Compact, trailer-mounted vacuum excavators are being added to rental fleets in a growing number of equipment rental stores.
Vacuum excavators are two machines in one: a powerful, portable vacuum suitable for a multitude of work site clean-up tasks and a “soft” excavation tool. Because they can do many different jobs, they appeal to a broad range of equipment renters.
Depending on the make and model of the vacuum excavator, soft excavation displaces soil using either pressurized water or air delivered by a hose to a nozzle held by the machine’s operator. They are best-suited for making small, precisely controlled excavations. As digging progresses, the unit’s vacuum removes spoils that can be used to refill the hole later or be transported offsite.
Two widely used applications for vacuum excavators are “potholing”—the act of uncovering buried utilities to visibly confirm their locations before excavating—and cleaning up drilling fluid on horizontal directional drilling (HDD) sites. In addition, the vacuum capability is good for about any cleanup task on construction sites and equipment yards.
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. A good example is the popular Ditch Witch FX20 (27 horsepower, 540 cfm, excavating water pressure to 3,000 psi). There are five other Ditch Witch vacuum excavators ranging in size from the FX20 to the powerful FX60 (60 horsepower, 930 cfm maximum airflow, excavating water pressure to 3,000 psi).
When used properly, the equipment’s soft excavation technology can excavate around buried pipe or cable without the 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.
Potholing now is being required on projects where new utility installations cross or are in close proximity to existing utilities. Many HDD projects are requiring that a vacuum excavator be on site, and vacuum excavators are recognized as the fastest, most efficient method of potholing. Depending on the machine used and soil conditions, a 12-inch-square, 5-foot-deep pothole can be completed in 20 minutes or less.
A vacuum excavation’s digging capability is not limited to potholing. It can dig short trenches in areas where larger equipment can’t be used and in easements crowded with buried pipe and cable. Vacuum excavators are used for digging holes to set utility and light poles and poles to support signs, 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.
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 non-hazardous clean-up job.