A Modified Method for Measuring Pressure Drop in Non-medical Face Masks with Automated Data Acquisition and Analysis.

Background: Non-medical face masks, such as face coverings donned by the general population play an important role in reducing transmission of respiratory pathogens. Pressure drop or breathability of such masks is an important attribute especially with the advent of new standards such as ASTM F3502-21 that have specified pressure drop limits for general use of face coverings. Although several standards are available that discuss pressure drop measurement techniques, the methodologies reported are typically complex or are part of more sophisticated and expensive instruments. Thus, the applicability of such methods is often limited to medical device manufacturers. Objective and Methods: This manuscript adapts from the pressure drop measurements proposed in British Standard EN 14683:2019 and describes a methodology to create a simple 3D printed model of a pressure rig for measuring the breathing resistance across non-medical face masks. The method also enables real time pressure drop data acquisition and analysis of multiple samples or batches using Python and MATLAB scripts. Results: We performed a validation study by comparing the pressure drop obtained for one brand of respirators with our set up and compared it with data obtained by traditional means by CDC. An unpaired two-tailed student t-test (n=3) between the two means implied no statistically significant difference. Conclusion: The method we have developed can be easily implemented at community levels for characterizing the breathability of non-medical grade face masks.

Planning for Epidemics and Pandemics: Assessing the Potential Impact of Extended Use and Reuse Strategies on Respirator Usage Rates to Support Supply-and-Demand Planning Efforts.

During epidemics and pandemics healthcare personnel (HCP) are on the front line of disease containment and mitigation. Personal protective equipment (PPE), such as NIOSH-approved N95 filtering facepiece respirators (FFRs), serve an important role in minimizing HCP risks and are in high demand during public health emergencies. Because PPE demand can exceed supply, various public health strategies have been developed to reduce the rate of PPE consumption as supply dwindles. Extended use and limited reuse of N95 FFRs are strategies advocated by many governmental agencies used to increase the number of times a device can be used. Increased use of respirators designed for reuse-such as powered air-purifying respirators (PAPRs) and elastomeric half-mask and full facepiece air-purifying respirators- is another option designed to reduce the continuous need for new devices as the daily need for respirator use increases. Together, these strategies are designed to reduce the number of PPE units that must be discarded daily and, therefore, extend the longevity of available supply. The purpose of this paper is to theoretically estimate the impact of extended use and limited reuse strategies for N95 FFRs and the increased use of reusable respirator options on PPE consumed. The results suggest that a considerable reduction in PPE consumption would result from extended use and limited reuse of N95 FFRs and the increased use of respirators designed for reuse; however, the practical benefits must be balanced with the risks and economic costs. In addition, extended use and reuse strategies must be accompanied by proper procedures to reduce risk. The study is designed to support epidemic and pandemic PPE supply and demand planning efforts.

A General Framework to Test and Evaluate Filtering Facepiece Respirators Considered for Crisis Capacity Use as a Strategy to Optimize Supply.

During a public health emergency, respirator shortages can have a profound impact on the national response, such as for the current coronavirus disease 2019 (COVID-19) pandemic. Due to a severe shortage of respirators (particularly filtering facepiece respirators [FFRs]), there may be contexts in which understanding the performance of FFRs that are approved for use as part of a crisis capacity strategy is desired. This includes FFRs that are not covered under the National Institute for Occupational Safety and Health (NIOSH) Respirator Approval Program because they have been stored past their designated shelf life, have been decontaminated, or are approved by international certification bodies other than NIOSH. The purpose of this document is to provide a general framework to assess the performance of FFRs that are only being used as a crisis capacity strategy. The intended audience are those who are responsible for managing large amounts of FFRs. This framework includes a four-step process consisting of: 1) defining the population of FFRs to be sampled; 2) providing sampling strategy options; 3) inspecting and testing the sampled units; and 4) evaluating the results. In addition to the four-step process, we provide an example of how NIOSH recently evaluated the quality of FFRs sampled from ten U.S. stockpiles.