Nitrox fills

[tbone1004]

So there isn't a specific technical reason not to bank 40% and top it off with air for leaner mix except your dive profile doesn't need/use 40%?

correct. for what I want, it would require two banks, one of air, one of ean32, or firing up the compressor more regularly. Too much work, not enough benefit.
If helium wasn't so expensive, I'd consider banking ean36 or ean40, but would have to get on trimix sooner. Combine that with the fact that most of the cave and coast shops bank ean32, it makes sense to keep within what has been standardized.

 

[Caveeagle]

There isn't, the only reason people dont use nitrox all the time because it cost more than air usually

..or is not available.
....or they only offer pp blending which is a pita.

Banking 40% wouldn't make sense when two of the most popular spots are 90-95' which would put you over 1.4 po2

 

[BRT]

i believe in standard gases and 32% is an ideal balance for most caves and ocean dives. Banking EAN40 would require adding helium or air to almost all of my tanks when diving in the caves in Florida.

The only time they will really go down is when I'm teaching and have access to free air fills but not my compressor, and in cave country, most everything is banked ean32

I've done a bunch of shallow dives on 32% cause that is all I pump!

 

[BoltSnap]

..or is not available.
....or they only offer pp blending which is a pita.

Banking 40% wouldn't make sense when two of the most popular spots are 90-95' which would put you over 1.4 po2

If you are banking 32% and 21% air, you can bank 40% instead of the 32% and top off with air if you need less than 40%. Simple!

 

[BoltSnap]

To what pressure do Nitrox fill operations in the US fill in their Nitrox O2 bank systems? What is the highest pressure you see for Banked Nitrox?

 

[tbone1004]

To what pressure do Nitrox fill operations in the US fill in their Nitrox O2 bank systems? What is the highest pressure you see for Banked Nitrox?

regarding the banks, you can certainly do that, but it involves extra steps in the filling process. If you're banking both, you need a lot of long dives at 80-90ft and very few in the 100ft range to justify.

regarding the pressure. In cave country, 5000psi banks of ean32 are common. The tanks used are quite often former submarine ballast tanks so the pressure of the compressors is the limitation. 6000psi compressors are about as big as they get and those are incredibly expensive, typically close to 2x the price of 5000psi compressors

 

[teknitroxdiver]

If you are banking 32% and 21% air, you can bank 40% instead of the 32% and top off with air if you need less than 40%. Simple!

If 32% fits most of your dives (it does in cave country), banking 40% would just make more work for you. Instead of a single fill straight from the 32, you'd have to do two calculated fills every time. Better to bank 32 and partial-pressure blend on the rare occasion you want a richer mix. Keep the most common situation the simplest to accommodate.

 

[BoltSnap]

regarding the pressure. In cave country, 5000psi banks of ean32 are common. The tanks used are quite often former submarine ballast tanks so the pressure of the compressors is the limitation. 6000psi compressors are about as big as they get and those are incredibly expensive, typically close to 2x the price of 5000psi compressors

So no issues with going to higher than 3000PSI in the bank system with 40% or less Nitrox?

 

[BoltSnap]

If 32% fits most of your dives (it does in cave country), banking 40% would just make more work for you. Instead of a single fill straight from the 32, you'd have to do two calculated fills every time. Better to bank 32 and partial-pressure blend on the rare occasion you want a richer mix. Keep the most common situation the simplest to accommodate.

I understand your point, the end user demands 32% in most cases and thus it is most efficient for them to bank the most popular mix in their situation. I am referring to the situation where there isn't a typical mix and people plan their gas fill according to their dive's max depth.

 

[BRT]

Hard to go wrong with 32% in rec diving. Takes a shallow breather to get into decompression with 2 dives of 32%.