In-depth survey report: partnering to control dust from fiber-cement siding, Twickenham Square, Huntsville, Alabama.
Qi C; Kratzer J; Echt A
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 358-15a, 2014 Apr; :1-22
Background: Workplace exposure to respirable crystalline silica can cause silicosis, a progressive lung disease marked by scarring and thickening of the lung tissue. Quartz is the most common form of crystalline silica. Crystalline silica is found in several construction materials, such as brick, block, mortar and concrete. Construction tasks that cut, break, grind, abrade, or drill those materials have been associated with overexposure to dust containing respirable crystalline silica. Fiber-cement products can contain as much as 50% crystalline silica and cutting this material has been shown to cause excessive exposures to respirable crystalline silica. NIOSH scientists are conducting a study to develop engineering control recommendations for respirable crystalline silica from cutting fiber-cement siding. This site visit was part of that study. Assessment: NIOSH staff visited the Twickenham Square construction site in Huntsville, AL on September 24-26, 2013. During the site visit, they performed industrial hygiene sampling which measured the exposures to respirable dust and respirable crystalline silica of two workers who cut fiber-cement panel siding. An engineering control measure was implemented by connecting a dust-collecting circular saw to a regular shop vacuum. The shop vacuum provided local exhaust ventilation to remove the dust generated from cutting fiber-cement siding using the dust-collecting circular saw. The NIOSH scientists also monitored the wind speed and direction at the site, and collected data about the work process in order to understand the conditions that led to the measured exposures. Results: Air sampling for respirable crystalline silica showed that on all three days, both workers' 10-hour time weighted average (TWA) exposures to respirable quartz (the most common form of crystalline silica) were in the range of 0.007 to 0.012 mg/m3. These results were considerably lower than the NIOSH Recommended Exposure Limit (REL) of 0.05 mg/m3, applicable up to a 10-hour workday in a 40-hour workweek, and the Threshold Limit Value (TLV) of 0.025 mg/m3 TWA applicable for an 8-hour workday and a 40-hour workweek. The TLV is a product of the American Conference of Governmental Industrial Hygienists (ACGIH). The observed exposures were also considerably lower than the OSHA Permissible Exposure Limit (PEL) for respirable dust that contains greater than 1% quartz, with the 8-hour TWA exposures during the sampling periods in the range of 0.07 to 0.15 mg/m3, and the corresponding PEL in the range of 0.97 to 1.76 mg/m3. Conclusions and Recommendations: The exposure levels indicated that the evaluated engineering control measure was effective in reducing the workers' exposures to concentrations below the NIOSH REL for respirable quartz, and the OSHA PEL for respirable dust containing silica. This engineering control measure has the potential to provide an effective, simple and low cost solution for workers cutting fiber-cement siding.
Region-4; Control-technology; Engineering-controls; Construction-materials; Construction-industry; Construction-workers; Dusts; Silica-dusts; Fibrous-dusts; Respirable-dust; Dust-control; Dust-control-equipment; Respiratory-protective-equipment; Respiratory-protection; Quartz-dust; Cements; Concretes; Cutting-tools; Sampling; Vacuum-equipment; Ventilation; Exhaust-ventilation; Control-equipment; Control-systems; Dust-collection; Work-practices; Air-samples; Air-sampling; Time-weighted-average-exposure; Exposure-levels; Exposure-limits; Cyclone-air-samplers; Permissible-limits;
Author Keywords: Respirable dust; Respirable crystalline silica; Fiber-cement siding; Engineering control
Field Studies; Control Technology
NTIS Accession No.
National Institute for Occupational Safety and Health