Nitrox to Air

[ScubaBill1955]

I recently got to HP100 steel tanks. One had 26% nitrox and the green nitrox label on it. The other one had the green nitrox label on it but was filled with "regular" air. I was thinking of just using regular air in them as I will probably not have a need for nitrox. (I am nitrox certified).

I was told by a LDS that if I go from nitrox to air or air to nitrox that I would have to have the tank "cleaned" for both. Does that sound right?
They currently have stickers that say they have been cleaned for 22% or above air mixture.

The cost would be $35.00 to have them cleaned. Maybe I should just keep using nitrox.

 

[AndrewJD]

Not right. You shouldn't have to worry about switching between Nitrox and Air. Any shop that can give you Nitrox should be able to give you the 21% variety as well.

Jonathan

 

[Xaryo]

I was told by a LDS that if I go from nitrox to air or air to nitrox that I would have to have the tank "cleaned" for both. Does that sound right?

It depends on the cleanliness of the air used. If it is air used for partial pressure blend, there is no need to make your cylinders "O2 clean" again. That air won't contaminate your cylinders.


If the air is not compatible for partial pressure blend i.e. not "O2 clean" and you want to put nitrox after that, you must clean your cylinders again or use premixed nitrox.

A detail you should mention is: specify if the stickers are simply a "Nitrox" band or a "O2 clean" sticker. There is a big difference.

If you got your cylinders second-handed, I would take no chance and clean them for Oxygen service.

Maybe I should just keep using nitrox.

No, just making sure the air you use is clean.

 

[sunkmail]

It somewhat depends on what the dive shop uses to fill your tank ...

All the shops I know use 'clean' air ... it's the same air they use to make the nitrox, so no extra cleaning is required when switching between nitrox and regular air.

I have heard that some places, mainly those that do not have nitrox, don't have the same filtering on the compressors, and they do need cleaning before going to nitrox.

I can't see any reason why you would need to clean your tank to go to regular air - if anything (worst case), you would be cleaning your tanks to put dirty air in them. If your LDS says you do (need cleaning), you may want to get them to explain why.

Another thing to remember, air can also be called EAN21

 

[coldsmoke]

Tanks only need to be o2 cleaned if the nitrox is made by partial pressure blending in the tank.

There is no need to o2 clean your tanks if the shop is continous blending.

There is no need to o2 clean tanks to put regular air in, but some shops might not put regular air in without removing the o2 clean sticker. In which case you would likely need to re-o2 clean them before pp blending.

Nitrox stickers are usless and are not required although some shops say they are.

AndrewJD is right. If the shop is pp blending then they can supply you with clean air so that you don't have to re-clean your tanks.

Basically there's lots of misinformation out there and much of it comes from the LDS. But, it's their compressor they make the rules.

Do a search and you'll find days of reading.

Hunter

 

[rstofer]

Nitrox stickers are usless and are not required although some shops say they are.

The Nitrox sticker should warn divers not trained in Nitrox that the gas in the cylinder is NOT air and they shouldn't just grab the cylinder (however they might accomplish that) and start diving.

Personally, I like the VooDoo Gas stickers better. Particularly the one that warns the unsuspecting diver not to use the tank even is someone tells them to.

I have Nitrox stickers on all of my tanks. There is Nitrox in just 2 but, should I decide tomorrow to put Nitrox in the little 50s there is no reason not to. All I have to do is add the blend label with MOD and %O2. As it is, the air tanks have a blend label with 185 feet and 21%

The good news is that my LDS fills tanks with the same air they use for partial pressure blending - SafeAir they call it. So, my tanks are O2 cleaned, labeled for Nitrox and ready for any blend I need.

Richard

 

[Nismo]

A long as you stay below 40% oxygen you are ok.

 

[divestoclimb]

A long as you stay below 40% oxygen you are ok.

According to Luxfer (or at least their lawyers), that's not true.
If you're partial pressure blending, that's definitely not true.