Oxygen Tank Duration
Gauge pressure × cylinder factor ÷ flow — how many minutes are really in the tank before you leave the unit.
Written by Apex Respiratory Editorial Team
Set 0 for the theoretical max.
Enter gauge pressure and flow to calculate duration.
Transport math that keeps you honest
Cylinder factors convert gauge pressure to liters of gas: D 0.16 · E 0.28 · G 2.41 · H/K 3.14 · M 1.56 L/psig. A full E cylinder (~2000 psig) at 10 L/min holds under an hour — plan the elevator waits, imaging delays, and the return trip.
The safe-residual field (default 200 psig) reflects the common practice of never planning to empty a tank: regulators read imprecisely near zero and flow becomes unreliable.
Educational use only. Calculated duration is theoretical — verify gauge and flow at the bedside and leave a margin. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
Sources
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Medical gas therapy chapter (cylinder duration factors).
- American Association for Respiratory Care. AARC Clinical Practice Guideline: Oxygen therapy for adults in the acute care facility — 2002 revision & update. Respir Care. 2002;47(6):717-720.