Hydroexcavation Contractor Gets Creative on Project in Downtown Philadelphia

From:  Dig Different Magazine   Written By:  Cory Dellenbach 

Pennsylvania’s Ecotech Hydro Excavation removes 3,000 cubic yards from below a hospital for an expansion project.

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Ecotech Hydro Excavation crews got a big challenge when they took on a job to expand a Philadelphia hospital. The job called for removal of 3,000 cubic yards of debris using 400-plus feet of hose and pipe, working in tight spaces and finding a way to break up the material.

“It was definitely a challenge,” says Ryan Frank, operations manager. “We just needed to think outside the box and get creative.”

The air excavation and hydroexcavation company based in Quarryville, Pennsylvania, wasn’t afraid to tackle the job, which spanned nine months. The company takes on work throughout Pennsylvania, New York, New Jersey, Delaware, Maryland and other areas of the Northeast.

“This has been one of our biggest and toughest jobs,” Frank says. “It was a lot of the worst-case scenarios of every aspect of what we do.”

Taking on the job

The downtown Philadelphia hospital was undergoing an expansion, but it couldn’t go any higher than its nine stories because of ordinances, and there was no room to expand laterally.

“The best option was to expand down,” Frank says. “There was an area in the center of the hospital that was just a crawl space and not a full basement, so that is where they would add extra offices.”

The general contractor was given the option of building a temporary hallway within a permanent hallway; laborers would hand-dig the soil into 50-gallon drums. The drums would then be carted out of the building and emptied into a dumpster. After the drums were cleaned out and brought back in, the process would repeat.

“One of their guys thought about vacuum excavation and they contacted us,” says Frank. “A total of 3,000 cubic yards of dirt, rocks and bricks had to be removed. Our estimate for the job was around $650,000 and the bid for doing it with the drums came in at $1.3 million, just to get the material out of the hospital. So there was a substantial cost savings going with vacuum excavation.”

Ecotech crews determined that the only way to get to where the excavation would take place was through crawl spaces and utility access areas in the lower level of the hospital. “We set up the vacuum truck outside at their loading dock area and ran 400 feet of pipe and hose into the center of the hospital,” Frank says.

The company’s GapVax HV-56 hydroexcavator was parked on the opposite side of the road away from the hospital, and its boom was stretched over the road to allow cars to pass underneath. The hose was positioned over scaffolding on the sidewalk closest to the hospital, giving pedestrians a safe place to walk.

A need for stronger pipe

Crews used 6-inch PVC pipe connected to 6-inch hoses from the hydroexcavator to the center of the hospital.

In the first few days on the job, workers were already running into issues. “Our initial problem was that everywhere there was a bend in the pipe, the pipe would want to blow apart from the rocks,” Frank says.

Crews also had two elevation changes to contend with: a 17-foot drop into the work area, and a 20-foot upward incline out of the work area. “Trying to keep productivity up in that long-distance remote excavation was a big factor,” Frank says. “One thing we found is that the elevation changes made a tremendous difference.”

Debris going down the hose became more of an adversity than the material going back up. “You had to have so much cfm to get the material to pull 400 feet, but you couldn’t have the cfm up too high,” Frank says. “When that material would hit the downslope it would come screaming down that hill, build up too much velocity and damage everything it came into contact with.

“Anything plastic or metal on the hose was just wearing through because the material was dry and very abrasive. The pipe also had to be light enough for two men to carry it through a crawl space.”

To deal with these challenges, crews switched to 5/8-inch thick-walled pipe made for waterline installation and used heavy rubber elbows to make the bends.

Finding easier ways to work

Finding a way to break up dirt to vacuum was another challenge.

“An air knife wasn’t a possibility and other air-spade tools like jackhammers were incredibly slow,” Frank says. “We ended up finding an electric mini-excavator that we pushed through the hallways of the hospital on a wood skid and dolly.”

Crews connected the mini-excavator to the available power source and as one worker used the machine to break up dirt, another vacuumed it.

“The GapVax kept up,” Frank says. “The material we were able to pull out of the building was going faster than what we could get broken up, so the truck and mini-excavator worked well in tandem.”

Ecotech was allowed just one truck on the job site. Two vacuum boxes were set up near the truck.

“Once we had the material in the truck, all we had to do in the middle of the day was switch hoses and move it to one of the two vacuum boxes,” Frank says. “We didn’t have to move the truck and we could just keep on working.”

Gaining confidence

The new offices in the hospital’s basement were completed in late 2015.

“Inside the hospital no one even knew Ecotech was there working or that there was construction going on,” Frank says. “We all worked really hard and did a great job. All parties involved were impressed and happy with the end result.

“More than anything it gave us confidence knowing there wasn’t a job we couldn’t successfully do.”

 

To see the full article click the link below:

http://www.digdifferent.com/editorial/2016/09/hydroexcavation_contractor_gets_creative_on_project_in_downtown_philadelphi

 

 

 

 

Uncovering the Benefits of Hydro Excavation

From: Trenchless Technology

Written By: Tisyn Milne

While the One Call System is a good starting point to identify a utility’s location, properly exposing the infrastructure is the only sure way to know where it truly lies, and how the pipe or wire has been run. With millions of kilometers of buried utilities beneath Canada’s surface and records inaccurate or incomplete, it is surprising that there is not more property damage and personal injury occurring every time somebody puts a shovel in the ground. Even backyard landscaping can cause millions of dollars in damage when utility lines get hit, service is interrupted and expensive repairs have to be undertaken.

One can only imagine the ten-fold risk and additional expense when it comes to large scale infrastructure projects taking place across Canada. In a 2011/2012 report by Statistics Canada it was revealed that 40 percent of all damages to underground infrastructure occur due to a failure to notify, a frightening 84 percent of damages cause a service interruption, and 75 percent of all damages are due to outside force through usage of a backhoe or mechanical excavation.

In recent years, many initiatives have focused on mandating safer installation, exposure, maintenance and repair of buried utilities. While the One Call System is a good starting point to identify a utility’s location, properly exposing the infrastructure is the only sure way to know where it truly lies, and how the pipe or wire has been run. This is where hydro excavation comes in as an essential tool of visually locating utilities to mitigate the risk of striking underground infrastructure.

With current government regulation prohibiting the use of mechanical means to dig within 45 cm of buried cables or pipes, hydro excavating is an ideal method to expose underground infrastructure, drill pile holes, trench slots, install signs and poles and conduct landscaping and potholing.

A Vital Industry

What is standard practice in Canada today, began more than 50 years ago in the Alberta oil and gas fields where hydro excavation machines were used to ‘daylight’ buried gas pipes and other utility lines. Cold weather, and even permafrost, would only allow year-round excavation by using heated water, which made Hydro Excavators all the more popular.

