Polystyrene Latex Sphere Filter Efficiency as a Function of Particle Size and Flowrate.
NIOSH 1984 Sep:38 pages
The effects of particle size and flow rates on respirator filter efficiency were studied. Filter efficiency for polystyrene latex spheres was investigated, and the aerosol particle size at which maximum penetration occurred. Various flow rates were used to evaluate the particle size region to determine if a shift in the maximum penetrating particle size occurred at these different flowrates. The study indicated that a particle size at which a minimum efficiency occurred does exist and varies as a function of flowrate and filter type, and varies by manufacturer within the same filter type. The study indicated that high efficiency filters gave excellent percent efficiencies when tested at or near the worst case conditions. Under these worst test conditions the dust and mist (DM); dust, fume and mist (DFM); paint, lacquer and enamel mist (PLEM) filter efficiencies were significantly lower than efficiencies required by the silica (7631869) dust, silica mist, and lead (7439921) fume filter efficiency tests. Minimum efficiencies for high efficiency filters occurred at larger particle sizes than for other filters. The authors suggest that the Sibata Respirator Model 634A Filter Efficiency Test System, which uses a light scattering detector, is not as sensitive for monitoring instantaneous filter efficiency when using a polystyrene latex (PSL) aerosol challenge as the dioctyl phthalate (DOP) and NaCl challenge with a CNC (count efficiencies) detector system, particularly at small particle sizes.
NIOSH-Author; Aerosol-particles; Aerosol-sampling; Respirators; Respiratory-protective-equipment; Pulmonary-system; Personal-protective-equipment; Dust-control; Metal-fumes;
NTIS Accession No.
Respirator Research; Respirators; Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Pulmonary-system;
Division of Safety Research, NIOSH, U.S. Department of Health and Human Services, Morgantown, West Virginia, 38 pages, 18 references