator can be. Contractors can be contracted to complete a wide array of applications,” he says. “Over the years I have witnessed hydro excavators being used to trench, clean cattle crossing guards, clean swine transport trailers, clean a various array of storage tanks, vacuum rock off flat roofs, clean car wash pits, cleaning drill rigs, pressure test gas lines, and unfreeze frozen pipes and valves.”

Reis says hydro and vacuum excavators can also be used for power pole replacement, digging post holes for sign replacement, and general investigation when a buried obstacle is suspected of being present on a job site.

Reis says vacuum and hydro excavators aren’t meant to replace more traditional digging equipment on certain jobs.

“A hydro excavator isn’t to replace a backhoe or excavator; it’s to go along with it,” he says.

McMaster says hydro excavators are so versatile and powerful that they can typically tackle jobs that end up being larger in scope than expected, rather than having to switch back to another digging machine.

“Given their power and versatility, those using hydro excavators rarely need a Plan B. That said, soil conditions, hitting a large vein of granite or other very hard rock, and other issues may require a change in excavation tactics,” he says. “However, hydro excavators can be used to pothole to investigate soil and terrain conditions ahead of where they are currently digging, giving operators an excellent opportunity to make sound, fact-based decisions on the best tactical approach and the insight needed to proceed with confidence.”

If a job is expected to be particularly large, it’s most efficient to bring several hydro or vacuum excavators with you to the job site, Schmitt says.

“Many large projects will require several hydro excavators to complete the job on a set deadline,” he says. “A contractor can also have operators operating one truck for additional efficiencies and productivity.”

Reis agrees, adding that sometimes adding multiple crews or multiple machines is the best call for efficiency. Other times, it’s best to have vacuum excavators of various sizes on hand for different types of jobs, such as a smaller excavator to cut dots or trenches while searching for a utility line and then using the larger excavator to run the final trench across the utility line.

The creation of vacuum excavation has advanced precision excavation, but what sort of technological advances are starting to be present within vacuum excavation as the field advances?

McMaster says the digital versus analog options will vary based on the specific needs of the job, and it’s important not to choose technological options just for the appearance of upgrading.

“Employing the right technology within the trucks is critical. Some manufacturers offer lots of technological bells and whistles from digital and touchscreen displays, computer controls, etc.,” he says. “While these can be attractive, it’s important to think through what you need and what will work best in the field. For example, while they work well in perfect conditions, using touch-screen controls in negative 40-degree weather while wearing gloves is not practical.”

What can customers expect in the coming years? McMaster says prioritizing environmentally safe excavation practices will be on the top of the list.

“In terms of what’s next, we think a lot of future improvements will focus on environmental benefits—focusing on payload to adjust for what roads will accommodate; silencer and acoustics technology to minimize noise and disruption; smaller and even more maneuverable equipment that will further reduce footprint and destruction of the surrounding environment,” he says.

Schmitt says there will also be innovations in payload weight management to maximize customer profit and to adhere to state and federal regulations.

“The big industry change currently in process is the design and manufacturing technique changes,” he says. “Weight enforcement on hydro excavators is a growing area of concern for many contractors and operators and OEM such as Vactor and Westech are looking at the new design, materials, and building techniques to reduce overall vehicle weight providing the customer with maximized legal payloads. Increasing payload increases customer productivity.”

Experts highlighted some of the vacuum, air, and hydro excavation models that their companies currently offer. The following details were provided by the noted companies.

From Cusco Fabricators Inc.: Hydroex 5327—Their biggest, most powerful model is made for large capacity jobs where blasting and vacuum power are paramount.

Sewer Jetter Hydroex (SJX)—This combination truck eliminates the need for an additional piece of equipment. Designed with municipalities and sewer authorities in mind, the SJX affords purchasers the option to not only excavate their sewer systems but also to clean and maintain them afterward.

Industrial Vacs—Suited for spill remediation and fracking remediation.

Duravac—Features their largest debris tank and is best suited to extreme weather conditions.

Turbovac—This is designed to handle heavy sludge, slurries, and liquid waste while offering powerful blower system options and cyclonic filtration technology.

Mastervac—The Mastervac allows users to suction a very wide range of materials, from heavy, wet slurry slop to fine particulates, like fly ash and sand. Dual baghouse systems ensure these materials finite materials are filtered and trapped before getting to the blower. It is a very versatile piece of equipment used in applications like oil field carbon soil remediation, as well as cement and mining operations.

From Federal Signal:
Coyote Hydro Excavator
—TRUVAC by Westech released its Coyote Hydro Excavator, which was launched by Federal Signal at the ICUEE show in Louisville, KY, in October. The Coyote was designed to be a mid-sized hydro-vac with maximum legal payload capabilities while not sacrificing performance. The classic style control system and subtle operator features aim to put the user first with its design.

From Super Products LLC:

Mud Dog Hydro Excavator: A safe, efficient and versatile alternative to traditional digging equipment, the Mud Dog is designed for operator convenience and performance consistency in the harshest environments. Each model, either 16-yard or 12-yard debris body and 1,500 or 2,000-gallon water tank capacities, was created to meet the challenges of a variety of excavation projects and job site conditions. This allows an operator to always choose the best application based on each job. Mud Dog vacuum excavators also offer versatility with the introduction of an Air Excavation option, allowing for both water and air excavation in one unit, to always have the best application for the job, on the job.