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Researchers at Hull University have released a paper to the effect that divers breathing a mix of Oxygen at a ppO2 of less than 1.0 and Hydrogen making up the rest seem to off-gas so fast that a slow ascent rate (5m/min) means no deco is ever required.

Pretty funky, huh.. tho I don't know I'd want to mix Hydrogen and Oxygen myself..
 

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Hm, can't see my local diveshop wanting to do fills
 

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Dunno really........ thinking about it
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This isn't a date stamped item by any chance?  


This could take the lining off your lungs a treat.
 

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Discussion Starter · #6 ·
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Happy April first


Somebody had to do it...
 

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Using Hydrogen/Oxygen has been known about for a while, I'm fairly sure I saw something about NOAA or the USN testing it years ago since it is less likely to cause HPNS than helium (and much easier to get).  Hydrogen and Oxygen simply mixed together don't spontaneously react, they need a source of ignition.  However, if one or the other is in suitably small percentages then it wont sustain a reaction, I think it is less than 4% fO2 and I seem to recall that it is fO2 rather than ppO2 that determines the reactivity.  

If I recall the reports correctly, the divers descended to about 100ft (being Americans), then switched to heliox 10% and continued the descent to 200ft or thereabouts and switched to heliox 4% to clear the excess oxygen and then to hydrogen/oxygen 4% and continued the dive on that.  They had to switch similarly on the way up to clear the hydrogen.
 
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