(a) Non-powered air-purifying particulate respirators (series N, R, and P). (1) Non-powered air-purifying particulate respirators utilize the wearer's negative inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove particulates from the ambient air. They are designed for use as respiratory protection against atmospheres with particulate contaminants at concentrations that are not immediately dangerous to life or health and that contain adequate oxygen to support life.

(2) Non-powered air-purifying particulate respirators are classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that includes oil-based liquid particulates.

(3) Non-powered air-purifying particulate respirators are classified according to the efficiency level of the filter(s) as tested according to the requirements of this part.

(i) N100, R100, and P100 filters must demonstrate a minimum efficiency level of 99.97 percent.

(ii) N99, R99, and P99 filters must demonstrate a minimum efficiency level of 99 percent.

(iii) N95, R95, and P95 filters must demonstrate a minimum efficiency level of 95 percent.

(b) Powered air-purifying particulate respirators (PAPR classes HE and PAPR100). (1) Powered air-purifying particulate respirators utilize a blower to move the ambient air through the air-purifying filter elements (filters) to remove particulate contaminants and deliver clean air to the respiratory inlet covering. They are designed for use as respiratory protection against atmospheres considered not immediately dangerous to life or health and that contain adequate oxygen to support life.

(2) Powered air-purifying particulate respirators are classified into two classes, HE and PAPR100, and three series, HE, PAPR100-N, and PAPR100-P. The N-series filters are restricted to use in those workplaces free of oil aerosols. The P-series filters are intended for removal of any particulate that includes oil-based liquid particulates.

(3) All three filter series, HE, PAPR100-N, and PAPR100-P, for powered air-purifying particulate respirators must demonstrate a minimum efficiency level of 99.97 percent.

The components of each air-purifying particulate respirator must meet the minimum construction requirements set forth in subpart G of this part. Each air-purifying particulate respirator described in § 84.170 must, where its design requires, contain the following component parts:

(a) Respiratory inlet covering. (1) Tight fitting respiratory inlet coverings must be designed and constructed to fit persons with various facial shapes and sizes either:

(i) By providing more than one size; or

(ii) By providing one size which will fit varying facial shapes and sizes.

(2) Full facepieces must provide for optional use of corrective spectacles or lenses, which must not reduce the respiratory protective qualities of the respirator.

(3) Loose fitting respiratory inlet coverings must be designed and constructed to fit persons with various head sizes, provide for the optional use of corrective spectacles or lenses, and insure against any restriction of movement by the wearer.

(4) Mouthpieces must be equipped with noseclips which are securely attached to the mouthpiece or respirator and provide an airtight seal.

(5) Respiratory inlet coverings that incorporate a lens or faceshield must be designed to prevent eyepiece fogging.

(6) Half-mask facepieces must not interfere with the fit of common industrial safety spectacles, including corrective safety spectacles.

(7) Respiratory inlet coverings must be designed and constructed to provide adequate vision which is not distorted by the eyepieces.

(b) Filter unit. The respirator manufacturer, as part of the application for certification, must specify the filter series and the filter efficiency level (i.e., “N95,” “R95,” “P95,” “N99,” “R99,” “P99,” “N100,” “R100,” “P100,” “HE,” “PAPR100-N” or “PAPR100-P”) for which certification is being sought.

(1) Filters for non-powered respirators (series N, R, and P) must be prominently labeled as follows:

(i) N100 filters must be labeled “N100 Particulate Filter (99.97% filter efficiency level)” and must be a color other than magenta.

(ii) R100 filters must be labeled “R100 Particulate Filter (99.97% filter efficiency level)” and must be a color other than magenta.

(iii) P100 filters must be labeled “P100 Particulate Filter (99.97% filter efficiency level)” and must be color coded magenta.

(iv) N99 filters must be labeled “N99 Particulate Filter (99% filter efficiency level)” and must be a color other than magenta.

(v) R99 filters must be labeled “R99 Particulate Filter (99% filter efficiency level)” and must be a color other than magenta.

(vi) P99 filters must be labeled “P99 Particulate Filter (99% filter efficiency level)” and must be a color other than magenta.

(vii) N95 filters must be labeled as “N95 Particulate Filter (95% filter efficiency level)” and must be a color other than magenta.

