Oxygen tank math. How long does a tank last? If you have a six hour transport and the patient is on oxygen how many cylinders will you need for the transport?

Basic Info Needed

D cylinder contains 350 liters of oxygen
E cylinder contains 625 liters of oxygen
M cylinder contains 3,000 liters of oxygen

Safe residual pressure is 200 psi. (Curriculum absolute - a medical director can change)

To use the math formula each cylinder size has its own CONSTANT.

D cylinder is 0.16
E cylinder is 0.28
M cylinder is 1.56

Formula

(PSI in tank - safe residual pressure)  x  CONSTANT
Flow rate in LPM

Math Problems Worked

Example A) You are to run a non-rebreather mask at 12 LPM.  Your D cylinder has 1600 psi remaining.  How long will the tank last?

So take 1600 minus 200 multiply by 0.16 then divide number by 12.  The answer is in minutes.  18.6 minutes is the answer.

Example B) You are to run a non-rebreather mask at 10 LPM.  Your M cylinder has 1800 psi remaining.  How long will the tank last?

So take 1800 minus 200 multiply by 1.56 then divide number by 10.  The answer is 249.6 minutes or 4 hrs and 15 minutes.

Work the Following Problems

1) E cylinder tank with 900 psi remaining.  Nasal cannula at 3 LPM.  How long will it last?

2) M cylinder tank with 2000 psi remaining.  Simple face mask at 8 LPM.  How long will it last?

3) D cylinder tank with 2000 psi remaining.  Non-rebreather mask at 15 LPM.  How long will it last?

4) D cylinder tank with 1200 psi remaining.  Nasal cannula at 2 LPM.  How long will it last?

5) D cylinder tank with 1000 psi remaining.  Non-rebreather at 10 LPM.  How long will it last?