Which cylinder has about 7,000 liters of capacity?

• A. D cylinder
• B. M cylinder
• C. H cylinder
• D. E cylinder

Answer: (C)

The amount of gas a cylinder can hold is linked to its size—the bigger the cylinder, the more liters it stores. Among common medical oxygen cylinders, the largest typically used is the H size, which is designed to hold about 6,900 to 7,000 liters of oxygen when full. The other sizes store noticeably less: D and E cylinders are only a few hundred to under 700 liters, and the M size is around 3,000 liters. So, when you see “about 7,000 liters,” that points to the large H cylinder. This matters for planning how long oxygen will last at a given flow rate; for example, at 2 L/min, the H cylinder would last on the order of 58 hours, whereas the smaller cylinders would run out much sooner.