We all know that compressed Air stored in the diving cylinder comprise of atmospheric gases that hold a maximum pressure rating of 3000 to 4500 psi. When we say atmospheric gases, we refer to a combination of Oxygen, Nitrogen and other inert gases that make up the earth’s atmosphere. In terms of proportion, Nitrogen accounts for around 78% of air followed by Oxygen at 21% and the remaining 1% comprise of inert gases such as Argon and Carbon Dioxide.
Non-divers are perhaps predisposed to the notion that the same proportion occurring in breathing gases is ideal for use in the conduct of scuba diving activities. While most recreational divers are geared up with an open circuit scuba set designed to be ‘Air’ compatible (out of the box), many seasoned scuba divers would prefer the use of Enriched Air Nitrox (EANx). Nitrox gases contain higher proportions of Oxygen at a maximum rate of 40% and lowered proportions for Nitrogen. For example, a mixture of EAN32 implies a combination of 32% oxygen and 68% nitrogen. Wonder why Nitrox mixtures are regarded as better suited to scuba diving than the regular Air mix? Well here’s how.
The lowered Nitrogen content in Nitrox or EANx mixtures decelerates the absorption of Nitrogen into the blood and bodily tissues to effectively extend No Decompression Limits (NDL) or No Stop Times and increase bottom times than what the regular breathing gas mixture would allow. Consequently, use of Nitrox gases in the conduct of repetitive dives will help reduce Residual Nitrogen Time (or the duration of excess Nitrogen discharge from the body) and likewise allow for shorter surface intervals between 2 consecutive dives. Now you wouldn’t experience these benefits in the use of atmospheric Air mixtures. Nonetheless, these advantages are not available without cost considerations. Whereas Air can be easily derived from the atmosphere and prepared (apart from being virtually free), Nitrox mixtures are generally expensive. Using Nitrox gases during your dive would cost you around $10 per tank and would likewise require the diver to undergo formal training to get Nitrox certified.
Neophyte divers would initially dispense with the idea of using Nitrox mixtures. But as the scuba diver advances with training and skill; with a number of certifications and open dives in his dive logbook, the intent of using more specialized scuba equipment also arises. Therefore, it would be wise to invest on Nitrox-compatible scuba equipment early on from the scuba regulator, octopus regulator and dive computer. The Aeris A1 scuba regulator is Nitrox-compatible and can handle gas mixtures of up to 40% Oxygen without requiring special preparations or maintenance. To improve your margin of safety, get a matching A1 Octopus regulator that has been configured for Nitrox use as well. Meanwhile, the Aeris XR-2 Wrist Dive Computer [http://www.scubasuppliers.com/site/1408308/product/10.2610] can be programmed to function as an Air computer and then as a Nitrox computer for mixtures of 21% to 50%.