IV. Considerations in the Selection of Respirators
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| CONSIDERATION | Surgical Masks Not Certified by NIOSH as Dust and Mist Masks |
Cup-Shaped, Disposable-Mask, Particulate Respirators (PRs) Certified by NIOSH |
Powered, HEPA-Filter, Halfmask Respirators and Postitive-Pressure, Air-Line, Halfmask Respirators Certified by NIOSH |
| RELIABILITY OF PROTECTIONFace-Seal Leakage |
Negative-pressure operation markedly decreases the level and reliability of protection delivered by these masks. Users cannot assure themselves that they are receiving adequate protection because there are no proven fit tests for them and they cannot be fit checked by their users. Employers cannot assure that protection is being received b their employees. |
Negative-pressure operation markedly decreases the level and reliability of protection delivered by these masks. Users cannot assure themselves that they are receiving adequate protection because there are no proven fit tests for them and they cannot be fit checked by their users. Employers cannot assure that protection is being received by their employees. |
Positive-pressure operation markedly increases the level and reliability of protection delivered by these respirators. Users can assure themselves that they are receiving adequate protection because these respirators can be quantitatively fit tested and fit checked by their wearers. Also, users can readily detect whether or not air is being forced into their facepieces, which indicates protection is being received. Employers can assure that protection is being received by their employees.
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| Filter Leakage | Filter reliability has not been adequately evaluated against droplet nuclei. |
Filter reliability has not been adequately evaluated against droplet nuclei. |
HEPA filters are highly reliable against any size aerosol. Filter reliability is not an issue with air-line respirators, since no filters are used.
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