Atomic T2 Titanium reg Nitrox friendly?

[limbo]

My understanding always was that Titanium regulators don't deal too well with Nitrox.
The manufacturer allows for up to 40% on this model.

Is it true that Titanium regs can't be used for tech deco stops on 100% oxygen since the first stage would 'catch fire'?

Looking forward to your input.


Edit by limbo; just found the thread from July 2005 http://www.scubaboard.com/showthread.php?t=101760
and that answers a lot of questions already.

What's up with the funny avatars in this forum??????

 

[Sadamune]

Is it true that Titanium regs can't be used for tech deco stops on 100% oxygen since the first stage would 'catch fire'?

To be more precise, a titanium regulator shouldn't be used with O2 percentages over 40%. The reason for this prohibition is that in the event of an O2 fire, the titanium in the first stage could ignite and create an extremely hot fire. The claim that titanium will spontaneously ignite in the presence of O2 is a myth. In fact, the aerospace industry has been using titanium pressure vessels to store pure O2 for decades. However, should someone be stupid enough to attach a reg that hasn't been O2 cleaned to a cylinder of O2, an O2 fire could occur, and if the reg were made of titanium, the fire could then ignite the first stage metal body itself. It is the contamination in the regulator, such as oil droplets or dust deposited by dirty air compressors, that can catch fire in the presence of high O2 concentrations. Such a fire would likely destroy any reg, but if the reg were made of titanium, then a much more intense, and therefore dangerous, fire could result. In either case the regulator will be destroyed. The extent of destruction is just a matter of degree ;-)

If you choose to use a titanium regulator, just be sure to have it O2 cleaned before you use it with EAN40 or less (the manual should state that) and everything will be great. As most people use EANx gas mixes well below 40%, this restriction is really very minor. Otherwise, for those who are not cost conscious, titanium alloy is really an excellent material for regulators.

Cheers,

Sadamune

 

[limbo]

Thanks Sadamune,

That's very insightful and helpful.

 

[DA Aquamaster]

Minor comment, but O2 will not spontaneously combust on contact with oil contamination present inside a regulator. There still needs to be an ignition source. Normally, this ignition source is created due to rapid compression of the O2 inside the regulator if the valve is rapidly turned on and with the the purge button not depressed.

If this occurs, the contaminants inside the reg provide fuel for the fire as will the 0-rings. Viton and EPDM o-rings are preferrred as they are more resitant to burning than Nitrile o-rings, but they are still not fire proof. And viton orings produce phosgene gas during combustion - one of the gases used in trench warfare during WWI.

That said, the damage from a regulator fire is normally limited to a flash fire that scorches the o-rings causing serious leaks. However, it has been known for structural failures to occur and as indicated above titanium regs have the potential for much more serious fires due to the surface of the material and how it interacts with the oxygen during a fire in high O2 environments

 

[Sadamune]

Thanks DA Aquamaster, you are quite right. O2 won't cause oil to spontaneously combust, but such contaminants can ignite inside a regulator if the temperature is sufficiently high and they are exposed to high concentration O2. Such high temperatures in a regulator are caused by adiabatic heating, which is the heating that results from the compression of a gas. Slowly turning on the cylinder valve while depressing the purge button on the second stage will slow the 1st stage pressurization and thus reduce the temperature due to adiabatic heating.

So, keep your EANx regs O2 clean and go slowly on the cylinder valves; everything will be just peachy.

Cheers,

Sadamune

 

[Captain Larry]

Buy any Atomic reg and you won't be disappointed. Use it, and any piece of dive gear, according to the manufacturer's recommendations and you will be happy. Do anything else (there are a lot of "what if'ers on this board) and you are experimenting and may not have a happy outcome.
That said, I have a no questions asked 100% satisfaction return policy. I have never had an Atomic returned. I have used each of the current models of the Atomic and have been happy with each one. They are virtually indistinguishable in their easy breathing qualities. I personally use the T2 because 1. I prefer it and 2. because titanium will not corrode in salt water.