Re: on-gassing while ascending

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Posted by Gerry on December 04, 2000 at 15:44:52:

In Reply to: on-gassing while ascending posted by JRM on December 04, 2000 at 14:53:47:


You asked: "Assuming a bounce dive profile, do *all* compartments begin to offgas at the begining of ascent?"

In a bounce dive (quick descent, immediate ascent) only the fastest tissue group would saturate to the point that off gassing would start at the beginning of ascent. For the slower tissues, on-gassing will continue during ascent until you ascend above the depth where tissue PPs are greater than breathing gas PPs. Tables take this into account. An ascent at the rate specified by the table will get you to the point where the tissue begins to off gas before the PP differential exceeds the M value for the tissue group.

The dive profile that would permit all tissue groups to begin off gassing immediately upon ascent would be the opposite of the bounce dive. Theoretically, to saturate all tissues at a given depth, you'd have to stay at that depth for an infinite time. Realistically, a looong dive will saturate to near the depth, and soon after you stary up, all tissues will be off gassing.

Hope this helps.


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