The most versatile construction machine available for rental stores?

Many would vote for the loader-backhoe, for years a proven workhorse.

Others 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;

- A powerful, portable vacuum suitable for a multitude of work site clean-up tasks.

“Because they can do so many different jobs, they appeal to a very broad range of equipment renters,” says Richard Levings, product manager at The Ditch Witch Organization, manufacturer of underground construction equipment and two vacuum excavator models. "Therefore, 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 sucks up spoil which can be used to refill the hole later or be transported offsite.

Levings 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”—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, and excavations made with vacuum excavation equipment usually causes less disruption of traffic and other surface activities.

Vacuum excavation’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 Levings. “They are effective for digging holes to set utility and light poles and poles to support signs and they are 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, grease traps, keeping directional drilling jobs free of excess drilling fluids, and virtually any clean-up 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, but that appears to be changing, and rental customers are finding innovative uses for the equipment.

Levings says rental store managers say the customer base is expanding from utility crews and contractors to include general contractors, municipality utility and street crews, other government agencies, landscapers, and fencing contractors. Once they take out a machine, many renters discover new ways they can use it.

Rental Plus, Carol Stream, Illinois, has three Ditch Witch FX30s.

Says operations manager Mike Reedy: “We rent them on a regular basis to utility companies and utility contractors, directional drilling contractors, and cities. Utilities use them to pothole and to dig pole holes in congested easements where they can’t use big digger derricks. Electrical contractors use them to remove standing water from manholes. Golf courses have rented them to clean out sand traps and to correct drainage. Sand can be quickly removed without damaging the under base.”

Reedy says demand for the equipment is steady.

“Customers are always finding new things they can do with them,” he adds.

A Hertz Equipment Rental store in Livermore, California inventories four Ditch Witch FX60 models.

“They are out most of the time, and customers are very happy because we get a lot of repeat business,” says Dean Hudson, Hertz branch manager. “They have been used to pothole, to suck up water from the playing field before a football game, to clean out bins in a ready-mix concrete plant, to clean soil from trench, and to clean out storm drains and meter boxes. The hose can be extended to 150 or 200 feet and performance at ground level is just as good as it is at 10 feet. Customers have even vacuumed under houses.”

Nebraska Rents in Omaha, Nebraska, a Caterpillar rental store, has just put its first FX30 in service.

“With everything that’s going underground today, we believe there is huge potential, and it’s going very well,” says equipment rental salesman Rusty Rogers. “We’re renting to water and sewer contractors, plumbing contractors and some electrical contractors and cable installers. They use it for potholing and general clean up.”

The two Ditch Witch vacuum excavator models are well suited to rental applications, says Levings.

The FX30 is powered by a 28-horsepower diesel engine, and its blower develops 500 cfm and up to 15 inches of mercury, providing powerful suction force. Maximum water pressure can be controlled in increments from minimum of 0 to maximum output of 300 psi for excavating. It has an 500, 800, or 1200-galllon debris tank and a 100, 200, or 500 -gallon supply tank to hold water for excavating.

The larger FX60 is powered by a 56-horsepower liquid-cooled diesel engine. For vacuuming, the machine’s belt-driven blower develops maximum airflow of 900 cfm and up to 16 inches of mercury. For excavating, soil is displaced by water at pressures to 3,500 psi. The FX60 can be equipped with 325, 500-, 800-, or 1,200-gallon debris tanks. Water supply for excavation is contained in 100, 200 or 500-gallon tanks.

Both models are available as a trailer-mounted package or on skids for mounting on tracks. Rental operations are reacting to the growing demand for vacuum excavators.

“We have implemented strategic relationships with some of the better known vacuum excavator manufacturers,” says Ernie Delle Donne, United Rentals vice president sales. “This category of equipment has provided an excellent stream of rental revenue for our branches that have entered this market. We believe that as the economy recovers and the telecom networks expand again, there will be an even greater need for vacuum excavators to locate buried utilities.”