Nitrox

[Mr. Nice Guy]

Hello,

Am thinking about taking a course. Is there a benefit of using Nirtox when diving cold water?

 

[MechDiver]

IMO, there is a benefit to diving nitrox, period.

In fairness, there are numerous threads on the board that deal with pros and cons of nitrox. You might do a search using "nitrox" and read those over.

MD

 

[Uncle Pug]

Nitrox is all we dive <100'... we never use air (unless on a trip and nitrox is not available.)

However...

That would not be workable if we had to rely upon an LDS for gas fills... even here in the PNW.

Make sure that:
1. Nitrox is available.
2. The price is with in reason.
3. That *availability* is practical for you.
4. The LDS does not exhibit *nitrox paranoia*.

 

[Mr. Nice Guy]

I did read some of the 57 post.

One included the following
"Just finished my nitrox class
The benefits as they were explained in class are:

1. If you dive to the NDL limit, then Nitrox will give you better bottom time and can shorten your SIT time.

2. If you dive nitrox as you do on air then it is safer.

3. It extends the depth at which you may get narced.

4. Generaly people say they feel better after diving Nitrox."

I didn't see mention of a benefit of using Nitrox in the posts that I have. I id not read all the posts.

I just received a flyer from the one and only dive shop in the local area which states in an ad for a Nitrox class "If you are a cold weather diver you need this class"

I was wondering if there was an actual benefit from Nitrox in diving cold?

 

[Uncle Pug]

Mr. Nice Guy once bubbled...
I was wondering if there was an actual benefit from Nitrox in diving cold?

...cold water increases the risk of DCS.... Nitrox decreases the risk of DCS... if used to increase safety rather than to extend bottom times. No free lunch.

BUT... the issue remains... what kind of availability of nitrox fills can you expect from the LDS that is the only game in town?

 

[Mr. Nice Guy]

Thanks for the responses.

What would be in questions regarding availability?

If it was available? Or is there a quality issue? Or the mixtures?

 

[Jester]

If the LDS is offering the Nitrox class, one would have to assume they can do/can get Nitrox fills. Otherwise, they'd be steering their business to someone else.

 

[Uncle Pug]

Mr. Nice Guy once bubbled...
What would be in questions regarding availability?

The key word is practical availability.

Do they require your tank overnight for a fill?

OR

Do you need to drive a significant distance to drop off a tank for fill and then wait either for several hours or come back the next day?

OR

Do you need to drop the tank off and wait a week to get it back?

OR

Do they charged $12~15 a fill ... (especially annoying if you are only getting the top half of the tank filled!)

OR

You find that the tank fill person can't fill your tank with nitrox... only the *boss* can do that.

OR

You get the feeling that they think they are doing you a favor by filling your tank.

All of the above are what I found to be SOP for nitrox fills in my neighborhood (lotsa shops in the Puget Sound area)... and it just didn't cut the mustard... so I put in my own fill station... but then you might not find that practical

BTW Hoover... MNG stated that this was the one and only dive shop around.

 

[Mr. Nice Guy]

I have not taken the class yet, as is obvious.

Do you need a "special tank" for nitrox or can the same tank be use for both air and nitrox?

Thanks

 

[Diver0001]

Uncle Pug once bubbled...

...cold water increases the risk of DCS.... Nitrox decreases the risk of DCS... if used to increase safety rather than to extend bottom times. No free lunch.

BUT... the issue remains... what kind of availability of nitrox fills can you expect from the LDS that is the only game in town?

As far as I know there are no studies to support the claim that Nitrox reduces the risk of DCS. You might want to flip this into the deco forum for Dr. Powell's opinion.

Having said that, if you use Nitrox with air tables or then you will obviously be further from your NDL's, and it stands to reason that this is safer than air on the same profiles. You can also express this as "if it was a nodeco dive on air than using nitrox makes it even safer". I won't argue that point (which I suspect is the point you were trying to make) but I will make 2 comments about it. (1) there is no experiemental evidence (yet) to support this claim. The logic of the claim, however, is so convincing to me that I'll accept it as fact. And (2) statistically you have about 1:100,000 chance of getting a DCS hit if you dive air within the air tables. It's unclear to me if a using nitrox will really give us a statiscally significant improvement in these numbers. Maybe in the 5th or 6th place behind the decimal. Improving you skills, (controlled slow ascents, safety stops, staying away from the limits, using proper exposure protection and taking into account the DCS predisposing factors) are also very important in avoiding DCS and likely have a bigger impact on your safety.

The thing that people forget is that not all Nitrox dives fall within the air limits and using Nitrox with Nitrox tables is like using air with air tables. You could also express this as "if you dive to the limits on Nitrox then you have a similar risk of DCS as when you dive to the limits on air.

I suspect we agree about this but I just wanted to put that under a magnifying glass for the sake of "Nice guy" who might not have seen the connection when he read your post.

R..