TY - JOUR
T1 - Total Outward Leakage of Half-mask Respirators and Surgical Masks Used for Source Control
AU - Myers, Warren R.
AU - Yang, Weihua
AU - Ryan, Kenneth
AU - Bergman, Michael
AU - Fisher, Edward
AU - Soo, Jhy-Charm
AU - Zhuang, Ziqing
N1 - Publisher Copyright:
© This work was authored as part of the Contributor’s official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 USC. 105, no copyright protection is available for such works under US Law.
PY - 2023/9/8
Y1 - 2023/9/8
N2 - Both respirators and surgical masks (SM) are used as source control devices. During the COVID-19 pandemic, there was much interest in understanding the extent of particle total outward leakage (TOL) from these devices. The objective of this study was to quantify the TOL for five categories of devices: SMs, National Institute for Occupational Safety and Health (NIOSH) Approved N95 filtering facepiece respirators (FFRs) without exhalation valves, NIOSH Approved N95 FFRs with exhalation valves (N95 FFRV), NIOSH Approved elastomeric half-mask respirators (EHMRs) with exhalation valves, and NIOSH Approved EHMRs with an SM covering the exhalation valve (EHMRSM). A benchtop test system was designed to test two models of each device category. Each device was mounted on a headform at three faceseal levels (0% faceseal, 50% faceseal, and 100% faceseal). At each faceseal level, the TOL was assessed at three flow rates of minute ventilations of 17, 28, and 39 L/min. The experimental design was a split-split-plot configuration. Device type, faceseal level, flow rate, and the interaction of device type and faceseal level were found to have a significant effect ((Formula presented.) < 0.05) on the TOL. This study found that the N95 FFRs without exhalation valves had the lowest mean TOL. The SMs had about three times higher TOL than the N95 FFRs without exhalation valves. The TOL of the N95 FFRV was comparable to that of the SM at 0% and 50% faceseal on average overall conditions, but the N95 FFRV had a significantly higher TOL than the SM at a 100% faceseal. The EHMRs had the highest TOL because of the exhalation valve. Using an SM to cover the exhalation valve did not improve the EHMRs’ efficiency in mitigating the TOL. Caution should be exercised when using N95 FFRVs as a source control measure against respiratory activities with heavy work rates, such as performing CPR. Results of this study showed that reduced faceseal leakage for N95 FFRs and SMs improves source control.
AB - Both respirators and surgical masks (SM) are used as source control devices. During the COVID-19 pandemic, there was much interest in understanding the extent of particle total outward leakage (TOL) from these devices. The objective of this study was to quantify the TOL for five categories of devices: SMs, National Institute for Occupational Safety and Health (NIOSH) Approved N95 filtering facepiece respirators (FFRs) without exhalation valves, NIOSH Approved N95 FFRs with exhalation valves (N95 FFRV), NIOSH Approved elastomeric half-mask respirators (EHMRs) with exhalation valves, and NIOSH Approved EHMRs with an SM covering the exhalation valve (EHMRSM). A benchtop test system was designed to test two models of each device category. Each device was mounted on a headform at three faceseal levels (0% faceseal, 50% faceseal, and 100% faceseal). At each faceseal level, the TOL was assessed at three flow rates of minute ventilations of 17, 28, and 39 L/min. The experimental design was a split-split-plot configuration. Device type, faceseal level, flow rate, and the interaction of device type and faceseal level were found to have a significant effect ((Formula presented.) < 0.05) on the TOL. This study found that the N95 FFRs without exhalation valves had the lowest mean TOL. The SMs had about three times higher TOL than the N95 FFRs without exhalation valves. The TOL of the N95 FFRV was comparable to that of the SM at 0% and 50% faceseal on average overall conditions, but the N95 FFRV had a significantly higher TOL than the SM at a 100% faceseal. The EHMRs had the highest TOL because of the exhalation valve. Using an SM to cover the exhalation valve did not improve the EHMRs’ efficiency in mitigating the TOL. Caution should be exercised when using N95 FFRVs as a source control measure against respiratory activities with heavy work rates, such as performing CPR. Results of this study showed that reduced faceseal leakage for N95 FFRs and SMs improves source control.
KW - COVID-19
KW - N95 filtering facepiece respirator
KW - healthcare
KW - respirator
KW - respiratory protection
UR - https://digitalcommons.georgiasouthern.edu/bee-facpubs/402
UR - https://doi.org/10.1080/15459624.2023.2257254
U2 - 10.1080/15459624.2023.2257254
DO - 10.1080/15459624.2023.2257254
M3 - Article
SN - 1545-9624
JO - Journal of Occupational and Environmental Hygiene
JF - Journal of Occupational and Environmental Hygiene
ER -