When customers began modifying vacuum trucks and sewer cleaners for hydro excavation use in the 1970s and 1980s, and even mounted vacuum components on all-terrain vehicles to get into remote locations the demand was recognized and the manufacturing of dedicated truck-and-trailer-mounted hydro excavation units began in the 1990s due to the growing demand.

The millennium hit, and hydro excavation was already widely accepted and used by utility contractors across Canada for locating and non-destructive digging. It was around that time, that Illinois-based Vactor Mfg. introduced its first dedicated HXX Hydro Excavator as a purpose-built unit and became a leading manufacturer for this ever-growing market.

Today, hydro excavation is considered to be a best practice by municipalities, contractors and public utility organizations alike. As the HydroVac Alliance of Ontario (HVAO) together with the Ontario Regional Common Ground Alliance (ORCGA) indicate in a recent report, the size of Ontario’s hydrovac market has grown significantly since the first custom-built hydro excavators appeared. The associations estimate that there are between 450 and 500 units in operation across Ontario responsible for a total annual revenue of $180 million to $200 million.

Extremely versatile, hydro excavators can be seen virtually on every street corner where they drill holes for fence posts, poles and signs or conduct daylighting of underground gas pipes. And once you see a hydro excavator in action, you will never forget the efficiency and power this unit demonstrates while completing a job. A recent study by the City of London says it best: “…The hydrovac unit effectively replaced the hand digging requirement being completed in 1/3 of the time and with 1/2 of the crew. The cost of using a shovel and backhoe compared to a hydrocvac unit on the identical job is 4.1 times greater.”

Born To Run

As hydro excavation becomes more and more popular, the importance of zero downtime applies to most hydrovac companies to ensure they can keep up with the day-to-day demand for their services. Industry veterans such as the Toronto-based PGC Services Inc. (PGC), a member of the Powell Group of Companies, trust a full service shop of the likes of Joe Johnson Equipment for new purchases, rental units, used equipment and to regularly service and maintain their hydro excavating equipment.

Regular inspections do not only benefit operators and customers, increase safety and are better for the environment, but they also lead to higher resale and trade-in values based on the service history.

In search of a safe, cost-effective and non-disturbing option to expose underground infrastructure when performing an excavation project, the past 30 years have seen a major shift to move from backhoe digging to hydro excavating. Associations such as the Canadian Common Ground Alliance (CCGA), the Centre for Advancement of Trenchless Technologies (CATT) and the members of the HVAO have become important advocates in promoting safe digging procedures, and with the increasing use of hydro excavation, Canada leads the pack as a nation that knows how to safely deal with its underground infrastructure.

Underground Maze of Utilities Solved with Ecotech

underground utilities

Next time that you get stuck in traffic, think about the traffic jam that is below you. There are over 35 million miles of in use and abandoned utility lines that are causing a huge traffic jam underground. Between the labyrinth of pipes, conduits and cables, it is difficult to tell what is dead or alive, because most utilities that are no longer in use remain underground.

Traditional digging can yield unwanted surprises and deadly consequences — especially in older parts of the cities where old utility lines (such as water and sewer) are still in use and undocumented.  When coming across these undocumented lines, all work must stop until workers know exactly if the line is live and if it is safe to dig. This delay costs time and thus costs money. While newer plastic pipes are often color-coded to indicate their function, older pipes were often made of similar materials, making them difficult to differentiate, adding even more to the confusion to the underground maze of utilities.

There are so many chances to get it wrong, to dig near unmarked (or incorrectly marked) lines: About 400,000 utility excavations occur every day across the United States, making it incredibly difficult to put something new underground without having some sort of conflict with other utilities underground.

The 811 “call before you dig” free service, is in place throughout all 50 states to help identify and locate underground utilities to prevent damage, injury and death; but industry experts say the system isn’t faultless.

The latest utility locating technology such as electromagnetic locating devices and ground-penetrating radar, have their limitations. Buried steel railroad, streetcar tracks, old brick or stones can all interfere with the locating devices making it difficult to know for sure if there is or is not an underground utility.

Records of what is underground and what is live are many times incomplete or nonexistent. In the past, recording what was underground was not as effective as it is today. Today, utility companies take their responsibilities very seriously when it comes to marking and protecting their utilities from strikes, but the utilities that were not marked in the past, are still present. No matter how accurate lines are marked going forward, the lines of the past will most likely always be there due to the high cost of removal.

It’s common to assume hand digging with a shovel is the safest way to dig when digging around known utilities, but this notion is not entirely true. Almost 20% of utility line hits are caused by shovels. Vacuum Excavation, whether using water or air, is the ONLY safe way to dig. The high pressure water or air is at a psi that will cut the soil with razor like precision, but is not strong enough to damage utilities.    Each year, millions of miles of new utilities are put underground, joining a mix of old and new pipes that snake through the ground at varying configurations and depths, increasing the amount of utilities and likeliness to hit something using traditional excavation methods.

 

Works Cited:
http://goo.gl/pcU57J
http://goo.gl/l0AOUo

Excavating in Remote Locations

Vacuum Excavating in remote locations is similar to traditional hydro excavation, except instead of working right off the boom of the Vac Trucks, an industrial vacuum hose is run up to several hundred feet from the truck to the location that is difficult to get to.

Remote Vacuum Excavation is used to solve many problems in regards to difficult excavation locations. Some of these problems are:

  • Low overhead clearance, inhibiting the truck to get close to the location
  • Tight spaces, that the truck cannot fit through
  • Unstable soil, that would be dangerous for the truck to drive on
  • Underground utilities that are close to the soil, that cannot be driven over

Whenever these barriers occur in excavation projects, remote excavation is a great tool to excavate those hard to reach places. The truck can be parked away from the difficult excavation site and the pipe can run all the way from the truck to the excavation site.

Advantages to Remote Vacuum Excavation

  • There is no need for hand digging, that can be incredibly slow, strenuous, and can damage delicate utilities
  • Low Clearance spaces can be avoided
  • You can remove the material up multiple stories with the high powered vacuum
  • Excavating around the maze of underground pipes and utilities with vacuum excavation removes the risk of damaging the utilities.
  • Excavating in narrow spaces, places with low clearance, or anywhere else a machine or truck cannot reach is made easy and simple with vacuum excavation
  • You can excavate indoors (in basements for example), where other excavation equipment can’t reach without having to hand dig.

If you or your company has a difficult project, that you have no idea how you will be able to excavate because of its location or sensitive utilities feel free to call us at 1-855-463-2683. We will be happy to come to your job site, at no cost to you, to evaluate the project and provide you with some options that we can hopefully provide for you to complete your project.

Top Ten Myths about Underground Utilities

“Depths of utilities can be assumed.”

Locator depths are estimations, because the surface grade often changes since the time that the utilities were originally installed. Many times utilities are installed before excavation, fill and development happen that can change the surface grade dramatically.  The depth of utilities can never be assumed. Even small portions of utility lines that are as small as a city block can dip or rise in depth. It is important that utilities are exposed to verify their exact location and depth.

