AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
The Effect of Simulated Air Conditions on N95 Respirator Performance
JOEL RAMIREZ, Patrick O'Shaughnessy, University of Iowa
Abstract Number: 94 Working Group: Control Technology
Abstract Despite previous research in the field of respirators efficiency and resistance to flow, uncertainty still remains regarding the effect of moisture in a respirator. The objective of this study was to determine the effect of different simulated air conditions on the resistance to flow, as a measure of comfort, and the efficiency of N95 Filtering Face-piece Respirators. A penetration curve and resistance to flow (Rf) of two models of N95 filtering face-piece respirator (FFR) were evaluated in a test system developed to mimic inhalation and exhalation, and provide changes to relative humidity (RH) and temperature (T). Penetration was tested before and after a 2-hr Rf test using a sodium chloride aerosol measured with a scanning mobility particle sizer. The Rf test was performed under four T and RH conditions. A second round of tests included the addition of an inorganic dust to determine the effect of dust loading on Rf. Results showed that the critical condition was simulated condition 3. For simulated condition 3, model A inhalation Rf increased on average 2.43 mm H2O; model B inhalation Rf increased on average 9.34 mm H2O; model A had, on average, a penetration difference between the before Rf test and after Rf test of 0.91%; Model B had, on average, a penetration difference of 0.75% between the before Rf test and after Rf test; most penetrating particle size (MPPS) for Model A was 40.6 nm before Rf test and 46.3 nm after Rf test; and MPPS for Model B was 48.4 nm before Rf test and 55.1 nm after Rf test. When the FFRs were challenged with an inorganic dust, Rf for Model B increased faster than for Model A. Results of this study shows that air conditions that involve high RH (i.e. simulated condition 3), increase FFR Rf.