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Performance Evaluation of DM and DFM Filter Respirators—WORKING DRAFT 9.15.92

The saccharin test agent has a relatively large size of 2.0 to 2.4 microns [μm] (count geometric mean, with 99.5% of the particles below 7.0 microns).[1] Given the data provided with the validation study for the QLFT, NIOSH estimates the saccharin test aerosol has a mass median aerodynamic diameter (MMAD) of about 4.5 to 5.0 microns.
  Lastly, in 1992, Iverson et al. reported results for a proposed quantitative fit test for DM- and DFM-filter masks.[2]

They reported that Submicron aerosol test agents used in many fit tests can be used with high-efficiency particulate (HEPA) filter elements but cannot be properly used with dust/fume/mist particulate filter elements because the aerosol is not completely stopped by these filter elements.

Iverson et al. investigated the leakage of aerosols ranging from 0.7 to 15 μm at 32 L/min/mask through one type of NIOSH-certified, filtering-facepiece, DM-filter half- mask (Model 8710 from the 3M Company). They reported that a 2.5-um aerosol particle met their QNFT criteria of 0.3 percent or lower filter leakage through their DM filter. 205 NIOSH concludes that it has been well known for over two decades that face-seal- leakage test protocols based on certain aerosols for quantitative fit testing (QNFT) and qualitative fit testing (QLFT) required the use of HEPA-filters on the tested masks. This is because the test aerosols used in these protocols (e.g., less than about 2.5 μm aerodynamic diameter) will infiltrate NIOSH-certified DM and DFM filters.


204Tbid., p. 161.

206 Tbid., p. 163.

  1. ↑ 3M Company: Comment of Minnesota Mining and Manufacturing Company with Respect to the Permanent Lead Standard Quantitative Fit Test Provision, OSHA Docket No. H-049A, Exhibit 6–16, (July 1, 1981), Attachment 1 Validation data for the Saccharin QLFT.
  2. ↑ Iverson, S. G., S. G. Danisch, H. E. Mullins, and S. K. Rudolph: Validation of a Quantitative Fit Test for Dust/Fume/Mist Respirators: Part 1, Appl. Occup. Environ. Hyg. 7(3):161-167 (1992).
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