 

“It will never happen to me mentality.”

It is easy to think a utility strike will not happen to you, because you have never had a disastrous strike before, but utility strikes happen every day and it is important to never skip safety measures. Cutting corners, rushing to get the job done, getting lazy or complacent on the job, can all lead to major consequences.

 

“Exposing to the depth of the utility is good enough.”

Only exposing the depth of existing utilities is not proper practice and may violate OSHA regulations. Along with exposing the depth of utilities, you must also verify that no utilities are hiding underneath and always expose to the depth of the intended bore path. Visually observe the drill head as it passes the utility, and again during each pass of the reamer. The reamer can shift in the bore during pullback and strike a utility that appeared to have plenty of clearance.

 

“Just drill deeper to avoid existing utilities.”

Drilling deep creates problems such as locating and exposing for current and future excavation. At approximately 10’, locators become less accurate with locating the underground infrastructure. If the existing utility goes undetected, an underground strike can occur. Also, best practices dictate that the existing utility being crossed be exposed to the depth of the intended bore. That is difficult for deeper bores and if the line at that depth is ever damaged, the utility will have to dig deeper requiring a longer response time and greater expense.

 

“Sewer lines don’t need to be or cannot be located.”

If a sewer line is damaged during the installation of a utility, the sewer will eventually clog because of the intersection of the newly installed utility. To relieve the clog, a plumber will run a snake into the sewer and can damage the intersecting line. If it is an electric line, the plumber could be electrocuted. If it is a gas line, the gas can migrate into the sewer and ignite once inside homes or businesses.

 

 “No locate marks = no utilities.”

If there are no marks, this could mean that it was not yet located. Many states have a positive response system so that it can be verified that all utilities have cleared the area.

On-site, privately installed lines may not be recorded by the utility companies or located by the locating service. Inspect the area for evidence of underground activity, disturbed and repaired soil or pavement, utility boxes, conduit coming out of the ground, etc.

 

“My responsibility for damage prevention ends when I call 811. If something happens, 811 is liable.”

811 does not locate utilities. They coordinate with the utilities and their contracted locating services to have the area located. It is the responsibility of the excavator to verify that locates have been completed and are accurate. This includes contacting utilities that don’t subscribe to 811, looking in the area for signs of utilities (outbuildings, pipeline markers, light poles, utility boxes, meters, etc.) and exposing the utilities to verify the locates. If an excavator damages a line, there are always costs to bear and effects on reputation.

 

“Exposing utilities (potholing) is included as part of the contract price for the drilling.”

This shouldn’t be assumed. To ensure potholing activity is included and is not shorted, it is recommended to separate this activity from the drilling in the quote. The project owner and contractor should work together to emphasize this as an important and integral part of the job.

 

“We have to accept whatever the caller gives us.”

When a contractor calls the Call Center or Utility, both parties have to be explicit and detailed with the information provided so an accurate and safe locates can be made.

 

“Electric strike alert systems can predict an electric strike.”

In some cases, the system may activate in the proximity of an energized line, but it cannot be relied upon to detect the line before a strike happens.  If the electric strike system activates, always assume an electric strike has occurred.

Some strike systems detect a strike using only voltage detection via a voltage limiter. The voltage limiter is located away from the machine on a ground stake and detects the voltage difference between the ground stake and the drilling machine.

Other strike systems use both voltage and current detection. In addition to a voltage limiter, a current coil detects current flowing through the drill string.  The system will only activate the alarm when voltage, current, or a combination of both voltage and current is above threshold limits.

For either system, if the alarm sounds, assume a strike has occurred.

Other strike systems use both voltage and current detection. In addition to a voltage limiter, a current coil detects current flowing through the drill string.  The system will only activate the alarm when voltage, current, or a combination of both voltage and current is above threshold limits.

For either system, if the alarm sounds, assume a strike has occurred.

For the original article and more information, visit ICUEE.

Benefits of Vacuum Excavating

From:  Keeping Our Finger On The PULS

By:  Ryan Frank, Ecotech

Vacuum Excavation is a non-mechanical, non-destructive way of safely exposing buried utilities.  This process also allows for workers to stay on the surface and out of the excavation. By virtually eliminating accidental line damage and trench cave-ins.  This is the only true method for identifying the accurate depth of a utility. 

As part of an overall damage prevention program especially when dealing with high value utilities, we always recommend vacuum excavation to expose all utilities in the proposed path of excavation.  For projects where high volume vacuum excavation services are needed, and with large quantities of spoil being removed from the job site, we partner with Ecotech.

Ecotech’s hydro excavation team uses high pressure air or water to expose buried utilities.  This process allows us to dig through any type of soil including clay, rocky soil, or even frozen earth without damaging buried utilities or harming underground lines.  A vacuum hose then transfers both soil and water to the debris tank on the truck.

It is against the law to dig with traditional excavating equipment without a 1Call and the risk of digging without knowing where to dig is just too great.  Whether you are excavating near an electric line, water or sewer pipes, or a fiber optic cable, with traditional equipment and even digging by hand. 

This means that the ability to physically determining on-site the location, nature and depth of underground utility services is critical to reducing the risk and consequences of inadvertent damage during construction.  If it’s underground, and it’s delicate, expensive or dangerous, you should be using vacuum excavation in order to visually confirm the location of the utilities before you dig.   

 

 

Hydro-Excavation: Versatile and Safe

By Ron Weber, Assistant Marketing Manager, Vac-Con, Inc.

The real beginning of Hydro-Excavation dates back to the California gold rush of the 1800’s where miners used steam pump-pressurized water to erode soil. This process was called hydraulic mining.  It wasn’t for well over a hundred years that such processes as vacuum, water pressure systems and heat were introduced to better the “art of controlled erosion ”

Utility companies and contractors are becoming more and more aware of the benefits of hydro or vacuum excavation. The versatility and safety is certainly at the forefront of those benefits. As more and more customers focus on those two key areas, the industry will continue to develop and evolve in many different ways.

Safety made easier

When comparing vacuum or hydroexcavation to traditional digging, some of the advantages are that there is less material removal, cleaner cut footprint, and there is minimal post-excavation restoration. The big advantages of vacuum excavation as it pertains to safety is the ability to safely uncover buried utilities, i.e. no floods, explosion, fires or power outages causing inconvenience or damage to public and people. These are all important areas to consider before digging.  Trench rescue is another area related to vacuum excavation safety.  While it might be uncommon, it is an effective, safe and quick way to remove material.

Trench rescue situations usually are the result of mechanical excavation or a trench that simply collapses on a worker. It is a major safety-related issue when comparing traditional digging to vacuum excavation.

