# Thread: Living in a sealed room

1. Hello,

Assuming a completely sealed garage of the size 5 x 5 x 3 m --> 75m3 or 160.72cubicfeet.

The activity level of the person should be stated. Daily : 3 consecutive hours of anaerobic exercise --> lifting / 2 consecutive hours of anaerobic exercise --> lifting / 1h30 of aerobic exercise(i.e boxing) / 9 hours sleep. ( Total : 5 hours anaerobic exercise + 1h30 aerobic exercice + 2 hours at rest + 9 hours sleep)

Part of the garage door can be opened(1.50 x 2 m), giving on a parking lot, and there is a big entrance giving on the outside air on the same floor several meters away.(about 5 x 5 m). There are very few cars that ever go through this parking lot.(2-3 daily passages)

The garage is in Paris where the ground altitude is 45 m. The garage is on the first floor hence maybe approx 50-55 m over sea level.

If the garage is kept closed, how long would a person with the described activity level last before having to open the 1.50 x 2 m opening?
How long would it take for the garage to come back to it's original air concentration and hence be "ready" for another "bout" of the person's cycle? Do tools exist/methods to reduce time for air to return to it's original concentration?.

Gabriel

2.

3. If the garage is kept closed, how long would a person with the described activity level last before having to open the 1.50 x 2 m opening?
Don't put this on the biology section, i'd say it's better off in Math section. But as a biologist, i can tell you, that there is not enough information to tell you how long it would take.

Because;
- We do not know the tolerance of the person on the hight of CO2 or the % of O2.
- We do not know the rate in which the person uses O2, as it is not standard.
- The effects of these exercises have not been tested in the amount of O2 usage, or the amount needed in a minimum. Neiter have you told me the intensity of the training.
- We do not know the gender, size, weight or diet of the person.
- No room is totally sealed.
- We don't know the concentration of CO2 already in the air, or the concentration of O2.

How long would it take for the garage to come back to it's original air concentration and hence be "ready" for another "bout" of the person's cycle?
It would be a guess, but 30 - 90 seconds. But if you want the state to be back to total equilibrium exactly, then >1.000.000 years.

Do tools exist/methods to reduce time for air to return to it's original concentration?
Literally everything will reduce time for air to return to it's original concentration. I can not think of anything that would do the opposite thing, other then block the opening in which air could enter.

4. Originally Posted by Zwolver
If the garage is kept closed, how long would a person with the described activity level last before having to open the 1.50 x 2 m opening?
Don't put this on the biology section, i'd say it's better off in Math section. But as a biologist, i can tell you, that there is not enough information to tell you how long it would take.

Because;
- We do not know the tolerance of the person on the hight of CO2 or the % of O2.
- We do not know the rate in which the person uses O2, as it is not standard.
- The effects of these exercises have not been tested in the amount of O2 usage, or the amount needed in a minimum. Neiter have you told me the intensity of the training.
- We do not know the gender, size, weight or diet of the person.
- No room is totally sealed.
- We don't know the concentration of CO2 already in the air, or the concentration of O2.

How long would it take for the garage to come back to it's original air concentration and hence be "ready" for another "bout" of the person's cycle?
It would be a guess, but 30 - 90 seconds. But if you want the state to be back to total equilibrium exactly, then >1.000.000 years.

Do tools exist/methods to reduce time for air to return to it's original concentration?
Literally everything will reduce time for air to return to it's original concentration. I can not think of anything that would do the opposite thing, other then block the opening in which air could enter.
Zwolver thanks for answering some of my questions and providing feedback on how the others could be answered.

For the time back to an approximation of the original concentration you state 30-90 seconds. I am lacking knowledge in science in that I thought it would take at least more than an hour. Are you positive we are talking less than an hour?

Because it is a parking lot, albeit with an opening very close by, I was thinking lack of wind would hamper time for concentration to be approx. the same. Same for tools, I was thinking something like a "fan" would help mix the "fresh air" with the garage air and hence reduce time of outside exposal. But in the light of your answer, I am thinking my conception of how air(particles?) "moves" is wrong. If you have some time it would be good if you could link me to knowledge explaining this mixing. How does upon opening the air in the garage somehow, even with lack of wind, go outside and mingle, and vice versa?

