"Worst-case" aerosol testing parameters: III. Initial penetration of charged and neutralized lead fume and silica dust aerosols through clean, unloaded respirator filters.
Am Ind Hyg Assoc J 1989 May; 50(5):271-274
The initial instantaneous count efficiencies were determined for dust and mist (DM); paint, lacquer, and enamel mist (PLEM); and dust, fume, and mist (DFM) respirator filter media against certification silica (14808607) dust and lead (7439921) fume aerosols. A direct comparison was possible with initial count efficiency values using the certification aerosols and the efficiencies measured using the worst case scenario tests. In a second part of the study the effect of aerosol charge on filter initial penetration values by silica dust and lead fume aerosols was examined. For both aerosols the effect of the charge was less than or equal to 5 percent. The aerosol charge effect, however, appears to be larger for silica dust as reflected by the relative differences in the efficiency values. This difference may be due to the generation methods used or to the ability of the one aerosol to maintain a higher charge. The findings demonstrated that the initial count efficiency was significantly affected by the particle size. The percent efficiencies of the filters decreased as particle size was reduced in going from silica dust to lead fumes. Lead fumes are therefore more penetrating and offer a more discriminating test that the silica dust particles. All filter types and flow rates tested revealed lower efficiencies when tested under the worst case aerosol conditions. Substantial differences were noted in the penetration levels at 16 versus 85 liters/minute flow rates.
NIOSH-Author; Mineral-dusts; Aerosol-particles; Personal-protective-equipment; Respiratory-protective-equipment; Equipment-reliability; Testing-equipment; Filter-materials
American Industrial Hygiene Association Journal