What is Nitrox?
Enriched Air Nitrox or EANx or simply Nitrox is a breathing gas that has the level oxygen increased to displace the nitrogen in the mix.
Why is it used?
The nitrogen in the air that we breathe when we are diving is absorbed into our tissues at depth, however unlike oxygen which our body easily metabolizes, nitrogen that is absorbed must work its way back out the same way it came in. Under pressure it works its way into our tissues and if we take in to much nitrogen under pressure, we can no longer ascend directly to the surface and must 'decompress' by doing planned, manditory stops to try and let the nitrogen bubbles work its way out. As recreational divers, we follow the no-deco limits and thus nitrogen that we breath is the limiting factor of the length of a dive at any given depth.
By limiting the nitrogen in our breathing gas we are able to extend our bottom times beyond the air no-deco limits, or we dive the air tables on Nitrox with a far greater safety margin because we have less nitrogen in our system.
EANx does have its own risks, but when managed breathing Nitrox is a safe way to enjoy the sport of Scuba.
Does this mean I can dive deeper using Nitrox rather than air?
No, actually it is the opposite. The richer your Nitrox blend (the higher the percentage of oxygen) the shallower you will need to limit your dive. Nitrox is all about limiting your nitrogen intake and making your dive safer and nothing to do with diving deeper.
Who should learn to dive with Enriched Air Nitrox?
Anyone that plans to dive with Nitrox must learn the risks associated with the gas. Taking the Enriched Air Nitrox class also gives you a greater understanding of the air you breathe while diving. Even if you decide you won't be diving Nitrox on a regular basis, you will have a greater appreciation of how you body works under the stresses of diving.
Although limiting the nitrogen has definite benefits, there are also certain risks associated breathing oxygen under pressure such as oxygen toxicity. In any Enriched Air Nitrox class you will learn about all the risks and what precautions you must take to ensure you are using Nitrox safely.
If you think you are ready, sign up for an Enriched Air Nitrox course.
Do I need any special equipment to dive with Nitrox?
Yes. All of the equipment should be Nitrox compatible, from your tank through to your regulator.
Most regulators these days are Nitrox compatible for recreational Nitrox blends(up to 40%) from the manufacturer and you probably don't need to do anything with them.
Your scuba cylinder and valve on the other hand will likely need to be properly cleaned and overhauled. Many dive shops use the 'partial-pressure' blending method when filling scuba cylinders with Nitrox which means that at some point, there will be 100% oxygen being delivered into your cylinder. This means you tank and valve must be thoroughly cleaned to be devoid of any hydrocarbon residue which could lead to fire or explosion when exposed to 100% O2. All the o-rings in the valve and cylinder combination will have to be replaced with oxygen compatible materials such as Viton. This is an annual expense at a minimum, and must be done after every air fill from an air station that does not fill using 'hyperclean' or oxygen compatible air.
Enriched Air Nitrox when used correctly can make your scuba adventures safer or longer, and even if you aren't going to dive it regularly, just taking the class will improve your understanding of the physiological changes your body undergoes each time you slip beneath the surface.
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A common question from new divers is "What gear do I need to buy, and how much will it cost me?"
The easy answer is: "If you stick with the sport, you will eventually need to buy almost everything!" However, the order and necessity with which you need to buy your gear is the issue at hand.
Another common question is "Can I rent scuba equipment?"
Aside from the basic gear required to begin your training, the sport of scuba has a lot of other pieces of equpiment that you will aquire as you become involved in the sport. Some of this equipment can be rented some must be bought - like your mask, snorkel and fins.
There are many pros and cons to own your own gear and they vary, however the best reason to own your own equipment is that you are always ready to go diving. You don't have to scramble to get to a dive shop to rent anything and you will get to dive more often because of it.
Rental Item: Yes, wetsuits are commonly available for rent.
Pros / Cons of Ownership: There is an old saying that there are two types of divers ... the ones that pee in the wetsuit and the ones that lie about it. Rental wetsuits almost definitely have had someone marinating in their own urine at one time or another, so having your own is a nice perk. Having your own wetsuit also tends to mean you have a suit that fits you better rather than choosing the best fit of what is available in the rental fleet.
Cost: Wetsuits come if several types and several thicknesses. In Ontario, you tend to require a 7mm, wetsuit while in the tropics you can get away with a 3mm or less. A decent 7mm wetsuit will start at $200 and go up from there.
Rental Item: Yes, drysuits are available for rent in many dive shops.
