Nitrox - how to choose a regulator?

[Sasha_K]

Here is an odd question. Should the regulator (and/or gauges/computer) be specially marked that they can handle nitrox. Or can you use any reg for it?

I tried to educate myself a bit more, but search engines are not returning much - except for wikipedia entry - http://en.wikipedia.org/wiki/Enriched_Air_Nitrox

Thanks

[NitroWill]

Most any regulators will be just fine for recreational use of Nitrox..You only need to worry about nitrox compatibility when you get into higher levels of O2.. IT basically comes down to the grease and the viton o-rings. Most of the regs on the ST web site say if they are nitrox capable - but even if they dont say - they probably are ok for basic nitro use..

[ScubaToys Larry]

Here's a page you may want to look at: http://www.scubatoys.com/store/joelarry/nitrox.asp

[subsur]

what i learned at my Nitrox class - for O2 levels up to 40%, any reg should be fine. For higher O2 content, you should consider regulators specifically made for it. Some reg manufacturing company would say that you should only use reg XXX for O2 higher than 21% but it's probably their marketing strategy, maybe buna 0-rings are changes to viton.

[Sasha_K]

Great post Larry. Follow up question.

Ok, the problem lies in the fact that oxygen, under high pressure, can cause spontaneous combustion when it comes in contact with hydro-carbons. By using a membrane, or a continuous blended system, you can avoid the problems with the high pressure O2.

Does that mean that the 'piston' setup is not safe for nitrox?

[nferra2]

That refers to when they fill the tank. Some shops put pure oxygen in the tank, and then top off with air until they reach the desired level of oxygen. Some shops blend the gas as they fill your tank, so you never have a high concentration of oxygen in your tank.

[ScubaToys Larry]

Correct! So when it comes down to it... use any reg for recreational nitrox... piston, diaphragm, old, new, borrowed, blue... Just the tank needs to be set up depending on how they fill them - but if renting tanks - they will be taking care of that. If you are getting your own tanks filled with nitrox - then you have to know what they require.

[Sasha_K]

Great. Thanks for clarifying.

[namabiru]

Yeah, that's right. And should you decide you want to dive above 40%, where you would need an O2-clean reg, you can pick up a reg specific for this use, or just have one prepared for you so it's O2-clean and dedicated for O2-clean use.