VC EXT Exterior

How to Know When Hydro Excavation is not the Best Option – The Dos and Don’ts

Hydro excavation is a great tool for daylighting and safe digging but it’s not always the right decision. Circumstances, surroundings, and a number of other factors can all come into play.

Here are several things to keep in mind.

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1. Large scale excavations:

While hydro excavation is an effective tool to precisely dig and locate utilities, there are instances where traditional bucket excavation is more efficient. Prior to large scale excavations it is still a good practice to locate any potential utilities with hydro excavation. Only after locating utilities, it certainly may be more efficient to dig with traditional bucket excavation.

2. Soil remediation:

Many times, there are instances where soils has become contaminated with oils (mineral, PCBs, caustic, flammable, etc.). It is imperative that operators are aware of the types of material they are vacuuming and use the proper equipment to do such excavations. The amount of air that these vacuum excavators can move is astounding and vacuuming a flammable substance (even diluted with soil) can be catastrophic due to aeration. A simple spark or static electricity can cause an explosion where traditional bucket excavation lowers this risk.

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3. Environmentally / security sensitive areas:

Proper maintenance at these locations is imperative. Installments such as nuclear power generation facilities generally will not allow high pressure water to be sprayed into the ground for two reasons; 1. High pressure water can cut sensitive infrastructure if not properly performed. 2. Due to the high security level it is difficult to admit backfill into nuclear facilities and the grounds are constantly monitored for any outside contamination. Due to these constraints, it is more efficient to dump the material excavated back into the area it came from. This is an application where air excavation would be a better candidate.

4. Extremely compacted / dense or solid soils:

In coastal communities there is an abundance of coral beneath the surface. Hydro excavation can take hours upon hours and thousands of gallons of water to cut through the coral. It is best to locate all utilities in the excavation zone and then use the best tool to efficiently perform the application. For example, it is common to use hydro excavation to set power and light poles. Along the coast it is a well-known fact that at approximately 3 to 5 feet beneath the surface you will hit coral beds. If the area has been deemed clear of any utilities it may be more efficient to use traditional augers to perform these tasks.

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5. Easement areas:

Lets define these as areas that could be long distances from any paved roads or access points. While high vacuum excavation equipment can vacuum hundreds of feet away from the machine, it may be more effective and efficient to use a tracked vehicle to enter these areas because that’s what they were designed to do.

6. Limited access to water:

Perhaps the excavation zone is a long distance away from water. The hydro excavate you need water. If your water source is so far away that you spend more time sourcing water than excavating it may be best to locate utilities with a hydro excavator and then use bucket excavators.

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7. Cold climate storage:

Yes, hydro excavators can be winterized but if the practice of winterizing the machine creates more burden than benefit it may be better to use a different method without water.

Christopher Smith, VAC-CON

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