How long can one live in a sealed room?

[CCWilson]

What are the calculations to figure out how long someone can live in a sealed room of a certain volume? Please check mine.

Let's say that the room is 30 feet by 20 feet by 8 feet, or 4800 cubic feet.

I believe that high carbon dioxide levels will kill you before low oxygen levels will. Inhaled carbon dioxide is 0.04% by volume, exhaled is a bit over 4%. Inhaled oxygen is 21%, exhaled 15%, a difference of 6%.

A person breathes about 6 liters per minute, or roughly 9000 liters/day or roughly 300 cubic feet/day. Thus that person will decrease room oxygen by 300 x 6% = 18 cubic feet/day.
He will increase room carbon dioxide by 300 x 4% = 12 cubic feet/day.

Comfortable carbon dioxide levels are less than 1000 ppm (parts per million) (0.1% of room air).
Dangerous levels are above 10,000 ppm, especially above 30,000 ppm. Let's take 30,000 ppm (3% of room air) as our death point, although obviously that's arbitrary.

0.03 times 4800 = 144 cubic feet of carbon dioxide in the room would be deadly.
144 / 12 (cubic feet of CO2 exhaled per day) = 12 days to death in that sealed room.

Originally there were 4800 (room cu ft) * 0.21 = 1000 cu ft of oxygen (rounded)
After 12 days, 18 (cu ft/day of oxygen decrease) x 12 = 216 cubic feet oxygen lost.
That leaves 784 cubic feet of oxygen in the room, or 784/4800 = a little over 16% oxygen in the air. While people will have symptoms at 15% or less, it would be rare to die with oxygen levels above 10%.

So my conclusion is that in the above scenario, a person would die in around 12 days, and from carbon dioxide toxicity rather than oxygen deprivation. Are my calculations correct on this? Thanks.

 

[mfb]

If there is no water in the sealed room, dehydration will become a problem quicker. If there is water, there could also be devices to filter CO2 ;).
Oxygen consumption and CO2 production will depend on the activity and weight of the human as well.

 

[Julio R]

If there is water, there could also be devices to filter CO2 ;).

What do you mean by that? Is there a correlation?

 

[mfb]

The only correlation I see is that an empty room has neither, and if the room has something inside we do not know what is inside.

 

[maltman]

empty room and life expectancy

empty i understand from the discussion include Earth normal sea level atmosphere and nothing else

have you ever heard of the rule of 3's for survival?
generally in any extreme situation you cannot survive for more than:

3 minutes without air (suffocation)
3 hours without shelter for extremes of temperature (hypothermia or hypothermia)
3 days without water (dehydration )
3 weeks without food (starvation)

you will die if your core body temperature is not within 34C to 39C for an extended period
a typical naked human will die in 10C water within an hour, 0C water in at little as 15 minutes
in contrast, we do a little better with heat, but a sustained wet bulb temperature of 35C can
kill a healthy adult human within 48 hours

you computed a rough idea of breathing time
but you need to consider
to little heat, a few hours
to much heat, maybe a few days
no water - about 3 days

 

[tbrd]

Questions & answers

Such a good question, such silly answers. I was looking for a simple answer on that "how long before they run out of air" scenario so common to Star Trek and its ilk and this is the closest I've seen, and yet everyone seems to want to pollute the scenario with unnecessary complications.

 

[Pythagorean]

I'm glad you find unnecessary complications humorous. I say 30 minutes due to the maddening grasp of over-emphasized self-monitoring:

http://news.discovery.com/human/life/worlds-quietest-room-will-drive-you-crazy-in-30-minutes.htm

 

[mfb]

I was looking for a simple answer on that "how long before they run out of air" scenario

... and the first post has a good answer to that.

 

[Igitigit]

You are wrong because you are making the assumption that 100% of the air is oxygen. We all know that nitrogen makes up most of our air. Ha! I Win.

You are close though. Start at 20% or whatever the real oxygen levels are.

 

[rbelli1]

mfb answered the question. You will die in about 3 days due to dehydration.

However you will likely be uncomfortable due to both the dehydration and the excess CO2 before death.

BoB

 

[mfb]

You are wrong because you are making the assumption that 100% of the air is oxygen. We all know that nitrogen makes up most of our air. Ha! I Win.

All volumes are total air, the fraction of oxygen is taken into account by using the 6% reduction (relative to the air that entered the lungs).

This thread is from 2013.

 

[rbelli1]

Necropost on a thread about death. Kind of fitting.

BoB

 

[mfb]

I think this thread is done.