Impact of Three Cycles of Decontamination Treatments on Filtering Facepiece Respirator Fit
Michael S. Bergman, Dennis J. Viscusi, Andrew J. Palmiero, Jeffrey B. Powell, Ronald E. Shaffer
Decontamination and reuse of N95 filtering facepiece respirators (FFRs) may be a strategy for mitigating a supply shortage during an influenza pandemic. The objective was to determine if multiple decontamination treatments affect respirator fit. Quantitative fit tests were performed on three different surgical N95 FFR models before and after multiple applications of ultraviolet germicidal irradiation (UVGI), moist heat incubation (MHI), or microwave-generated steam (MGS). Ten test subjects initially qualified for each FFR model by passing (fit factor (FF) ≥ 100) a standard OSHA-accepted quantitative fit test. Fit was then evaluated over multiple consecutive donnings using an abbreviated fit test protocol: first on an untreated FFR and then on the same sample following one, two, and three decontaminations. FFRs were visually examined for physical degradation following each decontamination cycle. MGS and MHI treatments caused one FFR model to experience a slight separation of the inner foam nose cushion. MGS caused a melted headstrap in one FFR sample. UVGI did not cause any physical degradation. Fit test passing rate ranged from 90 % to 100 % and varied by respirator model/decontamination method combination and donning trial. Mean faceseal leakage (FSL) for each donning for all FFR models was < 1 % (i.e., corresponding to FF > 100). Tests were non-significant (p > 0.05) comparing the mean FSL of each of the four donning trials for all FFR model / decontamination method combinations. Three applications of the decontamination methods studied did not cause significant changes in respirator fit. Further research is needed before specific recommendations employing these methods can be made.
Keywords: filtering facepiece respirator, fit test, healthcare workers, N95, decontamination, N95 fit, pandemic influenza, respirator reuse