Performance of dust respirators with facial seal leaks: I. Experimental.
Am Ind Hyg Assoc J 1987 Oct; 48(10):836-841
The ability of half mask and single use dust respirators with facial leaks to provide protection against aerosols was evaluated. The performance of six commercial respirators fitted with a variety of filters was evaluated by mounting them on a manikin in an aerosol test chamber and measuring aerosol number concentrations inside and outside the masks under steady flow conditions. Fourteen particle sizes utilizing oleic-acid aerosols ranging from 0.14 to 11.34 microns aerodynamic diameter and seven flow rates, 2 to 150 liters per minute, were used. Leak and filter penetration were measured separately. Leak penetration was measured by blocking the filter inlets and placing a wire between the sealing edge of the respirator and the manikin surface. Filter penetration was measured by sealing the mask to the manikin with hot melt adhesives. Pressure drops across the respirators were measured. Particle sizes inside and outside the masks were determined using an optical counter. Filter penetration depended strongly on particle size and flow rate. Leak penetration depended strongly on particle size, but was weakly dependent on pressure drop. Flow rate through the mask was strongly affected by leak size, being proportional to the 2.7 power of the leak diameter. The authors conclude that the aerosol size distribution inside a respirator will be markedly different from that outside. The data obtained in the study will be used as the basis of a model for predicting filter and leak penetration of dust respirators.
NIOSH-Publication; NIOSH-Grant; Personal-protective-equipment; Respiratory-protection; Laboratory-testing; Simulation-methods; Aerosol-particles; Equipment-reliability
Environ and Nutritional Scis University of California 405 Hilgard Avenue Los Angeles, Calif 90024
American Industrial Hygiene Association Journal
University of California Los Angeles, Los Angeles, California