If possible for the time of a "cycle"(sealed garage) a very gross estimation would be good(Several minutes, several hours, several days?) :

- Average tolerance to CO2 and O2
- Average rate of usage
- Anaerobic training pulse would be halfway between max pulse and rest pulse for 3 hours out of 5. The other 2 would be rest pulse. (If this helps in determining intensity) / Aerobic training would be max pulse 45 min and halfway between max and rest for another 45 min.
- Person is male. Weight is 200 pounds. Diet is high in protein, high carbohydrate, average fat.
- The room is sealed in that even a small mice could not go through.
- 02 concentration and C02 will approximate that of a parking lot with very few passages.

By the way, apart from the approximations that will be given, can an 02 and CO2 sensor lead the person to know when it would be safe for him to open the room for air concentration to return approx. to original(assuming we know the tolerance of the given person to height of O2 and CO2) ?

Thanks for your information & looking forwards to hearing from you,

Gabriel

Ps : How can I move this to mathematics?

5. For the time back to an approximation of the original concentration you state 30-90 seconds. I am lacking knowledge in science in that I thought it would take at least more than an hour. Are you positive we are talking less than an hour?
5*5*3 is relatively small, in 30 - 90 seconds you would have more then half of the CO2 exit, and O2 replenish. Mostly because most enclosed rooms are significantly hotter then the outside. So you would gain a natural flow of air already simply by opening the door. Wind might even break the effect if provided it is doing the opposite as what you want it to do.

How does upon opening the air in the garage somehow, even with lack of wind, go outside and mingle, and vice versa?

If possible for the time of a "cycle"(sealed garage) a very gross estimation would be good(Several minutes, several hours, several days?):
I have thought about this, not long though, but i can not give you a straight answer right now. What i would concider safe, would be <4 Hours, Above 4 hours i think the CO2 level can get quite high. But i advice to open the door every hour.

By the way, apart from the approximations that will be given, can an 02 and CO2 sensor lead the person to know when it would be safe for him to open the room for air concentration to return approx. to original(assuming we know the tolerance of the given person to height of O2 and CO2) ?
Sensors can help yes, could be as easy as a display telling the temperature humidity and air pressure. I think those can be bought anywhere.

Ps : How can I move this to mathematics?
Moderators can, i'm no moderator.

6. I don't agree that it should be moved. It is as much a biology question as anything else.

You are going to have to decide the rate of oxygen use and the rate of CO2 production with the given level of activity. That's a biology question. Then you have to decide what is an acceptable level of O2 and CO2. Another biology question. With that, you can determine the time available with no ventilation. Once you have done that, we can probably find some rules of thumb for ventilation exchange rates in a HVAC handbook or something.

7. After searching about anaerobic exercise I found out that typical athlete (ie: male rower) consume: *max* 6 liter of oxygen per minute. VO2 max - Wikipedia, the free encyclopedia

So I convert 75 cubic meter garage to liter and get: 75000 Liter . Cubic Meters to Liters converter

And, I think Oxygen is only 21% of the clean air (everything else is Nitrogen), so we get a lower oxygen content: so oxygen in liter = 15750 Liter.
----

So.... The amount of minute the person can live in clean air is: 2625 minute, or 43 hour??

but... maybe the water vapor in air could be high... maybe its 75% of the clean air? so... it might be just 10 hour??? or it might be lower!
I recall it can be really hard to breath in enclosed space because of the humidity, also we did not calculate how much time before expelled CO2 concentration became toxic.
----

*also: you can install a rebreather to remove the CO2, some dehumidifier for the humidity, and use pure oxygen to make your garage liveable much longer... but pure Oxygen bring fire hazard.
+ ion generator to kill viruses and bacteria to mantain decontamination.

8. You won't be able to breathe all the oxygen in the room. You'll be dead before that. OSHA defines 19.5% as oxygen deficient. CO2 concentration might be more limiting. A limit of 2% has been suggested.
Carbon dioxide - Wikipedia, the free encyclopedia

9. Zwolver, you talk of 4 hours. Are you talking of 4 hours at max.aerobic rate? This would mean 9 hours of sleep would not necessitate opening of the doors.
Following msafwan's calculation and harold's knowledge of the 19.5% limit oxygen. It would be if I am not mistaken approx. 43h/10 -- > 4.3 hours at max aerobic rate. Corresponding to Zwolvers gross estimate. At rest it looks like it's 4.3 * 20 --> 80 hours before oxygen runs out if we assume the average of 0.3 l/oxygen/minute.