Versatility opens opportunities wide

The other big advantage of hydro or vacuum excavation is its versatility.  Most hydro-excavators come with either front or rear mount booms that have eight and ten foot boom extensions. Some of the versatile jobs that a hydro-excavator can do relate to plumbing, post installation (light posts, road signs, traffic lights, etc.), construction, landscaping, locating utilities (gas, fiber optics, etc.), potholing/day lighting, slot trenching, debris removal, cold weather and remote digging. Those are all examples of ways to safely, and effectively do many different jobs using hydro-excavation.

Safety can be compromised at any time when traditional digging occurs. One recent example of an underground utility strike happened in October 2012 and was fairly catastrophic. It affected thousands of people, disrupted traffic control and cost millions of dollars. On Monday, October 8th, 2012, Alaska Airlines, the 7th largest U.S. airline had to temporarily ground and delay hundreds of flights because their Sabre ticketing system was taken off line when two Sprint fiber optic lines were severed. The first cut, an underground line, occurred at a construction site along railroad tracks between Chicago and Milwaukee. The second cut, an aerial line, occurred somewhere between Seattle and Portland. Passengers were stranded throughout the west coast, and some experienced lengthy delays. This situation could have been prevented had they not used conventional digging methods.

Safety and versatility remain the biggest advantages of vacuum or hydro-excavation. Using water and vacuum to dig can definitely save in costly repairs and in time.  Its versatility allows for increased flexibility when working on a difficult job. The vacuum and hydro-excavation market is still in its early stages in the U.S., but the future certainly looks bright.

Tech Talk: No Shovel Required

From: Municipal Sewer & Water

By:  Doug Day

Hydroexcavation is gaining ground as a safe, precise and efficient alternative to conventional digging.

Hydroexcavation has been popular in Canada for 50 years, but it only started gaining traction in the U.S. about 15 years ago. It’s still not as widely used as it should be, according to Vac-Con Marketing Director Tom Jody, and there is huge potential for growth.

Ordinances requiring vacuum excavation in certain situations are common in Canada, and Jody says that demonstrates how much growth potential there is in the U.S. “Most communities in Canada require utility location with vacuum excavation or some sort of potholing before you’re allowed to excavate,” he says. “In some cases, you’re not even allowed to excavate with a conventional bucket machine; you have to use vacuum technology to do it.”

Many people may view hydroexcavation simply as a method for safely exposing underground utilities, but there are many other uses, especially in confined areas. “There are some situations where it’s a necessity because it’s impossible to get an excavating machine into a location,” says Jody. “Take for example getting behind a home in a residential neighborhood to expose the foundation to repair a utility line or drain tile.”

There are also times when hydroexcavation is the easiest method. Besides daylighting (potholing), it is useful for things like excavating for water valve replacements, trenching and cold-weather digging, as well as pipeline locating, identification and rehabilitation. “It is very precise; think about excavating a trench between someone’s prized flower garden and the wall of their house,” Jody says. “That’s something you can do with hydroexcavation that you couldn’t do with even the smallest of excavators. The applications are myriad and the equipment is relatively simple.”

Karl Lassberg works in sales and marketing for T-Rex Services Hydro Excavation and Industrial Vacuum Services, which owns the largest fleet of hydroexcavators in Texas. T-Rex, founded with one truck in 2001 by former NASCAR driver Bobby Hillin Jr., now has a fleet of more than 38 hydroexcavation and vacuum excavation trucks. “At the time, there wasn’t a lot of hydroexcavation going on in the southern Gulf region,” Lassberg says. “He just went out there and hustled, and the popularity of hydroexcavation has grown over the last decade as the awareness of the technology has grown.”

Lassberg cites one recent job as a good example of the versatility of hydroexcavation. The excavation was only 4- by 4- by 6-feet but required hand digging because the location was inside a parking garage. “It would have taken several days to dig and carry out 3.6 cubic yards of dirt by hand,” he says. “We ran a remote hose down a stairwell and it took us less than three hours. Our bill was much cheaper than a hand dig.”

He adds that hydroexcavation is also a good alternative to an auger for digging holes. “If you have only a couple of holes to dig with an auger, hydroexcavation can be competitive because the material is sucked straight into the truck and dumped off site,” Lassberg says. “You don’t have to worry about additional equipment to scoop it up and haul it away.”

The advantages are even greater when it comes to utility pole holes, usually 18 inches in diameter and 8 feet deep. Two people with posthole diggers will need about two hours to do a single hole, while it’s a 10- or 15-minute job with hydroexcavation.

Lassberg says electro-mechanical work has led to a lot of hydroexcavation work in recent years, such as grounding wire trenches, 6 inches wide and 18 inches deep, that used to be dug by hand. “We can hydroexcavate 300 to 400 feet of that in one day and cover it with a skid-steer instead of putting five guys trying to dig for days at a time.”

One such project was at a lighting conduit project at the Galleria Mall in Houston in September 2010 — 700 feet of trench (2 feet wide and 2 feet deep) underneath a sidewalk bordered by a long line of historic oak trees. “With all those tree roots, you have to dig a little differently and more conscientiously,” Lassberg says. “If you even skin a tree root you can kill the tree, so digging by hand is very tricky business.”

In this case, all the roots crisscrossing through the excavation area made any other sort of excavation impossible. Since tree roots can also be damaged by high-pressure water, the excavators used lower pressure and kept nozzles well way from the roots. The job also had to be done in 48 hours in a high-traffic area of the city. T-Rex brought in five trucks. “We started Friday at 9 p.m., and finished 40 percent ahead of schedule,” Lassberg says. “Two years later, the trees are still in great condition.”

Consider the options

Lassberg says there are three main issues to think about when considering hydroexcavation. Is there a source of water on site? Can the spoils be dumped on site? And how close can the truck get to the excavation?

“Most trucks require a water source, whether it’s a fracking tank, water truck, hydrant or a pond,” he says. “Dumping on site usually makes a job much more productive. Dumping offsite means driving to a dump site and back; sometimes there are dumping fees. Access within 15 or 20 feet from the dig site allows for the greatest productivity but we can work 300 to 400 feet away from the truck when necessary.”

The key pieces of equipment are a vacuum hose and a line for pressurized water. Compressed air can also be used, in which case it is called vacuum excavation (the generic term for the process). The water or air loosens the soil, and the vacuum removes the soil. “It creates a very accurate excavation and less impact on the surrounding environment with a much neater work space because you’re removing the soil into the debris tank,” Jody says.

Using air or water greatly reduces the possibility of damage that is common with a metal bucket. “It’s very easy to sever a fiber-optic cable with an auger or backhoe,” Jody says. “You could be shutting down the transfer of information to and from an entire city.”

