42 C.F.R. § 84.303 – General testing conditions and requirements.

(a) NIOSH will conduct capacity and performance tests on the CCER using a breathing and metabolic simulator to provide quantitative evaluations and human subjects on a treadmill to provide qualitative evaluations. Information on the design and operation of the simulator is available from the NIOSH Web site at http://www.cdc.gov/niosh/npptl. Technical specifications can be obtained from NIOSH by contacting the National Personal Protective Technology Laboratory (NPPTL) by mail: P.O. Box 18070, 626 Cochrans Mill Road, Pittsburgh, PA 15236. Telephone: 412-386-4000 (this is not a toll-free number). Email: npptl@cdc.gov.

(b) Capacity, performance, and wearability tests will continuously monitor the stressors listed in Table 1. The stressors and their respective acceptable ranges will be measured at the interface between the CCER and the mouth by instruments capable of breath-by-breath measurement. Stressor measurements will be evaluated as 1-minute averages. The operating averages of each stressor will be calculated upon the completion of each test as the average of the 1-minute measurements of the stressor recorded during the test. The level of any excursion for a stressor occurring during a test will be defined by the 1-minute average value(s) of the excursion(s).

Table 1—Monitored Stressors and Their Acceptable Ranges
Stressor	Acceptable range operating average	Acceptable range excursion
Average inhaled CO2	<1.5%	≤4%.
Average inhaled O2	>19.5%	≥15%.
Peak Breathing Pressures	ΔP ≤200 mm H2 O	−300 ≤ΔP ≤200 mm H2 O.
Wet-bulb temperature1	<43 °C	≤50 °C.
1 Wet-bulb temperature is a measurement of the temperature of a wet surface. It represents the temperature of the inhaled breathing gas in the CCER user's trachea.

(c) Capacity and performance tests will conclude when the stored breathing gas supply has been fully expended.
(d) NIOSH will determine a CCER to have failed a capacity, performance, or wearability test if any of the following occurs:
1. (1) A 1-minute average measurement of any stressor listed in Table 1 occurs outside the acceptable excursion range specified in Table 1; or an average stressor measurement calculated at the completion of a performance or capacity test exceeds the acceptable operating average range specified in Table 1; or
2. (2) A human subject cannot complete the test for any reason related to the CCER, as determined by NIOSH.
(e) Unless otherwise stated, tests required under this subpart will be conducted at the following ambient conditions:
1. (1) Ambient temperatures of 23 °C ±3 °C; and
2. (2) Atmospheric pressures of 735 mm Hg ±15 mm Hg.