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Ann Occup Hyg. 2015 Jan;59(1):122-6. doi: 10.1093/annhyg/meu083. Epub 2014 Oct 17.

Respirable silica dust suppression during artificial stone countertop cutting.

Author information

1
Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, 801 NE 13th Street, Oklahoma City, OK 73104, USA.
2
Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, 801 NE 13th Street, Oklahoma City, OK 73104, USA David-Johnson@ouhsc.edu.

Abstract

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-m(3) 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 69.6 mg m(-3) mass and 44.6 mg 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.

KEYWORDS:

countertop cutting; engineering controls; respirable silica

PMID:
25326187
PMCID:
PMC4290629
DOI:
10.1093/annhyg/meu083
[Indexed for MEDLINE]
Free PMC Article
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