the difference between air and regulators that doboth air and oxygen

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STOGEY

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What is the difference between regulators that you can use with just air and regulators that you can use with both oxygen,air and other mixed gases?

Also if you used a regulator that was designed for just air would it seaze up if you used it for mixed gases and oxygen?
 
As you know air already contains O2 but at a relatively low percentage.
Increasing the O2 percentage increases the ease with which certain materials will spontaneously ignite - Spontaneous combustion happens when the heat produced from oxidation is enough to ignite the substance without a spark.

So for a reg to be O2 clean you need to avoid the use of certain types of rubber compounds in o rings, certain lubricants and some sealing materials. Also remove any residual dirt subject to spontaneous combustion.

Check the manufacturers specs for the ratings of your reg with and without O2 cleaning.
 
PLEASE CORRECT ME IF I'M WRONG, but...

Just about any "99/100% oxygen" regulator would probably deliver air. The problem is that most SCUBA "grade E" air fills are not oxygen compatible because grade-E air contains traces of hydrocarbons (compressor oil) that while not poisonous to breathe, will "contaminate" the regulator. The next time pure oxygen is used there would be a serious fire risk. And re-oxygen cleaning the reg will rapidly become so expensive that you may as well buy another set to dedicate to your other gas or gasses.

As far as I understand, this is the reason that a pure-O2 regulator is usually kept only for that task. However, I would think that using oxygen-compatible air (if you can find it and trust the source) would be fine.

Another issue... many of the O2 regs are moderate-performance setups, because you'll be breathing gently (hanging or drifting on deco) and at a depth of less than 20 feet. Perhaps they're also detuned to prevent freeflow while you're breathing your other gasses. So they may not be wonderful performers at greater depth.

Thoughts, anyone?
 
STOGEY:
Also if you used a regulator that was designed for just air would it seaze up if you used it for mixed gases and oxygen?


Nope. As long as it doesn't blow up during filling it should be fine. :D

ps - blowing up a tank or reg is very very rare. this is one of those "better safe than sorry" issues.
 
Cleanliness, the kind of lubricant and the material that "rubber" parts like O-rings are made of (Vitron for high oxygen)
 
You could put O2 through an O2 clean reg, or hyper-filtered air through it.

however, like O2 clean tanks, eventually they'll get dirtier with each use. best not to use an O2 clean air for anything except o2.
 
STOGEY:
What is the difference between regulators that you can use with just air and regulators that you can use with both oxygen,air and other mixed gases?

Also if you used a regulator that was designed for just air would it seaze up if you used it for mixed gases and oxygen?
Pretty much any reg can be used for concentrations of oxygen (EANx) below 40%.

Regulators for gas that contains concentrations of oxygen above 40% should be cleaned of hydrocarbons and use oxygen-compatible parts (i.e. no rubber or plastics that are easily combustible).

Titanium regulators are not recommended for higher concentrations of oxygen.

Type of regulator used with other gases such as helium and argon isn't a concern, since they're inert. However, since mixed-gas divers are typically going deep, performance should be a primary concern.

... Bob (Grateful Diver)
 
https://www.shearwater.com/products/teric/

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