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From: Gary Casey <glcasey@adelphia.net>
Subject: Re:  dry ice in airplane

I agree with Ted, but let's do some math to confirm:  First you have  
to know the rate of sublimation of the CO2.  I would guess the CO2 is  
in a normal cooler and is there to keep something cold, not to cool  
something off, so would it sublimate at a rate of 1 pound in 4  
hours?  I don't see how it could be that fast, but I'll use that  
number.  How much air is in the cabin?  I'm thinking maybe 60 cubic  
feet and the air exchange rate would be high, as no airplane is well  
sealed - 10 changes per hour?  The weight of the air going through  
the cabin at sea level is then about 50 pounds per hour.  The CO2  
would represent 0.5% or 5,000ppm.  That's pretty high, but no where  
near enough to cause suffocation since the O2 concentration only  
drops by 0.5%.  Stratify the air in the cabin by opening vents at the  
front and keep the cooler in the back and the level would drop a  
lot.  Someone might know the amount of CO2 normal exhaled by a human  
and that would be a good comparison.  The numbers back up Ted's  
conclusion.
Gary Casey
>
> Posted for "Ted Noel" <tednoel@cfl.rr.com>:
>
>  Suppose you have an steady flow of CO2 into the cabin from the  
> cooler. If
> your cabin is sealed, the cabin pressure will rise and the  
> concentration of
> CO2 will rise.
>   BUT...
>   If you have any reasonable amount of ventilation, the probability  
> that this
> will cause a problem is close to nil. And the last time I checked,  
> a Legacy
> was unpressurized. I suppose that if you kept the cooler in your  
> lap with the
> lid cracked next to your face you might have a problem, but it  
> wouldn't be the
> CO2.
>   In short, relax. CO2 isn't like CO. CO binds almost irreversibly  
> with
> hemoglobin, and is deadly in very small concentrations. CO2 is  
> something you
> breathe out constantly. It is highly soluble, and it is very easy  
> to get rid
> of excess amounts.
>   Ted Noel MD
>  N540TF
>