Oxygen Tank Duration Calculator > Chart

Oxygen Tank Duration Calculator

The oxygen tank duration calculator takes into account the volume of oxygen in the tank (often measured in liters) and the prescribed flow rate (usually in liters per minute) to determine the duration of use.

Consider a patient with chronic obstructive pulmonary disease (COPD) who uses a portable oxygen tank for daily activities. Their doctor has prescribed a flow rate of 2 liters per minute.

They have an E-cylinder oxygen tank, which typically holds about 680 liters of oxygen when full.

Duration = Tank Volume / Flow Rate
Duration = 680 liters / 2 liters per minute = 340 minutes (or about 5 hours and 40 minutes)

Oxygen Tank Duration Chart

Tank Size	Capacity (Liters)	Flow Rate (L/min)	Duration (Hours)
M6 (B)	164	1	2.73
		2	1.37
		3	0.91
M9 (C)	248	1	4.13
		2	2.07
		3	1.38
D	415	1	6.92
		2	3.46
		3	2.31
E	682	1	11.37
		2	5.68
		3	3.79
M60	1,699	1	28.32
		2	14.16
		3	9.44
M90	2,549	1	42.48
		2	21.24
		3	14.16

Oxygen Tank Duration Times and Oxygen Tank Size Chart

Tank Size	Capacity (L)	Duration at Different Flow Rates (hours)
		1 L/min	2 L/min	3 L/min	4 L/min	5 L/min
M2 (A)	57	0.95	0.48	0.32	0.24	0.19
M4 (B)	113	1.88	0.94	0.63	0.47	0.38
M6 (C)	170	2.83	1.42	0.94	0.71	0.57
M9 (D)	255	4.25	2.13	1.42	1.06	0.85
E	680	11.33	5.67	3.78	2.83	2.27
M24	679	11.32	5.66	3.77	2.83	2.26
M60	1,699	28.32	14.16	9.44	7.08	5.66
H	6,800	113.33	56.67	37.78	28.33	22.67

Oxygen Tank Duration Formula

The Oxygen Tank Duration Calculation Formula is:

Duration (hours) = (Tank Capacity in Liters) / (Flow Rate in Liters per Minute) / 60

To calculate the duration for an E-cylinder oxygen tank (capacity 682 liters) at a flow rate of 2 liters per minute:

Duration = 682 / 2 / 60 = 5.68 hours

This means the E-cylinder will last approximately 5 hours and 41 minutes at a flow rate of 2 liters per minute.

How to determine how long an oxygen tank will last?

Identify the tank size and capacity: Each oxygen tank size has a specific capacity measured in liters. For example, an E-cylinder typically holds about 680 liters of oxygen when full.
Check the tank’s pressure: A full tank will have a pressure of about 2000 psi (pounds per square inch). As the tank empties, the pressure decreases.
Note the prescribed flow rate: This is the rate at which oxygen is delivered, measured in liters per minute (L/min).
Use the duration formula: Duration (hours) = (Tank Capacity in Liters) / (Flow Rate in L/min) / 60

Suppose you have an E-cylinder oxygen tank (680 liters capacity) and your doctor has prescribed a flow rate of 2 L/min.

Tank capacity: 680 liters
Flow rate: 2 L/min
Calculation: (680 liters) / (2 L/min) / 60 = 5.67 hours

Your E-cylinder oxygen tank will last approximately 5 hours and 40 minutes at a continuous flow rate of 2 L/min.

How long will a 2000 psi oxygen tank last at 12 liters per minute?

A 2000 PSI oxygen tank will last approximately 55 minutes at a flow rate of 12 liters per minute.

Convert PSI to Liters of Gas: A 2000 PSI tank typically holds about 660 liters of oxygen when full.

Calculate Usage Time

Flow Rate = 12 liters/minute
Time = Total Volume ÷ Flow Rate
Time = 660 ÷ 12
Time = 55 minutes

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