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.

(i) The following work schedule will be performed by each wearer in the test chamber:

(A) Two minutes nodding up and down, and turning head side to side; and

(B) Two minutes calisthenic arm movements.

(C) Two minutes running in place.

(D) Two minutes pumping with tire pump.

(ii) The facepiece must be capable of adjustment, according to the applicant's instructions, to each wearer's face, and the odor of isoamyl acetate must not be detectable by any wearer during the test.

(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/m3 corn oil aerosol having a mass median aerodynamic diameter of 0.4 to 0.6 µm.

(1) The following activities will be performed by each wearer in the test chamber:

(i) Two minutes, nodding and turning head;

(ii) Two minutes, calisthenic arm movements;

(iii) Two minutes, running in place; and

(iv) Two minutes, pumping with a tire pump into a 28-liter (1 ft3) container.

(2) The respiratory inlet covering will be adjusted, according to the applicant's instructions, to each wearer's face.

(3) The appropriate fit factor must be exceeded during the entire test.