Evaluation of the performance of the N95 companion: effects of filter penetration and comparison with other aerosol instruments

Details

• Personal Author:
  Eimer BC ; Rengasamy S ; Shaffer RE
• Description:
  Fit factor is the ratio of the particle concentration outside (Cout) to the inside (Cin) of the respirator and assumes that filter penetration is negligible. For Class-95 respirators, concerns were raised that filter penetration could bias fit test measurements. The TSI N95-Companion was designed to overcome this limitation by measuring only 40-60 nm size particles. Recent research has shown that particles in this size range are the most penetrating for respirators containing electrostic filter media. The goal of this study was to better understand the performance of the N95-Companion by assessing the impact of filter penetration and by comparing Cout/Cin ratios measured by other aerosol instruments (nano-Differential Mobility Analyzer/Ultrafine Condensation Particle Counter (nano-DMA/UCPC) and the TSI PortaCount Plus) using N95 filtering facepiece respirators sealed to a manikin and with intentionally created leaks. Results confirmed that 40-60 nmdiameter size room air particles were most penetrating for the respirators tested. A nonlinear relationship was found between the N95-Companion-measured Cout/Cin ratios and the other instruments at the sealed condition and at the small leak sizes because the N95-Companion measures only charged particles that are preferentially captured by the electrostic filter media, while the other instrument configurations also measure uncharged particles, which are captured less efficiently. The Cout/Cin ratios from the N95-Companion for experiments conducted under sealed condition suggest that filter penetration of negatively charged 40-60 nm size particles was less than 0.05%. Thus, the N95-Companion measured Cout/Cin ratios are due primarily to particle penetration through leakage, not through filter media, while the Cout/Cin ratios for the PortaCount, nano-DMA/UCPC, and UCPC result from a combination of face seal leakage and filter penetration. [Description provided by NIOSH]
• Subjects:
  Filtration Occupational Health Particulate Matter Personal Protective Equipment Respiratory Protective Devices Respiratory System Safety
• Keywords:
  Air-purifying-respirators Anthropometry Author Keywords: Face Seal Leakage Equipment-reliability Face-masks Filter Penetration Filters Fit Testing Leak-prevention Measurement-equipment N95 Filtering Facepiece Respirators N95-Companion Particle-counters Particulates Performance-capability Personal-protective-equipment PortaCount Plus Respirators Respiratory-equipment

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• ISSN:
  1545-9624
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  NPPTL - National Personal Protective Technology Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  417-426
• Volume:
  9
• Issue:
  7
• NIOSHTIC Number:
  nn:20040852
• Citation:
  J Occup Environ Hyg 2012 Jul; 9(7):417-426
• Contact Point Address:
  Samy Rengasamy, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, P.O.Box 18070, Pittsburgh, PA 15236
• Email:
  ARengasamy@cdc.gov
• Federal Fiscal Year:
  2012
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:8d2cc2bf1558cb7bebf31530afa5639ba3ad7a47729507c05446bf2a6da3f471552e7907b37e2b647b56e5e7589966697220111f7a30956a0fb1ee1f056798e7
• Download URL:
  https://stacks.cdc.gov/view/cdc/193570/cdc_193570_DS1.pdf
• File Type:
  [PDF - 426.31 KB ]