Quantitative Respirator Fit Testing Research Articles

A Feasibility Study of Quantitative Respirator Fit Testing by Controlled Negative Pressure

A Feasibility Study of Quantitative Respirator Fit Testing by Controlled Negative Pressure

Focus on —: Present Procedures in Quantitative Respirator Fit Testing: Problems and Potential Solutions

(1990). Focus on —: Present Procedures in Quantitative Respirator Fit Testing: Problems and Potential Solutions. Applied Occupational and Environmental Hygiene: Vol. 5, No. 11, pp. 762-765.

Noninvasive, quantitative respirator fit testing through dynamic pressure measurement.

A new method has been invented for the noninvasive and quantitative determination of fit for a respirator. The test takes a few seconds and requires less expensive instrumentation than presently used for invasive testing. In this test, the breath is held at a negative pressure for a few seconds, and the leak-induced pressure decay inside the respirator cavity is monitored. A dynamic pressure sensor is attached to a modified cartridge of an air-purifying respirator or built into the respirator body or into the air supply line of an air-supplied respirator. The method is noninvasive in that the modified cartridge can be mounted onto any air-purifying respirator. The pressure decay during testing quantifies the airflow entered through the leak site. An equation has been determined which gives the air leakage as a function of pressure decay slope, respirator volume and the pressure differential during actual wear--all of which are determined by the dynamic pressure sensor. Thus, the ratio of air inhaled through the filters or via the air supply line to the leak rate is a measure of respirator fit, independent of aerosol deposition in the lung and aerosol distribution in the respirator cavity as found for quantitative fit testing with aerosols. The new method is shown to be independent of leak and sensor locations. The concentration and distribution of aerosols entered through the leak site is dependent only on the physical dimensions of the leak site and the air velocity in it, which can be determined independently.(ABSTRACT TRUNCATED AT 250 WORDS)

New Methods for Quantitative Respirator Fit Testing with Sodium Chloride Aerosol

New Methods for Quantitative Respirator Fit Testing with Sodium Chloride Aerosol

New methods for quantitative respirator fit testing with aerosols

Quantitative respirator fit testing is generally performed by measuring the concentration of DOP aerosol leaking into the breathing space between the respirator and the wearer's face. In the conventional technique, the concentrations inside and outside the mask are determined photometrically through measurements of the scattered light intensities from the DOP clouds. DOP, however, has recently been implicated as a potential human carcinogen. We have adapted a continuous-flow condensation nuclei counter (CNC) for fit testing and have been able to use a variety of non-hazardous test aerosols which are not measurable by the conventional technique. The CNC enlarges submicrometer-sized particles into the light scattering range, so virtually any fine particle cloud can be used for fit testing. Comparison tests between photometer and CNC measurements show the utility of the new technique. The potential use of an aerosol electrometer is also discussed.