TI and Nitrox

[092364sjs]

HI
I have read several different opinions on this. Is the combination f these two elements a problem with 32 % nitrox or is it just for 40% and above. I have heard that Ti regulators can be used, but because there is a problem at 40% most people just do not recommend it for legal reasons.
THanks
SJS:doctor:

 

[runvus4]

Manufacturer reccomendations will be conservative to protect them against lawsuits.

Titanium in has a greater chance of igniting than brass and stainless steel when exposed to high percentages of O2 under pressure. The increased flammability is most evident when the metal is in powered state. I do not know in any difinitive way, but I strongly suspect that a solid block of Titanium when exposed to O2 under pressure will most likely not spontaniously ignite. After all Aluminum powder burns really well in power form even if it isn't exposed to high PO2 under pressure, but that's not stopping us from using it for oxygen tanks.

If you can afford a Ti reg, then you should be easily able to afford a reg that the mfg will support on Nitrox...

 

[padiscubapro]

runvus4 once bubbled...
Manufacturer reccomendations will be conservative to protect them against lawsuits.

Titanium in has a greater chance of igniting than brass and stainless steel when exposed to high percentages of O2 under pressure. The increased flammability is most evident when the metal is in powered state. I do not know in any difinitive way, but I strongly suspect that a solid block of Titanium when exposed to O2 under pressure will most likely not spontaniously ignite. After all Aluminum powder burns really well in power form even if it isn't exposed to high PO2 under pressure, but that's not stopping us from using it for oxygen tanks.

If you can afford a Ti reg, then you should be easily able to afford a reg that the mfg will support on Nitrox...

Several years ago NASA ran tests for oxygen compatibility using thin rods made up of the material in question and provided an ignition source..
The only metal that was worse than titanium was magnesium... with copper being the best..
Titanium ignited at ver low pressures with copper being several hundred times harder to ignite, SS was in the middle, brass being better and Monel being just below copper..

 

[runvus4]

I've burnt or witnissed being burnt magnesium wire, aluminum powder and steel powder. Never tried brass or titanium. If you set your mind to it, you can get almost anything to burn.

I'm still not worried that a solid chunk of the stuff, like the materials are used in regulators, will spontaniously combust. Most people don't use bunsen burners/blowtorches or other ignition sources on their gear prior to diving. Eshewing Titanium for flamability concern IMHO is only very minor amounts of factual risk and mostly liabiilty lawyer talking.

Still, better safe then sorry.

Titanium I feel is primarily a vanity metal for regulators. It's not like it's so much functionally better than steel/brass for regulators to justify the huge price increases. Sure it's more corrosion resistant, but you still have the same maintanence schedule for the o-rings such that unless people have a habit of leaving the reg soaking in salt water, the increased corrosion protection isn't going to be noticable. Just get a reg that the manufacturer will support for the PO2 of your mix and be done with.

 

[pos-tech]

s-pro ok's their mk25 ti to 40% out of the box, so with a cleaning.......