Calculate how long an oxygen tank will last based on cylinder size, current pressure, and flow rate. Plan transports and oxygen supply changes with accurate time estimates.
Full tank is typically 2000 psi
Pressure at which to switch tanks
Duration
4h 12m
Total Minutes
252 min
Total Hours
4.2 hrs
Duration accounts for a safe residual pressure of 200 psi before switching tanks.
Time Remaining
4h 12m
Usable Pressure
1800 psi
Tank Pressure
2000 psi
100% of full capacity
Flow Rate
2 L/min
Switch Tanks At
200 psi
75% remaining
11:20 PM
+63min
50% remaining
12:23 AM
+126min
25% - prepare switch
01:26 AM
+189min
Switch tanks
02:29 AM
+252min
Now
10:17 PM
2000 psi
Switch By
02:29 AM
200 psi
0.5 L/min
16h 48m
+756 min vs current
1 L/min
8h 24m
+252 min vs current
2 L/min
4h 12m
3 L/min
2h 48m
-84 min vs current
4 L/min
2h 6m
-126 min vs current
Duration calculated with 1800 psi usable pressure (tank factor: 0.28)
Knowing how long an oxygen supply will last is critical for patient safety, especially during hospital transports and emergency situations. Each cylinder size has a specific tank factor that relates its volume capacity to its pressure. By calculating the expected duration, nurses can ensure uninterrupted oxygen therapy and plan ahead for tank changes or transport needs.
Use the formula: Duration (minutes) = (Tank Pressure × Tank Factor) / Flow Rate. The tank factor depends on the cylinder size. Subtract a safe residual pressure (usually 200 psi) before calculating to ensure you switch tanks before they run empty.
Common cylinder factors are: D cylinder = 0.16, E cylinder = 0.28, G cylinder = 1.56, H/K cylinder = 3.14. The E cylinder is the most common portable tank, while H/K cylinders are the large stationary tanks used in facilities.
A safe residual pressure (typically 200 psi) ensures you switch to a new tank before the current one runs completely empty. This prevents sudden loss of oxygen supply to the patient and accounts for gauge inaccuracy at low pressures.
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