Evaluation of the QuantiFit2TM Compared to the PortaCountTM Pro+ for Respirator Fit Testing in a Firefighter Population: A Performance and User Preference Study

Abstract

Firefighters are routinely exposed to hazardous airborne contaminants and rely on tight-fitted self-contained breathing apparatus (SCBA) for respiratory protection. The effectiveness of these respirators depends on proper seal and fit, which are mandated for fit-testing annually under the Occupational Safety and Health Administration (OSHA) Standard 29 CFR 1910.134. Researchers have found that different fit-testing devices result in significantly different fit-testing results. Specifically, in a 2018 study, the author noted that fit factors were “not equal” and that the PortaCountTM Pro+ typically resulted in higher fit factor values (Wu 2018). The current study compared the performance and user preference of two OSHA-approved quantitative fit testing (QNFT) devices: the PortaCountTM Pro+, that uses condensation nuclei counting (CNC) technology, and the QuantiFit2TM, which uses controlled negative pressure (CNP) technology, in a firefighter population. Limited research exists comparing both technologies, even less related to firefighter populations. This study involved thirty-eight (38) active-duty firefighters from a northern Colorado fire department who were fit-tested on both devices during the same testing session using their personally-issued SCBA facepieces. Quantitative results, such as fit factors and pass/fail outcomes, were based on the OSHA minimum fit factor requirement of ≥ 500 for full-face respirators. Qualitative results were collected via a post fit-test survey to evaluate metrics such as clarity of fit-testing instructions, comfort, perceived efficiency, and overall device preference. Fit-testing pass rates did not differ significantly between the two devices (P > 0.05). Both devices yielded pass rates exceeding 94%, indicating comparable compliance performance. However, log10-transformed overall fit factors differed significantly between devices (paired t-test, p < 0.001). These discrepancies in fit factor values were interpreted as differences in measurement technology and reporting scales rather than regulatory performance equivalency. The linear association between fit factor values on both devices was analyzed using Pearson correlation analysis, which resulted in a slightly negative association. This means that a participant who scored high on the fit factor scale of one device, did not necessarily score high on the other device. Analysis of qualitative data from the post fit-test survey supported that there was no significant difference in clarity of instructions or comfort ratings between the devices. However, in terms of overall preference based on device test duration, 47.4% (18/38) of participants selected other fit-testing devices, 34.2% (13/38) selected the QuantiFit2TM , 13.2% (5/38) reported no preference, and 5.3% (2/38) selected the PortaCountTM Pro+ (binomial exact test, p<0.05). It was concluded that both the QuantiFit2TM and the PortaCountTM Pro+ provided reliable and comparable pass/fail rates for regulatory compliance. It should be noted that the PortaCountTM Pro+ fit-testing procedure used in this study followed the standard OSHA ambient aerosol CNC protocol, requiring approximately 8 minutes. However, OSHA also recognizes a modified ambient aerosol (“fast fit”) protocol for CNC technology, which reduces test duration to 2.5 minutes (OSHA 2019). Given that perceived test duration was the primary factor influencing device preference among study subjects, use of the “fast fit” protocol may have affected the outcomes of this study.