I know this is a total newbie question BUT...

[Buccaneer]

What is the advantages of diving on Nitrox? I have read several conflicting answers. Such as you can stay down longer/ go deeper/ it's safer/ less decompression. I have also seen statements that say alot of the above isn't really true. SO- which is it??

 

[JeffG]

Buccaneer once bubbled...
What is the advantages of diving on Nitrox? I have read several conflicting answers. Such as you can stay down longer/ go deeper/ it's safer/ less decompression. I have also seen statements that say alot of the above isn't really true. SO- which is it??

Strength
either a) Safer than air for a given depth/time (because of less N2 in "the mix")

or

b) longer bottom time allowed than air for a given depth


Weakness
O2 can be toxic at depth, so nitrox has a depth limit (which is shallower than air ie 36% Nitrox has a max depth of 100ft)


Other Stuff
At shallow depths ( ie < 60 ft) N2 loading may not be the biggest factor. Water Temp/Air supply might have a bigger effect on the dive.

 

[theskull]

And the answer is. . . both.

Nitrox can extend your NDL bottom time for a given depth. But this only helps if you are going deep enough that you won't run out of air long before you run out of bottom time. And it only helps if you are staying within the restricted depth at which you may safely breathe nitrox.

For most divers, nitrox can be a benefit on dives between 70 & 100 ft. depth.

It is an even bigger benefit on repetitive dives to these same depths, because you don't have as much residual nitrogen left over from the previous dive(s).

If you are diving regularly, and make repetitive dives beyond 60 ft. depth, you should take a Nitrox certification class (short & fairly inexpensive) so you can learn the WHOLE story and then decide whether nitrox is a benefit to you on a given dive trip.

I dive often, and personally use nitrox on about 1/3 of my dives.

theskull

 

[Boogie711]

It's longer dive times. You can't dive deeper on Nitrox - that can cause O2 toxicity and kill you.

Because you're diving say, 36% O2 when air is regularly 21%, that means instead of inhaling 79% Nitrogen, you're only inhaling 64% nitrogen.

That means you can safely stay at 80 feet for much longer than you could simply breathing air, because you're not absorbing as much nitrogen, therefore causing less risk of decompression sickness.

Now, why don't we breath 100% O2 then and never have to worry about nitrogen? Because oxygen is toxic at depth as well. If you exceed any deeper than 20 feet or so on pure O2, your body will be absorbing too much Oxygen. You can start to spasm and have seizures and ultimately drown.

Now - there's a lot more to all of it than this, but that's it Nitrox in a REALLY simple nutshell. Of course, get proper training, et al.

 

[Buccaneer]

Thanks for the fast response! I think I basically understand now. I am going to Hawaii fairly soon and my buddy wants us to get Nitrox certs before we go, he says so that we can dive longer- but the answer is, we MIGHT can depending on where (depth) we dive AND how many dives? RIGHT??

 

[d33ps1x]

Boogie711 once bubbled...
That means you can safely stay at 80 feet for much longer than you could simply breathing air, because you're not absorbing as much nitrogen, therefore causing less risk of decompression sickness.

Minor point. If you use all of the additional bottom time afforded by nitrox then you don't really reduce the risk of DCS. If your mixture affords you, say, 30% more bottom time and you use it, then you are still diving to the same risk level/limit.

 

[theskull]

You got it.

Hope you also got the part about oxygen being toxic based on the percentage and your depth.

As you will learn in your training, you CANNOT go deeper than 95 ft. on 36% or deeper than 110 ft. on 32%!

Get the training and dive safe,

theskull

 

[dc4bs]

Prety much.

1: You can make a single dive for a longer time on a given nitrox mix than on air at the same depth because there is less nitrogen in each breath to absorb.

If you normaly breath down your tank before you reach the NDLs on air then nitrox won't help you make dive times longer - you'll breath the tank down just as fast (here's where "option 2" come in...).

2: You can make "air-length" dives more often (shorter surface intervals) because you didn't take on so much nitrogen during each nitrox dive.

You really do need to take a nitrox course to learn about calculating partial pressures, equivalent air depths and at what depths various nitrox mixes are safe to use and why.

 

[Buccaneer]

If you normaly breath down your tank before you reach the NDLs on air then nitrox won't help you make dive times longer - you'll breath the tank down just as fast

Well, explain this: On regualr air you are using, say asingle aluminum 80 tank. But w/ Nitrox you are using TWO alum 80 tanks (one Oxy/one nitro) so with those two tanks being mixed, would n't you get more down time over using the single tank? I realize the mixture isn't 50/50 but still...you are working w/ 160 cu ft of gases over just 80?

or am I wrong altogether? when I see someone diving w/ 2 tanks I just assume one is oxygen and the other is nitrogen, or are you diving w/ it pre mixed and put into one bottle?

 

[friscuba]

Buccaneer once bubbled...
Thanks for the fast response! I think I basically understand now. I am going to Hawaii fairly soon and my buddy wants us to get Nitrox certs before we go, he says so that we can dive longer- but the answer is, we MIGHT can depending on where (depth) we dive AND how many dives? RIGHT??

I think what you'll get out of nitrox in Hawaii is more related to the benefit in how you'll fee after multiple dives and multiple days of diving rather than deeper/longer and gaining any time on your dives. Most of the dive operators here tend to run multilevel air profiles using computers. Some use air tables but that tends to be the minority.

There are some dives out there where you might push your limits on air, but it's not all that common on any of the organized tours.

Have fun,

Steve