Nitrox and titanium?

[teknitroxdiver]

Today on the dive boat I was looking at my dad's regulators, and noticed they're titanium. He has the Mares Ti-Planet, and the book on it says not to use it with nitrox. We're planning on doing a nitrox course within the next week, so this is a bit of a concern.

Is this an actual concern, or more of a liability thing? Of course, we won't be using more than 40%, probably just 32 or 36%.

thanks in advance

 

[Greg Barlow]

Today on the dive boat I was looking at my dad's regulators, and noticed they're titanium. He has the Mares Ti-Planet, and the book on it says not to use it with nitrox. We're planning on doing a nitrox course within the next week, so this is a bit of a concern.

Is this an actual concern, or more of a liability thing? Of course, we won't be using more than 40%, probably just 32 or 36%.

thanks in advance

It is fine to use with nitrox mixes that are typically used for sport diving. It would not be safe to use with mixes higher than 40% due to the titanium parts in the first stage.

Greg Barlow
Former Science Editor for Rodale's Scuba Diving Magazine

 

[Scuba Tech]

The concerns about O2 and ti originaly came from a NASA seminar in the late 90s (may have been 2000, dont remember). They use huge amounts of liquid O2 at insane pressures. As these findings were made public the dive industry had no choice but to protect its self from liability, interestingly Mares was the first to implement warnings on its Ti Planet. As far as I know only 2 or 3 incidents have been linked to the use of O2 and Ti regs and I would bet that thay are more likley due to some dumb *** with a can of WD40 oilling up his yoke screw then fault of the Ti regs!

 

[Spoon]

The concerns about O2 and ti originaly came from a NASA seminar in the late 90s (may have been 2000, dont remember). They use huge amounts of liquid O2 at insane pressures. As these findings were made public the dive industry had no choice but to protect its self from liability, interestingly Mares was the first to implement warnings on its Ti Planet. As far as I know only 2 or 3 incidents have been linked to the use of O2 and Ti regs and I would bet that thay are more likley due to some dumb *** with a can of WD40 oilling up his yoke screw then fault of the Ti regs!

thanks for the trivia, wondered how they linked nitrox and titanium. i always have this picture in my mind of some hapless diver of old was the scapegoat when his tank blew coz the nitro ignited coz of some weird reaction with the ti.

 

[padiscubapro]

The concerns about O2 and ti originaly came from a NASA seminar in the late 90s (may have been 2000, dont remember). They use huge amounts of liquid O2 at insane pressures. As these findings were made public the dive industry had no choice but to protect its self from liability, interestingly Mares was the first to implement warnings on its Ti Planet. As far as I know only 2 or 3 incidents have been linked to the use of O2 and Ti regs and I would bet that thay are more likley due to some dumb *** with a can of WD40 oilling up his yoke screw then fault of the Ti regs!

Itianium is one of the worse metals that can be used for an oxygen enriched enviroment (only magnesium is worse), It takes very little pressure over ambient to get titanium to burn with an ignition source.. pressurizing a system can be an ignition source.. for reference 100% oxygen pressureized to 2000psi can generate 1688 degrees f.. It is of extreme importance that the system be pressurized as slow as possible.. just cracking the valve and controlling how fast the system pressurises can be the difference between ignition or not.. Also the faster the system pressurizes the greater the chance of particle impingement causing an ignition (either from the gas itself (LDS tanks) or from particles created within the diver's tank)

Any reg that is going to be used for any nitrox mx must be maintained in an oxygen clean state to reduce this risk.. it should be oxygen cleaned and dedicated.. You don't want to increase the chance of ignition above what it already is..

NASA ran extensive tests on oxygen compatibility.. the key test were a metal "rod" that was 1mm in diameter, it was put in a chamber filled with oxygen, then a spark was applied.. the pressure was raised until it burned.. titanium burned not much over ambient pressure.. where metals like copper took extremely high pressures to burn..

BTW liquid oxygen is very LOW pressure... ITS a liquid you cant fit more in by raising the pressure.. liquid is NOT compressible..

 

[moxie]

"Any reg that is going to be used for any nitrox mx must be maintained in an oxygen clean state to reduce this risk.. it should be oxygen cleaned and dedicated.. You don't want to increase the chance of ignition above what it already is.. "

SSI and PADI training indicate regs are OK for mixes <40%, and that's the way I've always done it as have all I've observed. Tanks, yes. They need to be cleaned and dedicated regardless of FO2.

Please clarify.

