If a diver's surface air consumption rate is 1.72 bar per minute, what is the rate at 20 meters depth?

If a diver's surface air consumption rate is 1.72 bar per minute, what is the rate at 20 meters depth?

• A. 1.72 bar per minute
• B. 2.58 bar per minute
• C. 3.44 bar per minute
• D. 5.16 bar per minute

Answer: (D)

Gas consumption rises with depth because you breathe gas under higher ambient pressure. At 20 meters, the pressure is about three atmospheres (1 atm at the surface plus 2 more from the water). Since you’re drawing gas from the tank at that higher pressure, the amount used each minute scales by the same factor. Multiply the surface rate by 3: 1.72 bar/min × 3 ≈ 5.16 bar/min. So, at 20 meters, the rate is about 5.16 bar per minute (assuming similar exertion and gas mix).

Gas consumption rises with depth because you breathe gas under higher ambient pressure. At 20 meters, the pressure is about three atmospheres (1 atm at the surface plus 2 more from the water). Since you’re drawing gas from the tank at that higher pressure, the amount used each minute scales by the same factor. Multiply the surface rate by 3: 1.72 bar/min × 3 ≈ 5.16 bar/min. So, at 20 meters, the rate is about 5.16 bar per minute (assuming similar exertion and gas mix).