“Mom-and-pop concrete-cutting shops are going to face the biggest change to the way they do business,” says Alex Peck, industrial hygiene department manager for Terracon, a 51-year-old national consulting agency specializing in environmental site assessment and geotechnical evaluations, including construction materials testing. “The rule may not affect larger shops that may have already invested in dust control technology.” Peck and other experts foresee big changes in concrete cutting and drilling equipment. “Engineering control solutions, such as wet- and vacuum-assisted cutting and drilling methods, do a good job of isolating workers from silica hazards without materially changing the application. That helps the contractor meet the compliance requirement,” he says.
Field-tested, dust-control solutions are already available. “The tools that we need to protect workers are already out there,” reports Deven Johnson, director of training, health, and safety for the Operative Plasterer’s and Cement Masons’ International Association. To better understand how some of these tools perform, Terracon was commissioned by Bosch to test the dust extraction capabilities of their new Speed Clean™ Drill Bit System. Specifically, they examined the standard industry practice of preparing concrete anchoring holes through the “blow-brush-blow” method with the vacuum-assisted drilling technology of the Speed Clean™ Drill Bit System.
Mike Meister, Terracon senior project industrial hygienist and test lead, describes the “blow-brush-blow” method as the “bad old-fashioned way.” “You drill the hole, then blow it clean with compressed air, swab it with a dry stiff brush, and then blow it out again,” Meister explains. “The process kicks up an amazing amount of dust. When the operator was drilling holes in the floor, we couldn’t see his feet. A significant fraction of dust was in his breathing zone.” Terracon then tested Speed Clean™, an innovative drilling method that uses a hollowed high-speed carbide steel drill bit tip attached to a HEPA vacuum. Dust and debris is continuously removed by the vacuum’s sucking action as the drill bit progresses through the concrete. The result?
“No Detectable Dust”
“Our testing equipment found no detectable dust,” Meister says. “All drill bit sizes were below the detectable limit of the sampling we performed.” “Wet cutting and drilling can control silica dust, too,” Meister observes. “But water isn’t practical in cold weather. “I was explaining the system to a contractor working on a big hospital project. They’re replacing signage in the hallways, so drilling dust is forbidden. She understood it right away and said, ‘Oh my God, I need one of those!’”