Why Nitrox???
Mike Massaro Oct 30, 2022
Why Nitrox Certification
I get questions all the time about diving Nitrox. Is it for me? Why should I use it? How deep can I go? Let’s answer some of these questions and gain some insight into diving the breathing gas called Nitrox.
Diving on Air
As a scuba diver you know that the gas in our scuba cylinders is nothing more than compressed air. Room air is a composition of many gases that naturally occur but for our discussion lets agree that air has two key elements. These two elements are Oxygen and Nitrogen, with oxygen making up 21% and nitrogen 79%. As we dive and breathe, we metabolize oxygen and store nitrogen. Nitrogen is inert and it is stored in the body as we dive.
On a typical scuba dive the diver will breathe compressed air as they dive, metabolizing the oxygen and storing the nitrogen. The diver will On-Gas as they dive deeper down the water column with the nitrogen being stored in tissue. As the diver begins to ascend to the surface, nitrogen is released from the tissue and released through regular breathing. This is Off-Gassing and happens on every dive.
If we stay down too long and accumulate too much nitrogen, or ascend to the surface too fast, the release of nitrogen may be so great as to overwhelm our body’s ability to off-gas and the potential for Decompression Sickness or Arterial Gas Embolism increases. So how can we mitigate some of the risk of diving on air?
Nitrox
We know that room air has 21% Oxygen and 79% Nitrogen. We know that too much nitrogen can increase our diving risks. How can we reduce the amount of nitrogen in our breathing gas and mitigate some of this risk? Just add oxygen!
The US Navy and commercial dive operations have used Nitrox since the 1950s. NOAA started using Nitrox in the 1970s. Nitrox was shown to increase dive times and reduce surface intervals, the time necessary between dives. In 1985 Dick Rutkowski, retired NOAA Diving Program Manager, introduced the first Nitrox training course for recreational scuba diving.
Diving on Nitrox
When you dive Nitrox, you reduce the amount of nitrogen in your gas mix. The reduced nitrogen allows for longer dives, shorter surface intervals, and reduces the potential for DCS/AGE but not all at the same time. If you dive longer, you will still end up accumulating the same amount of nitrogen. Once you have accumulated your maximum nitrogen then you run the same risk for DCS/AGE and require the same surface intervals.
When you choose to dive nitrox, you are making the decision based on your diving profile and your diving goal. You learn in your Nitrox class how to choose the Best Mix, Maximum Operating Depth, and actual Partial Pressure (PPO2) of the mix.
Health Benefits
We have discussed how Nitrox may mitigate some risks when diving. Are there any health benefits? Some divers have reported not feeling as tired, having less fatigue, and overall, just a better feeling after diving nitrox. While there is no empirical evidence to support these claims, there is an abundance of anecdotal evidence.
Hyperbaric Oxygen Therapy (HBOT) is the breathing of oxygen under pressure. Similar to diving on Nitrox, but therapy takes place in a hyperbaric chamber not in the water. Benefits of HBOT have been reported for those with a variety of injuries and illness. Typical therapy protocols call for 100% Oxygen to be delivered at 1.5ATA to 2.0ATA for 60 minutes to 90 minutes per session. Up to 40 therapy sessions or more may be required to achieve results depending on the injury/illness.
The benefits of doing the therapy in the chamber are two-fold. One, the chamber provides a controlled environment for the therapy. You will receive consistent therapy as the time and depth are controlled on every dive. There are no environmental concerns such as weather, cold, etc.
As you can see, scuba diving on Nitrox can provide similar health benefits as receiving HBOT. Will it occur on one dive, probably not. If you are on vacation and doing ten dives during the week, you may see some health benefits from diving on Nitrox. Definitely something to consider.
Taking a Nitrox Class
Most agencies do not require any actual dives for Nitrox Certification. Diving technique stays the same for diving air or nitrox. It is important to understand diving limitations and restrictions, and how to safely analyze nitrox. Many take the class online, reading through the material, and passing the end of course exam. While this will get your certified, I prefer teaching the class in person so we can work through the math together and understand how it applies to scuba diving. You can complete a Nitrox Certification class in 4 hours, and it is 4 hours well spent.
Once you have received your Nitrox Certification you can continue diving as before but now you have the choice of diving Nitrox!
About the Author
Mike Massaro is a Scuba Instructor, Paramedic, Dive Medical Technician, and Hyperbaric Instructor. He owns Trilogy International and Trilogy Dive Center in Tampa, Florida. Trilogy has been providing training to public safety (fire, EMS, law enforcement) for more than 12 years. The dive center operates a 28’ x 72” dual-lock, multi-place hyperbaric chamber. Training and certification is available for Nitrox, chamber operations, Introduction to Hyperbaric Medicine, and more. Fore more information on hyperbaric medicine, HBOT, or to take a Nitrox class check Trilogy out on the web at www.trilogyhse.com and www.trilogyscuba.com.
