I'm in a 12x15x8 foot (3.6x4.5x2.4 meters) room with zero ventilation. How long can I keep the door shut and not experience suffocation, or other ill effects? Will oxygen seep in through the closed window, faster than I can breathe it? If possible, please cite references.
Oxygen in a Closed Room
- Thread starter halfpower
- Start date
- May 13, 2003
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What are you doing, and how are you breathing? This matters quite a bit. Now, depending upon your elevation, the average percentage of air in the atmosphere is 21%. Your body requires 14% oxygen in the air that you breath to maintain life (hence the effectiveness of CPR--your body doesn't use all of the oxygen you breathe in). Now, with a room that size, being 1440 cubic feet, that's equivalently 302.4 cubic feet of oxygen. Now all you would need to do is measure the size of your breath (use a balloon, and figure out the area), and remember that you are expelling air with 14% oxygen (thus a 6% decline or delta for each breathe taken), and figure out your breaths per minute, and the rest is easy... And all of the numbers is taken from CPR training... Sorry I couldn't provide specific citations.
Tas.
Tas.
- May 13, 2003
- 13,704
- 7
- 81
Oh, that isn't taken into account the window, for simplisity's <sp> sake. Also, please tell me that you aren't trying to figure this out so that you can place yourself in a dangerous situation? If that is the case, get some air breathing equipment, or something to that effect.
Tas.
Tas.
From what I remember oxygen is not your first problem, the CO2 in the air will kill you long before you run out of oxygen.
AFAIK that is how closed-cycle diving equipment works; it removes the CO2 from the air you exhale which means that it can be recycled.
In old submarines they used some simple chemical (I don't remember which one) to remove CO2 from the air when they were forced so stay submerged for a long time.
AFAIK that is how closed-cycle diving equipment works; it removes the CO2 from the air you exhale which means that it can be recycled.
In old submarines they used some simple chemical (I don't remember which one) to remove CO2 from the air when they were forced so stay submerged for a long time.
- May 13, 2003
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Condensed from a comprehensive paper by Garry, presented at the 21st biennial Australian Speleological Federation conference 1997 (published in the proceedings) and an article published in the 1993 Australian Caver No. 133, Pages 20-23. For more detailed information refer to these papers.
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Carbon Dioxide (CO2) is the body's regulator of the breathing function. It is normally present in the air at a concentration of 0.03% by volume. Any increase above this level will cause accelerated breathing and heart rate. A concentration of 10% can cause respiratory paralysis and death within a few minutes. In industry the maximum safe working level recommended for an 8 hour working day is 0.5% .
EFFECTS OF CO2 ON HUMANS
As each persons body has a slightly different reaction and tolerance to stressful situations the following symptoms are general, however nobody is immune to the dangers of CO2.
Table 2. Generally accepted physiological effects of CO2 at various concentrations by volume.
Concentration Comments
0.03% Nothing happens as this is the normal carbon dioxide concentration in air.
0.5% Lung ventilation increases by 5 percent. This is the maximum safe working level recommended for an 8 hour working day in industry (Australian Standard).
1.0% Symptoms may begin to occur, such as feeling hot and clammy, lack of attention to details, fatigue, anxiety, clumsiness and loss of energy, which is commonly first noticed as a weakness in the knees (jelly legs).
2.0% Lung ventilation increases by 50 percent, headache after several hours exposure.
Accumulation of carbon dioxide in the body after prolonged breathing of air containing around 2% or greater will disturb body function by causing the tissue fluids to become too acidic. This will result in loss of energy and feeling run-down even after leaving the cave. It may take the person up to several days in a good environment for the body metabolism to return to normal.
3.0% Lung ventilation increases by 100 percent, panting after exertion, Symptoms may include:- headaches, dizziness and possible vision disturbance such as speckled stars.
5 - 10% Violent panting and fatigue to the point of exhaustion merely from respiration & severe headache. Prolonged exposure at 5% could result in irreversible effects to health. Prolonged exposure at > 6% could result in unconsciousness and death.
