I am a long time NITROX diver, NITROX instructor and NITROX blender. I dive it, I teach it, I make it. On this FAQ page, I have compiled some of the most common questions people ask me about "the gas." I hope this site answers some of your questions. As in any other area of SCUBA diving, proper training is essential ! My passion for diving, and love of teaching combine together for really fun SCUBA classes. I offer an INTERESTING AND FUN NITROX course every month. Please contact me if you have any additional questions !

What is NITROX ?

NITROX is a breathing gas that many SCUBA divers use to extend bottom time and increase safety while diving. NITROX is simply a mixture of oxygen and nitrogen, but with a higher concentration of oxygen than normal room air. Air is composed of approximately 21% oxygen and 79% nitrogen. NITROX, Enriched Air NITROX, SafeAir, and EANx are names commonly used in the diving community to refer to oxygen-nitrogen mixtures containing more oxygen than ordinary air; that is, more than 21% oxygen. There are two standard NITROX mixtures (originally used by NOAA scientists), NOAA NITROX I with 32% oxygen and 68% nitrogen, and NOAA NITROX II with 36% oxygen and 64% nitrogen. In more advanced NITROX classes I teach divers how to use mixtures other than these two "standard" mixtures. In essence, you can start to fine-tune the mixture to your intended dive profile, enhancing your safety and enjoyment of the dive. This is called the BEST MIX concept. In even more advanced classes, such as Technical NITROX, we use very high concentrations ( 80 % and higher ) to aid in decompression.

Why use NITROX ?

The main benefit to diving with enriched air mixtures is the reduced amount of nitrogen in the breathing gas. Nitrogen is an inert gas and is not metabolized by the body. Nitrogen absorbed in the body during a dive is what usually puts divers at risk for decompression sickness (DCS), or the bends. Reducing the amount of nitrogen one breathes can directly reduce the risk of developing DCS.

Also, I feel much more alert and "crisp" while diving on NITROX. I am far less tired after a three or four dive boat trip. Before NITROX, after a long day of diving and teaching classes, I would come home and crash, now, its dinner and a movie. AND INCREASED SAFETY ! One recent student ( Hello Dr. R.K. !! ) came out of the water, climbed back on the boat and simply looked at me, smiled, and said " I feel ten years younger and I think my hair is growing back ! " You really do feel better !

Also, using the NITROX mixture EAD (Equivalent Air Depth ) concept, bottom times can be safely extended. Because no-decompression limits are based on nitrogen absorption, NITROX means less nitrogen, which means more bottom time. Many other divers also report that they feel less fatigued after diving with NITROX (compared to similar dives using air).

Is there any down side to using NITROX ?

The danger of oxygen toxicity, while present with any breathing mixture (including air deeper than 240 FSW), can become a problem with NITROX due to elevated partial pressures of oxygen (PO2). This can result in seizures, which are nearly always fatal underwater with standard SCUBA equipment, as they usually lead to drowning. This risk can be easily managed by adhering to recommended maximum operating depths (MOD) for enriched air mixtures. In the NITROX class, I instruct students on the simple math needed to calculate the maximum depth for the specific gas you are diving with. There are also simple tables that also show these M O D's.

What this means in real life is if you are diving with NITROX 32%, you would simply never go deeper that 130 feet of salt water on that particular dive. This is an absolute rule that cannot be broken. But in reality, how often do you go that deep anyway ? And if you NEED to, then grab a cylinder of air.

Another risk related to NITROX is that of fire or explosion resulting from improper handling and mixing of NITROX. All cylinders and valves used for partial pressure mixing of NITROX must be properly cleaned, labeled, and maintained (most regulators do not need special cleaning unless they will be used with NITROX mixtures containing more than 40% oxygen). Mixing and cleaning should only be done by appropriately trained personnel. Again, in real life this means you buy your NITROX equipment and NITROX fills from a certified NITROX dive store from a NITROX instructor and you don't have to worry about these hazards. In the old days, there were a lot of divers using NITROX with homemade, modified and dangerous equipment and mixing the gases in their garage ! Those days are long gone, and NITROX today is extremely safe.

