Vacuum Excavation vs. Hydro Excavation: Uncovering the Best Method for Your Project

By Emily Newton

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People have the best chances of getting optimal results with the available excavation methods when they know the main differences between each one. Here, we’ll look at vacuum excavation vs. hydro excavation and some of the primary reasons people choose them for their projects.

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Both Are Non-Destructive Methods

These excavation methods both fall under the non-destructive digging (NDD) umbrella. One of the main reasons people choose them is the significantly reduced likelihood of harm to underground utilities or other infrastructure. Creating tolerance zones around existing utilities is another safety measure to prevent costly outages across a network. They create boundaries around power lines so people can only use hand tools or NDD techniques in those areas.

Staying mindful of methods that will not damage underground lines is particularly necessary as people view such networks as vital to an updated grid and clean energy future.

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Some experts advocate for moving half the electricity distribution networks in the United States underground by 2040. Only about 20% of them are now. However, many utility company decision-makers are gradually transitioning to more underground networks. They understand this is a practical way to protect the infrastructure from wildfires and other weather-related risks. Putting the lines underground is also more aesthetically pleasing, making it the preference in areas known for beautiful scenery or historical architecture.

These trends support the increasing use of non-destructive excavation methods. Another similarity that comes up in vacuum excavation vs. hydro excavation discussions is that these options enable the convenient disposal of the displaced soil. It goes into a storage tank for easy removal to a desired location.

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How Do These Excavation Methods Work?

Vacuum excavation moves soil with powerful suction, loosening, and then pulling it from the ground. People use handheld water-jet or air knife tools to break up hard-packed soil or move around unexpected obstructions.

People often refer to hydro excavation as hydro vac because it combines water and air to move the soil. The process starts when workers aim pressurized water at the dirt. Besides breaking up the surface, the water mixes with the soil, making a slurry that a vacuum sucks up.

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Safety Concerns for Vacuum Excavation vs. Hydro Excavation

Vacuum and hydro-based options are much more efficient and less labor-intensive than conventional options. Relatedly, they’re less likely to injure people. Even so, site crews must receive safety training and ensure they pay attention at all times when operating the excavation equipment.

One of the main reasons is the power associated with the water or suction used for both these digging techniques. For example, water pressure can become hazardous at 2,500 psi, potentially damaging equipment or hurting people if the jets activate unexpectedly. Alternatively, strong suction can pull people’s arms, fingers or clothing into the vacuum nozzle.

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However, hydro and vacuum excavation do not require the prolonged periods spent underground that conventional options did. Cave-ins are some of the biggest risks underground workers face, particularly if they are standing in trenches to work on them. A single cubic yard of soil can equal a car in its weight.

People commonly choose hydro excavation to dig slot trenches. These openings are only a few inches wide, making them ideal for installing pipes or cables with minimum disruption to the surrounding Earth.

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Choosing Your Method Based on Soil Conditions

Soil analysis is an important safety precaution that tells people how to properly prepare the site before excavation begins. Knowing the soil’s type and likely characteristics when subjected to excavation methods. But how does an area’s soil affect vacuum excavation vs. hydro excavation considerations? It mainly comes down to efficiency and how each option works with the specific soil type.

Vacuum excavation is your best bet for working with various dry and wet soils, including sand or other loose materials. However, if the dirt is clay soil, heavily compacted, frozen or rocky, hydro excavation is more appropriate.

Although vacuum excavation can handle clay soils, you’ll notice the task is less efficient than when choosing hydro excavation. The water jets break up clay soil, making it more manageable. Vacuum nozzles can suck up clay, but more slowly than if the ground is already moist from water.

Rocky soil is better suited for hydro excavation. The rocks make the vacuum suction less powerful if they get stuck in it. They could also damage the machine’s internal system. Since hydro excavators use water and vacuum power, the liquid loosens compaction and tackles frozen areas, and the slush gets sucked up when Earth removal begins.

The Rise of Robots?

Beyond the specifics of soil and how they affect efficiency, it’s increasingly likely that more excavation methods will become automated soon. Decision-makers are becoming more interested in automating tasks across industries, often using robots to accomplish their goals. Early work has started in designing excavators that work with limited human oversight. 

These robotic applications are still relatively rare, but people can recognize their benefits. If robots get the job done as fast or faster than humans while enhancing safety, it makes sense to strongly consider them.

Even if robotic excavators eventually become common, they won’t replace people. The more likely outcome is that humans will learn skills to transition into new roles. For example, instead of aiming water sprays or vacuum nozzles at the Earth, they might program robots to do those things, then watch as the machines go through the desired movements.

Just as task and equipment-specific safety training is critical for safeguarding workers’ well-being now, employees will need to learn how to do their jobs around robotic machines. However, that’ll likely happen from a distance. Today’s vacuum and hydro excavators are often remote-operated machines. Tomorrow’s robotic excavators may share that characteristic.

Analyze Your Project’s Requirements Carefully

Discussions about vacuum excavation vs. hydro excavation have no universal answers confirming one method as better. Soil type is a major factor in the optimal method. The purpose of the excavation also comes into play because hydro machines work particularly well for digging slot trenches. Moreover, if your company does not own these types of excavators, another consideration may be how readily available each type is to rent in your area. Finally, no matter which option you go with, always engage with local authorities, especially when digging around buried infrastructure. Non-destructive methods like these make damage less likely but possible. Using a digital mapping solution to identify the location of underground assets improves visibility and reduces accidents.

Emily Newton is a construction and industrial journalist. She is also the Editor-in-Chief for Revolutionized Magazine. Keep up with Emily by following her by subscribing to Revolutionized’s Newsletter.