42 CFR 84.90
§ 84.90 Breathing resistance test; inhalation.
United States · 42 CFR — Public Health · Status: effective
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- Citation
- 42 CFR 84.90, § 84.90 Breathing resistance test; inhalation, United States, version 1 as recorded 2026-07-09, yourstate.us, https://yourstate.us/provision/201707
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Full text
(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.
Legislative history
This is a federal regulation, adopted through agency rulemaking under the Administrative Procedure Act — not enacted by a recorded vote of Congress.