Details:

Alternative Title:
Ann Occup Hyg
Personal Author:
Cooper, Jared H. ; Johnson, David L. ; Phillips, Margaret L.
Cooper, Jared H. ; Johnson, David L. ; Phillips, Margaret L. Less -
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
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:

Supporting Files

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  	annhyg_meu083_f0001.jpg	jpeg
  	license.txt	txt
  	meu083.nxml	txt

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