60plus
Contributor
Is anyone considering switching to hydrogen as an alternative?
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Hydrogen suffers from a major disadvantage as a breathing gas in that when mixed with oxygen percentages over 4% it becomes explosive. A gas mixture with less than 4% oxygen will not support life on the surface and in fact only becomes breathable below 35m. This means that a higher oxygen content mix must be breathed down to at least 35m. This is followed by a second mix which contains 4% oxygen and some combination of nitrogen and/or helium. This second mix acts as a buffer, reducing the oxygen content in the presence of an inert gas to the point where the diver can switch to a mixture of 4% oxygen and 96% hydrogen. Despite the logistical problems involved with using hydrogen there is a long history of experiments in using hydrogen in a breathing mix. This is because hydrogen is the lightest element and as such is the least dense gas at depth which makes it very easy to breathe even at extreme depths.