Hydro excavating and air excavation are very similar in regard to using a vacuum suction hose and a pressurized gun to dig through existing soil or ground. The key difference in the two processes is hydro excavating uses pressurized water to break away soil/ground and air excavation uses pressurized air. While these digging alternatives are similar in application and costs, the differences make one better for certain projects over the other.
Hydro excavation units consists of a water pump, vacuum system, and a tank for excavating waste material. Compared to traditional methods, hydrovacing requires one truck rather than countless backhoes and dump trucks. Hydro excavation is more cost effective, and the entire process requires less manpower, less equipment, and reduces the chance of potential underground utility repairs. With heavy machinery of other digging methods, hydro excavation is significantly safer in terms of work site safety. This whole process uses water to move soil so it is a better alternative on sites with underground utilities and infrastructure as water will not cause any damage. Hydro excavating has seemingly endless applications and can be used on virtually any type of ground. From loose soil, clay, frozen ground, hardened material, hydro excavating is the most versatile alternative to traditional excavation.
Air excavation, also known as dry suction, is essentially the same process as hydrovac excavating but using pressurized air to blast and move soil. One of the benefits of air excavating is that the dirt that is excavated remains dry throughout the entire process so it can be used later for back filling. Compared to hydro excavation, costs are similar. However, air excavation is a much slower process meaning the equipment and crews are needed for longer potentially increasing the overall cost of the project. Both hydro and air are the significantly safer options when it comes to excavation processes. There isn’t much difference between each respective method, however, compared to traditional excavation, they are both much safer for crews, infrastructure, and the environment.
Application is where air excavation falls short compared to a hydrovac. While air is usually the preferred method on projects close to public roads and highways because it reduces the risk of traffic hazards, air does not have the versatility that hydrovacs do. Clay and frozen ground are hard to excavate with only compressed air, so in these instances, hydrovac is the better option. Air also requires a two-man crew at all times where hydrovacs can be done solo. Air requires a two-man crew to operate the vacuum tube and the pressurized air gun. Hydrovacs can be used with a remote to control the tubes and a pressurized water gun to dig the soil. There are many reasons to use air over hydro or hydro over air, but the preferred method is hydro excavation due to the versatility and time reducing costs. Hydro excavation is also a safer option for the environment with our new RNG (renewable natural gas) units here at McRae’s Environmental Services. Most of the trucks on our fleet also carry an IST (idle shutdown timer) that prevents trucks from idling for extensive periods of time if not in use.