The gross weight of a fully charged CO2 bottle in a fixed CO2 system is 220 lbs. When the bottle is empty it weighs 120 lbs. What is the minimum acceptable gross weight of the CO2 bottle before it should be recharged by the manufacturer?

Correct Answer: Option C — 210 lbs

USCG regulations (46 CFR) require fixed CO2 cylinders to be recharged or replaced if their net weight drops below 90% of the stamped fully charged weight. For a 100 lb net capacity (220 gross minus 120 tare), 10% loss equals 10 lbs, making 210 lbs the minimum acceptable gross weight.