Originally Posted by Nateo
I would only be concerned if the room were completely airtight. I use a chest freezer as a fermentation chamber, and you definitely don't want to stick your head in it. In a normal room, I wouldn't worry about it.
I had to do all sorts of safty training for work that mentioned entering a 'vessel' or container that had 'other than oxygen' in it. Basically while your lungs work, there is no O2 to inhale. Sounds like your chest freezer suffers from the same sort of problem. Not that a few minutes open pulling out fermentors wouldn't change the air mix, but I can understand the whole 'don't stick your head in'
OP as for the room? doubtfull you have an airtight room. Normal rooms are just fine, most leak enough to not matter.