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 wetted-blade plus water curtain' spray
and 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.
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.
AplusA-online.de - Source: The Annals of Occupational Hygiene