However, as almost all non-rebreathing masks are disposable, and manufactured in 1 adult size, most ( from decades of clinical observation ) do not provide a good seal with an individual patient's face, thus permitting the inflow of large amounts of ambient air ( air follows the path of least resistance ), and diluting the oxygen provided.
22.
Other equipment produced by Fernez's company included : the Fernez model 3 breathing apparatus, for use in underground pipes and galleries ( such as mines or sewers ) where the tube is extended to 80 metres, charcoal filters against foul gases such as ammonia and sulfur, an oxygen rebreathing apparatus with soda to absorb CO2, a medical oxygen inhaler, and an air circulation helmet for the fire brigade.
