Nitrox discussion (Split from "Reasons not to use Enriched air" thread in Basic)

[DwayneJ]

The 1.4 / 1.6 is already a built in safety margin.

As to feeling better after nitrox... Sub-clinical DCS, that feeling of fatigue after a dive, I have read, can be due to the body acting on the increased nitrogen in the blood / tissues in a way that is similar to it fighting off the flu. Thus flu like fatigue, which is lessened by less N2 in the body.

I also feel better after doing deco on 100% verses 50% or 80%.

If this is all hogwash, please don't tell me and spoil the nice placebo effect I have working for me.

Check out the rebreather forums and discussions on modifying PPO2 levels based on depth and length of dive - There are good examples of individuals suffering oxygen toxicity between PPO2 1.4 and 1.6. The initial symptoms present themselves as involuntary spasms in their arms and legs and the individuals have recognized what was happening and moved to a shallower depth/lowered their PPO2 levels. I'm not aware of basic Nitrox training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2.

 

[ianr33]

. I'm not aware of any training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2.

Err.......pretty much the entire world uses 1.6 for deco.

 

[DwayneJ]

Err.......pretty much the entire world uses 1.6 for deco.

Task loading? Depth etc? Look at the original thread and the discussion on planning your total dive to PPO2 1.6 and max depth. Seems we have moved well past basic scuba discussions - Do you also believe novices should dive to 130 ft on EAN36 or routinely plan their dive using 1.6 PPO2?

 

[Blackwood]

Hmmmmmm, sounds like I have to put a lot more dollars in to get to learn the good stuff.

Check out the 5thd-X (erm... no URD) Intro to Tech video.

It was made by one of the only people on record as having rescued a toxing diver, and that's one of the topics covered.

 

[ianr33]

Do you also believe novices should dive to 130 ft on EAN36 or routinely plan their dive using 1.6 PPO2?

No,of course not.

You said:
" I'm not aware of any training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2."

Well, stage deco training uses and recommends 1.6. for decompression. I agree this is nothing to do with basic scuba but you said ANY which is a strong word.

 

[dumpsterDiver]

To me nitrox is more dangerous if you have the potential to drop too deep for the mix at the particular dive site you are at.

Another disadvantage for nitrox divers that use partial pressure mixing..if you are ever so carelsss as to forget to check your mix, AND forget to check your pressure gage on descent...it IS possible to find yourself at 60 or 80 feet and 500 lbs of pure oxygen in your tank. It is just super, super important that nitrox divers make sure they are going down with a full tank.

when diving less than 40 feet or more than 140 I will use air. For pretty much everything in between it is nitrox.

 

[Blackwood]

Using nitrox IN RECREATIONAL DIVING hasn't yet lead to a significant decrease in the number of hits even when used within air limits regardless of the fact that having less nitrogen in your system is better as is obvious.

I maintain that, since there are so few hits anyway, statistics regarding lowered instances of DCS are flawed.

 

[DwayneJ]

No,of course not.

You said:
" I'm not aware of any training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2."

Well, stage deco training uses and recommends 1.6. for decompression. I agree this is nothing to do with basic scuba but you said ANY which is a strong word.

Thank you - You are correct and I should not have used the word "any". What I meant was basic Nitrox training and I updated the post to reflect this.

 

[Colliam7]

Question: Is there any reason why I should not use Enriched Air for every dive? Is there a reason why I would want to sometimes use AIR opposed to Enriched Air?

First, congratulations on starting a thread that has stimulated 70+ responses in less than 24 hrs. (The only things you might have done to further increase response would have been to add in a question as to whether PADI has a standard applicable to the issue, or whether divers using nitrox should be allowed to dive using only air-integrated computers for pressure information, without a SPG back-up, and therefore should be required to carry a Spare Air on every dive.) I had a similar belief about enriched air after I finished my nitrox course, and for a while used only nitrox. Now, I seldom use enriched air in the <40% range, except when on a dive holiday with multiple dives each day, where 'free' nitrox is included. Within recreational diving limits (to 130' for purposes of this post) you can select an enriched air mixture that has an appropriate MOD, so that is not a reason in itself for using AIR, as opposed to Enriched Air. Making certain that you calculate the MOD for a particular mixture for a planned dive, and that you dive according to planned depth is (or should be) a given. Jim Lap also brings up a good point about managing your cumulative (over several days) oxygen exposure (OTU's, or the CNS clock). But, even when diving only nitrox for a week of 4- or 5-a-day resort dives, it is hard to push those limits. For me, the primary reason for not using nitrox is simply added expense - I don't see enough benefit for most dives to justify the added cost. That, coupled with a very small element of added inconvenience (some fill stations take a bit longer to do nitrox fills, or 'batch' them during a day), leads me to use air for the vast majority of my recreational diving.

 

[scubaskipper]

If cost is no object, use it within safe limits. It's another tool to get the job done. I see people use nitrox on 30ft. dives. To me a waste, to them, it makes them feel better, who's to say. I personally only use it in the 80-110ft. range.