(viii) R95 filters must be labeled as “R95 Particulate Filter (95% filter efficiency level)” and must be a color other than magenta.

(ix) P95 filters must be labeled as “P95 Particulate Filter (95% filter efficiency level)” and must be a color other than magenta.

(2) Filters for powered respirators (classes HE and PAPR100) must be prominently labeled as follows:

(i) HE filters must be labeled as “HE Particulate Filter (99.97% filter efficiency level)” and must be color coded magenta.

(ii) PAPR100-N filters must be labeled as “PAPR100-N Particulate Filter (99.97% filter efficiency level)” and must be color coded magenta.

(iii) PAPR100-P filters must be labeled as “PAPR100-P Particulate Filter (99.97% filter efficiency level)” and must be color coded magenta.

(c) Valves. (1) Inhalation and exhalation valves must be protected against distortion.

(2) Inhalation valves must be designed and constructed and provided where necessary to prevent excessive exhaled air from adversely affecting filters, except where filters are specifically designed to resist moisture.

(3) Exhalation valves must be:

(i) Provided where necessary;

(ii) Protected against damage and external influence; and

(iii) Designed and constructed to prevent inward leakage of contaminated air.

(d) Head harness. (1) All facepieces must be equipped with head harnesses designed and constructed to provide adequate tension during use and an even distribution of pressure over the entire area in contact with the face.

(2) Facepiece head harnesses, except those employed on filtering facepiece respirators, must be adjustable and replaceable.

(3) Mouthpieces must be equipped, where applicable, with adjustable and replaceable harnesses, designed and constructed to hold the mouthpiece in place.

(e) Breathing tube. Flexible breathing tubes used in conjunction with respirators must be designed and constructed to prevent:

(1) Restriction of free head movement;

(2) Disturbance of the fit of facepieces, mouthpieces, or loose fitting respiratory-inlet covering;

(3) Interference with the wearer's activities; and

(4) Shutoff of airflow due to kinking, or from chin or arm pressure.

(f) Drink tube. (1) For particulate respirators equipped with a drink tube, the respirator must meet all requirements of the standard with the drink tube in place.

(2) Dry drinking tube assembly will be subjected to a suction of 75 mm water column height while in a normal operating position (closed).

(3) Leakage through the drinking tube assembly must not exceed 30 mL per minute.

(g) Container. (1) Except as provided in paragraph (b) of this section, each respirator must be equipped with a substantial, durable container bearing markings which show the applicant's name, the type of respirator it contains, and all appropriate approval labels.

(2) Containers for respirators may provide for storage of more than one respirator; however, such containers must be designed and constructed to prevent contamination of respirators which are not removed, and to prevent damage to respirators during transit.

(h) Harness. (1) Each respirator must, where necessary, be equipped with a suitable harness designed and constructed to hold the components of the respirator in position against the wearer's body.

(2) Harnesses must be designed and constructed to permit easy removal and replacement of respirator parts, and, where applicable, provide for holding a full facepiece in the ready position when not in use.

(i) Attached blower—PAPR classes HE and PAPR100. Blowers must be designed to achieve the air flow rates required by the testing standards in § 84.175.

(j) Low-flow warning device—PAPR class PAPR100. (1) The design must include a low-flow warning. It must actively and readily indicate when flow inside the respiratory inlet covering falls below the minimum air flow defined in § 84.175.

(2) Any warning must be detectable by the wearer without any intervention by the wearer.

(3) Warning devices must be configured so that they may not be de-energized while the blower is energized.

(4) During use, warning devices must not switch off automatically and must not be capable of being switched off by the wearer.

(5) Any warnings which require different reactions by the wearer must be distinguishable from one another.

(6) If the warning provided is audible only, or other warnings are not readily apparent to the wearer, the minimum sound level must be 80 dBA.

(a) Resistance to airflow will be measured in the tight-fitting respiratory inlet covering of a complete particulate respirator mounted on a test fixture with air flowing at continuous rate of 85 ±2 liters per minute, before each test conducted in accordance with § 84.173.

(b) Resistance of a complete tight-fitting powered air-purifying particulate respirator system will be measured with the blower off if the manufacturer indicates that the respirator should not be doffed in the event of a blower failure.

