Effect of Particle Concentration, Sealing Condition and Breathing Rate on Total Inward Leakage for N95 Filtering Facepiece Respirators

Abstract

Several researchers have considered the relationship between total inward leakage (TIL) and other parameters such as sealing condition, particle concentration, type of particulate material breathing parameters, etc., however, there is dearth of information on the effects of varying particle concentration on the penetration efficiency of filtering facepiece respirators (FFRs), hence, this study aims to study the effect of varying NaCl particle concentration, sealing condition and breathing rate on the TIL as a result of the filtering efficiency of the filters.To achieve this, we followed the sampling procedure used by He et al., 2014. Four different sealing conditions (SCs) namely; fully sealed, fully opened, chin sealed, and cheek & chin sealed was used. NaCl aerosol particle was used at varying concentration levels of 100,000 (100K), 200,000 (200K) and 400,000 (400K). Also, we used mean inspiratory flow rates of 15LPM, 30LPM, 55LPM and 85LPM which we refer to as breathing rate throughout this study. Visual presentation of result was done with Python 3.8 and data analysis was carried out using R version 3.6.0 (2019-04-26). The statistical model statement follows the equation TILSC = βo + β1B + β2C + β3BC + £. where B is the breathing rate at the 4 MIF, 15, 30, 55, and 85; C is concentration and BC is the interaction between Breathing flow rate and the concentration. TILsc is the total inward leakage at the different sealing conditionsThe result shows that the variables have effect on the TIL for both fully opened and cheek and chin sealed condition with or without interaction between the variables at 0.05 confidence level. For fully sealed and chin sealed condition, the variables have no significant effect on the mean TIL response when interaction between variables was considered and when interaction between variables was not considered.In conclusion, there is statistically significance difference for mean TIL response with the change in sealing conditions, varying concentrations of NaCl particle and breathing rates.This study showed that in studying the effect of varying NaCl particle concentration, sealing conditions and breathing rate on the TIL, it is only under both fully opened and cheek and chin sealed conditions that the mean TIL response is significantly affected by the factors in consideration. Hence, workers should not expose their nose region at any time to prevent exposure.