Nitrox Diving
“Enriched air” sounds fancy and a little scary if you’ve never used it before, but what is it actually? And why might people want to use it? Nitrox refers to the blends of gasses which make up the air in scuba diving tanks. Traditional scuba diving tanks have compressed air made up of 79% nitrogen and 21% oxygen, mimicking the kind of air we breathe in every day. Enriched air on the other hand, refers to any mixture of gasses in a scuba tank with a higher than 21% oxygen. Different blends of these gasses make up the various ‘Nitrox blends’ which can be used in scuba diving. While enriched air may seem relatively new, this composition of gasses has been used in scuba diving back in the late 1970s. Like anything being absorbed by the body, it’s natural to be sceptical, however enriched air can be a useful tool for any diver with the right training.
If you scuba dive, you’re probably already familiar with decompression. At the end of the dive, its normal to make a safety stop as you ascend in order to let the nitrogen be released from your body, preventing decompression sickness. By having more oxygen and less nitrogen in a scuba tank, a person can extend their decompression limits and dive time because less nitrogen is absorbed into the body as you breathe in the enriched air. This means that there’s an overall lower risk of decompression sickness.
As you absorb less nitrogen at lower depths than you would otherwise using a traditional nitrox blend, you can stay underwater for longer than on a normal dive. This is especially useful for divers who may dive more than once per day which is common if you’re on a live-aboard. Although it has not been proven some divers have also reported feeling less tired post-dive when using enriched air.
While this amazing, enriched air has a few but very little disadvantages. One of these disadvantages is the depth limit that we have when using nitrox. The deeper you the the oxygen becomes toxic which is known as Oxygen Toxicity with symptoms including seizures, visual distortions, nausea and dizziness all of which you do not want to experience underwater. While this is a rare experience, it is important to have the proper training to calculate and familiarise yourself with the depths it is safe to dive at for the specific blend of nitrox you’re using, and to monitor it consistently throughout your dive. The more oxygen you have, the shallower your limit will be.
If you want to use enriched air when diving, PADI offers a specialised course for familiarising yourself with using it. The course covers how to analyse a tank, fill out an enriched air log and set your dive computer for nitrox dives. Before you dive with enriched air, you need to use an analyser to determine the blend of air in a tank and use this information to plan your dive time and depth. It is also important that the tank you’re using is marked with your name and date verifying that you have analysed your tank. Having a dive computer is also highly recommended equipment, so that your dive plan calculations for Nitrox are made easier.
Nitrox or enriched air is a great tool for diving, if it’s used responsibly. Using enriched air can extend your no decompression times, and help you achieve a more enjoyable diving experience.