FRESH AIR PORT MECHANISM FOR FACEPIECE USED ON SELF-CONTAINED OPEN-CIRCUIT COMPRESSED AIR BREATHING APPARATUS

摘要

Embodiments relate generally to methods, systems, and devices for opening and closing one or more ports (1402) to allow a wearer of a self-contained breathing apparatus (SCBA) (100) to breathe ambient air. Incorporation of a fresh-air port assembly (300) into the mask (102) of an SCBA (100) may enable the user to breathe ambient air when purified air is not required, and may allow a user to quickly switch to purified air when necessary. A fresh-air port assembly (300) positioned between the demand valve (104) and mask (102) of an SCBA (100) may be operable to disconnect and/or disable the demand valve (104) to allow ambient air into the mask (102), as well as to control the exhalation valve (202) of the mask (102) so that a user may easily breathe ambient air.