For patients who use supplemental oxygen, portable cylinders can be a great way to allow them freedom to move around as they please. Here we’ll review the types of oxygen cylinders, and how to determine the best size and key accessories.

What are the different sizes of Oxygen Cylinders?

Two sets of names are used to differentiate between oxygen cylinder sizes. The original set uses an alphabetical system, starting with A for the smallest size and E for the largest portable size. The new naming system begins with the letter “M,” for “medical,” followed by a number that signifies the amount of cubic feet of oxygen in that can be compressed into the cylinder. So the original B cylinder is now often referred to as an M-6 cylinder because it can hold 6 cubic feet of oxygen.

Below, see the handy chart that matches oxygen cylinder sizes with their dimensions, capacity and accessories.

Sample Oxygen Cylinder Specifications*

Older Name A B C D JD E H
Newer Name M-2 M-4 ML-6 M-6 M-7 M-9 M-15 M-22 M-24 M-60 M/MM/M122 M250
Diameter (in.) 2.5 3.2 4.3 3.2 4.3 4.3 4.3 5.3 4.3 7.3 8 9
Height (in.) 5.3 8.5 7.6 11.5 9.1 11 16.5 16.5 25.5 23 36 52
Empty Weight (lb) 0.7 1.6 2.8 2.2 3.3 3.7 5.3 8 7.9 22.3 39.5 114
Capacity (L) at 2,200 psi 42 13 165 164 198 255 425 640 680 1738 3455 7080
Transport Method Carrier Bag Carrier Bag Carrier Bag Carrier Bag Carrier Bag Carrier Bag Carrier Bag Carrier Bag Wheelchair Bag or Cart Not Portable Not Portable Not Portable
Regulator Type CGA 870 CGA 870 CGA 870 CGA 870 CGA 870 CGA 870 CGA 870 CGA 870 CGA 870 CGA 540 CGA 540 CGA 540

Illustrations by Patrick Holbrook, Sunset Healthcare Solutions

*This information is intended to be used as a guide. Dimensions and names may vary by manufacturer.

How do I know which size is best for my client?

The optimal size will depend on a client’s lifestyle and prescribed flow rate. The most common size is the M6. However, if the client is confined to a wheelchair, a larger E cylinder with a wheelchair bag may be more appropriate. Or, if he or she only leaves the house for short periods of time and weight is an issue, a smaller M4 cylinder may be better.

To determine how long an oxygen cylinder will last, there are several factors to consider: The patient’s prescribed flow rate in L/minute; the tank capacity in liters and whether they are using a regulator or a conserver. A regulator will provide continuous flow at a given flow rate. A conserver will sense when the patient is breathing and only expel oxygen when the patient is breathing in. Most conservers allow the tanks to last three to five times longer, but can be up to 10 times as expensive as regulators and are not reimbursed by insurance companies so they are not always worth the extra cost.

What accessories will my client need?

All patients should be supplied with a cylinder wrench and a “No Smoking” sign (it is recommended that patients hang a sign on all entrances to the building as well as in the room where the oxygen is being delivered).

For portable tanks, a carrier bag or cart is recommended. The most common bags range in sizes from M6 which can hold M6, M4 and M2 cylinders, up to E bags, which can be attached to a wheelchair or scooter. M6 bags often have straps to keep smaller cylinders in place. This can help reduce bag inventory by not having to stock separate bags for patients with small tanks. Many different styles are available with the most common being shoulder bags, backpacks and wheelchair bags. Bag type can be based on the patient’s preference; however, it is recommended that all bags are made of nonflammable materials.

The final accessory needed is a regulator or conserver. When selecting one, keep in mind that there are two main types of valves on oxygen cylinders. CGA 870 styles are used on tanks that are size E and smaller. CGA 540 style valves are used on larger, nonportable tanks. So you will want to select the type of regulator or conserver that matches the valve on your patient’s cylinder.

D/MI5 Cylinder

Approximate Remaining Supply Time
 
Liter Flow Per Minute
 12345
@2000 psi5 Hours2 Hours1 Hour, 15 Minutes1 HourNot recommended
@1500 psi3 Hours, 30 Minutes1 Hour, 30 Minutes50 Minutes45 MinutesNot recommended
@1000 psi2 Hours2 Hours30 Minutes20 MinutesNot recommended
@500 psi1 HourI Hour5 Minutes0Not recommended

D/MI5 Cylinder (Pediatric)

Approximate Remaining Supply Time
 
Liter Flow Per Minute
 1/161/81/41/23/4
@2000 psi3 Days1 Day, 12 Hours20 Hours9 Hours, 30 Min.6 Hours, 30 Min.
@1500 psi2 Days, 12 Hours1 Day, 6 Hours15 Hours7 Hours, 15 Min.4 Hours, 45 Min.
@1000 psi1 Day, 12 Hours18 Hours9 Hours4 Hours, 30 Min.3 Hours
@500 psi18 Hours9 Hours4 Hours2 Hours1 Hour, 15 Min.

E/M24 Cylinder

Approximate Remaining Supply Time
 
Liter Flow Per Minute
 12345
@2000 psi8 Hours4 Hours2 Hours, 30 Min.2 Hours1 Hour, 30 Min.
@1500 psi6 Hours, 30 Min.3 Hours2 Hours1 Hour, 30 Min.1 Hour
@1000 psi4 Hours2 Hours1 Hour, 15 Min.1 Hour30 Min.
@500 psi2 Hours1 Hour25 Min.15 Min.5 Min.

E/M24 Cylinder (Pediatric)

Approximate Remaining Supply Time
 
Liter Flow Per Minute
 1/161/81/41/23/4
@2000 psi6 Days3 Days1 Day, 10 Hours16 Hours11 Hours
@1500 psi4 Days, 12 Hours2 Day, 6 Hours1 Day12 Hours8 Hours, 30 Min.
@1000 psi2 Days, 20 Hours1 Day, 10 Hours17 Hours8 Hours5 Hours, 30 Min.
@500 psi1 Day, 10 Hours17 Hours8 Hours4 Hours2 Hours, 30 Min.

H/M250 Cylinder

Approximate Remaining Supply Time
 
Liter Flow Per Minute
 12345
@2000 psi4 Days, 6 Hours2 Days1 Day, 12 Hours1 Day19 Hours
@1500 psi3 Days, 3 Hours1 Day, 12 Hours1 Day17 Hours14 Hours
@1000 psi2 Days1 Day15 Hours12 Hours9 Hours
@500 psi1 Day12 Hours7 Hours6 Hours4 Hours

H/M250 Cylinder (Pediatric)

Approximate Remaining Supply Time
 
Liter Flow Per Minute
 1/161/81/41/23/4
@2000 psi68 Days34 Days17 Days8 Days, 12 Hours5 Days, 12 Hours
@1500 psi52 Days26 Days13 Days6 Days, 12 Hours4 Days, 6 Hours
@1000 psi34 Days17 Days8 Days, 12 Hours4 Days, 6 Hours2 Days, 18 Hours
@500 psi16 Days8 Days4 Days2 Days1 Day, 9 Hours
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