Oxygen Cylinder Duration Calculator
D Cylinder (0.16)
E Cylinder (0.28)
M Cylinder (1.56)
G Cylinder (2.41)
H/K Cylinder (3.14)
Estimated Duration
How to Use the Oxygen Tank Duration Calculator
Calculating how long an oxygen tank will last is critical for patient safety and transport planning. This calculator uses the standard medical formula to determine the remaining time in a pressurized cylinder before it reaches a safe "empty" level (the residual pressure).
The Calculation Formula
To find the duration of flow, we use the following physics-based formula:
Duration (Minutes) = ((Tank Pressure – Safe Residual) × Cylinder Factor) / Flow Rate
Understanding the Variables
- Tank Pressure: This is the reading from your regulator's pressure gauge (usually in PSI). A full tank is typically around 2000 PSI.
- Safe Residual: It is standard practice to never run a tank to zero. Most medical professionals use 200 PSI as the safety buffer.
- Cylinder Factor: This constant varies by the physical size of the tank. Common factors include:
- D Tank: 0.16
- E Tank: 0.28 (The most common portable size)
- H/K Tank: 3.14 (Large stationary tanks)
- Flow Rate: The amount of oxygen being delivered to the patient in Liters Per Minute (LPM).
Practical Example
If you have an E-Cylinder at 1500 PSI, a safe residual limit of 200 PSI, and the patient is on 2 Liters Per Minute:
- Subtract residual from current pressure: 1500 – 200 = 1300 PSI.
- Multiply by the E-cylinder factor: 1300 × 0.28 = 364.
- Divide by flow rate: 364 / 2 = 182 Minutes.
- Result: Approximately 3 hours and 2 minutes.
Disclaimer: This calculator is for educational purposes only. Always monitor tank gauges manually and ensure a secondary oxygen source is available during transport.