What is NItrox and what does it provide to divers?

Written by Yuliia Kliusa
10/11/2023 09:47:13 en Training | 0 comments

Lately hearing the word Nitrox is quite common among divers, especially if they are active divers or perhaps those who are preparing a diving trip. Perhaps in this article you will be able to find the answers to your questions about this mixture that has become so popular in the diving world.

What is Nitrox?

First, we should remember that the atmospheric air that we breathe normally is a mixture of gases that contains 21% Oxygen and 79% Nitrogen.

Knowing this, we can easily understand what Nitrox is, and what its difference is compared to Air.

Nitrox, also called Enriched Air NItrox (EAN), is the same mixture of gases, where the amount of oxygen exceeds 21%.

For example, EANx32 (where the number indicates the amount of oxygen) contains 32% oxygen and 68% nitrogen.

What types are most common in recreational diving?

There are 2 types that you can normally find in diving centers, they are:

1. EANx 32, which contains 32% oxygen and 68% nitrogen.

2. EANx 36, which contains 36% oxygen and 64% nitrogen.

You can also find EANx 40, which contains 40% oxygen and 60% Nitrogen, but the former are more used in recreational diving.

What does it provide to divers?

We already know that when we dive, our body accumulates an amount of nitrogen, which depends on factors such as: depth, time underwater, state of health and speed. This amount of nitrogen can change, if we change the values in our gas mixture. Exactly this is what happens in the Nitrox mixture.

By increasing the percentage of oxygen, and therefore decreasing nitrogen, divers will absorb less nitrogen during the dive and will have to eliminate a smaller amount during the ascent. Many divers also feel less tired after diving with Nitrox and show lower air consumption values, although there is no scientific answer to this.

Another use of Nitrox is that technical divers, who have been at depth (either breathing air or other mixtures) can shorten their decompression times in shallower water by switching to a mixture that contains between 50-80% of oxygen. This allows for faster removal of excess nitrogen when using air, or helium if they have breathed mixtures. In this case the diver usually carries another smaller bottle (cap bottle), with another concentration of Nitrox, adjusted with his own regulator, since he can breathe in shallow waters.

When is it recommended to use Nitrox?

It is good to use for any dive that allows you such a mixture, but normally renting the Nitrox bottle is a little more expensive than normal air, so divers who do a few dives a day and are shallow usually use normal air.

But if you do a lot of consecutive dives or plan to go deeper, as long as the mix allows, the NItrox is the best option for you!

Are there any limits when diving with Nitrox?

Yeah! Due to the risk of oxygen poisoning, depths are limited by its percentage in the Nitrox mixture: the partial pressure of oxygen should not exceed 1.4 ata. That is, the higher the percentage of oxygen, the less the maximum depth will be.

The recommended oxygen tolerance units should not be exceeded, especially on repetitive diving, as oxygen breathed at higher than normal partial pressures for long periods affects the central nervous system.

What maximum depth can I go to with Nitrox?

The depth limit depends on the amount of oxygen that we are going to have in the mixture. For this reason, we have to check the nitrox in the bottle, using an Oxygen meter that must be provided to you at the same Diving Center where you rent the bottle.

Knowing what type of Nitrox you have, you can do the calculation in the following ways:

1. Using the NItrox charts, which will give you longer decompression stop times at maximum depths.

2. 2. Dive computer, which will show you throughout the dive the time you can spend underwater without going into decompression and also the maximum depth allowed with the mixture you use. To obtain this data, it is necessary to configure the computer, entering the data of your mix.

Can I use an air regulator for Nitrox?

Yes, but with the oxygen percentage up to 40%. For higher concentrations, you should replace the washers with ones that do not require lubrication. This is because high oxygen concentrations produce combustion when coming into contact with oils and greases. Bottles and valves that come into contact with pure oxygen during mixing must be kept free of oxygen.

Is it necessary to have certification to be able to dive with Nitrox?

Yeah! Because Nitrox is a different mixture than Air, it also has different requirements and limits, which we have mentioned above and which each diver should know before using the mixture. Therefore, in order to rent the Nitrox bottle at the Diving Centers, it is mandatory to present the corresponding certification.

What does a Nitrox course cost?

This course is quite inexpensive compared to many other diving courses, and usually costs between 110-150 euros, depending on the diving center where you are going to take it. Sometimes you can find even cheaper in a package with another diving course, such as Advanced + Nitrox.