What are two ways the O2 cylinder can become depleted?

What are two ways the O2 cylinder can become depleted?

• A. Metabolic consumption
• B. Gas lost from the UBA
• C. Both metabolic consumption and gas lost
• D. None of the above

Answer: (C)

O2 depletion in a closed-circuit system happens from two sources: metabolic consumption and gas loss from the UBA loop. The body continually uses oxygen for metabolic processes, so the oxygen available in the system will decrease as you live and work. At the same time, the loop can lose oxygen due to leaks, fittings or hose failures, valve issues, or venting that lets O2 escape or be replaced by other gases. Both factors reduce the amount of O2 available to the diver, and they can occur together, making depletion a result of the combination of ongoing metabolic use and system losses. Selecting only one mechanism ignores the other, which is why the best answer is that both contribute.

O2 depletion in a closed-circuit system happens from two sources: metabolic consumption and gas loss from the UBA loop. The body continually uses oxygen for metabolic processes, so the oxygen available in the system will decrease as you live and work. At the same time, the loop can lose oxygen due to leaks, fittings or hose failures, valve issues, or venting that lets O2 escape or be replaced by other gases. Both factors reduce the amount of O2 available to the diver, and they can occur together, making depletion a result of the combination of ongoing metabolic use and system losses. Selecting only one mechanism ignores the other, which is why the best answer is that both contribute.