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Ensuring Respiratory Protection through Respirator Fit Testing and Real-Time Monitoring

Wu, Bingbing
http://orcid.org/0000-0002-4205-6550
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374058309808

Abstract Details

2018, PhD, University of Cincinnati, Medicine: Industrial Hygiene (Environmental Health).
Respirators can provide adequate protection only if they are properly selected for the task, fitted to the wearer, consistently donned, and properly worn. A proper respirator fit (determined by the tightness of facepiece seal) can be verified through fit testing prior to initial use. The objective of the first two studies included in this dissertation was to examine the utility of the optical particle counting (OPC) method for quantitative respirator fit testing. The rationale of this effort was to explore an alternative fit test method. While fit testing is very important to assess a respirator’s predicted protection level, it cannot guarantee the protection is maintained throughout the workplace deployment of this respirator. In fact, it is recognized that respirators are prone to leakage. Therefore, the objective of the next two studies described in this dissertation was to evaluate a low-cost Real Time Respirator Seal Integrity Monitor (ReSIM), which was designed for rapidly detecting performance failures of respirators, alerting the wearer, and thus helping to prevent overexposure. Overall, this dissertation consists of four studies (Study A – D). In Study A, the OPC-based MT-05U fit tester, which detected particles of = 0.3 µm, was examined in accordance with the ANSI standard Z88.10-2010 for evaluating new fit test methods. The OSHA-accepted PortaCount®, which is based on condensation particle counting method, served as the reference apparatus. Paired fit factors were measured with the two instruments operating in parallel. The evaluation was conducted with three high-efficiency respirators: P100 filtering facepiece respirator (FFR) and elastomeric half- and full-facepiece respirators equipped with P100 filters. MT-05U was tested on the NIOSH 25-member bivariate fit test panel, following the OSHA fit testing protocol. In Study B, the evaluation was extended to the less efficient N95 FFR. The PortaCount operated with N95-CompanionTM mode and MT-05U was examined using two operating size ranges: = 0.3 µm and = 0.5 µm. In Study C, ReSIM’s capability to detect leaks was assessed using a manikin-based set-up with two challenge aerosols generated in the test chamber: NaCl and combustion aerosol. While ReSIM performed a continuous air sampling inside an elastomeric half-mask respirator, which was donned on a manikin headform; an operator opened a specially designed solenoid-controlled valve intermittently, thus creating a small faceseal leak for pre-determined time intervals, and then closed it. The tests were conducted at three breathing flow rates: 30, 60 and 85 L/min. In Study D, ReSIM was tested on nine respirator-wearing firefighters exposed to NaCl aerosol in a 24.3-m3 exposure chamber while they performed simulated routine operational activities. Controlled leaks were established in the same manner as in Study C. Overall, results showed that the MT-05U could identify improperly fitted respirators as effectively as the reference method, and the ReSIM was capable of promptly detecting the breach in a respirator faceseal with high sensitivity and specificity. The efforts provided (i) an alternative method for quantitative respirator fit testing and (ii) a safety tool capable of alerting the respirator wearer of possible overexposure to hazardous aerosols in real time.
Sergey Grinshpun, Ph.D. (Committee Chair)
Jonathan Corey, Ph.D. (Committee Member)
Roman Jandarov, Ph.D. (Committee Member)
Michael Maier, Ph.D. (Committee Member)
Tiina Reponen, Ph.D. (Committee Member)
122 p.
Occupational Safety
aerosol; optical particle counter; condensation nuclei particle counter; faceseal leakage; low cost sensor; firefighter

Recommended Citations

Citations

  • Wu, B. (2018). Ensuring Respiratory Protection through Respirator Fit Testing and Real-Time Monitoring [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374058309808

    APA Style (7th edition)

  • Wu, Bingbing. Ensuring Respiratory Protection through Respirator Fit Testing and Real-Time Monitoring. 2018. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374058309808.

    MLA Style (8th edition)

  • Wu, Bingbing. "Ensuring Respiratory Protection through Respirator Fit Testing and Real-Time Monitoring." Doctoral dissertation, University of Cincinnati, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374058309808

    Chicago Manual of Style (17th edition)

ucin1535374058309808
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This open access ETD is published by University of Cincinnati and OhioLINK.