One of the most common things on top of dive boats is the green and yellow nitrox tanks. It is nothing new and nitrox tanks have been around for tens of years.
In fact, if you were to enroll in a scuba diving with nitrox class, you will definitely learn to handle the nitrox which is simply oxygen-enriched air. But there is a concern as to whether nitrox is actually safe to use.
Many people believe that nitrox is just like any other scuba gear package which is safe to use when used properly but turns dangerous when used the wrong way.
Let’s find out more!
What is nitrox?
Nitrox as we saw is air rich in oxygen. Nitrogen is mixed with a higher amount of oxygen that surpasses the air in our atmosphere. This simply means that it is above 21%. Often the quantity of oxygen in nitrox is at 32%.
This higher oxygen concentration has its benefits of course. Divers are less likely to develop decompression sickness, as well as shortening service intervals.
How does nitrox work?
Every diver is aware of the fact that when you go down into the water, the weight of the water surrounding your body or the water pressure causes your body to absorb the nitrogen from the air you breathe. It is therefore essential to learn the 3 scuba diving breathing techniques for beginners.
The deeper you get then the more the pressure and thus the more the body will absorb the nitrogen. When this nitrogen gets to a certain level, you will be forced to gradually rise again in stages. This allows you to prevent decompression sickness.
To put this further into perspective, according to the dive tables of the US Navy, when a diver goes down to 100 feet, he only has 25 minutes at that depth before he can come back up again. If the diver is at 60 feet, he has a time limit of one hour before he rises to the top again. This is when the diver is in the air.
However, the numbers are different when scuba diving with nitrox. Since the quantity of nitrogen is less, the air will not dissolve into the body as much. This allows divers to stay under for significantly longer. In fact, the same nitrogen will dissolve in the bloodstream at 105 feet when the diver is using nitrox as is with a diver using air at 80 feet.
The diver can stay down at that depth for an extra 20 minutes which is double the time.
The dangers of nitrox
Nitrox has some dangers. There is a risk associated with breathing high levels of oxygen and can result in oxygen toxicity. This oxygen poisoning comes with some highly unpleasant effects such as convulsions, visual distortions as well as drowning.
In fact, when the pressure increases, even normal concentrations of oxygen can turn toxic. However, for oxygen toxicity to occur when using normal air, a diver would need to go to depths of 220 feet.
Nitrox however brings the dangers of oxygen toxicity to within diving range. If you are diver using nitrox, then there are two main things that you will need to note.
The first thing is the amount of pressure of the oxygen to the lungs and the second is the oxygen exposure limit. These two factors are collectively known as the oxygen limit.
To calculate the oxygen limit, you will need to consider the partial pressures. To do this you will need to take the tank’s oxygen pressure and multiply it by the atmospheric pressure at the depth you plan to go down to.
As an example, think of a diver using air that is 21 percent oxygen and goes down to 132 feet which is at 5 atm of pressure, and is taking in oxygen at a partial pressure of 1.05. This is the same as breathing oxygen at the surface at 105%.
Most technical divers will not exceed a partial pressure of oxygen beyond 1.6. This is done for short durations which often no more than 45 minutes. In fact, most training agencies only allow two dives in half a day and that will be only an hour-long at a partial pressure of 1.4.
A good dive compass will help you navigate and find your way when in the deep blue where there are no landmarks to rely on.
Staying down for longer
Nitrox is best used for dives of between 50 and 100 feet. This is because decompression times take longer at shallower depths of under 50 feet. Divers will empty their tanks faster than their dive time allows.
A good dive watch can help you keep track of time when in the deep blue. If you are diving in the dark, then underwater dive lights will come in handy as well.
The buffer zone
Plenty of nitrox divers choose to use air tables when scuba diving with nitrox. This is especially so with divers who have had previous cases of decompression sickness, are older, or have physical injuries. This helps to add a buffer zone to the compression limits.
This allows divers who are using nitrox at 36% oxygen to get down to 60 feet and stay down for 60 minutes. While this doesn’t mean that the diver is completely safe, it does play by the rule that the further you are from reaching your compression limit, the less likely you are going to get the bends.
