Development of a Manikin-Based Performance Evaluation Method for Loose-Fitting Powered Air-Purifying Respirators

Area of Science:

• Occupational safety and health
• Respiratory protection technology
• Industrial hygiene

Background:

• Loose-fitting powered air-purifying respirators (PAPRs) are increasingly utilized in healthcare settings.
• Previous research by NIOSH established manikin headforms for evaluating filtering facepiece respirator fit.
• There is a growing need for standardized methods to assess PAPR performance using advanced headforms.

Purpose of the Study:

• To investigate the performance of PAPRs under various work rates.
• To gather data supporting the development of a manikin-based test method for PAPR evaluation.
• To assess the influence of different test configurations on PAPR performance.

Main Methods:

• Manikin penetration factors (mPF) were measured for three PAPR models across four work rates (REST, LOW, MODERATE, HIGH).
• In-mask differential pressure and aerosol concentrations were monitored using condensation particle counters.
• Two exhalation air return configurations (filtered and unfiltered) were evaluated on a NIOSH static advanced headform.

Main Results:

• PAPR model, work rate, and test configuration were found to significantly affect PAPR performance.
• All PAPR models demonstrated manikin penetration factors exceeding their assigned protection factors.
• Negative minimum pressures were observed in some combinations of work rate and model.

Conclusions:

• PAPR performance is influenced by the respirator model, work rate, and test setup.
• Advanced headforms offer potential for PAPR performance assessment, pending further method development.
• Future research should focus on optimizing manikin-based test methods and correlating headform results with human subject data.