Such accidents can happen even when underground utilities have been marked or mapped. “We’ve been on jobs where we had diagrams showing the precise locations of utility lines and after we expose them, they’re 3 feet off from where they were supposed to be,” he says. “There’s a huge amount of wiring and utilities underground in this country, to the point where you see dizzying pictures of all kinds of cables, wires and pipes crisscrossing each other in one excavation.”

So why hasn’t there been a greater shift toward hydroexcavation? Jody isn’t sure, but he has several examples of contractors who could have avoided incidents if they had chosen it over conventional techniques. “Part of it is just not knowing that the technology exists, but there are organizations around the country building awareness, including the Common Ground Alliance and local one-call groups that can help contractors become more familiar with it.”

With the right tools, hydroexcavation can be used in a myriad of specialized applications, Jody says. “Anywhere you need precision digging is a good application for hydroexcavation.”

 

 

Vacuum Excavation Is Gaining Ground

From:  Grading & Excavation Contractor Magazine

Written By:  David Engle

Invented a few decades ago to enable safe mechanical digging near buried utilities and other below-ground fixtures, vacuum excavation, or VE, may not be so quick as digging with backhoes, but the methodology is winning converts among contractors by the truckload.

Instead of attacking dirt in  massive bucket-sized scoops, a scalpel-like VE tool pierces with laser focus  and efficiency—applying air or water—striking the ground with impact and  precision.

In the pneumatic version, air  gets tightly compressed through a controlled aperture; in one such tool the  pressurized air emerges at Mach 2 speed, says Andrew Hartman, who is sales and  marketing manager of the tool’s maker, Supersonic Air Knife Inc., of Allison  Park, PA. Poked into the ground at a steady clips, the AirKnife will pulverize  it, expand it like a small seismic shockwave, kick it up skyward, and keep  excavating all day long. After all, it runs on air.

The resulting hole comes out at  usually 1 or 2 square feet in circumference, or whatever’s needed to expose the  underground element of interest.

Loosened material—whether carved  out by a water jet or air—comes out either as a muddy slurry or dry spoils,  depending on which. In either case, it’s then vacuumed up.

Compared to serious trenching  work, VE is but a limited “boutique” digging niche. As Hartman points out, only  a couple of companies make the high-performance nozzles that Hartman  sells—although venturesome excavators, he notes, have been known to fashion  their own crude ones by simply pounding a tube tip to a narrow edge.

Offering a bit of history: Air  “knives” were first introduced in 1986. The current patent ownership moved to  Hartman’s employer about eighteen years ago. Supersonic makes a half-dozen  variations now; some nozzles can handle either liquid or air.

A vacuum “sister tool” that Hartman  describes, runs from a compressor rather than a vac, and sucks or blows  material out through a discharge tube.

As for the VE market, Hartman  observes: “We’re still really in a kind of educational phase, even after some  thirty years of trying to get the average excavation crew to understand why  they need a tool like this and why they should be using it for the hand-dig  zone… There really are a lot of places where air should be used,” he adds, “but  still isn’t.”

Most commonly applied at the  very start of excavation work to verify utility markups and visually locate  buried lines, pipes, cables, wires, tanks, tree roots, etc., VE will enable  crews “to go in with heavy equipment with more confidence and be fairly certain  that you’re not going to run into trouble,” explains Hartman.

In this role, air- or water-  digging, plus vacuuming, is the alternative to shoveling by hand.

These days, though, as Ben  Schmitt, product manager of Vactor Manufacturing in Streator, IL, points out,  “The utility segment appears to be less than 20% of total vacuum excavation.”  Instead, recent demand for VE work has soared and shifted amidst the nation’s  booming oil and gas production sector.

To obtain VE services, Schmitt  adds, excavation contractors typically turn to VE experts. But larger digging  companies “are starting to purchase their own machines as well, when  justified,” he adds.

Immersion by Water by Pneuma Talk to devotees of air  excavation these days, and you will hear them extol VE virtues with a fervor  that almost sounds reverential. Since virtually all excavators began their  careers with conventional trenching and hoeing, they have comparative  experiences to draw upon. Their switch to specializing on VE reminds one of a  conversion of faith.

First, typically, comes a taste  of hydro digging (apparently, more pervasive than air, at least according to  the sources interviewed here). Afterwards comes the discovery of the aerated  alternative. Everyone likes the latter a lot. The reason? Above all, air  provides a remarkably desirable cleanliness at pneumatic job sites. These are a  triumph over messy, water-soaked, apocalyptic mud pits ensuing from hydro VE.

In a couple of cases, the  affection that air VE inspires is so complete, excavators will revamp their  businesses, virtually to forsake water for it’s sake—although it’s more typical  to hear diggers concede, “Yeah, we still do both.” This comes out a bit  grudgingly, though. Their hearts are with pneuma.

Torry Olive is operations  manager for BBU Environmental and Central States Environmental, two sister  companies that excavate Ohio and surrounding states. Hydro VE was launched by  BBU/CSE there about eight years ago, he recounts: “We played around with it a  bit. Basically, it consisted of using a regular turbo vac and a steamer unit.”

Then, clients started asking  about air. “So we did a little bit of research on it, went out and got an air  spade tool, and started using that with our turbo vac. Things just kind of grew  from there,” he says.

BBU/CSE started renting bigger  trucks for hauling “huge” pneumatic blowers that air VE requires; work managers  had discovered that the minimum practical size for VE with air is probably  around 6,300 cfm. BBU/CSE opted for versatile Guzzler trucks, which could  handle not only the super-sized compressors but be reconfigured, as needed, to  perform other tasks as well.

“Once we became proficient,”  Olive continues, “we started letting people know we have this technology and  can service this part of the industry.” Word-of-mouth in the Midwestern  petrochemical trenching market spread. “You do a job with one pipeline  inspector,” Olive recounts. “He likes the truck. He likes the technology. He  likes that fact that air material remains dry and there is no muddy mess. You  can dump it on site or back in the hole once you’re done digging. You don’t  have any impaction issues.” Then the duly impressed inspector “moves to another  area and tells everyone there about it. It just kind of spread that way.”

These days, Olive says, out in  the marketplace he finds, “One of biggest misconceptions is that you cannot go  through hard-packed surfaces with air. But you can. It takes you a little  longer, but you can do it,” he says with confidence.

In the wake of success and  growing demand, VE competitors have jumped in. “They’re more than capable of  getting our business,” Olive concedes. “But one of the things in the  environmental industry is loyalty. Once you get in somewhere, people like you  and typically they’ll keep you as long as you don’t make a serious mistake.  It’s not that we have a corner on the market, but with loyal customers, it is  working out really well.”

Ideal for the Sandy Southeast, Far West Christopher Niebuhr, president  and chief operating officer of Thompson Industrial Services LLC, based in  Sumter, SC, does air VE (and other) excavation work for firms like Duke Energy  and for multiple regional nuclear power stations. These days, he says, “We do  air more than any other kind.”

