Re: life support

[Martin Sanderse <sanderse@hotstar.net>]

Jonathan Wallace wrote:
> 
> I haven't found much information regarding life support and eradication
> of CO2 from the cabin.  What chemicals are used for CO2 scrubbing, how much
> is required per x amount of time, and to keep the sub at 1atm, how is excess
> pressure released from the sub assuming one uses a continual flow of air
> into the cabin during the dive?

Well, to make a long story short, you use SodaSorb, or some other chemical to absorb 
CO2.  This reduced the pressure in the hull, so you add oxygen until the pressure is OK.

I've got a couple of books on it.  Find an anethesiologist that is not afraid of 
lawsuits to check out you final design.

What I'd recommend though, is to not use anything, come up for air when it gets stuffy 
due to buildup of CO2, and use the chemicals for emergencies only.

Why?  Because your body can't detect a lack of oxygen, but can detect a buildup of CO2, 
and unless you've got a lot of money for testing equipment to be sure that levels are 
correct, the stuffy air test is a good one.  Addition of absorbing chemicals or oxygen 
will be a dangerous disruption of normal affairs.

I suppose those little glass vials you break and watch the chemical change colour like 
litmus paper for the test of concentrations are OK.

Anyway, I'll find the book and get the numbers tommorrow.

Martin