Respirable dust control in grinding gray iron castings.
O'Brien-D; Baron-P; Willeke-K
Am Ind Hyg Assoc J 1987 Feb; 48(2):181-187
Methods for controlling respirable dusts during high speed grinding of gray iron castings were evaluated. A pilot grinding operation consisting of a 0.76 meter (m) diameter grinder containing a 5 centimeter (cm) wide, 14 grit zirconia aluminum-oxide alloy, resinoid bond, fiberglass reinforced wheel was installed in a walk in enclosure. Grinding of 2.5cm by 30cm gray iron bars was performed at surface speeds of 49.8 to 62.0m/second using an automatic feed to maintain constant metal to wheel force for a 10 second grinding cycle. The grinder was exhausted at a basic rate of between 0.49 and 0.88m3/s. The size distribution and concentration of airborne particles produced by grinding were measured with an aerodynamic particle sizer. Effects of control measures such as increasing exhaust ventilation, installing baffles, or using an air jet to deflect the entrained air stream on the concentration and distribution of the particles were evaluated. Number spectra of the particle size distributions obtained during grinding and application of control measures were presented. Increasing the grinding rate increased the number of particles and median particle size. Baffles, when used alone at a ventilation rate of 0.57m3/s, reduced the concentration of respirable dust by 50 percent. When used in combination with the air jet, the baffles reduced respirable dust particle concentrations by a factor of 3 to 4. Increased exhaust ventilation plus the baffles plus the air jet reduced the concentration of respirable dust particles by about 20 fold. The authors note that contamination of the breathing zone can occur by deflection of the airstream by either the casting or the worker's body. Results in an actual production setting may differ in magnitude from those obtained in the study since the worker's technique, size and shape of the casting, cleanliness of the casting surface, and room air currents were not taken into account.
NIOSH-Publication; NIOSH-Grant; Respirable-dust; Metal-workers; Metallic-dusts; Dust-control-equipment; Dust-control; Abrasive-grinding; Grinding-equipment; Workplace-studies; NIOSH-Author
Environmental Health University of Cincinnati Dept of Environmental Health Cincinnati, Ohio 45267
American Industrial Hygiene Association Journal
University of Cincinnati, Cincinnati, Ohio