Diving using Nitrox?

[huckster]

I would like to take the PADI course on enriched air diving. Are specialized regulators required? I currently use a beuchat VX200. Is there any other equipment needed? Can someone explain the real benifits in using Nitrox i assume longer dives with less surface time required. When using Nitrox do you use different dive tables based on %

Thanks

 

[Meng_Tze]

Usually you do not need 'special regs' if diving mixes below 40% O2. Nitrox is best learned from a proper agency and I would suggest to go for that. There have been a lot of threads on the benefits of Nitrox.

What I can tell you is that generally nitrox diving is considered diving with oxygen enriched air. This has less nitrogen, the gas mostly associated with DCS and decompression requirements.

 

[boulderjohn]

When using Nitrox do you use different dive tables based on %

You have several choices.

1. Use different tables created for the specific % you are using.
2. Use a chart that will allow you to convert the tables you would otherwise be using.
3. Use mathematical formulae to make precise calculations.
4. Use a computer.

I will give you four guesses to choose the option used by most recreational nitrox divers.

 

[Web Monkey]

I would like to take the PADI course on enriched air diving. Are specialized regulators required? I currently use a beuchat VX200. Is there any other equipment needed?

For the mixes you'll probably be using (generally 30, 32 or 36%) almost any regulator that you're happy with on air, will work with Nitrox, however you should verify this with the manufacturer for any specific regulator.

If you own your own tanks, and the shop mixes nitrox using a technique called "partial pressure blending", you'll need to have your tank and valve O2 cleaned, and the valve may need to have some o-rings replaced.

Can someone explain the real benifits in using Nitrox i assume longer dives with less surface time required. When using Nitrox do you use different dive tables based on %
Thanks

You get longer bottom times, especially if you're doing repetitive dives or a reduced risk of DCS, depending on how you dive it.

Your nitrox class materials should include a nitrox table and you can also use a nitrox-capable computer. It's possible to use an air-based computer on Nitrox, but you'll still need to do some manual calculations to account for your daily maximum O2 exposure (CNS Clock).

All this and more should be covered by your instructor.

Terry

 

[mudhole]

I would like to take the PADI course on enriched air diving. Are specialized regulators required? I currently use a beuchat VX200. Is there any other equipment needed? Can someone explain the real benifits in using Nitrox i assume longer dives with less surface time required. When using Nitrox do you use different dive tables based on % Thanks

Wow with a name like huckster, you'll fit right in with this discussion. Meng_Tse has given a simple and accurate description of the gas and its benefits. In my part of the country, with most dives above 60 feet and usually two or three dives a day, nobody dives with nitrox. New divers that want to impress other new divers will make the false claims about the advantages of nitrox. You will get more time on a tank of air. . ., you won't get as tired after a couple of dives. . . all false claims.

If you are in a place where deep diving is the norm, then Nitrox might help with safety, or it might increase the danger. . . type Nitrox in the search engine and watch the hits jump out at you. Read with care, about Nitrogen in your breathing gas, also read with care the toxicity of Oxygen at depth.

Where are you going to buy this gas. . . not every shop has it, and not every shop mixes it safely. You must protect yourself from a higher O2 mix than what is safe. O2 is handled safely every day, and it is handled dangerously every day. You must learn to handle it safely as a tool. I don't dive with Nitrox, because it won't benefit my diving. . . If I were making lots of deep dives, and I had a safe source, I would use it for what it does well.

 

[MauiScubaSteve]

I assume longer dives

You get longer bottom times

false claims...You will get more time on a tank of air. . . false

Let's clear up the mud, it's all about the wording, or the typing. I've never heard of anybody claiming more time on a tank of air.

NDL's are longer with EANx for a given depth but very few divers (none) will lower their SAC due to EANx, so unless the tables or your computer are ending your dives before your tank ends the dive, you will not get longer dives or bottom times. Comparatively shorter SI's are always an option because less nitrogen loading occurs, unless other divers in your group dove similar profiles with air.

 

[boulderjohn]

so unless the tables or your computer are ending your dives before your tank ends the dive, you will not get longer dives or bottom times. .

Of course, many people do indeed have a SAC rate [briefly, the rate at which you use up the air in your tank] that mneas they are being forced up by decompression limits rather than the amount of air they have. Your wording implies that it is rare, but it is not at all rare.

 

[Web Monkey]

usually two or three dives a day, nobody dives with nitrox. New divers that want to impress other new divers will make the false claims about the advantages of nitrox. You will get more time on a tank of air. . ., you won't get as tired after a couple of dives. . . all false claims.

Unless you don't believe the Nitrox tables, you absolutely do get longer NDLs using Nitrox instead of air.

Nitrox obviously does not turn an 80 into a 130, so of course, if you hoovered down your 80 in 20 minutes, you will not be getting longer dives. However, many (most) divers eventually bring their SAC rate down low enough where the dive time is limited by the NDL and not the tank capacity, at which point, Nitrox will indeed give longer dives.

If you are in a place where deep diving is the norm, then Nitrox might help with safety, or it might increase the danger. . .

Deep dives are exactly where you don't want Nitrox. In fact, if you use an average Max PPO2 of 1.4, you'll find that a 130' dive requires EAN 28 or lower, which contains only a little less nitrogen than air, and only gets you about another 5 minutes.

type Nitrox in the search engine and watch the hits jump out at you. Read with care, about Nitrogen in your breathing gas, also read with care the toxicity of Oxygen at depth.

Nitrox has exactly the same O2 Tox problems as air. They just happen shallower. In fact, you're breathing EAN 21 right now.

Where are you going to buy this gas. . . not every shop has it, and not every shop mixes it safely. You must protect yourself from a higher O2 mix than what is safe. O2 is handled safely every day, and it is handled dangerously every day. You must learn to handle it safely as a tool. I don't dive with Nitrox, because it won't benefit my diving. . . If I were making lots of deep dives, and I had a safe source, I would use it for what it does well.

Before you dump on it, you should at least take the class. "Protecting yourself from a higher O2 mix" is what the class is all about. Every Nitrox diver needs to analyze his own tank before each use and know his max PPO2 and MOD. It's nothing to be afraid of, it's just a check, like making sure your air is on before entering the water.

Terry

 

[Nemrod]

You will get longer bottom times for a given depth with Nitrox and for people who have low SAC rates they may well get a longer dive in that they will be able to utilize the full deco limit applicable to the mix before reaching their turn/surface pressures. These are not snake oil claims--it is FACT.

N

 

[NSDiver]

All of this stuff is true, but for ME, nitrox has pretty limited use. I will only use it if the following apply:

1. Square profile dive (boat dive, cave dive), or a dive expected to be spent mostly in 80-110 feet of water.
2. Known buddy, diving nitrox, with a good SAC rate.
3. Not shallow (<60 feet), not deep (>110). At less than 60 feet, air NDLs are pretty long, and at greater than 110 (as was stated above), the %O2 can only be slighting higher than normal air.

Last time I bought nitrox ($12 a tank), it was for a boat dive in South Carolina, with 85-90 feet max depth. I didn't have a buddy, so I got paired with a couple of very new divers - who of course had new-diver-like SAC rates. I did not get close to the air NDLs, and surfaced on both dives with well over half a tank left. I wasted my money by violating #2 above.

-Nick