Loading and filtration characteristics of filtering facepieces.
Chen-CC; Lehtimaki-M; Willeke-K
Am Ind Hyg Assoc J 1993 Feb; 54(2):51-60
The variations in performances of different respirators of the same category were examined. The degradation of collection efficiency by aerosol loading was also examined. The aerosol penetration was determined for different brands of filtering facepieces; the experimental data were compared to theoretical predictions. Scanning electron microscopy studies and data obtained by pressure drop studies indicated that the dust mist filtering facepieces examined had similar fiber diameters and packing densities. Electrical force removal accounted for 69% of the total filtration for the respirator found to have the best filter quality at a face velocity of 10 centimeters/second and an aerosol size of 0.16 micrometer. However, the electrical force removal accounted for only 25% for the respirator having the worst filter quality under these same operating conditions. The removal efficiency of these facepieces was reduced over time by as much as this amount. The authors note that under the conditions of normal usage, the total aerosol particle load is not as high as in this study and the filtering facepieces are likely to be discarded before the electrostatic attractions are significantly diminished.
NIOSH-Publication; NIOSH-Grant; Respirators; Air-filters; Filter-materials; Respiratory-protection; Respiratory-protective-equipment; Personal-protective-equipment; Physical-properties
Environmental Health University of Cincinnati Dept of Environmental Health Cincinnati, Ohio 45267
American Industrial Hygiene Association Journal
University of Cincinnati, Cincinnati, Ohio