Vacuum excavation is a critical component of any horizontal directional drilling (HDD) project. Not only does it help with mud management (sucking up the fluid and transporting for disposal) but the process exposes underground utilities before drilling can begin (preventing crossbores and other utility hits).
This technology may not get the accolades as other HDD equipment, such as the drilling rig, drill pipe or reamers, but when done properly vacuum excavation is a key cog in the HDD wheel.
Operating vacuum excavation equipment safely cannot be dismissed as just another part of the project. From setting up the equipment onsite to confirming the exact location and depth of underground utilities, performing this application correctly makes your HDD job safer and more cost-effective. We reached out to vacuum excavation manufacturers for their expert advice on what you should and should not be doing with your vacuum excavation equipment.
It should go without saying that the goal of any jobsite is to safely start and the end day, accident-free. Proper training is the foundation of making sure everyone goes home at the end of each day.
“Vacuum excavation can be fun to do and watch but people need to know and understand that this is a piece of equipment built to move earth,” says Hi-Vac president Dan Coley. “That type of power is not only beneficial but dangerous and needs to be treated with respect. Vacuum excavation will continue to grow as the industry sees the benefits of both safe digging and precision excavations.”
“The vacuum excavation industry exists primarily because of safety,” says Tim Dell, partner at Rival Hydrovac. “Line strikes pose big risks to personnel and are expensive. Because of this concept, it is vital the operation of the vacuum excavation equipment is performed properly being that the basis for the process was born for safety reasons. A vacuum excavator poses risks as any heavy equipment, with some unique issues specific to this equipment.”
“Placing human eyes on utilities avoids the dangers of digging into unforeseen and incorrectly marked utilities found using ground penetrating radar,” says RAMVAC northeastern region industrial sales manager Jim Svandrlik. “Potholing is needed prior to boring for new lines where existing utilities are already are in place. This helps avoid serious injury or death, which can occur easily when digging blindly with yellow equipment.”
What are some of the some of the safety issues involved with vacuum excavation? Our panel gave us a myriad of safety concerns involved with this operation. All crewmembers involved in operating vacuum excavation equipment need to have personal protective equipment (PPE) such as face/eye protection, proper gloves and footwear, as well as reflective vests/shirts, hard hats and rubber mats, the latter when working around electrical lines. Routine maintenance also promotes safety.
“Vacuum excavators work in some extreme conditions and have a tough job. It’s important that maintenance is performed per the manufacturer’s maintenance schedule to ensure the equipment is functioning properly. An unmaintained vacuum excavator can create additional, unnecessary hazards to the jobsite,” says Nick Bruhn, product manager with TRUVAC by Vactor Mfg.
Operators always need to be aware of the high-pressure water or air wands on vacuum excavators, releasing water and air that is powerful enough to penetrate ground materials, tree roots and other materials that can cause severe injury or even death.
“Operators should not exceed the recommended psi when digging. Too much pressure can damage buried utility lines,” says Vermeer MV Solutions director of sales Brian Showley.
Showley also notes that being careless with the water or air wand or using it to pry material could result in damaging utility lines, the equipment or even injury. “Water wands should always be facing down,” he says. “There are two reasons wand direction is important. First, each wand has a porcelain piece that sits toward the back of it that can be damaged by the sudden impact of triggering the wand and slamming it forward. Second, accidentally triggering the wand can cause injuries.”
When asked about tips to prevent accidents on a jobsite, our panel offers a long list of them, such as Showley’s advice on the water or air wand. Some may seem simple and obvious such as wearing proper protective equipment to knowing your surroundings, to those involving a little more care such as making sure the water pressure isn’t too high to avoid damaging the underground utility being exposed to not using any body part to remove a blockage in the suction tube.
“Never stick your arm up the suction tube to dislodge debris,” says RAMVAC central region industrial sales manager Tim Van Til, noting that some units offer a reversible blower that will dislodge debris in seconds, requiring no effort from the operator.
Perhaps the term “common mistakes” for this section is misleading as it makes it sound like they are minor infractions, aka no big deal. Mistakes of any kind can be dangerous on the jobsite, dangerous to the crewmembers, as well as the project’s bottom line. Some of the more common ones include using the wrong or worn out nozzle and not knowing the vacuum capabilities of your equipment, as well as parking too close the dig site.
