Nitrox Certification?

[ericrd]

I think a lot of people would disagree with that. It depends on *how* you go about things as much as the tools you use.

The reason agencies refuse to publicly acknowledge the safety benifits may have more to do with liability than you think. The PADI public line and the things they write to their members, for example, are completely opposite on this point.

Moreover, all of these "safe enough" arguments are a load of b.s. if you're the one getting the hit. DCS incidents are still very common and I see nothing wrong with tilting the odds in your favor.

R..

Hence my addition - you tend to dive to the limits... when you'r 2 mins away from deco, I dont think it makes much difference whether you're on air on nitrox - you're close to the line !

eric

 

[El Tiburon]

I also get less dry mouth with Nitrox.

 

[Diver0001]

Hence my addition - you tend to dive to the limits... when you'r 2 mins away from deco, I dont think it makes much difference whether you're on air on nitrox - you're close to the line !

eric

Well that's certainly true. But being able to do something doesn't force you to do it either....

Maybe a car analogy would work.

Say your old car was able to go 120km/h and you drove it 100km/h..

Now say you buy a new car that can go 220km/h as safely as your old car went 120 but you still only drive 100......

Most people would feel safer (and rightly so) in the new car, I think.

That's the effect of diving nitrox on air schedules that I was talking about.

R..

 

[RonFrank]

I am seriously thinking of getting my nitrox certification. Could someone please give me some reasons why I should do it. Are the only benefits: slightly more bottom time & maybe feeling better after a dive.

When I was in FL, I dived a three tank dive at Jupiter. The Reef is about 70', and the entire dive is 70-80fsw. So Nitrox rocked. We were doing 45 minutes BT, and the one guy doing air was coming up after 30minutes.

If you are diving the Largo Reefs, Nitrox is rather un-necessary. Of course if you are dong 5 dives a day, you MAY feel better doing EANX36.

If you are diving the Grove, Nitrox is a good idea. Just make sure you limit the max depth if you are doing a mix that will not allow diving below 120sfw. I hit 117fsw, and really did not realize I was that deep until I looked at my puter. However I was diving Air so depth, while important, was not something I was worried about. The bottom I think is 130fsw.

 

[ScubaSixString]

Hence my addition - you tend to dive to the limits... when you'r 2 mins away from deco, I dont think it makes much difference whether you're on air on nitrox - you're close to the line !

eric

If you dive on AIR tables while using nitrox (assuming you still consider PO2) there is a safety margin. I don't have my tables with me right now but if you dive to 80 ft on EAN36 and stay within the AIR NDL (30 mins.) there is quite a safety margin there.

The behavior of SOME divers isn't a factor, as if you want the added safety factor you have to behave that way. Its the same as saying the safety on a gun provides no safety because some shooters leave it off.

 

[m3830431]

slightly more bottom time & maybe feeling better after a dive.

No more bottom time when your SPG hits 500 psi it is still empty.
Biggest advantage is less wait between dives and the unofficial
version it makes you feel better on a three dive day. It doesn't do
anything except limit your depth on a one dive day.

It isn't called geezer gas for nothing. :11ztongue

 

[WellBelowH2O]

No more bottom time when your SPG hits 500 psi it is still empty.
Biggest advantage is less wait between dives and the unofficial
version it makes you feel better on a three dive day. It doesn't do
anything except limit your depth on a one dive day.

It isn't called geezer gas for nothing. :11ztongue

Sure, if you're dives are limited by what you have left in your tank, than all it does is decrease your SITs. But for those of us with decent air consumption rates, our limiting factor is nitrogen loading, not air.

 

[HowardE]

I dive EANx36 in Boynton Beach, FL, and most of the dives are to depths of 60-70' on average... I usually get 1 hour of bottom time, which on the PADI RDP I would be a PG of S with the nitrox, but on air, my limit would be 55 minutes period. If air consumption is an issue for you, then nitrox may not be the answer... if you're good on your gas consumption, then nitrox adds quite a bit of bottom time.

 

[The Kraken]

A couple of things to keep in mind when considering Nitrox certification is the combination of your personal SAC rate, the type tank you're diving and the average depths to which you dive.

The occasional, recreational diver will probably have a SAC rate of .60 CFM or higher and will be diving an Aluminum 80. The average dive depths will probably be from 50 to 70 feet deep.

Given a SAC rate of .60 on an Aluminum 80 and having 500 psi at the end of the dive, the diver will have only 42 minutes bottom time at 50 feet and 34 minutes at 70 feet.

Using EAN36, the suggested bottom time for 50 feet is 150 minutes and 60 minutes for a dive to 70 feet.

Diving regular air, the diver will have a recommended bottom time of 63 minutes at 50 feet and 33 at 70 feet.

To really optimize a Nitrox certification the diver needs to give consideration to using a larger volume tank.

the K

 

[pants!]

Kraken, your post only applies to the first dive of the day.

Go back through your calculations and see how much bottom time a diver has after two dives on air to 70 feet for 34 minutes with a 1 hour SI.

You will notice that the diver would only have 25 minutes on air on just the second dive of the day even though that Al80 will last 34 minutes, and 22 minutes for the third.

By contrast, the same diver can bleed the tank dry (within reason, of course) on all three dives by just using EAN32.