Filter and leak penetration characteristics of a dust and mist filtering facepiece.
Chen-CC; Ruuskanen-J; Pilacinski-W; Willeke-K
Am Ind Hyg Assoc J 1990 Dec; 51(12):632-639
An aerosol generation and sampling system designed for studying filter and leak penetration characteristics of dust and mist filtering facepieces (disposable respirators) was described. The generator consisted of a Wright nozzle modified to increase the large particle fraction combined with a solid plate impactor and a virtual impactor. A laminator above the impactors reduced air turbulence thereby decreasing the deposition loss of large particles. Large particles and a portion of the submicron size particles flowed along the axis of the virtual impactor and were emitted from the device as the test aerosol. The output from the generating system was diluted by clean air and introduced into a 2 cubic meter test chamber used for respirator fit testing on humans or mannikins. The sampling train sampled the test aerosol at a flow rate of 5 liters per minute (l/min) before leading it into the sizing spectrometer. The probe was designed for an average flow rate of 32l/min. The probe orifice had outside and inside diameters of 16 and 8 millimeters (mm). The system was tested with a 3M model 8715 disposable respirator using corn-oil as the test aerosol. The respirator was tested sealed (intact) or with simulated leaks created by punching 2.0, 2.8, and 4.0mm diameter circular holes in a thin aluminum plate glued 6.5 centimeters from the probe near the right cheek. Aerosol penetration into the sealed respirator increased with increasing flow rate over the range 5 to 95l/min and decreased with increasing particle size. In experiments with leaks, aerosol penetration through the leak site was almost independent of particle size for particles having diameters of 0.8 to 4 microns. For a given flow rate, the slopes of the aerosol penetration curves (plots of penetration versus particle diameter) decreased with increasing leak size. The authors conclude that the aerosol generation and sampling system is suitable for studying filter and leak penetration characteristics of disposable respirators.
NIOSH-Publication; NIOSH-Grant; Respirators; Respiratory-protective-equipment; Laboratory-testing; Air-flow; Aerosol-particles; Aerosol-generators; Equipment-reliability; Industrial-hygiene; Equipment-design
Environmental Health University of Cincinnati Dept of Environmental Health Cincinnati, Ohio 45267
Respirator Research; Respirators
American Industrial Hygiene Association Journal
University of Cincinnati, Cincinnati, Ohio