Respirable Silica Dust Suppression During Artificial Stone Countertop Cutting

Details

• Alternative Title:
  Ann Occup Hyg
• Personal Author:
  Cooper, Jared H. ; Johnson, David L. ; Phillips, Margaret L.
• Description:
  Purpose:
  
  To assess the relative efficacy of three types of controls in reducing respirable silica exposure during artificial stone countertop cutting with a handheld circular saw.
  
  Approach:
  
  A handheld worm drive circular saw equipped with a diamond segmented blade was fitted with water supply to wet the blade as is typical. The normal wetted-blade condition was compared to (i) wetted-blade plus ‘water curtain’ spray and (ii) wetted-blade plus local exhaust ventilation (LEV). Four replicate 30-min trials of 6-mm deep, 3-mm wide cuts in artificial quartz countertop stone were conducted at each condition in a 24-m3 unventilated tent. One dry cutting trial was also conducted for comparison. Respirable cyclone breathing zone samples were collected on the saw operator and analyzed gravimetrically for respirable mass and by X-ray diffraction for respirable quartz mass.
  
  Results:
  
  Mean quartz content of the respirable dust was 58.5%. The ranges of 30-min mass and quartz task concentrations in mg m−3 were as follows—wet blade alone: 3.54–7.51 and 1.87–4.85; wet blade + curtain: 1.81–5.97 and 0.92–3.41; and wet blade + LEV: 0.20–0.69 and <0.12–0.20. Dry cutting task concentrations were 69.6mg m−3 mass and 44.6mg m−3 quartz. There was a statistically significant difference (α = 0.05) between the wet blade + LEV and wet blade only conditions, but not between the wet blade + curtain and wet blade only conditions, for both respirable dust and respirable silica.
  
  Conclusions:
  
  Sawing with a wetted blade plus LEV reduced mean respirable dust and quartz task exposures by a factor of 10 compared to the wet blade only condition. We were unable to show a statistically significant benefit of a water curtain in the ejection path, but the data suggested some respirable dust suppression.
  
  
• Subjects:
  Countertop Cutting Engineering Controls Respirable Silica Short Communication
• Source:
  Ann Occup Hyg. 2014; 59(1):122-126.
• Pubmed ID:
  25326187
• Pubmed Central ID:
  PMC4290629
• Document Type:
  Journal Article
• Funding:
  T01-OH008614/OH/NIOSH CDC HHS/United States
• Volume:
  59
• Issue:
  1
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:747be89b7b5ed87b359b1db6d2ef19860343d74e684fb9f07dd8c183be19c2f0
• Download URL:
  https://stacks.cdc.gov/view/cdc/32268/cdc_32268_DS1.pdf
• File Type:
  [PDF - 728.01 KB ]