Evaluation of cut-off saw exposure control methods for respirable dust and crystalline silica in roadway construction

Details

• Personal Author:
  Hubbard B ; McGlothlin, James D. ; Middaugh B ; Zimmerman N
• Description:
  Dust reduction equipment adapted for single-person operation was evaluated for gas-powered, commercially available cut-off saws during concrete curb cutting. Cutting was performed without dust control and with two individual exposure control methods: wet suppression and local exhaust ventilation (LEV). The wet suppression system comprised a two-nozzle spray system and a 13.3-L hand-pressurized water supply system with an optimum mean flow rate of 0.83 L/min for 16 min of cutting. The LEV system consisted of a spring-loaded guard, an 18.9-L collection bag, and a centrifugal fan with an estimated exhaust rate of 91 ft3/min. Task-based, personal filter samples were obtained for four saw operators during cutting durations of 4 to 16 min on five job sites. Seventeen filter samples were collected without dust control, 14 with wet suppression, and 12 with LEV, yielding a geometric mean respirable dust concentration of 16.4 mg/m3, 3.60 mg/m3, and 4.40 mg/m3, respectively. A dust reduction of 78.0% for wet suppression and 73.2% for LEV was observed vs. no dust control. A statistically significant difference (p < 0.001) was also revealed for wet suppression and LEV when compared with no dust control; however, a significant difference (p=0.09) was not observed between wet suppression and LEV. Despite these significant dust reductions, workers are still projected to exceed the ACGIH 8-hr timeweighted average threshold limit value for quartz (0.025 mg/m3) in less than 1 hr of cutting for both dust control methods. Further research is still needed to improve dust reduction and portability of both control methods, but the current LEV system offers important advantages, including a drier, less slippery work area and year-round functionality in cold weather. [Description provided by NIOSH]
• Subjects:
  Construction Industry Construction Materials Dust Occupational Exposure Occupational Health Particulate Matter Quartz Safety Silicon Dioxide
• Keywords:
  Author Keywords: Concrete Concretes Construction Construction-equipment Construction-industry Construction-materials Control Control-equipment Cutting-tools Dust-control Dust-control-equipment Dust-suppression Employee-exposure Equipment-design Exposure Particulate-dust Power-tools Quartz Quartz-dust Respirable Respirable-dust Road-construction Saw Silica Silica-dusts

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• ISSN:
  1545-9624
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Indiana ; Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  157-165
• Volume:
  9
• Issue:
  3
• NIOSHTIC Number:
  nn:20040485
• Citation:
  J Occup Environ Hyg 2012 Mar; 9(3):157-165
• Contact Point Address:
  Beauregard Middaugh, Purdue University, School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907
• Email:
  bmiddaug@purdue.edu
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2012
• Performing Organization:
  University of Cincinnati
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• End Date:
  20260630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f4951634a0ca7320bf5b5308fbf6c3ff6e347af5ace6336aa26545ec4d138ddb9daa78ff3799ca5c2cbe1b16906d520f033ac0fefe79c085778ed67f9e904da8
• Download URL:
  https://stacks.cdc.gov/view/cdc/193325/cdc_193325_DS1.pdf
• File Type:
  [PDF - 403.32 KB ]