In which emergency procedure do you turn off the oxygen cylinder?

In which emergency procedure do you turn off the oxygen cylinder?

• A. Oxygen cylinder completely open due to valve failure
• B. Oxygen cylinder overpressure
• C. Oxygen cylinder empty
• D. By-pass or demand valve stuck open

Answer: (D)

When a regulator component stops controlling gas, you must isolate the source. If the bypass or demand valve sticks open, gas will flow into the loop continuously regardless of breathing, so the only reliable way to stop that flow is to close the oxygen cylinder valve. This immediately stops all oxygen entering the system, allowing you to manage the situation, switch to a bailout, and prevent overdelivery of oxygen. Other scenarios mentioned involve different failures or conditions where the immediate stop of flow isn’t addressed in the same way, so the key action for the stuck-open valve is to shut the cylinder.

When a regulator component stops controlling gas, you must isolate the source. If the bypass or demand valve sticks open, gas will flow into the loop continuously regardless of breathing, so the only reliable way to stop that flow is to close the oxygen cylinder valve. This immediately stops all oxygen entering the system, allowing you to manage the situation, switch to a bailout, and prevent overdelivery of oxygen. Other scenarios mentioned involve different failures or conditions where the immediate stop of flow isn’t addressed in the same way, so the key action for the stuck-open valve is to shut the cylinder.