10 - 15% Intolerable panting, severe headaches and rapid exhaustion. Exposure for a few minutes will result in unconsciousness and suffocation without warning.
25% to 30% Extremely high concentrations will cause coma and convulsions within one minute of exposure. Certain Death.
Effects of O2 deficiency on Humans
If we consider an atmosphere consisting of just N2 and O2, where the O2 is at a lower concentration than the normal atmosphere, the human body would be affected in the following manner.
Table 3. Generally accepted physiological effects of reduced O2 concentrations.
O2% by volume. Symptoms
reduced from 21 to 14% First perceptible signs with increased rate and volume of breathing, accelerated pulse rate and diminished ability to maintain attention.
between 14 to 10% Consciousness continues, but judgment becomes faulty. Rapid fatigue following exertion. Emotions effected, in particularly ill temper is easily aroused.
10 to 6% Can cause nausea and vomiting. Loss of ability to perform any vigorous movement or even move at all. Often the victim may not be aware that anything is wrong until collapsing and being unable to walk or crawl. Even if resuscitation is possible, there may be permanent brain damage.
below 6% Gasping breath. Convulsive movements may occur. Breathing stops, but heart may continue beating for a few minutes - ultimately death.
The human body under average conditions inhaling air which contains approximately 21% oxygen and 0.03% carbon dioxide. The air breathed out of the lungs contains approximately 15% oxygen and 5.6% CO2. A person at rest inhales and exhales approximately 6 litres of air per. minute but in times of stress, this may increase to more than 100 litres per minute.
Of course, even in a closed room, the system is not perfectly sealed. ASHRAE states that each person should have 20CFM in normal working conditions. However, your room's CFM will vary due to it's sealant/gaps/etc. A normal leaky house has 0.5 air changes per hour (ie. 12CFM in your case).
From this information, as long as you are working normally (no welding/etc). You will have no problems with air quality (although other considerations - heat/etc) may be present.
--------------------------------------------------------------------------------
Carbon Dioxide (CO2) is the body's regulator of the breathing function. It is normally present in the air at a concentration of 0.03% by volume. Any increase above this level will cause accelerated breathing and heart rate. A concentration of 10% can cause respiratory paralysis and death within a few minutes. In industry the maximum safe working level recommended for an 8 hour working day is 0.5% .
EFFECTS OF CO2 ON HUMANS
As each persons body has a slightly different reaction and tolerance to stressful situations the following symptoms are general, however nobody is immune to the dangers of CO2.
Table 2. Generally accepted physiological effects of CO2 at various concentrations by volume.
Concentration Comments
0.03% Nothing happens as this is the normal carbon dioxide concentration in air.
0.5% Lung ventilation increases by 5 percent. This is the maximum safe working level recommended for an 8 hour working day in industry (Australian Standard).
1.0% Symptoms may begin to occur, such as feeling hot and clammy, lack of attention to details, fatigue, anxiety, clumsiness and loss of energy, which is commonly first noticed as a weakness in the knees (jelly legs).
2.0% Lung ventilation increases by 50 percent, headache after several hours exposure.
Accumulation of carbon dioxide in the body after prolonged breathing of air containing around 2% or greater will disturb body function by causing the tissue fluids to become too acidic. This will result in loss of energy and feeling run-down even after leaving the cave. It may take the person up to several days in a good environment for the body metabolism to return to normal.
3.0% Lung ventilation increases by 100 percent, panting after exertion, Symptoms may include:- headaches, dizziness and possible vision disturbance such as speckled stars.
5 - 10% Violent panting and fatigue to the point of exhaustion merely from respiration & severe headache. Prolonged exposure at 5% could result in irreversible effects to health. Prolonged exposure at > 6% could result in unconsciousness and death.
10 - 15% Intolerable panting, severe headaches and rapid exhaustion. Exposure for a few minutes will result in unconsciousness and suffocation without warning.
25% to 30% Extremely high concentrations will cause coma and convulsions within one minute of exposure. Certain Death.
