42 CFR §84.176
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
NIOSH will assess powered air-purifying respirator fit using either isoamyl acetate or generated aerosol.
- (a)Isoamyl acetate (IAA) fit test. The applicant must provide a charcoal-filled canister or cartridge of a size and resistance similar to the filter unit with connectors which can be attached to the facepiece in the same manner as the filter unit.
- (1)The canister or cartridge will be used in place of the filter unit, and persons will each wear a modified half-mask facepiece for 8 minutes in a test chamber containing 100 parts (by volume) of isoamyl acetate vapor per million parts of air.
- (2)Where the respirator is equipped with a full facepiece, hood, helmet, or mouthpiece, the canister or cartridge will be used in place of the filter unit, and persons will each wear the modified respiratory inlet covering for 8 minutes in a test chamber containing 500 parts (by volume) of isoamyl acetate vapor per million parts of air, performing the work schedule specified in paragraph (b)(2) of this section.
- (b)Generated aerosol fit test. The powered air-purifying particulate respirator system is tested in an atmosphere containing 20-40 mg/m 3 corn oil aerosol having a mass median aerodynamic diameter of 0.4 to 0.6 µm.