AirSpade and AirVac

An AirSpade and Airvac in a studio shot.

AirSpade and AirVac make a great combination for non-destructive digging.

AirSpades have become a preferred method for arborists on many jobs, ranging from vertical mulching, bare rooting, radial trenching, and soil aeration. AirSpade’s proprietary supersonic nozzle turns compressed air into a high-speed, laser-like jet that dislodges soil in a fraction of a second without damaging roots.

Use of an AirSpade is the best way to minimise damage to the tree’s root system and the most efficient technique available.

A tree-service must-have

Over the past 30+ years, the AirSpade has become a must-have tool for treeservice companies providing tree-health management and site construction services.

Applications using the AirSpade are safe for both trees and personnel on site. When paired with a standard 185cfm tow-behind air compressor, the AirSpade delivers exceptional performance for a range of applications at remote locations. Through ongoing engineering, research, and experimentation, AirSpade continues to develop new options, nozzle sizes, and accessories in response to demand from arborists and other end users. Councils and shires in Australia are increasingly specifying non-destructive digging when requesting tenders, more often than not using AirSpade in their Tender Scope of Works.

Powered by a common, tow-behind air compressor, excavating with the AirSpade offers several advantages over conventional tools such as picks, shovels, and backhoes, and is two to three times faster than hand excavation and causes less worker fatigue. They eliminate sharp metal edges, and are therefore harmless to buried, solid objects such as utility lines, telecommunication cables, tree roots, hazardous-waste containers, or military ordnance.

Arborist using an AirSpade to excavate around tree roots.
Use of an AirSpade is the best way to minimise damage to the tree’s root system and the most efficient technique available. Image: Knight Pneumatics

Excavation Rates

Excavation rates for the AirSpade are a function of soil type and nozzle size (air flow). Hard, stiff soils will have lower excavation rates than soft, sandy soils. For any given soil, the lower the unconfined compressive strength, the faster the digging.

As shown in the table, six standard AirSpade supersonic nozzles, ranging in size from 25cfm to 330cfm, are available. As a rule of thumb, the quantity of soil that can be excavated in a given amount of time is rough.

A table showing various nozzle sizes for the AirSpade.
Image: Prime Creative Media

Pairing AirSpade with AirVac

The next generation AirVac is the costeffective, mobile alternative to large, expensive vacuum-excavation trucks.

Engineered to be rugged and dependable, AirVac vacuums up to two cubic ft/min of dirt, sand, gravel, and muck. It safely uncovers underground utility lines, tree roots, or other buried facilities, and is ideal for trenching, potholing, and keyholing applications.

Soil is dislodged and driven airborne by the AirSpade, then vacuumed directly into the AirVac container. It’s ideal for small-diameter, deep excavation (potholing) where a hand shovel or backhoe bucket cannot be used. The recovered soil is easily replaced into the trench or hole.

Designed to run off a standard, 185cfm tow-behind air compressor, AirVac boasts a tank capacity of 11 cubic ft. (82 gallons) and an extra-wide dump door to facilitate emptying spoils for backfilling.

The powerful, multi-stage venturi vacuum engine is also detachable to provide ease of transport. Featuring all aluminium construction with heavyduty rear rails, loading the AirVac onto the bed of a vehicle is an easy task.

The tank lid is removable for access to the tank interior and is held in place with quick-release latches. Handles are provided on the AirVac for its lifting but are not intended to support the entire weight of the tank if full.

The AirVac has two wheels and rear handles for manual transportation. A wide dump door with quick-release latches is located at the front bottom of the tank so material can be easily removed or dumped back into the trench or hole.

For more information contact Andrew Knight on 0411 314 007, email, or log on to

The Knight Pneumatics home page showing various products, including AirSpade and AirVac.
Image: Prime Creative Media
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