A pressure-demand oxygen system is also referred to as a what?

• A. Continuous-flow system.
• B. Venturi-driven ambient-air system.
• C. Cabin pressure system.
• D. Pressure breathing system.

Answer: (D)

When oxygen is supplied only as you inhale and at a slight positive pressure, the system is described as a pressure breathing system. This on-demand delivery means the regulator senses inhalation and opens to push oxygen to you, effectively “breathing” for you as you breathe in. That on-demand, pressurized delivery is what sets it apart from other types.

A continuous-flow system provides oxygen all the time, regardless of inhalation. A Venturi-driven ambient-air system uses ambient air with a Venturi to mix in oxygen, not on-demand. A cabin pressure system deals with maintaining cabin altitude, not the oxygen delivery method. So the term pressure breathing system is the correct label for a pressure-demand oxygen setup.