In-depth survey report: control technology for dowel-pin drilling in concrete pavement.
Echt-A; Mead-K; Feng-HA; Farwick-D
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, EPHB-347-12a, 2011 Mar; :1-28
This study evaluated the ability of a commercially-available dust-control system to reduce respirable dust emissions during dowel drilling. Dowel drilling is a task performed during new concrete runway and highway construction (e.g., when a lane is added) or during full-depth repair of concrete pavement to provide load transfer across transverse pavement joints. Dowel drilling machines typically contain one or more pneumatic or hydraulic percussion drills aligned in parallel in a frame that acts to control drill alignment and prevent wandering. The dust control evaluated in this report included a close-capture hood surrounding each of the steels and bits at the work surface, a length of corrugated flexible hose connected to each hood, and dust collectors at the back of the dowel drill unit. Compared with the use of no dust control during dowel drilling in concrete, the dust-control system significantly (p less than 0.0001) reduced geometric mean respirable dust mass concentrations by 89 percent to 92 percent when measured with filter samples. Arithmetic mean respirable dust concentrations measured on filters were significantly (p less than 0.0001) reduced 88 percent to 90 percent by the use of the dust control system. The use of the dust control also significantly reduced respirable dust emissions (p less than 0.0001) by 86 percent to 88 percent when measured with a nephelometer. The different measurement techniques probably account for the disparity in results obtained with filter samples and the nephelometers. The measurements were conducted in a tent to exclude diesel exhaust particulate emitted by the compressor used to power the dowel-pin drill and isolate the drill from the effects of wind and weather during the tests. The use of this technique means that it would not be appropriate to compare the results to any exposure indices. Recommendations are offered at the end of the report to improve the system. These include recommending that the manufacturer consider installing a pressure gauge across each filter in the dust collectors to provide the drill operator with information needed to determine when to clean or change the filter.
Control-technology; Engineering-controls; Region-5; Construction; Construction-equipment; Construction-industry; Construction-materials; Construction-workers; Machine-operation; Machine-operators; Equipment-design; Equipment-operators; Respirable-dust; Dusts; Dust-collection; Dust-collectors; Dust-control; Dust-control-equipment; Control-equipment; Control-systems; Emission-sources; Concretes; Road-construction; Road-surfacing; Machine-tools; Pneumatic-equipment; Pneumatic-tools; Hydraulic-equipment; Filters; Sampling; Measurement-equipment; Power-tools; Silica-dusts;
Author Keywords: Construction Machinery Manufacturing; silica; crystalline silica; dowel drill; concrete; rock drill
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Engineering and Physical Hazards Branch, Mail Stop R-5, 4676 Columbia Parkway, Cincinnati, OH 45226-1998
7631-86-9; 14808-60-7; 65997-15-1
Field Studies; Control Technology
NTIS Accession No.
National Institute for Occupational Safety and Health