(c) The maximum allowable resistance requirements for air-purifying particulate respirators are as follows:

(a) Dry exhalation valves and valve seats will be subjected to a suction of 25 mm water-column height while in a normal operating position.

(b) Leakage between the valve and valve seat must not exceed 30 mL per minute.

(a) Twenty filters of each non-powered air-purifying particulate respirator model will be tested for filter efficiency against:

(1) A solid sodium chloride particulate aerosol as per this section, if N-series certification is requested by the applicant.

(2) A dioctyl phthalate (DOP) or equivalent liquid particulate aerosol as per this section, if R-series or P-series certification is requested by the applicant.

(b) Filters including holders and gaskets, when separable, will be tested for filter efficiency level, as mounted on a test fixture in the manner as used on the respirator.

(c) Prior to filter efficiency testing of 20 N-series filters, the 20 to be tested will be taken out of their packaging and placed in an environment of 85 ± 5 percent relative humidity at 38 ± 2.5 °C for 25 ±1 hours. Following the pre-conditioning, filters will be sealed in a gas-tight container and tested within 10 hours.

(d) When the filters do not have separable holders and gaskets, the exhalation valves will be blocked so as to ensure that leakage, if present, is not included in the filter efficiency level evaluation.

(e) For non-powered air-purifying particulate respirators with a single filter, filters will be tested at a continuous airflow rate of 85 ± 4 liters per minute. Where filters are to be used in pairs, the test-aerosol airflow rate will be 42.5 ± 2 liters per minute through each filter.

(f) Filter efficiency test aerosols:

(1) When testing N-series filters, a sodium chloride or equivalent solid aerosol at 25 ± 5 °C and relative humidity of 30 ± 10 percent that has been neutralized to the Boltzmann equilibrium state will be used. Each filter will be challenged with a concentration not exceeding 200 mg/m 3.

(2) When testing R-series and P-series filters, a neat cold-nebulized dioctyl phthalate (DOP) or equivalent aerosol at 25 ± 5 °C that has been neutralized to the Boltzmann equilibrium state will be used. Each filter will be challenged with a concentration not exceeding 200 mg/m 3.

(3) The test will continue until minimum efficiency is achieved or until an aerosol mass of at least 200 ± 5 mg has contacted the filter. For P-series filters, if the filter efficiency is decreasing when the 200 ± 5 mg challenge point is reached, the test will be continued until there is no further decrease in efficiency.

(g) The sodium chloride test aerosol will have a particle size distribution with count median diameter of 0.075 ± 0.020 µm and a standard geometric deviation not exceeding 1.86 at the specified test conditions as determined with a scanning mobility particle sizer or equivalent. The DOP aerosol will have a particle size distribution with count median diameter of 0.185 ± 0.020 µm and a standard geometric deviation not exceeding 1.60 at the specified test conditions as determined with a scanning mobility particle sizer or equivalent.

(h) The efficiency of the filter will be monitored and recorded throughout the test period by a suitable forward-light-scattering photometer or equivalent instrumentation.

(i) The minimum efficiency for each of the 20 filters will be determined and recorded and must be equal to or greater than the filter efficiency criterion listed for each level as follows:

(a) Three filters from each powered air-purifying particulate respirator for efficiency will be tested against a neat cold-nebulized dioctyl phthalate (DOP) or equivalent aerosol at 25 ± 5 °C that has been neutralized to the Boltzmann equilibrium state.

(b) Single air-purifying particulate respirator filter units will be tested in an atmosphere concentration of 100 mg/m 3 of DOP at the following continuous flow rates for a period of 5 to 10 seconds:

(c) Powered air-purifying particulate respirators with multiple filter units will be tested by dividing the flow rate specified in paragraph (b) of this section by the total number of filters used.

(d) The filter will be mounted on a connector in the same manner as used on the respirator and the total efficiency must be ≥99.97 percent.

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/m 3 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 ft 3) 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.

Noise levels generated by any powered air-purifying respirators that cover the ears (i.e., hood or helmet) will be measured at the entrance to each ear at maximum airflow obtainable and must not exceed 80 dBA.

