why hasnt nitrox replaced compressed air completely?

[chillyinCanada]

Thanks String, I think.

Hmmm

 

[djtimmy77]

I have used air tanks maybe a dozen times. During OW cert and then for a few FL Keys shallow dives...

We keep our tanks full of 36%, ready to go for 95% of our dives.. The cost increase over air fills here is negligible. If we are planning a deeper dive we adjust the tanks as necessary. Using big steel tanks, we are often limited by NDL.

 

[String]

You guys must have awesome SAC rates...

My abroad SAC rate is about 10slm and UK about 16SLM.

Even with 10 i rarely come across an NDL limited dive on most standard work dives. My standard tank is a 10l purely as its smaller and less bulky although i'll switch to a 12 for deeper ones.

 

[PhatD1ver]

first of all, nitrox doesn't double diving time, which is one reason, the second being that since you believe it does, training is required.

EAN extends the your no decompression diving time, but is unnecessary for most recreational divers because most will exhaust their primary air supply well before they reach their no-deco limits... the only time that isn't true is when they are diving between 18-40m and no-deco time can be extended to match their SAC and allow for longer time at greater depths....

But again, for the average recreational diver, the added expense just isn't worth the gains even in multi-dive scenarios...

 

[diver 85]

Cuz places then couldn't charge extra for something that's 'standard issue' @ a dive shop/resort------etc

 

[MXGratefulDiver]

Although I fully understand the desire for an increased safety margin and think I understand the point of using nitrox if you're doing three to five dives in one day, I don't really see a huge increase in bottom time if you're doing just a couple of dives in a day. With a couple of hours of SI, the type of profiles I usually dive and my SAC rate (15-16SLM or about .5 cuf in a wetsuit, 16-18 in a drysuit), it's usually gas, not NDL that's limiting my bottom time. And I'm not using an Al80, my standard tank is a 10L 300 bar or a 15L 200 bar.

You guys must have awesome SAC rates...

Depends on the profile. Take my dive last evening as an example ... 70 minutes at a max depth of 83 fsw and an average depth of 62 fsw. Even on EAN32 I ended up exceeding NDL by a couple minutes. Had I been diving air I would have exceeded it by about 18 minutes, and rather than making a slow ascent upslope that had my deco obligation cleared (per my dive computer) by the time I reached 40 fsw ... enabling me to do just a standard safety stop ... I would have had roughly 12 minutes of deco obligation remaining by the time I reached safety stop depth. And that's only for a single dive ... prior to which I had a surface interval of three days.

FWIW - I was diving a single HP130, and ended the dive with plenty of gas remaining (1400 psi) ... so gas consumption wasn't at all an issue.

... Bob (Grateful Diver)

 

[EastEndDiver]

t


if nitrox can double your diving time, effectively giving you twice the bang for your buck

Since when does Nitrox double your dive time.........I never get the memos anymore.

 

[MXGratefulDiver]

Since when does Nitrox double your dive time.........I never get the memos anymore.

I don't have the tables in front of me ... but diving standard nitrox mixes at specific depths can double your dive time compared to air, depending on which tables/algorithms you're using. RGBM comes to mind as one of the algorithms that does, at depths in the 70-90 fsw range, double or nearly so your allowable bottom time.

... Bob (Grateful Diver)

 

[drbill]

Not exactly a "modest" increase in cost out here... can easily be double the cost of air.

Despite the fact I'm a verified geezer, I've never certified for Nitrox. I may well do that in the future especially for intensive dive trips when Nitrox is "complimentary" or available at a modest cost. I've done trips where I've averaged about 7-8 hours underwater a day on air. Using Nitrox wouldn't double that!

 

[Water Boy76]

I can't believe that people are at the beginning of the thread were saying Nitrox isn't necessary because of their NDL's. Are you guys diving in 40ft of water?

My usual diving ranges from 95-130ft. If I didn't use various Nitrox blends, I would be sitting on the boat most of the day instead of diving.