Will use of NITROX reduce air consumption ?

Maybe. Probably. The amount of bottom time you can safely get out of a cylinder is dependant on a wide variety of factors. Using NITROX may reduce gas consumption. Breathing rate is primarily controlled by the carbon dioxide levels in the lungs rather than the oxygen level in the breathing gas. Breathing rate may be reduced indirectly by NITROX use through other factors, such as increased comfort level, greater physical stamina and warmth. Also, the mental clarity or "crispness" you will enjoy may reduce stress and anxiety sometimes experienced and this will reduce your breathing rate and gas consumption. What I have found, after many, many NITROX dives, is that I am warmer, have more energy and my cylinder lasts about 30% longer than when diving air. Combined with the increased mental clarity, I choose NITROX over air any day on most dives.

Can a NITROX diver get bent ?

Because there is still nitrogen in the breathing gas, NITROX diving can result in DCS just as air diving can. Used properly, however, NITROX can greatly reduce the amount of nitrogen absorbed, thus reducing the risk of developing DCS substantially.

If a NITROX diver gets bent, can he/she be treated in a chamber ?

Yes, a NITROX diver would go to the chamber just like any other diver. BUT a diver using NITROX has a greater chance of beating the bends because of the reduced nitrogen level than a diver using the same dive profile breathing air.

Will NITROX reduce nitrogen narcosis ?

Yes. Because nitrogen narcosis is a direct result of the increased partial pressure of that gas, diving on NITROX reduces the effects when compared to diving air at the same depth. You are less "narked" on NITROX.. I often dive NITROX on deep dives ( to 130 FSW ) when teaching a deep diving specialty. I am crisp and alert and 100% in touch with reality and the students on air are stuporous and slow in response. This is a direct result of both using NITROX on that dive, combined with the "deep" experience and training I have. Contrary to what many agencies and instructors teach, nitrogen narcosis starts to affect most divers around 50 FSW, a much shallower depth than taught in most recreational diving courses. I have made many dives to various depths in hyperbaric chambers and have tested both myself, other instructors and students as to their physical dexterity and mental reasoning. There is a drop-off in scores around 50 FSW and increasing as simulated depth increases. Diving NITROX greatly reduces the effects of nitrogen narcosis. One important component of the ocean / open water training in the NITROX course is the simple exam I administer at depth. Timing my students at both 90 FSW on air, then 90 FSW on NITROX, I have a simple 20 question test they must complete on a slate. What is your birth date ? How much lead are you wearing ? What is ( 4 + 4 ) X ( 3 + 3 ) ? List three Foreign car manufacturers ? Yep, you would be AMAZED at the difference in the time it takes to complete, far longer on air. The penmanship, and correctness of the answers, also leads me to believe we are all affected by nitrogen narcosis much more when breathing air, than when breathing NITROX.

Is NITROX used for deep dives ?

NITROX is actually limited to even shallower depths than air due to the increased oxygen content. The deepest you would want to use a standard NITROX mixture of 32% would be 130 FSW. Other mixtures, such as EAN 26 and EAN 28 can be used deeper, provided you are certified and trained and equipped to go to those depths.

Is NITROX safer than air ?

Yes, I believe so. Used properly, NITROX has the potential to make dive profiles safer. Also, if we use NITROX and follow the air dive tables, we are adding up to a 30% safety margin on our bottom times. Combined with the reduced fatigue and increased mental alertness, I feel that NITROX is safer than air.

To give both sides of the coin, I must add that due to the slight additional work in selecting a mix, filling, and analyzing, as well as the strict observance of an MOD, there are some that disagree with the idea that NITROX is, overall, "safer" than air.

I would suggest trying it for yourself, and you decide. I dive NITROX, my friends dive NITROX. I believe that you will agree, NITROX is the preferred breathing gas.

Drop me a line, via E-Mail to KEVIN ,and let's go get wet !!