Nitrox is not new: its origins date back a century, specifically to the time of the First World War, where it was used for military purposes. However, Nitrox did not enter the recreational diving community until the early 90s, and its use is widespread today.
Here you can find some enriched air diving courses.
Although you most likely know it or have heard of it, you may not be clear what Nitrox is or what its usefulness is. Below I will try to explain in the simplest way possible the most important aspects to take into account about it.
Nitrox is what any mixture composed of nitrogen-oxygen gases is called. Thus, air is a normoxic nitrox mixture that is composed of 21% oxygen and 79% nitrogen. There are also nitrox mixtures that have more or less oxygen than air, called hyperoxic and hypoxic nitrox mixtures respectively.
Thus, although the term "nitrox" is commonly used in recreational diving to refer to "nitrox enriched air" or "hyperoxic nitrox", it must be clear that, although all enriched air is nitrox, not all nitrox is enriched air.
Each of the nitrox mixtures has its own advantages, so the use of one or the other will depend on some factors.
Type of diving we are going to do:
Hypoxic nitrox has advantages in terms of depth; For this reason, it is widely used in medium-high depth diving. This is because, as it is a mixture depleted in oxygen, the maximum PPO2 (Partial Pressure of Oxygen) will be reached at greater depth.
In other words: at the same depth, there would be less chance of oxygen toxicity with hypoxic nitrox than with air, this mixture is not widespread in recreational diving, but it is in technical diving, nitrox Hypoxic together with Helium form the mixture called Hypoxic Trimix.
In contrast, hyperoxic nitrox, known in recreational diving by the word EANx (Enriched Air Nitrox), presents some advantages with respect to immersion time. To the Being a mixture with less nitrogen content than air, reduces the diver's exposure to nitrogen, so, in the same immersion profile, their tissues will take longer to saturate and, therefore, the LND (Limit of NO Decompression) takes longer to arrive.
This is very good for successive dives or for desaturation times on the surface, since as we have less nitrogen inside, we will be able to do more dives for a longer time if we compare them to doing them with air. The counterpart of this mixture is that being richer in oxygen, PPO2 occurs at a lower depth and limits us in depth.
Within a hyperoxic nitrox gas mixture, the percentage of oxygen can vary. Due to this, the EANx nomenclature is always accompanied by a number, which indicates the percentage of oxygen that makes up that mixture. For example, EANx32 means nitrox enriched air composed of 32% oxygen and 68% nitrogen.
All certifiers have specific courses for the use of different gases and combinations. The importance of good training before using these gases is vital for the diver, so much so that no diving center will allow any diver to dive with mixtures if they have not had the necessary and demonstrated training.
If you have any questions about how to train in mixed gas diving, consult your Diving Instructor: he will know how to advise and guide you.