Resistance to airflow will be measured with a breathing machine as described in § 84.88.

(a) Minimum inhalation resistance must be greater than zero mm of water-column height.

(b) Maximum exhalation resistance must be less than 89 mm of water-column height.

(a) Three powered air-purifying particulate respirators will be tested for a period of 4 hours each at a flowrate not less than 115 liters per minute for tight-fitting facepieces, and not less than 170 liters per minute for loose-fitting hoods and helmets.

(b) The relative humidity in the test chamber will be 20-80 percent, and the room temperature approximately 25 °C.

(c) The test suspension in the chamber will not be less than 50 nor more than 60 mg of flint (99 + percent free silica) per m 3 of air.

(d) The flint in suspension will be 99 + percent through a 270-mesh sieve.

(e) The particle-size distribution of the test suspension will have a geometric mean of 0.4 to 0.6 µm and the standard geometric deviation will not exceed 2.

(f) The total amount of unretained test suspension in samples taken during testing must not exceed 14.4 mg for a powered air-purifying particulate respirator with tight-fitting facepiece, and 21.3 mg for a powered air-purifying particulate respirator with loose-fitting hood or helmet.

(a) Twenty filters of each powered air-purifying particulate respirator design will be tested for filter efficiency against:

(1) A solid sodium chloride particulate aerosol, in accordance with paragraph (d)(1) of this section, if series PAPR100-N approval is requested by the applicant.

(2) A dioctyl phthalate or equivalent liquid particulate aerosol, in accordance with paragraph (d)(2) of this section, if series PAPR100-P approval is requested by the applicant.

(b) Prior to filter efficiency testing of 20 series PAPR100-N filters, the 20 to be tested will be taken out of their packaging and placed in an environment of 85 ±5 percent relative humidity at 38 ±2.5 °C for 25 ±1 hours. Following the pre-conditioning, filters will be sealed in a gas-tight container and tested within 10 hours.

(c) For powered air-purifying particulate respirators with a single filter, filters will be tested at a continuous airflow rate of 85 ±4 liters per minute. Where filters are to be used in pairs, the test-aerosol airflow rate will be 42.5 ±2 liters per minute through each filter.

(d) Filter efficiency test aerosols:

(1) Series PAPR100-N filters:

(i) A sodium chloride or equivalent solid aerosol at 25 ±5 °C and relative humidity of 30 ±10 percent that has been neutralized to the Boltzmann equilibrium state will be used. Each filter will be challenged with a concentration not exceeding 200 mg/m 3.

(ii) The sodium chloride test aerosol will have a particle size distribution with count median diameter of 0.075 ±0.020 µm and a standard geometric deviation not exceeding 1.86 at the specified test conditions as determined with a scanning mobility particle sizer or equivalent.

(2) Series PAPR100-P filters:

(i) A neat cold-nebulized dioctyl phthalate (DOP) or equivalent aerosol at 25 ± 5 °C that has been neutralized to the Boltzmann equilibrium state will be used. Each filter will be challenged with a concentration not exceeding 200 mg/m 3.

(ii) The DOP aerosol shall have a particle size distribution with count median diameter of 0.185 ±0.020 µm and a standard geometric deviation not exceeding 1.60 at the specified test conditions as determined with a scanning mobility particle sizer or equivalent.

(e) The test will continue until minimum efficiency is achieved or until an aerosol mass of at least 200 ±5 mg has contacted the filter. For PAPR100-P series filters, if the filter efficiency is decreasing when the 200 ±5 mg challenge point is reached, the test will be continued until there is no further decrease in efficiency.

(f) The efficiency of the filter will be monitored and recorded throughout the test period by a suitable forward-light scattering photometer or equivalent instrumentation.

(g) The minimum efficiency for each of the 20 filters will be determined and recorded and must be equal to or greater than the filter efficiency criterion for PAPR100-N and PAPR100-P, efficiency ≥99.97 percent, pursuant to § 84.170(b).

(a) Powered air-purifying respirators must be designed to allow for proper communication while worn.

(b) A Modified Rhyme Test 7 will be used to test the wearer's ability to communicate efficiently.

(c) The communications requirement is met if the overall performance rating is greater than or equal to 70 percent.