How long does oxygen last in a house-sized volume?

Factual Questions
1

Say I live in a one-story 1000 sq. feet home and I sealed everything up air-tight. How much time do I have to live before I run out of oxygen? Assume one average size human is the only consumer of oxygen.

Suppose I had to use the stove… how many minutes do I lose if I use a gas stove burner for 1 minute?

(I was thinking about this because sometimes I stay indoors for longish periods of time without opening my windows or my front door)

2

ok, I’ll take a shot. I am going to look at this problem from a straight out algebraic perspective, and assume that the air in the house remains constantly mixed, we’ll see where we get.
1000ft^2, figure an 8’ ceiling yields 8000 ft^3. To keep the math easy, we’ll round that down to 225,000 liters. According to this cite, we exchange 500ml about 17 times a minute while at rest. So, that is 8.5L/min. According to the same cite, the oxygen on exhale has dropped from 20% O2 to 15% O2, so I will extrapolate from that figure that our body “wants” about .5L of O2 per minute. (8.5L of air/minute, taking out about 5% of the total volume.) So, if basic metabolism requires about 1/2 liter of 02 per minute, and the house has 225K liters of air, which is 20% O2, yielding 45,000L of O2, I would say you will get about 90,000 minutes out of an entire house of air. That would be about two months worth of air.

This is obviously not right though, as it assumes that you would be able to capture all the O2, obviously the more you breathe, the less concentrated the O2 becomes, so you have to move more air through your lungs, which requires more energy from your muscles, which requires more O2… You can see, I think, that such a dynamic system is going to be pretty hard to model.

Hope this helps…

3

Yeah, I think we need to also know something about how the buildup of noxious gasses proceeds. Lack of oxygen probably isn’t the only thing that’s bad. Maybe someone can tell us the physiological effects of too much CO[sub]2[/2].

4

Thanks for that calculation… it does help give an upperbound of around two months.

I think you are right. I guess I would really like to know when I would start noticing the effects, in addition to the “how long do I have to live” question.

Also, I was wondering if I opened my front door (20 square feet surface), how long would it take (at most) for the oxygen levels to return back to normal?