Effects of O2 deficiency on Humans
If we consider an atmosphere consisting of just N2 and O2, where the O2 is at a lower concentration than the normal atmosphere, the human body would be affected in the following manner.
Table 3. Generally accepted physiological effects of reduced O2 concentrations.
O2% by volume. Symptoms
reduced from 21 to 14% First perceptible signs with increased rate and volume of breathing, accelerated pulse rate and diminished ability to maintain attention.
between 14 to 10% Consciousness continues, but judgment becomes faulty. Rapid fatigue following exertion. Emotions effected, in particularly ill temper is easily aroused.
10 to 6% Can cause nausea and vomiting. Loss of ability to perform any vigorous movement or even move at all. Often the victim may not be aware that anything is wrong until collapsing and being unable to walk or crawl. Even if resuscitation is possible, there may be permanent brain damage.
below 6% Gasping breath. Convulsive movements may occur. Breathing stops, but heart may continue beating for a few minutes - ultimately death.
The human body under average conditions inhaling air which contains approximately 21% oxygen and 0.03% carbon dioxide. The air breathed out of the lungs contains approximately 15% oxygen and 5.6% CO2. A person at rest inhales and exhales approximately 6 litres of air per. minute but in times of stress, this may increase to more than 100 litres per minute.
Of course, even in a closed room, the system is not perfectly sealed. ASHRAE states that each person should have 20CFM in normal working conditions. However, your room's CFM will vary due to it's sealant/gaps/etc. A normal leaky house has 0.5 air changes per hour (ie. 12CFM in your case).
From this information, as long as you are working normally (no welding/etc). You will have no problems with air quality (although other considerations - heat/etc) may be present.
For a short time you would probably get dizzy from the effects of over oxidation. But due to the small volume of the room you would bring up the co2 levels before you passed out. Then the CO2 level would eventually get you.
Now, if you struck a match in that room?
A: Boooooom
B: Match disintegrates in a flash
C: Every thing in the room ignites including you.
D: Smokey the Bear shows you before you do something foolish.
Now, if you struck a match in that room?
A: Boooooom
B: Match disintegrates in a flash
C: Every thing in the room ignites including you.
D: Smokey the Bear shows you before you do something foolish.
302.4 cubic feet of oxygen...Whoa!!!..... I think I'd have to douse myself in gasoline to burn that much oxygen in a day. On the other hand, solids have a much higher molar density than gasses.
I believe that too much oxygen will cause you to suffocate, not sure how much, as it will impede your lungs' ability to release CO2 and other harmful gases.
First of all, 100% O2 is not necessarily detrimental to anyone...the early astronauts (up to Apollo 1) all used 100% oxygen environments. Secondly, I have no idea what submarines used but I know NASA used Lithium Hydroxide canisters to remove the CO2 from the air.
Pulmonary Oxygen Toxicity occurs when a person is exposed to high oxygen levels for over 16 hours in pressures of 0.5 bar or more
Maybe the astronauts did, but not everything they did was necessarily safe, including but not limited to blasting off the face of the earth and space travel. Astronauts knowingly take extraordinary risks associated with their profession. Worth mentioning is that all of the crew of Apollo 1 died in a fire attributed to the pure oxygen environment, which also caused some things to burn violently that would not otherwise in a atmosphere like on the surface of the earth.
Number one: That may be why the spacecraft were only pressurized to 5.5psi.
Number two: If I remember correctly, the fire was attributed to a spark hitting Velcro in the pure oxygen environment.
Per my OSHA permit-required confined space training, humans are safe in environments containing 19.5% to 23.5% oxygen by volume. They may survive outside this range for a period of time depending on the disparity in oxygen concentration from this range, the person, and other factors. Typical air contains 21.5% oxygen. The air you exhale is about 16% oxygen. The bulk of the difference between inhaled and exhaled air is carbon dioxide, though some is water. I can't recall the approximate amounts of oxygen consumed per hour or anything - too tired tonight.
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