An oxygen cylinder should be taken out of service and refilled when the pressure inside it is less than which value?

An oxygen cylinder should be taken out of service and refilled when the pressure inside it is less than which value?

• A. 1,500 psi.
• B. 500 psi.
• C. 200 psi.
• D. 1,000 psi.

Answer: (B)

The key idea is maintaining a safe margin of oxygen so you don’t run out during patient care. For portable oxygen cylinders, you want to replace or refill when the pressure is about 500 psi. At full pressure you have a large remaining volume, but as you drop to around 500 psi you still have enough gas to continue delivering oxygen for several minutes while you arrange a refill or swap cylinders. This gives a reliable buffer for variable flow rates and unforeseen delays. If the pressure falls much lower, like around 200 psi, only a small amount of oxygen remains (enough for just a few minutes at high flow), which risks running out mid-treatment. So the practice is to take the cylinder out of service and refill once it hits roughly 500 psi.

The key idea is maintaining a safe margin of oxygen so you don’t run out during patient care. For portable oxygen cylinders, you want to replace or refill when the pressure is about 500 psi. At full pressure you have a large remaining volume, but as you drop to around 500 psi you still have enough gas to continue delivering oxygen for several minutes while you arrange a refill or swap cylinders. This gives a reliable buffer for variable flow rates and unforeseen delays.

If the pressure falls much lower, like around 200 psi, only a small amount of oxygen remains (enough for just a few minutes at high flow), which risks running out mid-treatment. So the practice is to take the cylinder out of service and refill once it hits roughly 500 psi.