Dry ice in an enclosed room.

George W Chacko gchacko at magnus.acs.ohio-state.edu
Tue May 5 16:13:54 EST 1992


In article <9205051816.AA25441 at umailsrv0.UMD.EDU> William_D_WARREN at UMAIL.UMD.EDU (ww40) writes:

>But as soon as you open the door of a cold room won't all of the CO2
>"fall out" ... Besides it would take many hours/days (?) for 16 kg of dry
>ice to evaporate at 4 C... and how may times (on average) would the cold
>room door be opened and closed during this period ???

I'd imagine at the rate CO2 evaporates, it would be more likely
to diffuse evenly in the enclosed space. CO2 displaces air upwards when 
concentrated; am I right here? I don't really see a zone of CO2
on the floor unless someone upends a canister.

The OSHA figures on toxicity (thanks Eric Hugo) are below and the more
important question would be how long would it take to achieve toxic
levels?

|permissible exposure limit (PEL)   5000 ppm or 9000 mg/m^3
|Short term exposure limit (15 min X 4 / day) 30000 ppm or 54000 mg/m^3
|The STEL value is the highest amt a healthy indiv. can be exposed to
|for the given time with no ill effects.

|For dry ice:
|density = 1.56    MW=44
|5 lb dry ice = 51.6 moles CO2 ~ 1100 liter of CO2

George



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