Why so?

“Because [clients] just refuse  to let us use a backhoe anymore,” he says. “They don’t know what’s underground  there.” As nuclear sites seek expansion, “They have 40-year-old drawings, but  don’t trust them.”

They call Thompson to bring out  the air knives. In contrast, for the occasional greenfield project,  conventional excavation is typically preferred, Niebuhr notes.

Thompson’s project manager for  nuclear digging, Jerome L. Lawson, discusses his steady work assignments for  the past several years that have been heavily skewed to air VE. Thompson, he  recalls, first launched pneumatic service in 2001. Since then his crews have  dug hundreds of holes this way. Prior to that, says Lawson, “when digging with  a mini-excavator or big track hoe, you’d ruin things. You’d scrape stuff and  then tear lines away—fiber optic cables,” for example. Those days are over now.  Nuclear site work firmly dictates about a 70% overall preference for  compressed-air power as the tool of choice. “Surveyors come out and mark the  ground for what we call ‘a soft dig,’” says Lawson, meaning either air or water  but no heavy stuff. “They locate where they think the lines are. Point me in  the right direction to dig, and I go to whatever depth or width they need.”

One of the most ardent advocates  of air work we spoke with is John West. He’s vice president of Ultra Engineering  Contractors Inc., of Winchester California and sponsors an informative air VE  website, www.digwithair.com. With over 20 years in the excavation business,  UEC’s service territory reaches all of California south of Sacramento, West  says. The “ultra” part of the company name refers to extremely safety-conscious  digging. “That’s all we do is dig safely,” he says. This accounts for why, for  the past three years straight, UEC has been hauling forth its pneumatic tools  more or less exclusively, 99% of the time. Hydro serves as a rare backup only.  Previously, UEC had paired hand digging with hydro.

Why the radical shift to the  air?

“We saw a need for it. There  weren’t a lot of guys out there offering it. A lot of clients began asking for  it. So we got into it,” he answers.

Ultra has enjoyed steady growth  since, and has added round-the-clock emergency repair services for  utility-related sites. “We’re running our trucks full time every day,” he says.  “We’re booked up typically for months in advance. We’ve got two more trucks on  order. We’re really happy with the way things are going. Our clients are  extremely happy and the air technology, to me, seems to make the most sense.”

Why so?

“First and foremost,” West  continues, “we can use the same soil that we removed from the hole to put back  in. We back-fill and move on. We can do a lot more holes a lot faster, if a  client is asking us to do the backfilling.”

Selling-wise, “It’s a matter of  educating the market on what we’re capable of doing,” he sums up. “Once we get  out there and show them, typically we’ve got a costumer for life.”

Hydro VE Not Drying-Up Yet With such uplifting testimonials  about aeration’s advantages, water-digging would seem to be going down the  drain—but, of course, it’s not that simple. The hydroexcavators are extremely  well-entrenched. They too have passionate defenders. Several notable advantages  are repeatedly touted and seem to be keeping the industry afloat, as it were,  and ensuring that commercial job orders keeps flowing.

One steadfast advocate of  hydroexcavation is Jason Proctor. He’s product manager for the vacuum  excavation product line at Ditch Witch, a major supplier of hydro vacuum units  as well as conventional trenchers, plows, horizontal drills, back hoes, and  such.

Proctor acknowledges the  rapturous buzz that air has enjoyed, but nevertheless says he’s “just not seen  where air excavation is as productive as hydro.” Given that Ditch Witch’s  product line is currently conventional and hydro-oriented, Proctor also admits  a certain bias on this point. But he strongly hints that pneumatic equipment  may well be forthcoming for Ditch Witch. “Even though we don’t make air [tools]  today…that’s not to say we won’t have them in the future, and we absolutely  see the value of them,” he says.

All in all, water blasting is  simply faster-cutting and more productive than air, Proctor believes.

Another strength of water is the  fact that, against frozen ground “air excavation isn’t going to work that well.  But with hydroexcavation you can use heated water” to dislodge icy sod easily.  Hot water can also hasten the breakup of clay, and is useful for non-excavation  job-site chores like cleanup and scouring.

Lastly, Proctor notes, there’s  another downside with air VE, in that, wherever air is pounding dirt and kicking  it skyward, the work area requires shielding “You’re basically blasting the  ground apart. Surrounding homes, vehicles traffic and passers-by are more at  risk with flying debris” than with hydroexcavation, he says.

How about code and regulatory  status?

As it happens, in mid-year  AirKnife’s Hartman undertook to find out how both modes of VE have been  received in various codes and standards. He was hoping to learn that they’re  being widely recognized and officially adopted. What he actually found, he reports,  is that best-practices clauses still uphold hand-digging near utilities—or  prudent equivalents. The latter generally include a reference to pneumatic  digging, he adds. However, he says of the regulatory industry, “Nobody has  gotten as specific as to say that an air knife or similar tool must be used.  They get as far as mentioning pneumatic digging and then listing it in a  glossary somewhere…” he says with a note of disappointment.

Moreover, all of the locally  adopted best practices for digging ultimately seem to cite a common boilerplate  statement on this subject recently formulated by the utility industry’s Common  Ground Alliance. The latest version came out just this year. CGA’s discussion  on vacuum excavation “still reads pretty much the same” in 2013 as when first  introduced in 2010, Hartman adds. He regularly attends CGA meetings, and he  praises the nonprofit organization for getting the word out that air tools are  faster and safer than hand digging. However, he adds, this endorsement has  taken a remarkably long time to obtain.

A second bit of recognition for  soft digging dates back to 2003. At that time, a forerunner of the present CGA  participated with the US Department of Transportation in a grant to the New  York State Department of Public Service, aimed at defining best practices for  digging around buried utility lines. In those days, “damage to underground  structures” is “significant,” even when lines are properly marked. This  statement appears in a subsequent NYDPS white paper titled the “Vacuum  Excavation Demonstration Project” (VEDP), dated 2006 and published online at  www.digsafelynewyork.com. VE researchers back then also expressed concern that  “advances in vacuum technology…[and] in pneumatic and hydraulic equipment  intended to safely expose underground facilities are not being fully utilized  in the field.”

To remedy this, various  stakeholder from New York utility-marking organizations (e.g., Dig Safely New  York and the Northeast Gas Association) were assembled; the VEDP was the  result.

In the study project, a total of  seven local excavators participated. Results of their 106 VE digging sites were  then analyzed. The study sought to compare “soft” vacuum digging benefits  versus hand digging with shovels, assessing relatives costs, drawbacks, efficiency,  etc.

As the eventual report later put  it, “Perhaps most important question was Would the excavator use this  technology if they had to pay for it themselves, rather than having it  underwritten by grants?”

Results-wise, all but one of the  excavators agreed that “using vacuum excavation to locate utilities made the  task easier and more efficient.”

