Nitrox and regulator cleaning

[tmds]

I'm a newly certified Nitrox diver and was told by the LDS that I cannot use my current reg setup for nitrox and that I have to buy a dedicated reg and setup. My current setup is a Mares Proton Ice with Suunto Cobra computer. It has only seen hyperclean air. I have also read on other sights that if you are not exceeding 40% O2 that you don't have to worry about your reg being clean for O2 (even one person working in LDS). Any advice would be great, Thanks in advance.

 

[Boogie711]

Your LDS is trying to screw you over. I can't believe they would try to pull that over one someone. As long as you're under 40%, you're fine.

If you were going to be breathing a Deco reg with 100%, then yes, O2 clean is definitely the way to go. But just for recreational <40% mixes? Sheesh.

 

[rab]

For the reg, you don't need anything special for up to 40%. My Nitrox instructor recommended limiting to 39% because the studies on the combustibility show increased "danger" at 40% and up.

Now the tank and the valve need to be O2 clean. Regardless of how clean the air is (Grade OCA -- Oxygen Compatible Air), if the tank and valve didn't start O2 clean, then they aren't now either. Note that this is really only required when using partial pressure blending (pure oxygen into an empty tank topped off by air). If you're getting a fill from a continuous blend membrane system or from banked Nitrox, then you don't need the tank/valve to be O2 clean either. It's the contact with high-pressure O2 that is the concern.

-Rob

 

[padiscubapro]

For the reg, you don't need anything special for up to 40%. My Nitrox instructor recommended limiting to 39% because the studies on the combustibility show increased "danger" at 40% and up.

Now the tank and the valve need to be O2 clean. Regardless of how clean the air is (Grade OCA -- Oxygen Compatible Air), if the tank and valve didn't start O2 clean, then they aren't now either. Note that this is really only required when using partial pressure blending (pure oxygen into an empty tank topped off by air). If you're getting a fill from a continuous blend membrane system or from banked Nitrox, then you don't need the tank/valve to be O2 clean either. It's the contact with high-pressure O2 that is the concern.

-Rob

Rob,
Any store that wishes to maintaing their insurance (that includes those with membrane systems) if they are filling aluminum cylinders, both Catalina and finally luxfer have made it clear in their policies that ANTHING over CGA limits (thats 23.5%) must be maintained for oxygen service.. Both luxfer and catalina cylinders ARE oxygen clean from the factory.
Don't take my word for it go to http://www.catalinacylinders.com/oxycomp.html

Luxfer hasn;t updated their web site but I'm attaching a PDF from Luxfer.

I havent seen anything from PST or Faber yet but I hope its comming and we can finally end the 40% nonsense.. There have been NO STUDIES saying 40% is OK your instructor is misinformed.

The experts on Gas handling (NASA, CGA, HSE) all require anything above normal atmospheric oxygen to be handled as OXYGEN.
Most of todays modern regs use Oxygen compatible components and should be ok with weaker nitrox mixes out of the box. If they are compatible they will state it in the manual, if not most are easily converted with the proper cleaning, orings, and lubricants. Some manufactures have regs that out of the box can be used as decompression regs those will generally state so also.
I have done many repairs on regs I know have used weak nitrox mixes that have gone back and forth between oxygen compatible air and "standard" air.. It shows.. There are the usualy signs of incomplete combustion, Usually on the high pressure seat.. The usualy complaint is that the reg is free flowing or "burps" when not being actively breathed off of. This is a sign of IP creep.
Regulators that are using just Burna-N orings typically need service much sooner than those with the correct materials.. An active diver probably needs the regs serviced withing 6 months.. The orings become brittle and start to flake..
At lower Oxygen concentrations a "fire" is not as likely as a Rich deco mix but that does not mean things are not happening behind the scenes. Incomplete combustion can be very bad.. Even if the orings don't burn, alot of co and co2 is generated which could be very bad for the diver, if a contaminated Viton O ring burns, it creates PHOSGENE gas which is deadly.. Any time a diver goes back and forth they are rolling the dice, most of the time it will end up in their favor, but even if it comes up just once thats it...

 

[miketsp]

This was also discussed on thread
http://www.scubaboard.com/t57957.html

My USDivers/Aqualung Micra reg is only rated to 23.5% O2 according to manufacturer.

 

[MikeFerrara]

First of all I think all tanks and regs should be "clean" but beyond that...

Rob,
Any store that wishes to maintaing their insurance (that includes those with membrane systems)

All either of my 2 insurance companies ever required was that I meet agency standards. Both IANTD (the first agency to offer nitrox training to rec divers) and PADI say that anything under 40% doesn't require O2 sericed equipment. They both recommend following the manufacturers recommendations of course. I think the NOAA says the same thing.

if they are filling aluminum cylinders, both Catalina and finally luxfer have made it clear in their policies that ANTHING over CGA limits (thats 23.5%) must be maintained for oxygen service.. Both luxfer and catalina cylinders ARE oxygen clean from the factory.
Don't take my word for it go to http://www.catalinacylinders.com/oxycomp.html

Luxfer hasn;t updated their web site but I'm attaching a PDF from Luxfer.

