What is the expansion rate of propane per pound?

• A. 8.5 ft^3/lbs
• B. 4.2 ft^3/lbs
• C. 12 ft^3/lbs
• D. 6.7 ft^3/lbs

Answer: (D)

The main idea is expansion factor: how much gas volume you get from a given amount of liquid propane when it turns into gas at normal operating conditions. For propane, the standard expansion value used in this context is about 6.7 cubic feet of gas per pound of propane. That means one pound of liquid propane will yield roughly 6.7 ft³ of gaseous propane under the reference conditions used in practice. This conversion is handy for sizing equipment and comparing fuel supply to gas demand—so if you have, say, 10 pounds, you’d expect around 67 ft³ of gas. Real-world conditions (temperature, pressure, how completely it vaporizes) can shift the exact amount, but 6.7 ft³ per pound is the commonly used reference.