Nitrox Diving

I've been reading about Nitrox diving and so far I can't come up with a single reason to use just plain oxygen anymore. Well other than cost. Since the cost is only a bit more than the regular air, even that doesn't detract from the benefits. Of course there are benefits and disadvantages to using enriched air, however, if you are planning to do repeated dives or shallow depth dives, it's a good idea to invest in an enriched air tank.

The term Nitrox is used when describing the mixture of oxygen and nitrogen gases. The air we breathe is a mixture of mainly nitrogen and oxygen. When speaking of Nitrox for diving, the mixture used is called hyper-oxic, which means it contains more than 21% oxygen. It has other names you may be more familiar with like enriched air or the brand named SafeAir (22-50% oxygen). By comparison, the air we breathe is about 21% oxygen and 78% nitrogen. Divers like to use a nitrox mix with less nitrogen so it doesn't settle into the tissues when diving for longer periods.

Scuba divers must stop at a shallow point in the water before emerging to make sure the gases which have accumulated in the body have dissipated. If they do not make these “decompression stops” they may suffer decompression sickness (commonly known as “the bends”). This sickness can be fatal.

When purchasing the air for diving, a diver creates specific tables, using a  dive computer, so they can plan for the amount of gas needed and how many decompression stops they will need to make during the entire dive. Sometimes a diver only needs 1 stop, but dives in deeper water requires more gas and, since the pressure of water changes and more gas is used, will require more stops. Because of the dangerous outcome of having decompression sickness, many divers may even take an extra stop for safety reasons. During longer dives, some divers use buoys to mark where decompression stops take place. Longer dives also require divers to go ascend slowly from the depths, or this is also a risk of decompression sickness.

Using higher levels of oxygen, and less nitrogen, allows a diver to make shorter stops, and fewer stops. Avoiding the nitrogen accumulation in the body, will make a diver have a safer and easier dive. Divers use Nitrox mix at the greater depths. Using the too oxygen rich air can cause oxygen toxicity.

Oxygen toxicity can have a variety of affects on the body, depending on the amount of oxygen concentration. Divers can get disoriented, have problems breathing, and their vision can become blurry. Severe cases can be even more harmful and symptoms can include seizures.

Nitrox diving equipment is not necessarily safer than air, but it is safe, contrary to some opinions. Generally accidents that occur with Nitrox diving are blending of gases or human error when preparing the tanks. Because it is so safe and allows for easier dives, recreational Nitrox diving is being used more than traditional oxygen on shorter dives.

Nitrox diving lets divers do fewer decompression stops. The decompression stops which are made have also have less of a chance to cause oxygen poisoning. This makes for easier and faster dives.

Also Nitrox diving mixtures are especially good for divers doing continuous dives. A study showed that many cases of the “bends” were as a result of these continuous dives, as the nitrogen and oxygen build up in the system over a period of time. Using enriched air greatly reduced the risk, as the divers had more beneficial decompression stops. For a professional or beginner diver, having a smaller chance of getting decompression illness is extremely beneficial, as they are at the greatest risks because of repetitive dives.

There are risks of fire and of course the specialized equipment needs to have no grease. Human error can cause mistakes in the content of O₂. Mistakes in the numbers regarding the decompression stops and air needed for specific depths can cause serious health risks. Additionally if a mistake is made with the mixture needed for specific depths, a diver can risk drowning because of a convulsion caused by O₂ toxicity.

In the end it is important to remember that nitrox diving, while safe, is not much safer than regular air. It's safety is dependent upon human infallibility. It is best used in situations where divers are doing repeated dives over an extended period of time, or daily. As in dive vacations, where people may do up to 5-6 dives a day for a 5 day period.

Heavy enriched air, Nitrox diving, is also safest when used at relatively shallow depths, and not safe at all at extreme depths. While there are minimal risks, associated with nitrox diving, there are also benefits of lower decompression stops and allowing for longer and more productive dive periods.