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Effects of Faceseal Leakage, Combustion Material, Particle Size, Breathing Frequency and Flow Rate on the Performance of Respiratory Protection Devices

He, Xinjian
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378197327

Abstract Details

2013, PhD, University of Cincinnati, Medicine: Industrial Hygiene (Environmental Health).
The main goal of this study was to investigate multiple factors (faceseal leakage, combustion material, particle size, breathing flow rate, and breathing frequency) that affect the performance offered by negative pressure respiratory protection devices, including an elastomeric full facepiece, an elastomeric half-mask, an N95 filtering facepiece respirator (FFR), and a surgical mask. Challenge aerosols included NaCl particles and combustion particles generated by burning different materials. This research effort consists of five related studies. In study one (Chapter 1), the effects of faceseal leakage and origin of challenge aerosol (combustion of wood, paper and plastic) on the performance of a full facepiece and a half-mask elastomeric respirator were tested. The study revealed that the origin of challenge aerosol significantly affects the particle penetration through unsealed and partially sealed half-mask. Increasing leak size increased the total particle penetration. In study two (Chapter 2), the effect of particle size on the performance of an elastomeric half-mask respirator against combustion aerosols was examined. For the partially sealed and unsealed respirators, the penetration through the faceseal leakage reached maximum at particle sizes > 100 nm when challenged with plastic aerosol, whereas no clear peaks were observed for wood and paper aerosols. The particles aerosolized by burning plastic penetrated more readily than wood and paper. Study three (Chapter 3) was focused on the effect of breathing frequency on the total inward leakage (TIL) of an elastomeric half-mask respirator donned on an advanced manikin headform challenged with combustion aerosols. The frequency effect was less significant than flow rate. The greatest penetration occurred when respirators were challenged with plastic aerosol at 30 L/min and 30 breaths/min. Study four (Chapter 4) was conducted to investigate the effect of breathing frequency on the filter penetration (Pfilter) and the TIL for a N95 facepiece filtering respirators (FFR) and a surgical mask. For the tested FFR and SM, results show that Pfilter was significantly affected by particle size and breathing flow rate; surprisingly Pfilter as a function of particle size exhibited more than one peak under all tested breathing conditions. The breathing frequency effect on Pfilter was generally less pronounced, especially for lower MIFs. TIL was not significantly affected by particle size and breathing frequency for particles > 50 nm; however, the effect of MIF remained significant. In study five (Chapter 5), a conventional and a modified elastomeric half-mask respirators were fit tested using 25 human subjects. The modified half-mask (with polymeric micro-patterned adhesives tapes applied on the sealing surface to minimize the faceseal leakage) exhibited higher overall fit factors (geometric mean, GM = 7,907) than the non-modified half-mask (GM = 4,779) under the normal test condition (dry and shaved face). For all challenge facial conditions, including wet and/or unshaved face, the modified half-mask showed significantly higher fit factors than the conventional one, suggesting a special advantage offered by the former respirator. Overall, the results presented in this dissertation provide an extensive database, which is useful for respirator manufacturers, regulatory agencies, respiratory protection researchers, and end-users operating in various occupational environments.
Sergey Grinshpun, Ph.D. (Committee Chair)
Pramod Kulkarni, D.Sc. (Committee Member)
Roy Mckay, Ph.D. (Committee Member)
Marepalli Rao, Ph.D. (Committee Member)
Tiina Reponen, Ph.D. (Committee Member)
275 p.
Environmental Health
respirator; total inward leakage; filter; combustion aerosol; manikin; particle size

Recommended Citations

Citations

  • He, X. (2013). Effects of Faceseal Leakage, Combustion Material, Particle Size, Breathing Frequency and Flow Rate on the Performance of Respiratory Protection Devices [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378197327

    APA Style (7th edition)

  • He, Xinjian. Effects of Faceseal Leakage, Combustion Material, Particle Size, Breathing Frequency and Flow Rate on the Performance of Respiratory Protection Devices. 2013. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378197327.

    MLA Style (8th edition)

  • He, Xinjian. "Effects of Faceseal Leakage, Combustion Material, Particle Size, Breathing Frequency and Flow Rate on the Performance of Respiratory Protection Devices." Doctoral dissertation, University of Cincinnati, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378197327

    Chicago Manual of Style (17th edition)

ucin1378197327
799
© 2013, some rights reserved.Creative Commons License Effects of Faceseal Leakage, Combustion Material, Particle Size, Breathing Frequency and Flow Rate on the Performance of Respiratory Protection Devices by Xinjian He is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.