Which cylinder has an approximate capacity of about 350 liters?

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

Answer: (B)

In EMS oxygen cylinders, capacity is given in liters of oxygen at standard conditions, which helps estimate how long a cylinder will last at a given flow. The D-size cylinder stores about 350 liters, making it the cylinder with roughly 350 L of O2 when full. The E-size holds more around 680 liters, and the larger M and G sizes hold significantly more, so 350 liters specifically points to the D size. To see how long it lasts, divide the cylinder’s capacity by the flow rate. For example, at 15 L/min, a 350 L cylinder would run for about 23 minutes (350 ÷ 15 ≈ 23).