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Nitrox Benefits Explained for Beginners
If you scuba dive with a nitrox cylinder it means the gas mixture has a higher proportion of oxygen than standard air and therefore a lower percentage of nitrogen.
The main reason for certified divers to increase the oxygen rich content of the breathing gas is to extend the time they can stay underwater at certain depths.
Pros and Cons of Diving Enriched Air Nitrox
If you're a certified diver you'll already know that standard air contains almost 21% oxygen and around 78% nitrogen.
By comparison, enriched air nitrox (EANx) typically contains a gas mix between 32% and 36% oxygen - the two most common mixes.
Why is that important?
The primary benefit of nitrox dives is absorbing less nitrogen, and at a slower rate, into body tissues.
As a consequence, it usually results in longer "no decompression limits" - often called the bottom time.
Pro Tip: Nitrox safety guidelines and procedural standards for professional and recreational divers state that the mixture of nitrogen and oxygen gases must follow certain requirements. Hence, diving with enriched air requires special training.
Benefits of Nitrox Diving
- A reduction in nitrogen absorption results in lower nitrogen levels. This in turn may also reduce the risk of decompression sickness (a diving hazard called the bends) because less nitrogen is absorbed into body tissues. The diver should need less time to off-gas saturated nitrogen.
- Plus, because the risk of nitrogen narcosis is lowered, divers can often stay underwater longer at certain depths when compared to diving with regular air.
- Divers who make repetitive dives (2 or 3 in one day) also benefit from being able to make shorter surface intervals between dives to off-gas nitrogen.
- One of the less known advantages of nitrox diving is reduced fatigue. Research shows that some sport divers report feeling less tired after using a nitrox gas mix when compared to regular air.
Disadvantages of Nitrox Diving
Most dive centers charge extra for enriched air nitrox tank fills. Even so, there are limitations and risks associated with nitrox diving.
- Not all dive schools have nitrox filling facilities and the special training required to dive with enriched air nitrox (EANx).
Higher oxygen levels increase the risks of getting oxygen toxicity, particularly at greater depths. Thus, divers need to track oxygen absorption and exposure.- This also affects the maximum nitrox diving depth limits, usually thirty (30) to forty (40) metres (100-130 feet) depending on the gas mixture.
- Divers will need to complete specialised training to use nitrox safely, including:
- Learning how to analyze the gas mix.
- Understanding the maximum depth limits for nitrox. The maximum operating depth (MOD) calculation is based on the partial pressure of oxygen (PPO2).
- Nitrox-compatible equipment, such as dive computers and gas analysers, may be required to avoid issues with oxygen exposure over time.
Specialty Training for Nitrox Divers
Using a higher scuba tank oxygen percentage obviously means the nitrogen content will be a lot less than the mix used in standard air-filled scuba cylinders.
In other words:
If you increase the amount of oxygen to thirty two percent (32%), the nitrogen content is lowered to sixty eight percent (68%).
The effect of less nitrogen absorption generally means the diver will have a longer dive time before reaching the no-decompression limit (NDL).
So, because nitrogen gas absorption is directly related to the risks of developing decompression sickness, diving with enriched air nitrox is the preferred choice for divers who make multi-day dives or repetitive dives.
Nonetheless, not all divers benefit from using nitrox. But, if you intend to dive with enriched air you need to get trained for using it safely.
Another section explains how to get the enriched air certification and make longer dives using the gear needed for nitrox diving. The course educates divers to the additional risks of oxygen toxicity and how to use oxygen specific nitrox scuba equipment.
In Summary
Training to dive with enriched air nitrox requires an understanding of specialised compatible gear, such as enriched air dive tables or a nitrox dive computer.
You also learn how to identify equipment markings for diving with increased oxygen contents, such as nitrox tank filling and using oxygen analyzers.
Here's the deal:
Divers must complete an Enriched Air Nitrox certification course before they dive with gas mixes higher or lower than the industry standard.
You can get the nitrox certification through several scuba training organisations like PADI®, National Association of Underwater Instructors (NAUI0, and Scuba Schools International (SSI).