In-depth survey report: control technology for crystalline silica exposure during pavement milling using a Wirtgen Milling Machine equipped with a vacuum cutting system.
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-282-23a, 2013 May; :1-19
From June through August 2012, National Institute for Occupational Safety and Health (NIOSH) researchers and the Silica/Milling-Machines Partnership coordinated by the National Asphalt Pavement Association (NAPA) conducted field testing of a vacuum cutting system (VCS) on a Wirtgen W 210i cold milling machine. The tests included 11 total days of air sampling across four different highway construction sites in Wisconsin. At each site, full-shift personal breathing zone sampling for respirable crystalline silica was conducted for the operator and ground man during the course of normal employee work activities. The arithmetic mean respirable crystalline silica exposure for the operator was 0.0071 mg/m3 with an upper 95% confidence limit of 0.011 mg/m3. The arithmetic mean respirable crystalline silica exposure for the ground man was 0.0066 mg/m3 with an upper 95% confidence limit of 0.0093 mg/m3. The geometric mean respirable crystalline silica exposure for the operator was 0.0061 mg/m3 with an upper 95% confidence limit of 0.019 mg/m3. The geometric mean respirable crystalline silica exposure for the ground man was 0.0061 mg/m3 with an upper 95% confidence limit of 0.013 mg/m3. All 22 full-shift personal breathing zone samples collected from the operator and ground man were below currently published regulatory and recommended occupational exposure limits for respirable crystalline silica. Based on the results of this study, NIOSH researchers recommend that Wirtgen should consider making the VCS system a standard feature on all Wirtgen half-lane and larger milling machines. NIOSH researchers also recommend that other manufacturers of half-lane and larger cold milling machines should consider implementing local exhaust ventilation as a control for silica exposures.
Region-5; Control-technology; Engineering-controls; Construction; Construction-equipment; Construction-workers; Milling-industry; Machine-operation; Machine-operators; Equipment-design; Equipment-reliability; Performance-capability; Air-sampling; Road-construction; Road-surfacing; Air-sampling-techniques; Breathing-zone; Employee-exposure; Exposure-assessment; Silica-dusts; Respirable-dust; Exposure-levels; Exposure-limits; Exhaust-ventilation; Air-flow; Dust-control; Dust-control-equipment; Vacuum-equipment; Cutting-tools; Statistical-analysis;
Author Keywords: Silica; Asphalt; Engineering Control
Field Studies; Control Technology
NTIS Accession No.
National Institute for Occupational Safety and Health