42 CFR 84.143 - Terminal fittings or chambers; Type B supplied-air respirators; minimum requirements.
(a) Blowers or connections to air supplies providing positive pressures shall not be approved for use on Type B supplied-air respirators.
(b) Terminal fittings or chambers employed in Type B supplied-air respirators, shall be:
(1) Installed in the inlet of the hose.
(2) Designed and constructed to provide for the drawing of air through corrosion resistant material arranged so as to be capable of removing material larger than 0.149 mm. in diameter (149 micrometers, 100-mesh, U.S. Standard sieve).
(3) Installed to provide a means for fastening or anchoring the fitting or chamber in a fixed position in a zone of respirable air.