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Although workplace protection factor (WPF) and simulated workplace protection factor (SWPF) studies provide useful information regarding the performance capabilities of powered air-purifying respirators (PAPRs) under certain workplace or simulated workplace conditions, some fail to address the issue of total PAPR unit performance over extended time. PAPR unit performance over time is of paramount importance in protecting worker health over the course of a work shift or at least for the recommended service lifetime of the PAPR battery pack, whichever is shorter. The need for PAPR unit performance testing has become even more important with the inception of 42 CFR 84 and the recent introduction of electrostatic respirator filter media into the PAPR market. This study was conducted to learn how current PAPRs certified by the National Institute for Occupational Safety and Health would perform under an 8-hour unit performance test similar to the dioctyl phthalate (DOP) loading test described in 42 CFR 84 for R- and P-series filters for nonpowered, air-purifying particulate respirators. In this study, entire PAPR units, four with mechanical filters and one with an electrostatic filter, were tested using a TSI Model 8122 Automated Respirator Tester, with and without the built-in breathing machine. The two, tight-fitting PAPRs, both with mechanical filters, showed little effect on performance resulting from the breathing machine. The two loose-fitting helmet PAPRs indicate that unit performance testing without the breathing machine is a more stringent test than testing with the breathing machine under the conditions used. The PAPR with a loose-fitting hood gave inconclusive results as to which testing condition is more stringent. The PAPR unit equipped with electrostatic filters gave the highest maximum penetration values during unit performance testing.
Acknowledgments
The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health (NIOSH). Mention of a commercial product or trade name does not constitute endorsement by NIOSH or the authors.
Notes
A 3M Company acquired Racal in 1998, but the products tested were purchased before the buyout and were, therefore, Racal products.
B User instructions supplied with filter clearly state that these filters are NOT for use against oil aerosols.
A The minimum protection factor is the protection factor (PF) calculated from the maximum unit penetration measured during testing.
B Average flow rate for first battery pack (replaced after first 4 hours).
C Average flow rate for second battery pack.
D Value in parentheses is maximum penetration value after first 4 hours of testing (when battery pack was changed).
A The minimum protection factor is the protection factor (PF) calculated from the maximum unit penetration measured during testing.
B Average flow rate for first battery pack (replaced after first 4 hours).
C Average flow rate for second battery pack.
D Value in parentheses is maximum penetration value after first 4 hours of testing (when battery pack was changed).