Now for CO2 cycling is about 3l per minute. There is about 0.033 % C02 in atmosphere, figure that might be approx. closer to 0.05 % in a parking lot?

Recommended work guidelines are 0.5 % max.(0.5 % safety before 1% weak legs symptom appear) So thats 375 l. At rest it's 0.3l/co2/min. Adjusted with humidity that 93.75 l

That's 5 hours at rest before safe co2 barrier is crossed over.(only?) and 10 before first physical symptoms appear.

Do these calculations look good to you?

zwolfer you say in 30-90 seconds more than half of the co2 would leave and 02 replenish. Does this then hit the law of diminishing returns to return to equilibrium years and years later(hence your > >1.000.000 years) At what time would it be approx. considerable in concentration to the original, in ten minutes time?

Do building materials of the room impact time that can be spent safely before needing to open the sealed room(i.e concrete, steel, wood...)? Do appliances & objects impact too.(Consisting in an electric stove, fridge, lamp and books.)

Msafwan you talk of also: you can install a rebreather to remove the CO2, some dehumidifier for the humidity, and use pure oxygen to make your garage liveable much longer" Are these devices autonomous(in that you do not have to carry it around every step you take and preserve the sealed nature of the room?)

I've heard of monoxide levels being dangerous, especially in garages. The garage in question does not have a car but there are two to three cars in the outside parking lot. Modern cars. Left on just the time it takes to park them.

Gabriel

10. Originally Posted by gcourtois
Do building materials of the room impact time that can be spent safely before needing to open the sealed room(i.e concrete, steel, wood...)? Do appliances & objects impact too.(Consisting in an electric stove, fridge, lamp and books.)
I think the only thing this would affect is the room heatup. In a well insulated room, with the walls absorbing no heat, the air will heat up according to its heat capacity which is .00121 J per cubic centimeter per degree K. Heat capacity - Wikipedia, the free encyclopedia
This works out to 1210 joules per cubic meter per degree, and with 75 cubic meters that's 90750 joules per degree. At a rate of 100 watts (=100 j/sec), which is a reasonable number for aerobic exercise, it would take 907.5 seconds, or about 15 minutes to raise the temperature 1 degree C. After a couple of hours, it's going to get hot in there if it was comfortable to start.

CO won't be expelled from humans, as our combustion is biologic, and we can not producte CO.

The levels of CO in an open parking garage, where wind can blow trough easily are negligible. Low enough to keep enough hemoglobin active in the blood.

How long it would take to get a decent equilibrium.. Well, take the 30-90 seconds, depending on heat, and windconditions, it'll be somewhere in between, but take a minut halftime. To reach 99% you would take 11 minuts. (by my own calculations, which are probably not 100% correct, but still)

12. Hello,

Zwolver and Harold, thanks for your feedback. Now if you have time could you browse through these calculations to see if they are roughly correct?

Originally Posted by gcourtois
Zwolver, you talk of 4 hours. Are you talking of 4 hours at max.aerobic rate? This would mean 9 hours of sleep would not necessitate opening of the doors.
Following msafwan's calculation and harold's knowledge of the 19.5% limit oxygen. It would be if I am not mistaken approx. 43h/10 -- > 4.3 hours at max aerobic rate. Corresponding to Zwolvers gross estimate. At rest it looks like it's 4.3 * 20 --> 80 hours before oxygen runs out if we assume the average of 0.3 l/oxygen/minute.

Now for CO2 cycling is about 3l per minute. There is about 0.033 % C02 in atmosphere, figure that might be approx. closer to 0.05 % in a parking lot?

Recommended work guidelines are 0.5 % max.(0.5 % safety before 1% weak legs symptom appear) So thats 375 l. At rest it's 0.3l/co2/min. Adjusted with humidity that 93.75 l

That's 5 hours at rest before safe co2 barrier is crossed over.(only?) and 10 before first physical symptoms appear.

Do these calculations look good to you?

zwolfer you say in 30-90 seconds more than half of the co2 would leave and 02 replenish. Does this then hit the law of diminishing returns to return to equilibrium years and years later(hence your > >1.000.000 years) At what time would it be approx. considerable in concentration to the original, in ten minutes time?

