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This study evaluated workplace performance of a full facepiece, negative pressure, air-purifying respirator with P100 filters in a lead refining plant. Air samples for lead were collected inside and outside the respirators worn by workers who were properly trained and quantitatively fit tested. Trained observers assisted in the study to ensure sample validity. Three to four pairs of air samples per day were collected from each worker for a total of 52 valid sample sets. Lead was found on all the outside samples, and concentrations were below the detection limit for all but one of the inside samples. The single measurable inside sample yielded a workplace protection factor (WPF) of 297. WPFs for the rest of the samples were estimated using the assumption that lead was present at the detection limit for the in-facepiece samples. Calculated WPFs were rounded down to the nearest 100 then subjected to a rank and percentile function. The 5th percentile WPF was approximately 900 using this approach. These WPFs exceed the assigned protection factor (APF) of 50 for this respirator class recommended by the National Institute for Occupational Safety and Health and listed by the Occupational Safety and Health Administration. These results support the APF of 50 for this respirator and indicate the respirator provided adequate protection as used in this study.

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pressure) particulate filter respirators. (1) The new certification regulation, 42 CFR 84, which contained these tests, eliminated the need for unique tests of particulate respirators used for various aerosols. At the same time, 42 CFR 84 established three series of filters, N, R & P with three levels of filter efficiency, 95, 99 and 99.97%. According to NIOSH, these new filters can be used without regard to aerosol size. The most critical filter selection issue is the presence of oil aerosols in workplace air. While certain laboratory tests may show a difference between 30 CFR 11 and 42 CFR 84 compliant filters, there are no data to show if or how these changes affect respiratory protection in the workplace. Therefore, this study was undertaken to: • measure the performance of By Craig E. Colton, C.I.H. Craig Colton is a Certified Industrial Hygienist with the 3M OH&ESD Laboratory. In this workplace study, there was no difference in performance among a dust/mist respirator approved under 30 CFR 11 and two N95 particulate respirators approved under 42 CFR 84. While the new NIOSH standard imposed stricter filter performance requirements, its implementation did not result in a significant difference in protection provided by the new respirators.

This study evaluated the workplace performance of a hood-style supplied-air respirator during aircraft sanding operations. Air samples were collected inside and outside the respirators worn by workers during normal work activities. The samples were analyzed for chromium, strontium, and magnesium. These contaminants were not detected on any inside sample from the valid sample sets. Program protection factors (PPFs) were estimated for the valid sample sets using the limit of detection as the inside sample mass. When it was possible, PPF estimates were made using each element individually and a combination of all three elements. The PPF estimates were in the range of >11000 to >65000 regardless of the elements used in the calculation. Examination of the PPF estimates for different elements reveals the differences are largely artificial. The results indicate the tested respirator performed well above its assigned protection factor of 1000. No worker was overexposed to chromium, strontium, or magnesium during the study. This study also illustrates the difficulty in locating workplaces with sufficient contaminant concentration and duration to measure the capabilities of high-performing respirators.