It's a simple machine, really, just a high-pressure water pump and a powerful vacuum. But for K2 Construction of Lincoln, Neb., the Tornado hydro-excavator has become an important part of the company's success.
K2 bought two hydro-excavators about 2-1/2 years ago and uses them for a wide variety of tasks from locating utilities to excavating in tight quarters. "We try to keep up to date on technology with the different types of bore rigs and locators we have and these vac trucks are another tool we're using to improve our work," said Ryan Beekman, superintendent of K2 Construction's Underground Services. "The use of a vac truck on any construction project — commercial, highway/heavy or residential — can make the work safer, easier and faster."
Among the features on K2's self-contained Tornados, each unit includes a 12-yard debris tank, 1,600 gallons of water on the truck, 721 Roots blower systems, and a Cat 2510 water pump. The 560,000-Btu boiler systems keep the water heated to 200 degrees and the water pump generates 1,000 pounds per square inch to 3,000 pounds per square inch of water pressure for fast, precise, non-destructive excavation by erosion.
The boom rotates a full 180 degrees off the back of the truck to cover either side and, with its extension hoses, K2 can work effectively more than 200 feet from the truck. "The capability to remote off the truck is good for work in back yards and for landscaped areas you can't pull the truck right up to," Beekman said.
"A typical hydro-excavator is one you pull behind a pickup truck that might hold three yards of debris," Beekman noted. "We have 10 times the suction, twice the water pressure and can haul four times the debris. These vac trucks can do in two or three hours what would take that smaller unit a full day. We own a small one but I don't think we've used it in more than a year and a half because these are so much more efficient."
According to Beekman, the benefits provided by their larger units include safety as well as savings in time and money.
"First of all, it's just safer. We don't have a guy in a hole with a spade and a probe trying to find a high-pressure gas line or a high-voltage electric line. In locating lines of any kind, we don't damage the infrastructure. It's a lot better to 'hit' a line with water than a backhoe bucket and we're able to turn down the water pressure so we don't cut through the outside coating of any of the lines we're exposing. And there are no spoils to damage yards and streets."
K2 uses the vac trucks ahead of all of its crews, Beekman said, including its boring crews, open cut crews and concrete crew.
"Whatever the job is, we save thousands of dollars by getting out in front of all of our crews with the vac truck," he said.
"We use it to find all the existing utilities ahead of the boring crew so when they show up they already have the depths and they can just start shooting. When they're done, we can suck the mud out when they pull back. Especially on water mains ... A 30-inch hole over 1,000 feet long is a lot of mud to displace. We vac that so it doesn't run on the street or leave a bunch of slop on the owner's property."
K2's open cut crew uses the hydro-excavator to clean out manholes. "When we have to jet a sanitary line, we can get all the sand or mud out of the line before the guys enter the hole," Beekman said. "Our concrete crew uses it a lot to dig footings, particularly in the winter. It's a lot easier to use than digging through frost all day with a backhoe. This winter we were cutting through 30 inches of frost pretty quickly."
Beekman said having the boiler also helps anytime a crew has to cut through clay because it cuts it up and, with the hot water, the clay doesn't stick together.
The ease with which crews can excavate with the hydro-excavator also makes it an ideal tool for slot trenching telephone poles, setting concrete and metal bollards, and for other more specialized applications.
"We do a lot of slot trenching when there are numerous utilities in a small space. We can slot trench it in an hour or an hour and a half as opposed to having a backhoe and two guys with shovels in there for two days. It's very clean and doesn't leave any spoils so you don't have to worry about rain the next day and mud running all over the road."
K2 Construction also slot trenches a lot of telephone poles and can dig a pole hole in 30 to 45 minutes for those even if the ground is hard.
"We use it for setting bollards too, either concrete or metal posts. We core an 8-inch hole 3 feet deep, suck down 8 inches, set the bollard, and we're done."
When Union College, in Lincoln, rehabbed its swimming pool, they couldn't figure out how to clean their 16 10-gallon sand filters. K2's crew removed sand from the filters in about half a day, and cleaned out 8 feet of drain line that was full of sand.
K2 has even used one of its trucks to dig a grave that was too close to structures for a backhoe to dig.
Beekman said the vac truck crews empty the debris tank up to three times a day at either of two stockpile sites the company has in Lincoln. After it dries, the spoils make a good topsoil they use for reseeding on their projects.
The bottom line, Beekman said, is that the company's vac trucks are indispensable on its projects for the added safety, capabilities and efficiency they provide.
In addition to using the vac trucks on its own projects, K2 rents the trucks out for drain tile, wash bay clean out, tree planting, pre-construction engineering, sewer and lift station clean out, and many other applications.