Mr Carcharodon
Contributor
I share ianr33’s concern about this. I doubt that it is correct that UWATEC computers compensate their decompression algorithm for temperature. I of course do not know what UWATEC does explicitly since they have not been forthcoming in discussing that. They just say they use a “modified 8 compartment Buhlmann” without defining what “modified” is. They have said they take breathing rate into account. If anyone knows more about the UWATEC algorithm they can chime in.
The things that would make this tricky to model would be the dynamic levels of perfusion during a cold dive. As the diver chilled the perfusion of extremities would drop off causing the time constants for those tissues to increase. But chilling and perfusion of the extremities is going to be dependent on body mass, exposure protection and fatigue. Also chilling varies from place to place on the body. And there are other tissues, like the CNS, whose perfusion rates and time constants will be essentially independent of temperature. I think there are too many unknowns for a computer to arrive at a reasonable solution. Also I believe that Buhlmann’s m-values were all determined for warm subjects. They may not apply to a cold dive so there is no basis to calculate limits from.
This really comes back to the fact that divers should plan their own dives and not let computers do that for them. Becoming chilled over the course of the dive will raise your DCS risk as faster tissues convert to slower tissues. But that can be mitigated by staying farther away from NDL limits or padding the decompression on the way up.
