To Nitrox or not to nitrox ,Why and how ?

[AfterDark]

OK so what are the advanages of NITROX? Recently I'd been diving with a partner that used NITROX. I don't what mix but the max depth for the dive was 120fsw. I dive with air. When my bottom time was at 10 min left I infromed him of that fact. He showed me his PDC it indicated he had 13 min bottom. WTF around here a NITROX costs $30.00 air is $7.00. What advantages does one get for the extra $27.? What is the NITROX advantage?

 

[Blackwood]

OK so what are the advanages of NITROX? Recently I'd been diving with a partner that used NITROX. I don't what mix but the max depth for the dive was 120fsw. I dive with air. When my bottom time was at 10 min left I infromed him of that fact. He showed me his PDC it indicated he had 13 min bottom. WTF around here a NITROX costs $30.00 air is $7.00. What advantages does one get for the extra $27.? What is the NITROX advantage?

As I believe has been mentioned, the differences on a single dive are very depth-dependent, and the overall differences are much more evident on repet dives.

Here's a simple single-dive comparison to illustrate the depth effect.

*I'm not sure about that NAUI EAN32 @ 120' number, it doesn't seem to scale.

 

[Steve50]

WTF around here a NITROX costs $30.00 air is $7.00. What advantages does one get for the extra $27.? What is the NITROX advantage?

The deep appreciation from whoever charged you $30 for Nitrox...

 

[Tortuga68]

What PPO2 are they using for those tables, 1.6? The 'normal' MOD for recreational EAN32 is 110'

The other benefit, as already mentioned, is reduced SI (again for repeat dives obviously)

WTF around here a NITROX costs $30.00 air is $7.00. What advantages does one get for the extra $27.? What is the NITROX advantage?

If you can't subract 7 from 30 then nitrox might not be the right gas for you

 

[Blackwood]

What PPO2 are they using for those tables, 1.6? The 'normal' MOD for recreational EAN32 is 110'

Some or the 32 tables I've seen go to 120 (1.5), and some to 130 (1.6). I don't recall seeing one bottom out at 110 (1.4).

 

[Tortuga68]

Interesting. I know it varies between agencies etc but I thought 1.4 for NDL and 1.6 for deco were accepted maximums. Apparently not

 

[Blackwood]

Interesting. I know it varies between agencies etc but I thought 1.4 for NDL and 1.6 for deco were accepted maximums. Apparently not

They certainly may teach 1.4 or 1.2 max planned po2, but many (most?) still "allow" 1.6 as contingency/emergency.

 

[Tortuga68]

Understood, but contingincy isn't MOD (by normal definitions of MOD) and therefore I wouldn't have thought it would be used for tables

But it seems clear that 1.5 was used for the posted table

I still don't get the anomally that you pointed out (110 and 120 have same NDL)

 

[Blackwood]

Understood, but contingincy isn't MOD (by normal definitions of MOD) and therefore I wouldn't have thought it would be used for tables

These tables may predate the current recommendations. Idunno.

Also, why provide less information? Say I have to go down 10 feet to help free an entangled diver. What kind of deco do I do? Am I still on a no-stop profile?

I still don't get the anomally that you pointed out (110 and 120 have same NDL

Same NDL and 120 seems much too high. I may have copied it down wrong. Will have to check against a table.

 

[Tortuga68]

Also, why provide less information? Say I have to go down 10 feet to help free an entangled diver. What kind of deco do I do? Am I still on a no-stop profile?

I get your point, but I don't think that it shoud be included in the 'standard' table. NDL is NDL, whether it's based on 1.4, 1.5 or whatever. Can you get away with more if you need to, sure. Anyway, the table is probably based on 1.5 as you said. Still don't know why it has the same time for 120 as 110