Calculating Oxygen Cylinder Duration
Planning Oxygen Usage
Determining How Long Your Oxygen Cylinder Will Last
Using the Cylinder Duration Formula
Estimating Oxygen Supply Time
- Step 1: Cylinder Pressure
- Locate the cylinder pressure (psi).
- Subtract a residual pressure of 200 psi to account for errors.
- Step 2: Cylinder Constant
- Refer to the cylinder constant values:
- "D" cylinder: Constant = 0.16
- "E" size: Constant = 0.28
- "M" size: Constant = 1.56
- "G" size: Constant = 2.41
- "H" and "K" size: Constant = 3.14
- Choose the constant based on your cylinder size.
- Step 3: Flow Rate
- Determine the flow rate in litres per minute.
- Typically, regulators provide a maximum of 15 litres per minute.
- Specialist applications may have higher flow rates (e.g., scuba diving, 25 litres per minute).
- Adjust the flow rate as needed (e.g., 6 litres per minute for a nasal cannula).
- Step 4: Calculate Duration
- Use the formula: (Tank pressure - Residual pressure) x Cylinder constant / Flow rate
- Calculate the time in minutes that the cylinder will last.
Example Calculation
Estimating Duration for a "D" Cylinder at 15 Litres Per Minute
- Step 1: (2000 psi - 200 psi) = 1800 psi
- Step 2: Cylinder Constant for "D" size = 0.16
- Step 3: Flow rate = 15 litres per minute
- Step 4: (1800 psi x 0.16) / 15 litres per minute = 19.2 minutes
- Estimated Duration: Approximately 19 minutes (rounded down)
Use this formula to calculate the duration of your oxygen cylinder based on your specific parameters.