By Jeremy Tanner, Training Manager
Spend a day on the water with veteran divers, and chances are you will see those distinctive green-and-yellow banded cylinders marked for "Nitrox". Once a staple of the technical diving community, this breathing gas is now accessible to sport divers, yet still carries the stigma of being complicated to learn. With the potential for increased diving safety, many agencies encourage new divers to learn Nitrox, and a Nitrox course may include dives or may be completely academic.
What is Nitrox?
The air around us is comprised of mostly oxygen and nitrogen, along with other trace gases. When teaching Open Water, we generalize that air contains about 21% oxygen and 79% nitrogen. Enriched Air Nitrox, when used by the diving community, is a blend of increased oxygen and decreased nitrogen. Popular mixes have an oxygen content of 32% and 36%, commonly labeled EAN32 and EAN36.
The Advantage of Longer Dives
By increasing the oxygen content, we decrease nitrogen. Nitrogen loading, as you recall, is what creates our time limits for diving at a given depth. By lowering the nitrogen exposure, we can stay longer at the same depth. For example, take a dive to 50 feet on air, and your SSI dive table will allow 70 minutes of bottom time. Do the same dive on EAN36 and the same table will allow for 160 minutes of bottom time! However, reaching your no-decompression limits on Nitrox will still put you at an increased risk of decompression sickness.
The Advantage of Increased Safety Margins
Many Nitrox divers choose to dive their preferred mix while treating their dive as an air dive. For the example used above, a diver who spends 70 minutes at 50 feet while using air will reach their no-decompression limit. Perform the same profile using EAN36 and you will end your dive with an additional 90 minutes of potential bottom time, thus staying far away from the "danger zone" of the no-decompression limit.
The Limitations of Nitrox
The Nitrox diver must choose between the two advantages: increasing bottom time will decrease the extra safety margin, and vice versa. Nitrox divers also encounter a new risk: oxygen toxicity. This risk is easily managed with proper training. In order to avoid oxygen toxicity, the Nitrox diver may need to choose shallower depths. Contrary to what you may have heard, Nitrox does not allow a diver to reach deeper depths versus diving with air.
How to Learn Nitrox
At Pompano Dive Center, we offer Nitrox courses throughout the year. You can choose to join a scheduled course, or we can set a course date to meet your schedule! Most of the course can be completed in the comfort of your home using e-learning. Once the e-learning is complete, you will meet with your instructor to review, take a test, and learn how to analyze a Nitrox cylinder. If you own a Nitrox-compatible computer, we will also teach you how to program it. Nitrox courses start at $169, but can be bundled with other courses for a limited time price of $99. To schedule your training, call our shop at 954-788-0208, or email our training manager at email@example.com.