Use of non-O2 clean regulators for 50% deco mix

[Caveman]

This has been on my mind for a while and I was hoping a few people on this forum can weigh in.

It seems to be a generally accepted norm that pretty much any reg on the market can handle EANx mixes up to 40%. But what is the general feeling amongst tech divers around the globe for using regulators that aren't O2 clean for 50% deco stages? Opinion on the subject seems to be very divided from the people I have met during my diving career. There are those who believe that it is not necessary to O2 clean a reg for 50% as long as you do not go beyond and so long as you open the tank valves with care, and then there are those who are adamant that regs need to be O2 clean for any mix above 40%.

Any feedback will be much appreciated.

 

[Celt]

My philosophy when dealing with oxygen is simply, if I can 100% eliminate any one of the 3 things needed for combustion ( heat, fuel, and oxygen) I’m happy, but others might not.

 

[Oldbear]

What does the manufacture recommend? There are REASONS why a manufacturer will only rate a reg at 40%, 50%, 80% etc. It is usually in the engineered design, materials made from and intended use.

If you want a reg that uses EAN 50...get one rated for it.

 

[Searcaigh]

All my stage regs are O2 cleaned.

 

[Zef]

This has been on my mind for a while and I was hoping a few people on this forum can weigh in.

It seems to be a generally accepted norm that pretty much any reg on the market can handle EANx mixes up to 40%.

This is based on lubricants and internal parts such as viton o-rings compared to nitrile. The manufacturers/brands generally state that regs are clean enough to use with 40% mixes straight out of the box.

But what is the general feeling amongst tech divers around the globe for using regulators that aren't O2 clean for 50% deco stages? Opinion on the subject seems to be very divided from the people I have met during my diving career. There are those who believe that it is not necessary to O2 clean a reg for 50% as long as you do not go beyond and so long as you open the tank valves with care, and then there are those who are adamant that regs need to be O2 clean for any mix above 40%.

Any feedback will be much appreciated.

I am not a tech diver but dive with a bunch of people who are. I believe the general consensus, at least here in Belgium, is that the higher the %O2 the more likely one might experience a bad day when not using properly O2 cleaned equipment. Fire makes for a particularly scarring bad day, so if one is going to choose which way to err, it is best to err on the side of prudence and use O2 clean regs with O2 compatible components like viton o-rings. Another plus for viton o-rings is that buna-n o-rigs are said to breakdown quicker in the presence of higher concentrations of O2 whereas the viton ones are much less affected...this translates into potential increased frequency of failure or need for service if using standard o-rings with frequent higher than normal O2 applications.

-Z

 

[Jim Lapenta]

PM sent. O2 cleaning procedures if set up as a standard practice take no longer and cost maybe 50 cents more for o2 compatible lube and gloves for reg service.
Even if the kit does not come with o2 compatible orings, using the same procedure is just good practice as far as cleaning, reducing the risk of contamination, and keeping things organized.

 

[Kohanbash]

Does peoples opinion change for first stage vs second stage and O2 clean requirements?

 

[StefinSB]

Does peoples opinion change for first stage vs second stage and O2 clean requirements?

The 2nd stage doesn’t see high pressure ... That being said, if you already us O2 cleaning procedures for the 1st stage, there is no reason to suddenly abandon that for the 2nd.

 

[Bigbella]

Many of whom I know in the commercial diving industry, are of the mind that most of the regulators, manufactured today, can already tolerate higher percentages of O2 than their ratings would suggest; that the warnings come as more of a manufacturer's effort at c.y.a than anything else; that combustion can potentially occur with either nitrile or viton o-rings; and that the combustion products of viton o-rings and their lubricants, though somewhat less common, are far more toxic, than that of conventional nitrile.

Some manufacturers of full-face masks, for example -- Poseidon, among them -- only officially approve of their use with 21% O2; but have been heavily used within the industry, with far, far "richer" mixes than that, for decades . . .

 

[Centrals]

2nd stage is not an issue while there is concern on the 1st stage because of the pressure.
As already suggested: suitable O-ring and lube(eg. MCG-111) as well as keeping the dust away!