Dive analysis and profile comparison - mockup

[Pedro Neves]

Hi Robert:

On 2013-05-23 13:30, Robert Helling wrote:
> and again what is that supposed to tell you? If have no intuition about the meaning of percentages of M-values. I just did a quick calculation: A diver that has never dived in his life but has always breathed air at surface pressure is at 47% of the M-value for the fastest compartment and at 67% for the slowest.

 From Erik Baker's article on M-values: "For a given ambient pressure, 
an M-value is defined as the maximum value of inert gas pressure 
(absolute) that a hypothetical "tissue" compartment can "tolerate" 
without presenting overt symptoms of decompression sickness (DCS)."

The % M-value is, in my opinion, an indication of how close the inert 
gas tensions of each compartment are from that "limit". To me this is 
useful, as it might indicate an "aggressive" decompression (i.e., an 
ascent that brings the inert gas tensions of "my tissues" too close to 
the theoretical limits. It is  my understanding that to prevent this was 
one of the reasons that people now "play" with GF, right?

> So any additional gas loading would be above those values [BTW: is it clear to you what calculation I just did?].
I understand the calculations, but I don't understand why you say that 
"any additional gas loading would be above those values". In order to 
have additonal gas loading you have to increase the ambient pressure. If 
you increase the ambient pressure you increase the M-value, to the 
relationship between the actual inert gas tension on each tissue and its 
theoretical limit (the M-value) would change accordingly.


The only thing that would give me some information (and again I would think that is of very limited usefulness) would be to compute the ceiling for each individual compartment as that is a reasonable depth in meters (or feet).

That ceiling is the M-value, that can be expressed in different ways...

Maybe I'm just not expressing myself in a clear way.

All the best:

Pedro
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