What is nitrox ?
If you remember back to your Open Water course, you may remember that the air you breath contains about 79 percent nitrogen. Nitrogen, not oxygen or air, places more limitations on your recreational diving. How long a diver can remain at depth, or how long a diver must decompress before surfacing are nitrogen issues. NITROX is an "enriched air" mix. That is, you are breathing a mixture that contains less nitrogen than the normal 79 percent. The net effect of breathing a reduced percentage of nitrogen is that you absorb less nitrogen into your body compared to breathing air. Nitrox provides you increased safety OR more bottom time.The below No Decompression Limits table gives a comparison of air and two popular Nitrox mixtures. Nitrox I is 32 percent oxygen and 68 percent nitrogen. Nitrox II is 36 percent oxygen and 64 percent nitrogen. You can easily see that using Nitrox almost doubles your bottom time.
Maximum No Decompression Bottom Time Limits Depth
(ft)Compressed Air
(minutes)Nitrox I
(32%)Nitrox II
(36%)35 205 No limit No limit 40 140 No limit No limit 45 100 310 No limit 50 80 200 200 60 55 100 100 70 40 60 60 80 30 50 60 90 25 40 50 100 20 30 40 110 16 25 30 120 13 25 * 130 10 20 * PADI Dive Planner NOAA Dive Tables The benefits of Nitrox continues on the surface. By using Nitrox one can shorten the required surface interval between repetitive dives, or make a longer dive with the same surface interval as a comparable air dive. Why? Because by using Nitrox, you the diver, absorb less nitrogen on a dive than on air.
Is Nitrox a "Safer" gas?
Using a gas mixture containing less than 79 percent nitrogen, but using air tables or computers (which assume 79 percent nitrogen), the diver is able to build a "safety factor" into the dive profile. You're assuming you've absorbed more nitrogen than you actually have. You are decreasing your risk of DCS (Decompression Sickness).Dangers of Nitrox.
Nitrox can cause some serious problems if not used within limits. Diving with Nitrox the diver needs to pay attention to their diving depths because of the higher oxygen content. Breathing too much oxygen can cause CNS (Central Nervous System) oxygen toxicity. As a result the diver must closely adhere to the Maximum Operating Depth (MOD) of the Nitrox mixture. Nitrox I cannot be used below 130 feet (NOAA tables) and Nitrox II cannot be used below 110 feet (NOAA tables).
Recommendations on using Nitrox.
1. Be trained and certified for Nitrox diving.
Never dive with enriched air if you haven't completed a sanctioned course. Sun Fun Divers offers an IANTD Enriched Air course.2. Get your Nitrox from a reputable source.
All divers must be certain of the quality of their breathing air. Sun Fun Divers has Nitrox mixtures to meet your needs.3. Always personally analyze your gas before use.
Only an analysis can confirm the actual percentage of oxygen in a Nitrox mixture. Never use a cylinder of containing enriched air unless you analyze it first.4. Never exceed the Maximum Operating Depth (MOD) of the Nitrox mixture you are using.
Always know, or calculate, your MOD and never dive below that limit. Inform your dive buddy of your MOD.5. Use only dedicated cylinders for Nitrox.
Sun Fun Divers can inspect your cylinder for Nitrox and provide the proper labelling, or sell you new cylinder for Nitrox.How do you get started to use Nitrox?
Sun Fun Divers can answer all your questions concerning Nitrox. Sun Fun Divers offers an IANTD (Internation Association of Nitrox and Technical Divers) course in enriched air. Better yet, Sun Fun Divers can integrate your enriched air (Nitrox) certification into a dive charter so you can start Nitrox diving right away.
