A manikin-based assessment of loose-fitting powered air-purifying respirator performance at variable flow rates and work rates

Abstract

Loose-fitting powered air-purifying respirators (PAPRs) are used in healthcare settings, although barriers to routine, everyday usage remain, including usability concerns and potential interference with work activities. Loose-fitting PAPRs are approved by the National Institute for Occupational Safety and Health (NIOSH) and must meet minimum performance requirements, including a minimum airflow requirement of 170 L/min. One course of action to address usability concerns is to allow for the use of PAPRs designed with reduced airflow rates. The primary objective of this study was to assess the effect of PAPR flow rate and user work rate on PAPR performance, using a manikin-based assessment method. PAPR performance was quantified using the “Manikin Fit Factor” (mFF), a ratio of the challenge aerosol concentration to the in-facepiece concentration. Flow rates from 50–215 L/min and low, moderate, and high work rates were tested. Two models of NIOSH Approved loose-fitting facepiece PAPRs were tested, both having an Occupational Safety and Health Administration Assigned Protection Factor (APF) or expected level of protection, of 25. A two-way analysis of variance with an effect size model was run for each PAPR model to analyze the effects of work rate and flow rate on PAPR performance. Flow rate and work rate were found to be significant variables impacting PAPR performance. At low and moderate work rates and flow rates below the NIOSH minimum of 170 L/min, mFF was greater than or equal to 250, which is 10 times the OSHA APF of 25 for loose-fitting facepiece PAPRs. At high work rates and flow rates below 170 L/min, mFF was not greater than or equal to 250. These results suggest that some loose-fitting facepiece PAPRs designed with a flow rate lower than the current NIOSH requirement of 170 L/min may provide respirator users with expected protection at low and moderate work rates. However, when used at high work rates, some loose-fitting facepiece PAPRs designed with lower flow rates may not provide the expected level of protection.

Keywords:

• Faceseal leakage
• healthcare
• loose-fitting facepiece
• manikin fit factor
• PAPR
• usability

Acknowledgments

The authors would like to thank National Personal Protective Technology Laboratory staff members Nora Payne, Tyler Quinn, and Jeremy Brannen for their review of this paper.

Conflicting interest

The authors report there are no competing interests to declare.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Disclaimers

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. The use of trade names is for identification purposes only and does not mean product endorsement by the Centers for Disease Control and Prevention. Mention of any company or product does not constitute an endorsement by the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. N95, PAPR100-N, PAPR100-P, HE, and NIOSH Approved are registered certification marks of the U.S. Department of Health and Human Services (HHS).

Additional information

Funding

This project was supported in part by an appointment to the Research Participation Program at the Centers for Disease Control and Prevention administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the Centers for Disease Control and Prevention.