What is Nitrox?


This brief information does not replace a Nitrox course and is for general information only.

The word nitrox is an artificial word consisting of the words nitrogen and oxygen, also known as EAN (Enriched Air).
It refers to a gas mixture consisting of nitrogen (N2) and oxygen (O2). Strictly speaking, our normal breathing air is a nitrox mixture.

Which roughly consists of 21% oxygen, 79% nitrogen and 1% other gases.

In diving, the term nitrox is used primarily in connection with the artificial alteration of the ratio between N2 and O2. The proportion of nitrogen (N2) is reduced and more oxygen (O2) is replenished.
The most common nitrox mixtures are usually EAN32 and EAN36. The number stands for the percentage of oxygen in the breathing gas.

normale Luft EAN32 EAN36
  • O2

  • noble gases

  • N2

  • O2

  • noble gases

  • N2

  • O2

  • noble gases

  • N2

Why less N2:

The law of Henry knows everyone who has already beheaded a champagne bottle or just opened a bottle of sparkling water.

In the core statement it means:
The amount of a gas above a liquid is equal to the amount of dissolved gas in a liquid.
And if not, physics makes sure it is only a question of pressure, time, solubility and temperature.

Less nitrogen (N2) in our breathing gas means less saturation with N2 during our dives.

Means when diving:

When we dive down the pressure on our body rises so that according to Henry an unbalanced relationship between the pressure around us and the pressure in our body arises and thus also the saturation of our breathing gases.
In the so-called compression phase our body saturates nitrogen, while oxygen is processed by our body and can be exhaled again. At first, strongly perfused tissue such as the central nervous system and muscles are saturated.

As we ascend, we reduce the ambient pressure again so that the nitrogen can escape again.
It is important that we do not emerge too quickly, as the body cannot immediately break down all the saturated nitrogen via the lungs or breathe it off again. This is the reason why every dive should end with a so-called safety stop.

The maximum time at which depth we can stay and for how long, so that the standardized safety stop is still sufficient, can be read on the so-called decompression tables. This time is called no decompression time. This is a time limit in which we can emerge safely while observing the safety stops.

If we exceed this so-called no-stop time, extra stops must be observed and/or additional cylinders with corresponding decopression gases must be carried along. This is forbidden as a recreational diver and at the latest from here the area of technical diving begins.

If we do not adhere to these decostops and safety stops, the so-called diver’s disease or decompression sickness can occur.

In this case, the nitrogen escapes from our body too quickly and so-called microbubbles form in our blood. If the proportion of microbubbles becomes too large, it can not diffuse sufficiently from the avioles (be breathed) and these are pumped further into the bloodstream and thus enter the arterial circulatory system of our body.

The less nitrogen (N2) there is in our breathing gas (diving bottle), the less we can saturate.

Advantages of Nitrox:

  • You can stay much longer at certain depths and explore the underwater world.
  • They absorb significantly less nitrogen during your dive, which in turn helps reduce the formation of microbubbles.
  • And finally you will feel a much fitter feeling after the dive.

The disadvantages of Nitrox:

  • So the gas mixture of your tank has to be checked and analysed before each dive so that you know and respect the maximum allowed depth to the gas mixture. To do this, you must enter your measured value and depth in a list and sign it.
  • Since oxygen has a toxic effect on our body from a certain pressure on, Nitrox diving has to be paid attention to the diving depth. With a Nitrox mixture with 32% O2, i.e. EAN32, it ends at 33 meters and with an EAN36 mixture at 30 meters. If these maximum depths are exceeded, there is a risk of oxygen poisoning.

No decompression time Displacement of our ambient air with 21% O2 compared to EAN32 and EAN36

  • Umgebungsluft

  • EAN32

  • EAN36

↑ Minutes / → Depth in meters

This table serves as a rough overview of the no decompression time shifts with Nitrox and is in no case intended and approved for use in practice.

The Nitrox course can be taken together with the OWD.