All reported that VE saved time.

All but one reported that VE  saved money.

How about VE enabling workers to  avoid damage?

Six of seven companies said “yes,”  (again, out of a total of 106 VEs job sites; two minor inadvertent, unavoidable  damage incidents occurred that likely would have happened by hand-digging as  well, the report noted).

Participants also felt that VE  was better suited to some sites and tasks than others. Especially apt roles for  VE include: utility location verification; potholing; directional-bore  projects, especially where routes cross utility or gas lines or where lines are  within roads or paving; locating existing facilities for repair or rerouting;  utility projects with spatial constraints; urban projects; and projects seeking  to limit surface disturbance.

Of seven participating  excavators, all reported they would indeed consider purchasing or renting VE  equipment for themselves in the future.

All in all, the study proved VE  to be a resounding success. VE demonstrated “clear and distinct advantages over  hand digging to locate utilities.” VE “…saves design, excavation, and  construction time and…money, minimizes damages, while complying with  construction codes,” the VEDP report states.

At the time of its publication,  the study was so eye-opening for New York excavators that the NYDPS decided to  thump the results in a promotional booklet.

Naturally, the study steered  clear of endorsing either hydro or air against each other. Nor did it tout  equipment brands. But there was frank discussion of several key differences,  including statements such as these:

  • “… water…at high pressures can damage underground  utilities, and there are documented cases of this occurring.”
  • Water is also “a very good conductor of electricity” which  means it presents a hazard of electrocution.
  • “In cold or freezing temperatures, working with water can  be difficult,” as “equipment can freeze, and there may be sloppy, difficult  conditions at the discharge points. Environmentally friendly antifreeze  solutions are often required,” the report says. More favorably, the report  notes that hot water easily cuts frozen ground.
  •     Air excavation is superb for locating lines, being  nonconductive and carrying the lowest hazard. “When air hits a utility line, it  will flow around without damaging it,” the report states. Air also won’t damage  road base or tree roots

The report took note of the  perception that a water excavator’s cannon-like force cuts holes much faster  than air. Thus, it conceded, water “works best in moderate temperatures for big  jobs, especially if a convenient dump and water refill source” are present.

As for comparative market  reception of air versus water in New York, the report stated: “Until recently  [as of 2006], compressed-air vacuum excavation equipment was the most commonly  used. Now, with the advent of less expensive water systems, those have become  more prevalent.”

On the other hand, the report  noted that air offers easier use, and this would seem to portend a boost in its  market share. Air equipment is also typically “smaller, lighter and more  economical” than hydro support tools, the report notes.

Air can cut all soil types,  including clay or densely packed soils, but works best with sandy soil or loose  loam, the report adds.

In contrast, hydro digging  requires larger trucks and trailers to carry water—in fact, two tanks often are  needed, one to haul the fresh water supply and another to cart away the muddy waste.  When fresh water is exhausted, an excavation gets put on hold until the tank  can be refilled. Contrast this with air VE in which “On-board compressors  generate a limitless supply of air,” the report concludes approvingly.

When it comes to cleanup and  restoration, air again seems to present a big advantage. Getting rid of hydro  VE mud is comparatively difficult. It’s usually not suitable for back fill  after the underground utility elements have been laid bare. So, the excavation  contractor must come up with dry fill. Conversely, with pneumatic excavation  the dry spoils of the dig sit handily nearby, ready for reuse in the same hole.

Market Opinion Update, 2013 A quick survey of our excavators  interviewed here adds a few further insights, essentially confirming the  determinations in New York. Following is a sampling of quotes and observations.

Comparing Water VE to Air…

DitchWitch’s Proctor: A  lot of the customers insist that productivity with water “outweighs the ability  to put dry spoils back in the ground.” This preference is confirmed by the  sheer numbers of customers “who still continue to do hydro versus air  excavation,” he adds.

Thompson LLC’s Lawson: “I  used water on a trench about 100 feet long, 11 feet wide and 9 feet deep. It  took me about a month…with two water guns.” The same job with air would have  taken six months, he estimates.

UEC’s West describes how  much faster air is than water, when you factor-in the comparative time needed  for backfill/mud removal/restoration. “A lot of places won’t even take mud  anymore,” he begins. And here’s one head-to-head comparison: Working against  one of Ultra’s competitors in Southern California, “using the exact same trucks  as they did and working exactly the same delineation, we outperformed them,  digging eleven holes [with air] in the same time frame it took them to dig  three. … Air makes so much more sense,” he concludes. “One truck can typically  do 15 holes a day from start to finish. That includes backfilling and putting  in the cold patch.”

On VE Messiness in Environmentally Sensitive Areas…

Lawson: “Sometimes,  inside a nuclear site you especially don’t want to splash water everywhere…”

Olive, on digging near  petrochemical or gas facilities: “Our [air digging] crews can work  three day straight and not have a waste lagoon full of oily water that’s got to  be solidified or pumped out or hauled to a landfill,” he says. “With air, at  the end of day you just basically have got a big, dry pile of dirt.” Clients  are ecstatic. “That seems to be the big kicker.”

On Avoiding Damage to Underground Lines…

Proctor, rebutting the  negative claim in the New York VEDP that hydro work can damage utility lines:  “CGI advises that water [VE] is ‘very safe,’ so long as the pressure does not  exceed 3,000 psi and the nozzle producing the linear stream of pressurized  water is not aimed directly at the utility lines.”

AirKnife’s Hartman: “If  you’re talking about pipelines that have a protective coating on them or a  fiber optic cable that is buried directly…you can still cause damage to it,  even with a hand shovel or with a pick.”

Vactor’s Schmitt: “Hydroexcavation does not produce the sandblasting effect the way air does.  This reduces the potential for damage to underground utilities.”

On Worker Safety…

Olive: “If we’re going  down to find a utility line or a pipe, somebody has to get in the hole and work  on it. Water in the hole—sometimes mixed with oil—will loosen up the wall of  your excavation. I don’t like putting anyone in a hazard like that.”

West: “Out of the 15,000  holes we’ve dug, we haven’t had an electric line break once. But if we were  ever to crack [one]… with air, you’re a lot safer, especially with the fact  that we use a Fiberglas air lance. So we’re insulated from the tip…”

Hartman: “The person  going into the trench will be digging with a shovel, a piece of steel that  usually has a fairly sharp edge on it. Or somebody will go down with a 20-pound  steel digging bar with a chisel point that you kind of hurl into the ground  like a spear. And, to be honest, who is the one you’re going to send down into  the hole? It’s usually the enthusiastic 18-year-old who just joined the crew.  And you’re saying, ‘Okay, now somebody has to dig by hand. Here you go. Go down  that hole and do it. Good luck.’ Using air excavation…air is coming out at only  90 psi. It is easily deflected… It’ll break up soil. It will blow it away. But  anything solid and nonporous, the air just goes around it.”