Do building materials of the room impact time that can be spent safely before needing to open the sealed room(i.e concrete, steel, wood...)? Do appliances & objects impact too.(Consisting in an electric stove, fridge, lamp and books.)

Msafwan you talk of also: you can install a rebreather to remove the CO2, some dehumidifier for the humidity, and use pure oxygen to make your garage liveable much longer" Are these devices autonomous(in that you do not have to carry it around every step you take and preserve the sealed nature of the room?)

I've heard of monoxide levels being dangerous, especially in garages. The garage in question does not have a car but there are two to three cars in the outside parking lot. Modern cars. Left on just the time it takes to park them.

Gabriel
Another related question, assuming the sealed garage is made out of extra-hard iron(type xc75 to be exact) and the person wishes to lift weights inside this garage(weightlifting, powerlifting). Would the iron of the weights/bar be attracted/repulsed to the cubic sealed iron room?(Imagine magnet) Would this depend in turn on the type of iron the weights/bar are made of?(I posed this question here as it extends on the sealed garage subject, but if no response or demanded, I'll move it to physics)

Thank you once again for your information,

Gabriel

13. As it is mostly biology about oxygen use and co2 tolerance. The calculations do not have to be perfect, as a biologic system never is. So your calculations look sound.

About the magnetism topic, if you were in a sealed container, made from steel, lifting a metal pullingweight. You could magnetise it, and hence the weight becomes heavier to lift (in the start). But you can not generate a magnetic field, simply by lifting it, as your weight is not magnetic, you don't generate static energy with iron, and for magnetic energy to form, you need a coil, and rotate, or lift it with at least 40 hertz, to have any reasonable effect. And lifting anything 40 times a second, is improbable.

There is an ionisation probability, but i doubt you have the generators for this in your room.

Magnetism from your weigth is out of the question..

14. Originally Posted by gcourtois

Now for CO2 cycling is about 3l per minute. There is about 0.033 % C02 in atmosphere, figure that might be approx. closer to 0.05 % in a parking lot?

Recommended work guidelines are 0.5 % max.(0.5 % safety before 1% weak legs symptom appear) So thats 375 l. At rest it's 0.3l/co2/min. Adjusted with humidity that 93.75 l

That's 5 hours at rest before safe co2 barrier is crossed over.(only?) and 10 before first physical symptoms appear.
I don't quite see where you got the 93.75 liters from. 375 liters/0.3 liters per minute would be 1250 minutes, or ~20 hours.

15. Harold,

If I am not mistaken co2 content in air in a garage will hover around 0.05%
0.05% of the 75000l total gives us 37.5 total co2 to start with. Assuming 75% humidity that gives us approx initial co2 level of 9 litres.
First physical symptoms threshold is 1% or 750 l max of C02. Adjusted to humidity that's 187.5.
That gives us 150 l to consume before c02 physical symptoms appear. Or 150/0.3 --> Approx 8h20 minutes if at rest.
If work safety guidelines of 0.5% are to be respected, that's approx 90- 37.5 -- > 52.5 l to be consumed before threshold reached. that's a little less than 3 hours at rest.

Zwolver, as for magnetism that would mean in effect that the mass of the iron off the floor(for say the "deadlift") would be the same where it done in the middle of a gym, unless I purposefully try to create magnetic energy?( which will not happen in any lifts, If it implies creating an oscillation 40x a minute with the iron, this will not happen unless I try to do so and then again...)

Gabriel

16. Originally Posted by gcourtois
Harold,

If I am not mistaken co2 content in air in a garage will hover around 0.05%
0.05% of the 75000l total gives us 37.5 total co2 to start with. Assuming 75% humidity that gives us approx initial co2 level of 9 litres.
Are you assuming that 75% humidity means that 75% of the atmosphere is water? That's wrong. 75% humidity refers to a relative humidity, i.e., the percentage of the amount that would result in saturation (i.e., it rains at 100%). Relative humidity - Wikipedia, the free encyclopedia
At 100% relative humidity and 20 degrees C, there is only about 15 grams of water per kilogram of air.

17. Haha, true, i had totally overlooked that.. thats funny ..

i thought the 93,75liters were some kind of failsafe, to be 1/4th of the maximum of minimal co2 tolerance/oxygen requirement..

100% humidity would be i'd be swimming then, hehe..

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