42 C.F.R. § 84.85 – Breathing bags; minimum requirements.

(a) Breathing bags shall have sufficient volume to prevent gas waste during exhalation and to provide an adequate reserve for inhalation.
(b) Breathing bags shall be constructed of materials which are flexible and resistant to gasoline vapors.
(c) Breathing bags shall be installed in a location which will protect them from damage or collapse by external forces, except on apparatus classified for escape only.