Vacuum Excavation

On this page I will show you our:

• methods of Vacuum Excavation
• applications for Vacuum Excavation

Vacuum excavation is simply excavation using a high volumn vacuum pump to draw the earth or other solid material up from the ground and deposit to either a vehicle collecting the spoils or to some other location. The material being vacuumed up could be either solid earth, previously excavated ground, compacted deposits of various materials such as silts and even manure or organics.

The vacuum will draw the material up when you put the end of the hose into it however it hastens the process immensly iff the material is broken up.

Methods of Vac-Excavation

There are two different methods used to break up or dig the solid material and Renopipe has equipment and capability to use either method.

• high pressure water (Hydro-Vac)
• high velocity air (Air-Vac)

They both have there strengths and weaknesses and the type of excavation they are best suited to however the best method in general is Air-Vac. See the descriptions below for an explaination of this.

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Hydro-Vac

Air-Vac uses vacuum as the method for collecting and transfering the material to be excavated however the method for breaking up the material so it can easily be vacuumed up is, as the name suggests - Water.

Water is pumped out through an attachment which has a nozzle fitted with a jet. A certain flow volumn coupled with pressure maintain optimum ground cutting power while using as little water as possible.The vacuum then collects the mud back to a tanker for removal and disposal.

Advantages

• although not as safe as Ai-Vac this is still Non Destructive Digging in the correct hands
• nitial equipment needed is cheaper to purchace than Air-Vac

Disadvantages

• although mechanical digging is out of the question there is still a very, very, small chance of damaging underground services and definately more chance than when using Air-Vac
• when executed manualy which is the best way of being safe around services it is quite heavy hard work
• along with the above it can be quite muddy and messy work
• excavated material usually has to be taken offsite to satisfy the EPA
• there is a potential for water to get into electrical conduits if they are unsound

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Air-Vac

Air-Vac uses vacuum as the method for collecting and transfering the material to be excavated however the method for breaking up the material so it can easily be vacuumed up is Air.

Air is forced into the ground using a nozzle which is configured to cause the air to exit at High Velocity (speed). This fills all the minute cracks and spaces in the ground with air and explodes it.

Advantages

• this is True Non Destructive Digging at its best and you are protected from the potential damage cause by mechanical excavtion methods to underground services
• the excavated material is not automatically classed as waste by the EPA llike hydro-vac waste is and so it usually can be kept onsite for backfill etc See Vacuum Loading page for different options on where we can transfer the vacuumed material to.
• the actual task is lighter and easier work than hydrovac if being done by hand held attachemnts
• the attachments thus being lighter because of not having heavy slugs of mud and huge vacuum pull as with hydro-vac are a lot less lickely to damage infrastructure
• the high velocity air will break up the ground easily but will not damage infrastructure
• because no water is used it is a lot safer to use around electrical cables and conduits than hydro-vac
• when executed correctly, with only a little dust suppression and a lot of technique, it is a lot less messy than hydro-vac which can be fairly muddy
• air-vac can be doone just about anywhere if you have the equipment as you are not reliant on a water supply as with Hydro-Vac

Disadvantages

• it is said that it may not dig very heavy clays etc as easily as hydro-vac (although i feel this is debatable)
• a very large air compressor is needed for it to work efficiently comared to the relatively small high pressure water pump needed for hydro-vac

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Applications for Use of Vacuum Excavation

Here is a list of some of the applications or places you would use Vacuum Excavation

• potholing to expose underground services
• trenching for services and footings etc where no mechanical access is possible such as in back yards of residences
• non destructive digging for when there are too many underground services in close proximity
• where it is impractical to use mechanical methods such as small confined areas in or outside buildings such as under shearing shed floors
• where is is actually more speedy and cost effective to do so such as excavation of road cattle grids

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