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# Oxygen depletion in an unventilated airliner?

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# Oxygen depletion in an unventilated airliner?

21st Apr 2012, 18:18

Join Date: Jan 2007
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Oxygen depletion in an unventilated airliner?

If the aircraft sits on stand for some time, with no air conditioning, doors closed and a full load of passengers, how much will the oxygen/CO2 ratio change? Is this a threat to people with breathing difficulties? Have any studies been done?

21st Apr 2012, 18:41

Join Date: Aug 1998
Location: Ex-pat Aussie in the UK
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Endless Forms Most Beautiful » Blog Archive » Friday Fiction Facts: Trapped in an airtight room!

T = Number of hours before CO2 reaches toxic levels and your character(s) could die.

(Volume of air inside the room in cu ft) x (3% or 0.03)

T = ---------------------------------------------------------

(Number of people) x (one person's hourly production of CO2 in cu ft)
For a full Airbus A319:

Cabin length: 23.78m, Diameter: 3.7m = rough volume: 256 m³ = 9 040 ft³
Number of people: 156 passengers + 4 cabin crew
Resting CO2 rate = 0.4 ft³/hour (0.19 L/min from this NASA study)

From Wiki: Carbon dioxide - Wikipedia, the free encyclopedia
Adaptation to increased levels of CO2 occurs in humans. Continuous inhalation of CO2 can be tolerated at three percent inspired concentrations for at least one month and four percent inspired concentrations for over a week. It was suggested that 2.0 percent inspired concentrations could be used for closed air spaces (e.g. a submarine) since the adaptation is physiological and reversible.
So, time to 3% CO2 limit = about four and a quarter hours.

Mind you, I think someone might open a door or turn on the aircon before then

21st Apr 2012, 22:12

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And the lav/galley vent fans and the avionic ventilation system fans are all running and pumping used air overboard.

22nd Apr 2012, 08:19

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Also aircraft are not airtight.

22nd Apr 2012, 10:57

Join Date: Aug 1998
Location: Ex-pat Aussie in the UK
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Not airtight by any means - but there wouldn't be enough air exchange to matter if the packs and fans were off.

22nd Apr 2012, 19:48

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NASA knows well. They had this question with Apollo13

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