Oxygen Tank Duration Study Guide is a series of multiple choice question designed to solve for every possible variable in the calculation you may see on any Respiratory Exam.
Oxygen Tank Time Left
Tank Duration in min
Tank Pressure in psi
Flow rate in L/min
Oxygen Cylinder Conversion Factors in psi-1 L-1

• D Tank = 0.16
• E Tank = 0.28
• G Tank = 2.41
• H/K Tank = 3.14
• M tank = 1.56

Online Oxygen Tank Duration Calculator


1. A size D cylinder of oxygen has a remaining pressure of 1200 psi. The patient’s flow rate is 3 L/min. When will the tank be completely empty?

A. 45 min
B. 1 hour 19 min
C. 1 hour 5 min
D. 1 hour 30 min

Answer: C.


2. A size G cylinder of oxygen has a remaining pressure of 2000 psi. The patient’s flow rate is 10 L/min. When will the tank be completely empty?

A. 10 hours 10 min
B. 9 hours 8 min
C. 8 hours 2 min
D. 5 hours

Answer: C.


3. Correctly match the Oxygen cylinder conversion factor to correct tank size.

A. D tank = 3.14,  E tank = 0.28, G tank = 2.41, H tank =  0.16
B. D tank = 0.16,  E tank = 0.28, G tank = 2.41, H tank = 3.14
C. D tank = 0.28, E tank = 0.16, G tank = 3.14, H tank = 2.41
D. D tank = 0.16, E tank = 2.41, G tank = 0.28, H tank = 3.14

Answer: B.


4. A patient states his E tank cylinder only lasted 1 hour at a flow rate of 2LPM. What psi of oxygen was in his tank?

A. 1000 psi
B. 378 psi
C. 429 psi
D. 1240 psi

Answer: C.



Liquid Oxygen Duration Test Question:

  • Duration: Oxygen remaining in liquid O2 cylinder in min
  • Capacity: Liquid O2 in cylinder in L
  • Factor to convert liquid to gaseous O2
  • Reading on cylinder (example 0.33)
  • Flow: O2 flow rate L/min

6. The liquid capacity of a home liquid oxygen system is 40 Litres. The home care patient uses the system for 8 hours during sleep at a flow of 3 L/min. How many days with the home oxygen system last?

A. 24 days
B. 29 days 
C. 42 days 
D. 12 days

Answer: A.


7. If the capacity of a liquid oxygen cylinder in 4.0 L and the reading on the gauge is ⅓ full. How long with the liquid oxygen last if the flow is at 2 L/min.

A. 567 min
B. 766 min
C. 340 min
D. 102 min

Answer: A.