Pros / Cons of Ownership: Renting a drysuit is not very cost effective, and is often only done during a drysuit course (before you have purchased your own) or if you are trying out a suit before you buy that style or brand. Drysuits require special training before you should dive in the open water with one. Once you have purchased a drysuit, you must maintain the neck and wrist seals as well as the zipper to ensure that it does not become a wetsuit!
Cost: Entry level drysuits start around $900 and can cost as much as $3000.
Buoyancy Compensator Vest (BCD):
The air bladder covers both the divers back and wraps around the sides of the diver. This style slightly more stability on the surface, but can be uncomfortable if over inflated.
A Back Inflate BCD has the air bladder strickly behind the diver. This offers better control of the divers trim and is typically more comfortable. If the BCD has too much air in the bladder on the surface it tends to push the diver forward in the water.
Back-Plate and Wing:
A BP/W is a very simple harness that is similar to a back inflation BCD. They typically do not have any pockets or weight integration, though some manufacturers have pockets that may be added. The back-plate is a steel or aluminum plate that is used to mount the scuba tank or tanks (doubles).
Rental Item: BCD's are standard rental equipment in all dive shops.
Pros / Cons of Ownership: There are MANY different BCD's available on the market and they offer a wide variety of features. Most notibly is a feature called integrated weights. Some BCD's have built in pockets with quick releases to store your weight allowing you to transfer some or all of your weight off your belt and into your BCD. BCD's do require periodic maintenance to ensure proper inflation / deflation and emergency dumps. Renting several different BCD's is a good way to help decide which is right for you.
Cost: BCD's can be purchased as low as $250 and as high as $800.
First Stage: Connects directly to your tank valve and has both high and intermediate pressure outlets.
Second Stage: Connects to the intermediate pressure ports on your first stage and steps the pressure down to ambient for the diver to breathe. These are your mouthpieces.
Rental Item: Regulators are standard rental equipment in any dive shop.
Pros / Cons of Ownership: Your regulators require constant care and should be serviced annually to ensure they are in a safe and working condition. Annual service can run anywhere from $50 to $100.
Cost: An average set of 'regs' will include a first stage, two second stages and a submersible pressure guage (SPG) starting at around $500 and can run up to $2000.
Rental Item: Many dive shops will also rent a dive computer.
Pros / Cons of Ownership: Having a dive computer - while not mandatory for diving - will increase your bottom time and your enjoyment of diving. Many log your dives and can be connected to a computer to print out your dives for your log book. They are available in simple forms and some even have integrated air pressure.
Cost: A simple computer starts at about $200 and more advanced computers will cost $1000 - $2000.
Rental Item: Absolutely every dive shop rents tanks.
Pros / Cons of Ownership: Tanks require both annual and quinquennial (every 5 years) maintenance. Tanks are the heaviest and most bulky item, so many divers will rent them from a shop close to the dive site to limit the need to transport them. Tanks are best purchased in matching pairs - this limits the need to adjust your weight between dives and most trips are atleast two dives. The more tanks you have, the more difficult it becomes to manage their annual servicing.
Cost: An aluminum tank will cost you around $200 while a steel tank (which comes in variety of sizes) will cost between $300 - $600 each.
For a details discussion on scuba tanks read Scuba Tanks - Steel Vs. Aluminum ....
Other Standard Kit:
Gloves: Can be sometimes be rented, but are a low cost item that is usually owned. ($30 - $50)
Hood: Can be sometimes be rented, but is usually owned. ($40 - $80)
Knife: Usually not a rental item. Expensive knives are easily lost. Spend less and buy two ... ($30 - $150)
Compass: Sometimes included as part of the console on the 'regs' available as a wrist mount unit also. ($50 -$70)
SMB: A Surface Marker Buoy is a safety device that every dive should have. This in not a rental item. ($40 -$100)
Lift Bag: Used to lift heavy items from the bottom. They require some practice and are typically not a rental item. ($50 and up)
Pony Bottle: A secondary - redundant air source - requires a second set of 'regs' and some training. Often can be rented. ($200+)
Flashlight: Every diver should have atleast a small light for use on any dive. A larger light for night dives can be rented. ($100 - $1500)
Camera: Often a rental item, many divers like to bring a camera on every dive. A low cost digital camera with an underwater housing starts at about $500
The hierarchy of buying your own scuba gear (what to buy first):
- Mask, Snorkel and Fins
- Environmental Protection (your wetsuit, boots, gloves and hood)
- Cutting Tool
- Life Support (your regulators)
- Dive Computer
- Surface Marker Buoy (SMB)
Some equipment, like a drysuit or a pony bottle, even a liftbag require special training and or practice before you use them during a dive. Talk to an instructor and learn the do and dont's before using any new piece of equipment.
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