Newbie: Reg Nitrox question

[kotik]

A few places mention that diaphragm regulators should not be used as deco regs, but I don't remember if they have specific limits on O2 percentage. Do people not use diaphragms for high O2?

I've used a diaphragm regulator from the beginning with 100% O2.

 

[Storker]

A few places mention that diaphragm regulators should not be used as deco regs, but I don't remember if they have specific limits on O2 percentage. Do people not use diaphragms for high O2?

Some of the more popular stage/deco tank regulators around here are, AFAIK, the Apeks DS4 or DST. Both are diaphragms.

I guess the tech community here never got that memo...

 

[dberry]

One caveat about assuming <40% O2 is safe with any reg: some shops fill nitrox by adding pure O2 on top of a tank with air.

 

[tbone1004]

One caveat about assuming <40% O2 is safe with any reg: some shops fill nitrox by adding pure O2 on top of a tank with air.

you still have to analyze before hand

 

[dberry]

you still have to analyze before hand

Sorry, didn't get that; 'splain please. (Unless you're referring to John (NESS), who almost burned his hand off).

 

[boulderjohn]

One caveat about assuming <40% O2 is safe with any reg: some shops fill nitrox by adding pure O2 on top of a tank with air.

But your regulator never sees that. Three is no regulator on the tank when that is done, so your regulator only sees the final mix.

They are also far more likely to put the O2 in first and then add the air. You can add the O2 first followed by air, add the O2 on top of a partial mix followed by air, or put the O2 on top of air. The last choice, I would guess, is so rare to be considered nonexistent. If you are trying to end with 3,000 PSI, you want that last bit coming from the compressor or your banked air, not the O2 supply bottle being run through a booster to get the PSI up that high.

 

[dberry]

Oops, of course the regs wouldn't be on the tank during the fills. Doh.

 

[tbone1004]

Oops, of course the regs wouldn't be on the tank during the fills. Doh.

only time it would be an issue is if the fill is wrong and has pure O2 in it, or some other unreasonably high fO2 due to a bad fill. That said, the analyzers can handle it, so you should be analyzing before you leave the shop which means it won't be wit ha regulator