Achieving the right mix
Nitrox at 32% oxygen helps to make life much easier for divers. All you will need to do when you get to a dive shop is choose a tank and then adjust your dive schedule accordingly. But 32% is not the only mix that you can get.
If you require, the dive shop can provide you with nitrox that has up to 40% oxygen. This however is the recreational limit allowed.
The type of equipment
If you are wondering whether the normal standard scuba diving equipment can hold oxygen concentrations of over 40%, then you will be pleased to know that they can. This is according to the US Navy a well as the National Oceanic and Atmospheric Association.
While many people may think otherwise, oxygen will not actually burn but instead increases the ability to surround objects to catch fire. The more the oxygen concentration, the more the fire will burn and the hotter the flame.
Other dangers of nitrox
Other than the dangers of oxygen toxicity, there are some other limitations of using nitrox.
1. There is a need for special gear
Even while nitrogen can be contained in the standard equipment, you will still need extra gear to monitor the mixture of nitrogen ad oxygen. One of these is an oxygen analyzer. The good thing is that the majority of dive shops that stock nitrox allows the user to use their own oxygen analyzer.
If you are going to regularly use nitrox then you will need to purchase your own oxygen analyzer.
In certain dive sites around the world, users will need to have dedicated nitrox tanks that come with the proper decorations. It is also recommended to carry dive computers that are to be used together with the nitrox tanks.
For recreational divers that use a mixture with 40% oxygen, it is still possible to use the normal dive regulators. However, if you are a technical diver and plan to use higher oxygen concentrations, then you will need to take the right precautions.
2. Risk of explosion
Oxygen is a catalyst for explosions and since nitrox is manipulated oxygen concentrations, then there is a high need to take the required precautions to minimize the risk of explosions.
When making nitrox, pure oxygen is used. The mixture is then put into the scuba tanks. Any object and equipment that is involved should be oxygen clean. This normally entails the use of lubricants and other chemicals that prevent the occurrence of explosions.
3. It is expensive
To develop nitrox, certain equipment needs to be purchased and certain procedures followed. What’s more, you will need pure oxygen and this is very expensive. This is why diving with nitrox is costlier than using air.
4. It is not very simplest to obtain
Recreational divers are turning to nitrox thanks to its benefits. However, you are still not going to find nitrox at all dive shops. Even if you were to enroll in an enriched certification course and get your own analyzer, you may still find it hard to access nitrox.
5. Dive planning with nitrox
If you are a diver who doesn’t spend time planning on the no compression limit when using air, you might want to stay away from nitrox.
For safe diving with nitrox, it will require you to conduct more planning on your dive even more than when using air.
The first thing will be for the diver to analyze the tank and then consider the nitrogen absorption as well as the partial oxygen and how long he will be under its exposure.
If you plan to get more performance in your descent then the free diving fins can prove a worthy choice.
Is it worth it to use nitrox when diving?
Many people oppose the use of nitrox, especially in the recreational diving sector. While many discourage nitrox use, it continues to gain popularity by the day.
If you are planning on going spearfishing, then nitrox can really help to boost your performance underwater. You may need to decide between the scuba diving gear and the spearfishing mask and the spearfishing wetsuit.
Since it is clear that nitrox isn’t going anywhere, the next question becomes, is it really beneficial to use nitrox while diving especially when you consider the serious health risks associated with its use?
The dos and don’ts on Nitrox
Before you can use nitrox in your dive, you need to first get the necessary qualifications and certifications. Never dive with nitrox without the right training. The training should be gotten from a reputable source.
Second, the quality of nitrox should be good. Stay away from contaminants and always verify the mixture of oxygen and nitrogen before a dive.
Ask the one who is providing you with the nitrogen for a tour of the storage system or compressor. Understand their operating procedures to be able to judge the quality of their work. Never try to make your own nitrox.
Analyze the nitrox before using it. This is the only sure way to understand the percentage of oxygen to nitrogen. Also, when you are doing the analysis, use two inline analyzers. These will help validate the results.
Check to ensure that you do not go beyond the MOD or maximum operating debt. This will keep you safe from some of the dangerous effects of oxygen toxicity such as convulsions.
Globo Surf Overview
Scuba diving with nitrox may come with some great benefits allowing the divers to go deeper and stay under for longer but the benefits can only be realized if used correctly.