What happens when the pipeline owner finds a problem? They dig in to fix the issue, but they can’t, nor should they, dig too far. That’s where hand excavation or a suitable alternative comes into play.
Enter the vacuum excavator, most commonly of the hydro -excavation variety, a truck-based machine akin to sewer cleaners commonly owned by municipalities; though, those in the industry are quick to point out that the trucks are completely different animals.
“Use of this type of equipment began in the late 1980s to the early 1990s and has grown in its acceptance and use ever since,” says Bryan Jones, of Badger Daylighting. “Today, it is standard equipment on pipeline projects.”
Badger, a vertically integrated company that began more than 20 years ago, builds and operates its own fleet of hydro -excavation equipment from more than 100 offices across North America. Its headquarters are in Calgary, Alberta.
According to the Vac-Con Inc. website, vacuum excavation in the oil and gas industry began in the 1960s in Canada where the vacuum truck operators began using a high-pressure water stream that, when heated, made easy work of turning frozen earth into muddy slurry that the excavator could suck into its holding tank.
The real growth, Jones points out, came in the 1980s when the National Energy Board in Canada, increased the safe zone for transmission pipelines to 30 m (100 feet) either side of a pipeline marker. Only non-destructive methods of excavation are permitted to be used within the safe zone, of which hand digging was the only accepted practice at the time.
That was fine, Jones added, but hand excavation is a time consuming process and is limited in its application. As a result, various companies began exploring for non-destructive alternatives to hand digging, and hydro-vac technology quickly became a focus for those working around pipelines.
Because of its relatively safe operation — i.e., using a jet of water and a vacuum hose — hydro-excavation is on par with hand excavation.
“We started building them in 1992 and when people saw them out on pipeline projects, it just made sense because you’re restricted to hand excavation, but this is so much faster,” Jones says. “You really saw an increase in the use of hydro-vacs in the pipeline sector through the 1990s. It’s to the point now where most pipeline operators will recognize vacuum excavation as an acceptable alternative to hand digging, while some will go so far as to specify the use of vacuum excavation around their facilities.”
Uncovering the Benefits
This initial onslaught of vacuum excavation equipment was used mainly to daylight the underground utilities to prevent damage. As the machines evolve, so too are the uses.
This includes slot trenching, cleaning out hydraulic fracturing tanks and removing the spoils from horizontal directional drilling operations. Jody adds that this oil and gas work makes vacuum excavation, particularly hydro-excavation, the fastest growing market in the industry.
With that growth, it is important to note that vacuum excavation equipment will not replace the tried and true backhoes and mechanical excavators on the jobsite.
“Hydro-vacs will augment a contractor’s resources and will typically not replace equipment. If there are no buried facilities in a work area, then a backhoe or excavator will be the more cost effective way to complete the work,” Jones says. “However, if there are buried pipes or cables, then the only safe alternatives are hydro-vac or hand excavation. It’s another tool in the in the contractor’s toolbox. Always use the right tool for the job.”
When discussing safety, Jones and Jody point out that, though nothing is 100 percent safe, vacuum excavators in many instances are safer and more precise than hand digging because shovels have the ability to damage pipes from wearing away at the coating to outright ruptures if the pipe is weak.
“Hydro-vacs are an option because of the safety factor but what has really driven the growth of hydro-vacs in the sector is the rate of production,” Jones says.
Some look at the use of hydro-vacs as an added cost, but Jones points to a Baltimore project where a contractor had a less expensive air vacuum excavator daylighting in front of a directional drill to install conduit. With the air vacuum, the project averaged 500 ft of conduit installed per day. With a hydro-vac, productivity jumped to 2,100 ft.
Productivity is important in an industry where contractors are constantly looking at their margins to ensure projects are profitable. “You bring a hydro-vac along and spend $3,000 a day on it but guess what you get 300 percent more production and every day that you can save on your project timeline, that’s just pure profit,” Jones says.
That is not to say that the oil and gas industry does not use air vacuum systems. The equipment is good for loamy, sandy soils where wetting is not necessary. Because the spoils are not wet, they can be replaced on-site. Air vacuums are sometimes the preferred method when working with contaminated soils or around electrical facilities where wetting might not be ideal.
