Nitrox is a mixture of gases with a higher proportion of oxygen than standard compressed air, which contains approximately 21% oxygen and 79% nitrogen. Nitrox, also called “enriched air,” typically has an oxygen ratio that varies between 32% and 36%, reducing the amount of nitrogen. This is what allows divers to extend their bottom time and decrease the risk of nitrogen accumulation in the body.
However, this higher concentration of oxygen brings with it some limitations and safety regulations, especially when it comes to the depth of the dive.
So, does nitrox allow you to go deeper?
Here comes the big myth: many people think that nitrox allows you to go down to greater depths, but the reality is quite the opposite. The nitrox course teaches you how to use this mixture safely, but it also introduces you to the limitations that come with increased oxygen. Unlike compressed air, nitrox actually limits the depth of the dive due to oxygen toxicity.
Oxygen Toxicity and the Depth Limit
Oxygen becomes toxic at high concentrations when inhaled at higher pressures. As we drop, the partial pressure of oxygen (PpO₂) increases, and from certain levels it can cause serious neurological effects, including seizures. This is known as “oxygen toxicity” and is a risk that nitrox divers should be very aware of.
Each nitrox mixture has a maximum operating depth (MOD), which is the depth at which the partial pressure of oxygen is maintained at a safe level (usually 1.4 ata). For example:
- Nitrox 32: The maximum depth is approximately 34 meters (110 feet).
- Nitrox 36: The maximum depth is approximately 29 meters (95 feet).
These depths are lower than those that could be reached with compressed air, so the use of nitrox, rather than allowing greater depths, limits the depth of dives to avoid the risk of oxygen toxicity.
What Is Nitrox Really Good For?
Nitrox is especially useful for those dives where the diver remains at a medium depth (usually between 18 and 30 meters). Under these conditions, enriched air allows the amount of nitrogen that the body absorbs to be reduced, decreasing the risk of decompression sickness and extending the background time.
Advantages of Diving with Nitrox:
- Longer Bottom Time: The lower proportion of nitrogen allows the body to absorb it more slowly, which prolongs the safe time spent underwater without having to perform decompression stops.
- Reduced Fatigue: Many divers report feeling less tired after nitrox dives, although the exact relationship between nitrox and fatigue is still being studied. Lower nitrogen absorption appears to help the body recover more quickly.
- Reduced Risk of Decompression Sickness: The buildup of nitrogen in the body is the main cause of decompression sickness. With nitrox, by reducing the amount of nitrogen inhaled, the risk of buildup decreases, especially on repetitive dives.
What Will You Learn in the Nitrox Course?
The nitrox course is an additional certification that allows divers to learn how to safely use this enriched air mixture. Some of the topics covered include:
- Nitrox Physiology: You will understand how nitrox affects your body and why it is a mixture that requires careful handling.
- Maximum Depths and Oxygen Toxicity: You will learn how to calculate the maximum operating depth (MOD) based on the specific nitrox mixture you are using and how to avoid the risks associated with oxygen toxicity.
- Using the Oxygen Analyzer: It is essential to analyze the gas mixture in your tank to ensure that you are diving with the proper oxygen ratio, and the course teaches you how to perform this check independently.
- Nitrox Dive Planning: Nitrox planning involves the use of dive boards and computers specific to this type of mix. You will learn how to calculate your bottom times and schedule your dives safely, respecting the limitations of nitrox.
Myths and Facts about Nitrox in Diving
Myth 1: “With nitrox I can dive deeper”
Fact: Nitrox doesn’t allow for deeper dives; in fact, it limits the maximum depth to avoid the risk of oxygen toxicity. Its real benefit is in the increase of bottom time at moderate depths and in the decrease in the risk of decompression sickness on successive dives.
Myth 2: “Nitrox is only for advanced divers”
Fact: Although it is advisable to have some basic diving experience before taking the nitrox course, this certification is accessible to any recreational diver who wants to expand their knowledge and safety.
Myth 3: “Nitrox is unnecessary for recreational dives”
Fact: While not essential, nitrox is ideal for divers who plan to go on multiple dives in a single day or dive for several days in a row, as it helps reduce nitrogen buildup and prolongs safe bottom times on moderate dives.
Should You Get Nitrox Certified?
If you’re a recreational diver who plans to do repetitive dives, such as on a dive trip or expedition, the nitrox course is a very useful investment. Lux Divers offers this specialization course, and we’re here to help you gain the skills and knowledge needed to dive with nitrox safely and get the most out of your dives.
With a greater understanding of diving physiology and nitrox handling, you’ll improve your experience on the water, prolonging the time of your dives without having to worry as much about decompression limits.
Conclusion
The use of nitrox in recreational diving is a powerful tool for maximizing bottom time and reducing the risk of decompression sickness. However, it does not allow diving to greater depths and in fact requires extra precautions due to the risk of oxygen toxicity. Becoming nitrox certified is an important step that not only expands your knowledge of diving physiology, but also allows you to dive more safely and for a longer time.
Dare to improve your dives and take this opportunity to discover the world of nitrox with Lux Divers!