Buzz
Submarine crew members aboard an attack submarine perform a drill while docked at a navy base in Niteroi, Brazil, on May 27, 2014. YASUYOSHI CHIBA/AFP via Getty ImagesImportant Points
- Inside submarines, oxygen is replenished, carbon dioxide is removed, and exhaled moisture is filtered to maintain breathable air.
- Oxygen is provided from pressurized tanks, oxygen generators, or canisters, with levels controlled by computerized systems or periodic releases.
- Carbon dioxide is chemically extracted using substances like soda lime, while moisture is managed by dehumidifiers or chemical processes to avoid condensation inside the vessel.
The air we inhale consists of notable amounts of four gases:
- Nitrogen (78 percent)
- Oxygen (21 percent)
- Argon (0.94 percent)
- Carbon dioxide (0.04 percent)
As we inhale air, our bodies use the oxygen and transform it into carbon dioxide. The air we exhale contains roughly 4.5 percent carbon dioxide. Our bodies do not process nitrogen or argon.
A submarine (or even a spaceship) is a sealed environment holding people and a finite supply of air. To maintain breathable air in a submarine, three essential tasks must be carried out:
- Oxygen needs to be replenished as it is consumed. If the oxygen level in the air becomes too low, suffocation occurs.
- Carbon dioxide must be removed from the air. As carbon dioxide concentrations increase, it becomes a dangerous gas.
- Moisture from our exhaled breath must be eliminated.
Oxygen is provided through pressurized tanks, an oxygen generator (which produces oxygen by electrolysis of water or other methods), or an "oxygen canister" (you may recall these canisters due to issues on the MIR space station -- they generate oxygen through a very hot chemical reaction). Oxygen is either released continuously by a computerized system that monitors the oxygen levels or periodically in batches throughout the day.
Carbon dioxide is chemically removed from the air using soda lime (a combination of sodium hydroxide and calcium hydroxide). The carbon dioxide is trapped in the soda lime through a chemical reaction and eliminated from the air. Other similar chemical reactions can achieve the same effect.
Moisture is extracted either by a dehumidifier or through chemical processes. This prevents moisture from condensing on the walls and equipment inside the vessel.
