[backhoe]

But I have one question. I assume one has to turn off the Air/heating system into the room. So, if the window and door are sealed, won't the air run out?

Eminently reasonable question... I knew the answer back in the 1960's, but it's flown out of my empty head since then.

It's a function of the number of cubic feet in the room, versus how many people are in it, how much air they exhale with each breath ( per minute ) versus how many times you can rebreath stale air- you can rebreath your exhalations a few times before they grow so O2 depleted they are useless...

All I can tell you is that the bigger the sealed room the better, and a few oxygen bottles would be a great help.

[Dixielander]

CARBON DIOXIDE (CO2)caution

Never exceed a CO2 percentage in a room by 3%. To determine how long you can stay in an enclosed room use this rule of thumb formula: length x width x height of room in feet x .03 (number of people in room) = Safe Stay Time (SST) in hours.