(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).