 

[TwoTanks]

From everything I've read and beed taught, regs only need to be O2 clean if they are going to be used with nitrox over EAN40. Deco regs for oxygen and high O2 mixes are the only ones that will actually be exposed to the high oxygen pressures and must be O2 cleaned.

TT

 

[padiscubapro]

"Any reg that is going to be used for any nitrox mx must be maintained in an oxygen clean state to reduce this risk.. it should be oxygen cleaned and dedicated.. You don't want to increase the chance of ignition above what it already is.. "

SSI and PADI training indicate regs are OK for mixes <40%, and that's the way I've always done it as have all I've observed. Tanks, yes. They need to be cleaned and dedicated regardless of FO2.

Please clarify.

Most manufacturers state exactly what I stated.. With Brass regs you probably will get away with it for a while but, it catches up.. there are lots of examples of incomplete combustion.. which a diver would never know about.. its usually seen when servicing regs (especially the HP seat - On these regs you see IP creep many times, which if the person tests their own gear (which they should) they would see this).. The big problem here could be The co that is created, which the diver will breathe.. Also remember contamination is cumulative, so the oild and stuff build up over time unless they are removed.. A freshly serviced reg (unless silicon is used) is pretty compatible for a reasonable period unless the LDS has pretty poor gas...

Brass is a highly compatible metal which most regs are made of thats why people tendd to get away with things as long as the gas they breath doesnt have too much condensing hydrocarbons, Titanium is a completely another issue, It burns quite readily... Titanium regs have burned below 100% and have injured people.. There is no magic safety number, its about reducing risks.. Some metals self extinguish once, other metals burn util the material is gone (titanium is one of these)...

I think my life is worth more than a few hundred $$ for having dedicated regs.. And BTW PADI and the other agencies (that tell you you can use up to 40%) also tell you you must follow manufacturer recommendations, instead of being upfront.. All the manufacturers tell you to keep the gear oxygen clean..

The easiest way is to only buy oxygen compatible gas (why do you want to breath the crappier gas anyway??)

ATOMIC states the following

NITROX (EAN) USE &#8212; ALL MODELS
IMPORTANT NOTICE - READ BEFORE YOU USE THIS REGULATOR
These regulators have been assembled, cleaned and made compatible for
enriched air Nitrox (EAN) to a maximum 40% oxygen concentration at a
maximum pressure of 3500 psi. They do not require additional cleaning or servicing.
IF THE REGULATOR BECOMES GROSSLY CONTAMINATED WITH DIRT, OILS, OR
GREASES FROM ANY SOURCE, HAVE THE REGULATOR RE-CLEANED BEFORE
USING IT AGAIN WITH EAN. DO NOT USE SILICONE OR HYDROCARBON
GREASES IN OR AROUND REGULATORS BEING USED FOR EAN NITROX OR
OXYGEN MIXES. DO NOT UNDER ANY CIRCUMSTANCES USE THESE REGULATORS
WITH PURE OXYGEN OR ANY GAS MIXTURE EXCEEDING 40% OXYGEN (EXCEPT
THE M1). FAILURE TO COMPLY WITH THE ABOVE WARNINGS COULD CAUSE
SERIOUS PERSONAL INJURY OR DEATH FROM FIRE OR EXPLOSION.

NITROX (EAN) USE &#8212; T2 ONLY
At time of purchase, you must decide if this regulator is to be used with EAN
or standard compressed air. If you desire to use EAN, this product must be
dedicated for EAN only and identified as such. Do not switch between EAN and
standard compressed air, as compressed air may contain traces of hydrocarbons
which could contaminate your regulator system with potentially flammable
residues incompatible with EAN. If you use or test this regulator with compressed
air, it must be re-cleaned before EAN use.

B2, Z1/Z2
These regulators may be used interchangeably with air or EAN mixes of up to
40% oxygen concentration at 3500 psi maximum. They need not be dedicated
for EAN use, provided that they are used with air or EAN mixtures that meet
minimum dive industry purity standard
​

for the brass models they tell you it doesnt necessarily have to be decicated as long as the gas meets purity standards.. (unfortunately many LDS never test their gas)​

 

[Blackwood]

liquid is NOT compressible..

Liquids ARE compressible. Hell, even solids are compressible.

Just much less than gasses.

 

[padiscubapro]

Liquids ARE compressible. Hell, even solids are compressible.

Just much less than gasses.

For what we are talking about its not worth mentioning.. If you really wanted to get anal, even atoms COULD be compressed but would be see that in real life..

A change in temperature will result in a change in volume as far as the container will allow, then the pressure will rise.. changing pressure doesn't raise the volume available..