I havent seen anything from PST or Faber yet but I hope its comming and we can finally end the 40% nonsense.. There have been NO STUDIES saying 40% is OK your instructor is misinformed.

PST tanks come O2 clean. I got that from PSI.

The experts on Gas handling (NASA, CGA, HSE) all require anything above normal atmospheric oxygen to be handled as OXYGEN.
Most of todays modern regs use Oxygen compatible components and should be ok with weaker nitrox mixes out of the box. If they are compatible they will state it in the manual, if not most are easily converted with the proper cleaning, orings, and lubricants. Some manufactures have regs that out of the box can be used as decompression regs those will generally state so also.
I have done many repairs on regs I know have used weak nitrox mixes that have gone back and forth between oxygen compatible air and "standard" air.. It shows.. There are the usualy signs of incomplete combustion, Usually on the high pressure seat.. The usualy complaint is that the reg is free flowing or "burps" when not being actively breathed off of. This is a sign of IP creep.
Regulators that are using just Burna-N orings typically need service much sooner than those with the correct materials.. An active diver probably needs the regs serviced withing 6 months.. The orings become brittle and start to flake..
At lower Oxygen concentrations a "fire" is not as likely as a Rich deco mix but that does not mean things are not happening behind the scenes. Incomplete combustion can be very bad.. Even if the orings don't burn, alot of co and co2 is generated which could be very bad for the diver, if a contaminated Viton O ring burns, it creates PHOSGENE gas which is deadly.. Any time a diver goes back and forth they are rolling the dice, most of the time it will end up in their favor, but even if it comes up just once thats it...

I can't argue what you've seen but I haven't seen HP seats damaged by nitrox. The "nitrox kits" I've seen for regs didn't even come with a different HP seat that I remember.

As far as I'm comcerned lacking any "studies" our own experience of thousands of fills and lots of nitrox use is enough. Sure once in a while some one smokes something while pumping or boosting pure O2 but I haven't ever heard of any problem with mixes under 40%. I haven't even noticed o-rings wearing faster.

 

[chrisch]

European regulations also kick in at 23%, but only for the commercial users. Sports divers all work to 40%.

Has anyone had experience running 50% through standard regs? I am mystified as to why it should be accepted at 40% - the NASA stuff on O2 cleaning doesn't really support the 40% theory.

Chris

 

[MikeFerrara]

Has anyone had experience running 50% through standard regs? I am mystified as to why it should be accepted at 40% - the NASA stuff on O2 cleaning doesn't really support the 40% theory.

Chris

I have.

I think the only significance of the 40% is that's what recreational nitrox classes usually go up to.

 

[padiscubapro]

All either of my 2 insurance companies ever required was that I meet agency standards. Both IANTD (the first agency to offer nitrox training to rec divers) and PADI say that anything under 40% doesn't require O2 sericed equipment. They both recommend following the manufacturers recommendations of course. I think the NOAA says the same thing.

Mike two minor corections but Agency standards dont "recommend" last time I checked the manufacture standards had to be followed, but the agencies do have guidelines for when there is no manufacturer policy in place.

2nd of all IANTD WAS NOT the first Agency It was IAND.. not the same company but it was the precursor to IANTD.. IAND was formed By D.R. and up until the formation of ANDI by D.R. and E.B. IAND only had a handful of certifications (mostly friends and relatives) and the cards were produced by E.B. for the most part. In 1988 ANDI (it was meant to replace IAND) was formed by D.R and E.B. Eventually D.R and E.B parted ways, and IAND truely started and shortly thereafeter IANTD came into being in the early 90's I dont remember the eact year (probably 90 or 91).

And Before taking over IANTD Tom was an IT for ANDI, a few other people left ANDI with him including Bret G. (only an instructor at the time). Many of the heads of the other agencies were with ANDI originally...

ALso I don't know how long you have been in the Industry but for Dema 91 or 92 (I dont remember the exact year) PADI, Skin DIver And DAN originally had ANDI and IANTD banned from dema for promoting a gas that was "going to kill hundreds of divers". In fact DAN even said the divers who were using Nitrox could NOT be treated if they were bent.

Somewhere around 94, Padi began to allow distinctive specialties to instructors who were Nitrox instructors from ANDI and IANTD.. somewhere around 96 it became officially endorsed with a standard outline..

 

[Sideband]

IF, a tank must be O2 clean for anything over 23%, and
IF filling with standard air contaminates that O2 clean status,
Then anyone that gets a EAN fill using partial pressure will need to stop filling their tank and get it recleaned. Partial pressure fills contain all the same nasties that a standard air fill would from that compressor. In fact, a commercial premix would probably be the only viable fill method to keep the tank "clean". I doubt many shops will have a compressor that they use only for EAN fills and a seperate compressor for standard air.

I don't but the whole idea. PADI and NAUI both teach 40% as the limit for needing specially cleaned equipment.

Joe