Charlie Johnson one of ANDI's ITs put together a collection of all the relevant publications (its currently 2 large binders).. I haven't updated my copy in about 2 years but I'll look through it and see If I can find the 2 listed below..
The thing that stuck me was going through these documents some are from the scuba industry manufacturers, they specifically state for nitrox service the technician must follow ANDI oxygen service standards. Another thing that was true (not sure if it still applies), Germany has 2 major gas suppliers, both require ANDI gas blending and service tech certs to buy oxygen, they didn't recognize any other agencies ratings.
CGA uses a similar standard.. I would have to look up the numbers but its around 23%
I don't kniow about current NASA standards, but in the past they also supported this stance.
Originally I didn't support ths stance myself, but I have come to support it also.. I do all my own reg service, my main regs were always overhauled quite often, while my other regs went at least a year between service. The regs that were exposed to nitrox that weren't rebuilt using viton and oxygen compatible lubricants showed considerable degradation on all the orings that were exposed to the high pressures.. It wasn't greatly noticable on my main regs due to the frequency of service but was quite evident on those with "normal" service intervals.
Burna-nitrile does work but sooner or later the odds are there will be a problem.. Here is an extreme example that at least shows how unpredictable things can be...
I dive an Inspiration rebreather my oxygen reg unknown to me had a burna nitrile o ring on its DIN face.. I dove this for months without any problems.. I always slowly cracked the valve to bring the reg to pressure.. earlier this year someone else used the rebreather, and tuned on the valve quickly.. The oring combusted! Other than burn marks on the reg and valve there was no other damage(could have been much worse), but it clearly illustrates the unpredictability of the problem. In lower o2 concentrations I highly doubt complete combustion, but with a fuel source such as compressor oil, incomplete combustion is definately a possibility... I'd rather not find out that one of my orings were damaged when I try to take a breath at depth.. Regs are cheap, my life isn't.
Joe
