| Today's scuba divers are lucky that technological | | | | Upon inhalation, you take in 21% oxygen in the air. |
| advances have given them breathing equipment | | | | While exhaling, you give out air that is roughly 18% |
| designed to facilitate a safe and healthy scuba diving | | | | oxygen and 3% carbon dioxide. Carbon dioxide may |
| experience. About a century ago, scuba divers had to | | | | not be as toxic as carbon monoxide, but if the |
| breathe underwater using long tubes or sacks of air | | | | concentration of carbon dioxide increases, it will |
| or such other methods. As you can imagine, there | | | | affect the levels of oxygen intake ultimately leading |
| were problems and perils associated with such | | | | to oxygen starvation. |
| devices compared to the pressurized tanks and valve | | | | Disorientation, light-headedness and in the extreme |
| regulators that modern divers use. | | | | situation, even death can be a result of oxygen |
| For every 10 m (33 feet) deep that you dive, the | | | | starvation. Regulator/tank systems release the |
| pressure increases by 14.7 lbs. Obviously your chest | | | | exhaled gas into the water, solving this problem. |
| and lung muscles have to work overtime to | | | | Underwater breathing is largely through the mouth as |
| counteract this and your lung air is compressed. If | | | | nose breathing would open the mask to water and |
| you were to breathe free surface air which has a | | | | fog the glass. The same mouthpiece and hose is |
| steady pressure of 1 atmosphere (14.7 lbs), you | | | | used for inhalation as well as exhalation. The |
| would find it difficult to counteract the outside | | | | equipment uses some ingenious engineering to expel |
| pressure. Thus, you need pressurized air when you | | | | the exhaled carbon dioxide to the surroundings. |
| are underwater. | | | | The open circuit 2-stage scuba diving regulators used |
| Remember that the gases inside the body get slightly | | | | in today's breathing equipment deliver air to the diver |
| compressed as you dive deeper. Seal level air | | | | matching the surrounding pressure. Emile Gagnan and |
| comprises about 78% nitrogen and 21% oxygen with | | | | Jacques Cousteau originally developed this Aqua-lung |
| traces of other gases. This ratio is inadequate | | | | design using one-stage scuba diving regulators. The |
| underwater where your oxygen requirement is | | | | air pressure in the tank is about 200 atm. The |
| greater in order to balance the outside pressure. | | | | 2-stage design allows you to reduce the air pressure |
| Modern equipment is designed to provide the right | | | | to around 10 atm using the first stage regulator. In |
| gas ratios and pressures required by divers at various | | | | stage two, the regulator matches the air pressure to |
| depths. | | | | the ambient pressure, delivering the optimal pressure |
| The other problem is to do with the diving masks | | | | to the lungs of the diver. |
| used by most recreational scuba divers. These masks | | | | Modern breathing equipment provides healthy, safe, |
| force the diver to wrap his moth around the | | | | pressure regulated air to modern scuba divers. This is |
| mouthpiece of the regulator and breathe mostly | | | | a result of the years of effort and ingenuity shown |
| through their as the nose and eyes are enclosed. | | | | by scuba gear designers over the last century. |