New Reg For Nitrox

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CMcNally

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Port Jeff, NY
I am thinking about taking a nitrox course this summer, but I had a real quick question... I know I would need an O2 cleaned tank (which means another tank), but would I need a new regulator? I currently dive a Mares V16 Epos. Would it be as simple as replacing the o-rings (with Vitrox rings?). I'm just trying to get some info on a Friday night...cm
 
Here's Vance Harlow's musing on the subject (from his "Scuba Regulator Maintenance and Repair" book)

O-RINGS FOR OXYGEN AND NITROX SERVICE
Viton O-rings are currently fashionable for "oxy-cleaning" regulators that will be used with nitrox or straight 02. There's a lot of debate in the tech diving community as to whether they are really necessary. I personally don't bother with them except for very high F02's, and not necessarily even then. The problem isn't that nitrile O-rings will explode in 02, or even combust - just that they are not generally considered compatible for long term exposure to 02. Actually, there's no such thing as a completely 02 compatible O-ring - all O-rings degrade in a high F02 situation. It's just that some do so faster than others. There's no question that nitrile oxidizes faster than viton, just whether the difference is enough to worry about in a regulator that will see regular servicing. Aviation practice, it's interesting to note, is to use nitrile for 02 applications. Nitrile, of course, works fine with nitrox mixes in the normal recreational diving range, and many divers use nitrile with straight 02 without problems. Since your regulators manufacturer probably designed your regulator with specific o-ring compounds in mind, why mess things up if it isn't necessary? Viton O-rings behave differently than nitrile, and there's no assurance that a generic viton O-ring will perform as well as the OEM one the engineers who designed the regulator speced for it. Many manufacturers are now offering nitrox kits. There's a lot of debate as to what the point of these are, since most of the manufacturers say they are only good for recreational nitrox mixes, and those mixes work fine with an unmodified regulator. What seems to be going on is that the liability obsessed manufacturers are selling what are actually straight-02 kits and calling them nitrox kits, figuring to make a few dollars more off the more gullible nitrox divers. Usually the rebuild kits for these "nitrox regulators" can be used on the air versions of the same regulators, making them ideal for converting air regulators for straight 02, since the components of the kits come with the blessing of the factory engineers.
 
The regulator is OK as it stands but as a practical matter it depends on what the course director and fill station require. This may be a non issue, or somebody might "suggest" that you have the reg modified for Nitrox.

Technically, even for straight oxygen service, only the first stage of most regs should be subject to oxy modifications. The first stage is targeted due to the high pressure and gas speed to which it is subjected. However, in such case, it would be better to obtain a "NITROX" version of the V16 reg, or perhaps another brand altogether. Since O2 is not the objective, an ordinary, non Nitrox version of your reg should be satisfactory.

Confirmation comes from looking at the regulator components. The V16 regulator 1st stg contains nitrile and silicone rubber, and a titanium seat. I don't know what kind of grease. As indicated, these components are not suitable for exposure to O2 but should give no problem for short term exposure to EAN < 40%. However, some dive organizations may require it nonetheless.
 
In my opinion: A lot of the "hype" about nitrox is finally beginning to die.
Fact: As long as I'm diving a standard sportdiving mix and my local shop is filling with the continuous-blend or membrane method, I shouldn't need to do anything special, (except mark my tanks).
If you fill by the partial-pressure method it would be wise to have a clean tank. (It will at least keep the LDS happier)
If you dive "hot mixes", (mixes above 40%), it would pay you to service your reg.
First and foremost: Always go by your initial training.....but then realize that many of the statements you will later read are bunk. Many are created to get your money. I've used dirty 19 year old regs with 50% nitrox. I've seen 1100 psi of pure oxygen put into 12 year old dirty tanks with no ill effects. (Experience over hype) This isn't to say that you should do any of these things but just to show that some ploys are just that.
(Just listing some things that are tried and proven to me but I am not advocating them to anyone else)
Norm
 
https://www.shearwater.com/products/peregrine/

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