Excavating Without Digging

suction excavator

Suction excavators, also known as vacuum excavators, have become an increasing common tool for civil engineering contractors over the past 10 or 20 years, but they are still a sufficiently new concept that their safe use has not yet been formally set down.

That is about to change, with work starting by a UK industry association to produce a new code of practice.

Suction excavators have proved particularly well suited in the utilities sector to extract spoil from a trench at minimum risk to underground pipes and cables. It is not only safer, proponents of the technique say, but also quicker.

It is easy to see how vacuum suction technology has moved from light duty domestic cleaning chores to increasingly heavy duty industrial applications, from leaf and litter gathering, to sludge removal to the current ultimate of excavating earth, sand, clay and stone.

Typically, the fans are capable of creating an airflow of up to 44,000 cubic metres per hour with a maximum vacuum of 55,000 Pa. This air flow enables the operator to suck up materials up to 250 mm in diameter through the air intake suction nozzle. A ground engaging tool such as an air-jet or water-jet lance can be used in tandem, if required, to break up the material and make it easier to suck up.

vacuum excavator

Sometimes it is the delicacy of suction excavators that is required. They can be used, for example, to excavate around tree roots, to remove trees without damaging the roots so that they can be replanted elsewhere. It is like keyhole surgery for diggers.

Sometimes it is their speed that is useful – for example, they are used on the railways for removing old track ballast in renewal operations.

And other times it their flexibility is the key asset – directing the hose into an area that even the smallest and most nimble mechanical digger could not gain access.

There are now several hundred of these machines at work across Europe, with their numbers growing rapidly.

The leading European manufacturers of suction and vacuum excavators are the German companies Mobile Tiefbau Saugsysteme GmbH (MTS) and Reschwitzer Saugbagger Produktions GmbH (RSP).  In the USA, manufacturers include Ditch Witch, Vermeer and Pacific Tek.

Despite the safety benefits of suction and vacuum excavators, their use is not without risks and, like any heavy machinery, they must be used only in accordance with the manufacturer’s instructions. However, what constitutes an appropriate level of operator training and how the use of the machines should be managed remains in development as the market matures.

suction machinery

In the UK, the need for a review of safe practices and the management of suction and vacuum excavator hit home after an incident in 2015 that resulted in the death of the operator of a truck-mounted machine. Meetings were called among users to see what lessons should be learned and this led to the creation of a special interest group within the long-established Construction Plant-hire Association (CPA).  The first meeting of this new Special Interest Group for Suction and Vacuum Excavators (SAVE) was held in February 2016 and it was agreed that its first task had to be the development of a good practice guide.

Group members have since agreed that the guidance will cover the use of truck-mounted, trailer-mounted, self-propelled and static suction types but not the gully suction-type machines used for sludge removal operations.  The CPA tells us that there will be a dedicated section on the selection, preparation and use of supporting crew who assist the excavation operation using a ground engaging tool such as an air-jet or water-jet lance that loosen the material if require, making it easier to suck up.

The aim is to have the guidance published in early 2017.

Steve Rhine

About Steve Rhine

Community Manager at MachineryZone USA - All latest construction news on MachineryZone Mag!