42 C.F.R. § 84.90 Breathing resistance test; inhalation.
Title 42 - Public Health
(a) Resistance to inhalation airflow will be measured in the facepiece or mouthpiece while the apparatus is operated by a breathing machine as described in §84.88. (b) The inhalation resistance of open-circuit apparatus shall not exceed 32 mm. (1.25 inch) water-column height (at a flow rate of 120 liters per minute). (c) The inhalation resistance of closed-circuit apparatus shall not exceed the difference between exhalation resistance (§84.91(e)) and 10 cm. (4 inches) water-column height.
Title 42: Public Health
PART 84—APPROVAL OF RESPIRATORY PROTECTIVE DEVICES
Subpart H—Self-Contained Breathing Apparatus
§ 84.90 Breathing resistance test; inhalation.
