The most versatile construction machine available for rental stores?

Many would vote for the loader-backhoe, for years a proven workhorse. Others would say the honor belongs to the skid-steer loader and its array of multi-purpose attachments.

But before making a decision for any most-versatile-rental-machine award, consider the credentials of a new contender: the vacuum excavator.

      A vacuum excavator is two machines in one:

•      A "soft" digging tool that can make small, precisely controlled excavations for virtually any purpose; and
•      A powerful, portable vacuum suitable for a multitude of work-site cleanup tasks.

"Because they can do so many different jobs, they appeal to a very broad range of equipment renters," says Greg Adkins, product manager at The Charles Machine Works, Inc., manufacturer of Ditch Witch underground construction equipment. "So it is not surprising that more and more rental stores are adding vacuum excavators to their fleets of equipment."

What sets vacuum excavators apart from other machines that dig is their "soft" excavation technology, which, depending on make and model, displaces soil using either pressurized water or pressurized air delivered by a hose to a nozzle held by the machine's operator. As digging progresses, the unit's vacuum removes spoils that can be used to refill the hole later or be transported offsite.

Adkins says that most of the vacuum excavators in rental stores are compact models that dig with water and are mounted on trailers that can be pulled by pickup trucks.

For digging, one of the primary assignments for vacuum excavators is "potholing," or uncovering buried utilities to visibly confirm their locations before construction involving any type of excavating. Depending on the machine used and soil conditions, a 12-inch-square, 5-foot-deep pothole can be completed in 20 minutes or less. The equipment's soft excavation technology excavates around buried pipe or cable without the risk of damage inherent with backhoes, excavators, or other mechanical tools. Also, excavating with vacuum excavation equipment usually causes less disruption of traffic and other surface activities.

But a vacuum excavator's digging capabilities are not limited to potholing.

"They are used to dig short segments of trench in areas where larger equipment can't be used, and in easements crowded with buried pipe and cable," says Adkins. "They are effective for digging holes to set utility and light poles and poles to support signs. They are also used to make small excavations to repair pipe and pipe joints, to cut off service lines, to plug unused pipelines, and to attach anodes for cathodic corrosion protection systems. Jetting attachments are useful in cleaning out conduit and sanitary and storm sewer lines."

Small excavations made by the machines are easier and less expensive to fill and repair than the larger ones made by mechanical equipment.

As vacuums, vacuum excavators are versatile, all-purpose machines for cleaning out manholes, catch basins, conduit and pipe, vehicle wash pits, and grease traps; keeping directional drilling jobs free of excess drilling fluids; and virtually any cleanup job.

Vacuum excavators appear to have great appeal as a rental machine, but to date they have not been widely available in equipment rental centers. This appears to be changing, as rental customers are discovering more and more innovative ways to use this versatile equipment.