Another advantage of vacuum excavators is versatility when it comes to working in remote or confined spaces, such as behind and between homes where getting other equipment is not feasible. Vacuums on the truck-based excavators can pull material laterally for 600 ft and in some instances 700 to 800 ft to the holding tanks, according to Jody.
Digging into Options
When looking at the equipment, pipeline owners have several options and a vast array of players, from companies like Badger that make and operate their own equipment to companies like Vac-Con, Ditch Witch, Super Products and others that distribute their wares.
No matter the situation, Jones and Jody urge doing plenty of research before plunking down $400,000 or more on a truck-based machine.
“This equipment is asked to operate in seriously harsh environments. All of the equipment can fail or break as a result of heavy applications and wear,” Jody says. “Being able to keep the equipment running and online is an important factor for the operators and the contractors. Robustness and reliability are important.”
He adds that it is important to find a reputable company with experience in the industry and one that can help the new owner get up to speed on using the new equipment.
“A contractor should carefully research the options and identify what would be the best piece of equipment for the specific application,” Jody says. “Do you need the bells and whistles?”
With that in mind, are more companies renting, leasing or buying their equipment? Jody sees it being a little bit of each, especially as contractors try to recoup from what he deems the “great recession” that struck in 2008.
Jones offers a different point of view.
“Some contractors buy equipment, some rent and some lease. However, rather than operate the equipment themselves, most contractors will outsource the work to a qualified hydro-vac supplier,” he says. “Outsourcing makes sense on a number of levels. High-efficiency equipment is available from suppliers on a 24/7 basis, and qualified hydro-vac suppliers will have developed a health and safety program specific to the safe and proper use of hydro-vac equipment. They will have developed job procedures for how the hydro-vac can be operated safely in a variety of hazardous work environments, and their workers will have been trained in those procedures. Contractors are fully capable of running equipment themselves, but qualified hydro-vac suppliers will get more done in less time, and the work will be done safely.”
As for the future of vacuum excavators in the North American oil and gas industry, both Jones and Jody see the potential for growth, especially as companies look to improve pipeline integrity and the shale plays and tar sands continue to boom.
“It’s an effective tool that can be used remotely to locate and excavate,” Jody says. “We may not have explored all of the limits of the versatility of the machine at this point. I find that aspect of it most interesting.”
Mike Kezdi is assistant editor at Benjamin Media Inc. and a contributing staff editor of North American Oil & Gas Pipelines. Contact him at email@example.com.
Hydro excavation is a straightforward process: Use a high-pressure stream of water to loosen hard soils, reduce the soil to muddy slurry and vacuum away. The nozzle at the end of the water line plays an important role in the job performance.
A relatively new player in the hydro excavation nozzle business is Hydra-Flex Inc., which started offering products for the market this spring.
“Hydra-Flex was founded with a mission of ‘finding a better way’ to manufacture fluid handling products for the car wash industry,” says Justin Jovle, Hydra-Flex product line manager. “Because of the strong reputation we had earned in the car wash industry we were approached by a number of users in hydro excavation that wanted to know if we could develop a nozzle that could provide the same results for them.”
What contractors may not realize, he says, is that by optimizing the water stream quality, jobs get finished quicker and use less water.
“Choosing the correct nozzle is like having the right tool in your toolbox. By using the correct nozzle for the job, the contractor is able to ensure safe and efficient excavation,” Jovle says. The company manufactures different types of nozzles, with rotating or linear designs and a variety of flow rates that vary by soil conditions and job type.
Although vacuum excavation is a safe digging alternative to mechanical methods, Jovle recommends that a nozzle should feature a protective coating such as rubber or urethane to reduce the risk of striking a pipe with sharp metal and potentially causing damage.
Also important is the pressure rating of the water stream, which many best practices guides recommend running at 1,500 to 2,500 psi around utilities. Hydra-Flex nozzles can handle up to 3,200 psi, but the impingement mechanism allows them to run at lower pressures, Jovle says.
“Hydra-Flex’s Ripsaw and Switchblade nozzles are constructed with stainless steel housings and tungsten carbide wear surfaces to withstand harsh environments and provide longer life than ceramic nozzles,” Jovle says. “A more reliable, longer lasting nozzle means replacing nozzles less often, ensuring greater uptime.”
For more information, visit www.hydraflexinc.com.