Vacuum excavation services
What is vacuum excavating
Also known as non-destructive digging (NDD) or soft digging is a safe method commonly employed to assist in identifying valuable underground utility infrastructure when potholing.
How does hydro vacuum excavation work?
The vacuum excavation process utilises powerful air suction to remove loose materials and convey to a holding tank. Where materials are hard packed and bound together a high pressure water lance is used to breaking up and loosening materials around the target area, once broken into smaller pieces suction can be reapplied for removal of loose materials. These materials are held in holding/spoils tank which can be removed from the work area and taken to a suitable waste disposal location, stock piled on site, or reused to back fill the same location at completion of vacuum excavation works.
Benefits of using hydro vacuum excavator
- Safe alternative to mechanical excavation
Safety is paramount when conducting all works, and with more and more services now being installed or rerouted in the ever expanding underground utility network using vacuum excavation provides a safe option compared to mechanical excavators with powerful and sharp implement striking areas of possible underground pipes and cable assets.
- Potholing of assets
Where Telecommunication, Power, Gas, Water, Sewer assets have been electronically located and surface paint marked, vacuum excavation provides a simply and unique method of direct key hole excavation to the asset for physical identification. (you tube video)
- Able to get into hard to reach places
Even hand digging can have its limitation when working around congested areas. A vacuum hose is flexible and allows access to those hard reach spots. Hose extensions and accessories can be added to achieve desired results for each application exposing underground utility services. (you tube video)
- Contains spoils and waste in sealed tank environment
Hazardous materials are captured in a sealed holding tank which allows for controlled disposal. What happens to ground materials with interjection of foreign materials is unknown and can lead to personnel being exposed to possible dangers such broken glass, syringe, chemicals, asbestos, sharp metal fragments.
- Exposed utility assets in congested places
Where assets are located in a congested areas using vacuum excavation is ideal to safely work around and expose existing services without causing any damage.
- Pit cleaning for safe access
Utility services pits provide access to pipes, valves, cables, solenoids, services meters, expansion loops, but are exposed to weather and surrounding environmental elements. the pits are not completely sealed and usually have key holes for pit seal breaker lifting tools. Soil, leaves and other materials can build up inside the pits and quite often become homes for many friendly and not so friendly spiders, wasps, snakes and many other species. Vacuum cleaning is an excellent method of creating a clean and safer environment before introducing personnel to access pits.
- Ability to work with known and unknown subsurface content
Where soil structure is....
- Very low dust levels
Vacuum excavation machines are fitted with filtering systems to greatly reduce air borne material. Most vacuum units run with 10 micron filters. Any dust that may be created is usually from using the water lance to break up soil materials prior to vacuuming
- Reduced risk of asset damage
A great advantage of vacuum excavation is being able to minimise the possible risk of asset damage which could occur when using other mechanical excavation methods. When services and equipment has to remain energised vacuuming becomes a very valuable method of safe work procedure.
- Less destructive to surrounding environment
A benefit of being able to not disturb surrounding features and minimising large earth work excavations where possible by focusing on very specific areas utilising vacuum excavation
- Utility asset identification and verification of depth, size and type
Where underground utilities have been electronically located vacuum potholing is used to remove a small amount of subsurface material so physical identification can be made for depth, size and material type of service. A PVC tube is placed in the hole on top of the services as a marker and all utility service attribute are label on the tube for future reference
- Utility Line locating
Identify existing asset services and physically follow the service to verify any changes or anomalies not previously known.
- Faster compared to hand digging
Vacuum extraction is a very fast and efficient method, loose sand materials are quickly removed and where harder materials such as clay are encountered high pressure water is utilised to break up the material prior to vacuuming. Hand digging can lead to high fatigue and injury with constant bending and body movements of heavy loads.
- Access area’s where conventional excavation machines are not practical
Many locations within existing buildings, bridges, power lines or closed in area’s can have limit access for mechanical machinery. Vacuum excavating provides an excellent alternative in accessing those locations
- Construction assistance i.e. fence posts, light posts, traffic lights, sign posts, trench footings.
Using vacuum excavation for fencing construction has major advantages for post or pole installation as boundary fencing and underground services can run in close proximity to each other. Vacuum excavation provides a very safe method compared to mechanical auguring. If any underground Telstra services, water pipes, power cables have not been identified by electronic detection the vacuum will expose the service which is far better than cutting or breaking a service and exposing personnel to possible dangers or expensive company repair costs.
- Engineering inspection assessments
Various engineering inspections require physical identification, vacuum excavation allows for very small area to be removed without disturbance to the surrounding structure. The key hole created can be used to insert an video inspection camera.
- Vacuum instead of hand auger
Some requirements for drilling companies is to hand auger the first metre as an extra measure to avoid any underground services. A useful tool is vacuum excavation pothole prior to drilling by excavating a hole and inserting a PVC sleeve. The sleeve also assists the crew by working as a marker for all hole to drilled.
Foundation, footing, tanks and concrete slabs may require removal of surplus support material to obtain desired RL. Vacuum excavation provides excellent advantages by not having to remove existing structures.
- Anchor points
Vacuum excavators are high powered suction machines and can be applied to different engineering tooling application. The power of suction can act as an anchor point for equipment machine bases.
Hydro vacuum excavators come in various sizes depending on the required task they share the same basic mechanical process. Below are few of the main mechanical components and their basic function
- Hose – Flexible hose conveys the materials
- Tank – the spoils tank holds the captured materials
- Filtration – cyclonic separator and fine filters remove small particulars
- Blower pump – positive displacement blowers pump large volumes of air with powerful suction
- Motor – to drive blower and accessories
- Water pressure pump – provides high pressure water to lance for material break up
Duty of Care
It is important to understand “duty of Care” when working near underground utility services. Asset owner with AS5488-2013 QL-A require positive validation of underground service, this can only be done by potholing by hand or using non-destructive digging (vacuum excavation).