Schmitt: Operator safety  training is of course critical, which Vactor provides. “The biggest safety  concern with VE is… the larger units operate at 28-inches Hg of vacuum, which  is capable of pulling almost 800 pounds through an 8-inch diameter hole. If an  operator is not careful, a significant injury or fatality can occur… Vactor  provides many standard safety features to quickly and safely disable the vacuum  should an emergency occur.”

Hydro VE water pressure can  range up to 3,000 psi, he says. “This can severely injure the operator or  damage underground utilities.”

Air VE can also produce static  electricity so tools must be properly grounded, he adds.

On market trends, client preferences…

Olive: When first  introducing “soft digging” to clients, hydro is more intuitive and  understandable, “and hydro has been around for many years,” he notes.

In comparison, if you say  “pneumatic excavation,” lay-people “don’t really grab the concept of what  you’re talking about. Pneumatic is the new kid on the block. A lot of people  still just haven’t been exposed to it.” Both water and air, he finds, “are  still not widely accepted.”

Proctor: “The vast  majority of [VE] contractors” are using hydro vacuum excavation.” Unofficially,  he puts the figure at 70% or more, “just because hydroexcavation is much more  effective and productive.”

Schmitt: “Some utility  companies, departments of transportation or power plants can specify pneumatic  excavation for a given job for a number of reasons….”

Work, Equipment, “Parting Tips”…

Olive: One challenge for  men excavating at distances away from the truck, “whether for pneumatic or  hydro, is coping with the boom limited to 20 to 25 feet,” which all of them  have. “Once you get away from using that boom [i.e., excavating where the boom  isn’t available for hose support], that is where it gets tricky. Basically,  excavation is not efficient out there.” The worker winds up man-handling a  6-inch-diameter hose. This usually happens if the truck boom can’t get close  enough. So, he advises, try to arrange the job site to overcome this.

West, on trucks: “We like  having everything on one truck, having one equipped with every piece of  equipment we can think of that would possibly be needed to get the job done.”  Olive also buys trucks through a custom shop that builds to his design specs,  so the $400,000 vehicle with a turbo vac can be used for work besides pneumatic  excavation. GapVax and Badger are two preferred equipment suppliers for  pneumatic and hydro.

Lawson on compressors: “Make sure you find out what psi to cut with,” as newcomers to vacuum  excavation usually lack the necessary field experience to know which power  combinations can cut what.

The water standard is 2,000 psi,  he adds.

“If you want to go with air,  you’ve got to make sure your application tips are right and know something  about how they cut. Some people come in there and they don’t know how to use  the application right. Make sure you run tests on how much material you can  move over time,” in order to give the customer an accurate job quote.

Lawson on air against clay: “Clay is no problem. If you give me a 375 psi air compressor I can cut that  clay just as good with air as water,” he says. An under-powered 185 psi will  take much longer. And a very high-powered 750 “is definitely going to cut the  [expletive] out of it. I’ve’ gone as far down as 18 feet and [trenching] 200  feet long,” in clay, with 750 psi, he reports. Compressors require adequate  horsepower as well—60 to 100 horsepower, he advises.

Author’s Bio: Writer David Engle specializes  in topics related to excavation and environment.

 

Hydroexcavation and Conventional Digging Work Together

From:  Municipal Sewer & Water

Written By:  Doug Day

Working in sales and marketing for the largest fleet of hydroexcavators in Texas, Karl Lassberg doesn’t see conventional excavators as competition. “We’re really working in conjunction with mechanical equipment,” says Lassberg, of T-Rex Services Hydro Excavation and Industrial Vacuum Services.

Founded with one truck in 2001 by former NASCAR driver Bobby Hillin Jr., T-Rex now has a fleet of more than 38 hydroexcavation and vacuum excavation trucks. “At the time, there wasn’t a lot of hydroexcavation going on in the southern Gulf region,” Lassberg says. “He just went out there and hustled, and the popularity of hydroexcavation has grown over the last decade as the awareness of the technology has grown.”

Besides the usual safe exposure of underground utilities, it has also grown more popular for many other uses, especially in confined areas. Lassberg cites a recent job as a good example, a lift station for a restaurant. The excavation was only 4- by 4- by 6-feet but required hand digging because the location was inside a parking garage. “It would have taken several days to dig and carry out 3.6 cubic yards of dirt by hand,” he says. “We ran a remote hose down a stairwell and it took us less than three hours. Our bill was much cheaper than a hand dig.”

He adds that hydroexcavation is also a good alternative to an auger for digging holes. “If you have only a couple of holes to dig with an auger, hydroexcavation can be competitive because the material is sucked straight into the truck and dumped off site,” Lassberg says. “You don’t have to worry about additional equipment to scoop it up and haul it away.”

The advantages are even greater when it comes to utility pole holes, usually 18 inches in diameter and 8-feet deep. Two people with post hole diggers will need about two hours to do a single hole while it’s a 10- or 15-minute job with hydroexcavation.

Lassberg says electro-mechanical work has led to a lot of hydroexcavation work in recent years, such as grounding wire trenches, 6 inches wide and 18 inches deep, that used to be dug by hand. “We can hydroexcavate 300 to 400 feet of that in one day and cover it with a skid-steer instead of putting five guys trying to dig for days at a time.”

One such project was at a lighting conduit project at the Galleria Mall in Houston in September 2010 – 700 feet of trench (2 feet wide and 2 feet deep) underneath a sidewalk bordered by a long line of historic oak trees. “With all those tree roots, you have to dig a little differently and more conscientiously,” Lassberg says. “If you even skin a tree root you can kill the tree, so digging by hand is very tricky business.”

In this case, all the roots crisscrossing through the excavation area made any other sort of excavation impossible. Since tree roots can also be damaged by high-pressure water, the excavators used lower pressure and kept nozzles well way from the roots. The job also had to be done in 48 hours in a high traffic area of the city’s busiest area. T-Rex brought in five trucks. “We started Friday at 9 p.m. and finished 40 percent ahead of schedule,” Lassberg says. “Two years later, the trees are still in great condition.”

Lassberg says there are three main issues to think about when considering hydroexcavation. Is there a source of water on site? Can the spoils be dumped on site? And how close can the truck get to the excavation?

“Most trucks require a water source, whether it’s a frac tank, water truck, hydrant, or a pond,” he says. “Dumping on site usually makes a job much more productive. Dumping off site means driving to a dump site and back, sometimes there are dumping fees. Access within 15 or 20 feet from the dig site allows for the greatest productivity but we can work 300 to 400 feet away from the truck when necessary.”

When he first got involved in the industry, it seemed people assumed he was in competition with other excavators. “They were a little leery of me,” he adds. “The first thing I tell people is that hydroexcavation is a great tool to have in their arsenal — for the right job.”