Two Of A Kind: Comparing Hydro And Air Vacuum Excavation

As the oil industry continues to expand throughout Canada, so does the use of innovative options for excavation projects. While traditional excavators reign supreme for large-scale earth removal, vacuum excavation offers a non-destructive way of performing smaller projects that would otherwise call for manual digging.

Air vacuum and hydro vacuum are the two main methods of vacuum excavation, with both offering their own unique set of pros and cons. Learn what separates these two methods, as well as which one is the better fit for your civil construction project.

Two Methods, One Goal

Both air vacuum and hydro vacuum excavation set out to perform a common task: to remove as much dirt as possible in an accurate and non-intrusive way. This makes vacuum excavation a top choice for locating and exposing buried utilities and an effective alternative to digging narrow trenches by hand. This common goal is accomplished through two very distinct methods:

  • Air vacuum excavation relies on compressed air's kinetic energy to blast through and break up a wide variety of soils, rocks and other debris. These materials are then vacuumed into holding tanks on the vacuuming vehicle, awaiting transport and disposal.
  • Hydro vacuum excavation uses pressurized water to break through soil. The resulting slurry mix is then vacuumed and stored inside holding tanks until proper disposal.

Most vacuum excavation equipment comes in the form of a dedicated truck or a trailer outfitted with a holding tank and other equipment. It's possible for a single machine to be capable of handling of air and hydro vacuum excavation jobs, but most vacuum excavation tools are set up to work specifically with one type or the other.

Comparing Air vs. Water

Both air and hydro vacuum excavation have their own sets of advantages and drawbacks to note. For instance, air vacuum excavation is considered the "cleanest" form of extraction, since there's no wet slurry or mud to worry about disposing. However, dry excavation often adds fine dust particles to the air, prompting operators and other workers to don respiratory protection as a safety precaution.

In spite of the tremendous kinetic energy that compressed air offers, it's still not enough for compressed air to overcome frozen ground and select types of hardened soils. On the other hand, hydro vacuum excavation works on a wider variety of soil types and the jet-like action of the pressurized water helps quickly break down soils and other debris.

Unfortunately, this very same jet action gives hydro vacuum excavators a higher chance of cutting through cables and underground pipe. This can happen if the water pressure isn't adjusted properly. There's also a chance that the surrounding ground could be weakened through the hydro vacuum excavation process.

For hydro vacuum excavation, the excavation process itself is dictated by how much pressurized water is available for the task at hand. If there's no water source available, non-destructive digging operations come to a standstill until one can be found. The lack of water usage can also make air vacuum excavation relatively cost effective, at certain times.

Decision Time

So, does the above make either type of vacuum excavation better than the other? Keeping the drawbacks and advantages of hydro and air in mind, that ultimately depends on what the jobsite requires. This means considering a wide variety of factors ranging from soil type and condition to budgetary and safety concerns. For hydro vacuum excavators, quick and consistent access to a source of water is also part of the decision matrix.

Regardless of which option is chosen, it's important to have an understanding of how both types work and how they compare against each other in terms of capabilities and performance. Continue here to understand even more about this topic.