“Using improper nozzles when digging can negatively affect performance,” says Coley. “If the nozzles are not properly sized for the working GPM and pressure of the water pump, their performance will diminish. Not using the right type of nozzle for the soil conditions that are present will limit the performance and productivity. These types of mistakes can be avoided by properly training new operators on all operational and maintenance aspects of the equipment.”
The crew also needs to be aware of their surroundings on the jobsite, for a multitude of reasons. Make sure there are safety cones and signage positioned and any open holes fenced off or covered. “It is important to maintain a safe distance whenever the vacuum excavator’s tank door is open. Nobody should be standing near the rear of the machine,” says Showley. “Also, operators need to make sure they don’t get too close to open holes since cave-ins are possible in this line work. Operators also need to keep their limbs away from the front of the water or air wand and vacuum hose nozzle.”
Vacuum excavation has everyone focused on what is being uncovered in the ground; however, overhead objects above the project site could prove to be problematic, if ignored.
“Always ensure the boom is in the cradle prior to driving down the road to avoid hitting overhead items,” says Jim Svandrlik.
“Remember, when a vacuum excavator boom is being remotely controlled, often the contractor is looking down into the hole while the boom is lifting. This is something critical that must be evaluated pre-job,” says Dell.
Crewmembers also need to be aware of where the vac truck is being parked on the site. Why is this important? Overhead obstructions come into play here, as well as unsafe ground conditions.
“A common mistake is parking the truck too close to the dig site, “says RAMVAC western region industrial sales manager Craig Svandrlik. “Ground fails due to overall weight and vibration of truck can cause the truck, the operator or both to fall into the hole. Always use a spotter. Not using a spotter can lead to striking overhead obstacles with the vacuum boom. Hitting powerlines can send volts to the chassis, damaging chassis computers, and worse, electrocuting operators.”
Coley also notes that these “common mistakes” can occur when operators fail to know the full capabilities of their vacuum systems. “Vacuum systems range in size and configurations from 1,000 cfm and 16-in. Hg to 5,800 cfm and 28-in.,” Coley says. “A better understanding of the air velocity that the vacuum system can generate and how the Hg will assist, will help improve the operator’s set up of the jobsite. Sucking up dry material in a unit that is not built for it can cause material carryover and damage the vacuum blower by not having the proper filtration to handle dust.”
“Vacuum excavation is extremely dangerous and safety precautions with equipment design must be taken,” says Ben Schmitt, general manager of TRUVAC by Westech. “The premise of vacuum excavation is safe digging locating buried utilities. It’s extremely important all facets of the application are completed in the same manner as the premise itself. There are many hazards of vacuum excavation and ensuring everyone goes home safely after the application is first and foremost.”
What Is a Competent Person?
This is a critical position for any jobsite — this is a person who has oversight and management of the crew completing the project. It’s also a position required by OSHA and for good reason. Safety on a jobsite is paramount to the crew, as well as others in area of the jobsite.
“The competent person legislation is in place for a good reason,” says Rival Hydrovac partner Tim Dell. “An experienced and appropriately trained person as it relates to ground disturbance is a must in regards to safety. There will be issues related to properly shoring excavations to code when working within an excavation, identifying overhead obstruction, specifically power lines and ensuring that the truck is set up properly from a pressure point of view based on the job being performed.”
“It’s extremely important the operator of the equipment is well trained, capable and experienced with identifying potential dangers,” says Ben Schmitt, general manager with TRUVAC by Westech. “When hydro excavating, for example, there are regulated water pressures to utilize based on the application. Using too much pressure in a particular application could cause preventable damage to the underground infrastructure.”
Hi-Vac president Dan Coley also notes the importance of having the right person in this position. “One person must have the knowledge of the job and the know-how to safely guide the crews to complete the job on time and safely with minimal cost,” he says. “In this industry, if you do not have competence or a general understanding of the work and the equipment to do the work, you are more than likely going to get hurt.
“Hazard Assessment ‘Toolbox Talks’ and sign off sheets are required for every jobsite. These talks should be more than just ‘CYA’ but designed to ensure the job gets done in the safest and most productive manner,” Coley says.
“Everyone should be working to ensure that ‘Everyone goes home safe’ at the end of the shift,’” he says.