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

The penetration measured on the dust respirators represents overall leakage through filters, facepiece seal, and exhalation valves. The results indicate that penetration through the quarter- and half-mask dust respirator filters are a major source of penetration when compared with the results in Table C for the same facepiece [equipped with a HEPA filter] and subject.[1]

Also in 1976 NIOSH stated: Some filters used on the so-called "fume" respirators, look similar (to HEPA filters]. The basic difference is that the fume filter is less efficient (90-99% against 0.6-um [MMAD] particles) ... Less efficient are the so-called "dust" filters used on respirators designed for protection against "pneumoconiosis- and fibrosis-producing dusts"... This class of respirator accounts for as much as 90% of total sales. Their lower efficiency (80-90% against 0.6-um particles [MMAD]) results from being designed to withstand heavy dust loadings without unacceptably increasing breathing resistance. 192 The American National Standards Institute (ANSI) Z88.2-1980 respirator-use stan- dard cautioned in 1980: Limitations of filters, cartridges, and canisters used in air-purifying respirators shall be consid- ered in determining [assigned] protection factors. 193 For over two decades, statements have appeared in the professional literature re- garding the filter-penetration problems caused by certain test aerosols used for quan- titative fit testing (QNFT) and qualitative fit testing (QLFT) of face-seal efficacy. For example, the 1969 ANSI-recommended procedure for irritant-smoke fit test- ing 194 restricted its use to "a respirator equipped with a high-efficiency particulate filter" (to protect the wearer from irritant-smoke-leakage through DM- and DFM-fil- ters) and noted: Freshly produced smoke particles from this [smoke-generating] tube range from less than 0.1 to 3 microns (micrometers, μm) in diameter. 195

19NIOSH: A Guide to Industrial Respiratory Protection, DHEW(NIOSH) Publication # 76-189, Cincin- nati, OH, (June 1976), p. 32. 193 "American National Standards Institute, Inc.: American National Standard Practices for Respiratory Protection, ANSI Z88.2-1980, New York, New York, (1980), pp. 20 and 23, Table 5, footnote (a). 194 American National Standards Institute, Inc.: American National Standard Practices for Respiratory Protection, ANSI Z88.2-1969, New York, NY, (1969), p. 24.

195 Tbid., p. 25.

  1. ↑ Ibid., p. 21.
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