CFR > Title 42 - Public Health > CHAPTER I—PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES > SUBCHAPTER G—OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES (parts 80 to 87) > PART 84—APPROVAL OF RESPIRATORY PROTECTIVE DEVICES > SUBPART KK—Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks (§84.1100 to §84.1158) > 84.1137—Inhalation and exhalation valves; minimum requirements.

84.1137—Inhalation and exhalation valves; minimum requirements.

(a) Inhalation and exhalation valves shall be protected against distortion.
(b) Inhalation valves shall be designed and constructed and provided where necessary to prevent excessive exhaled air from adversely affecting filters, cartridges, and canisters, except where filters of dust, fume, and mist respirators are specifically designed to resist moisture as prescribed in § 84.1145.
(c) Exhalation valves shall be:
(1) Provided where necessary;
(2) Protected against damage and external influence; and
(3) Designed and constructed to prevent inward leakage of contaminated air.