Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Oxygen depletion in an unventilated airliner?

Tech Log The very best in practical technical discussion on the web

Oxygen depletion in an unventilated airliner?

Reply

Old 21st Apr 2012, 18:18
  #1 (permalink)  
Thread Starter
 
Join Date: Jan 2007
Location: Cowshitshire
Posts: 977
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?
ZeBedie is offline  
Reply With Quote
Old 21st Apr 2012, 18:41
  #2 (permalink)  
 
Join Date: Aug 1998
Location: Ex-pat Aussie in the UK
Posts: 4,126
Google is your friend:

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 m = 9 040 ft
Number of people: 156 passengers + 4 cabin crew
Resting CO2 rate = 0.4 ft/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
Checkboard is online now  
Reply With Quote
Old 21st Apr 2012, 22:12
  #3 (permalink)  
 
Join Date: Apr 2005
Location: Stockholm Sweden
Age: 68
Posts: 571
And the lav/galley vent fans and the avionic ventilation system fans are all running and pumping used air overboard.
Swedish Steve is offline  
Reply With Quote
Old 22nd Apr 2012, 08:19
  #4 (permalink)  
 
Join Date: Dec 1998
Location: .
Posts: 2,885
Cool

Also aircraft are not airtight.
spannersatcx is offline  
Reply With Quote
Old 22nd Apr 2012, 10:57
  #5 (permalink)  
 
Join Date: Aug 1998
Location: Ex-pat Aussie in the UK
Posts: 4,126
Not airtight by any means - but there wouldn't be enough air exchange to matter if the packs and fans were off.
Checkboard is online now  
Reply With Quote
Old 22nd Apr 2012, 19:48
  #6 (permalink)  
 
Join Date: Mar 2005
Location: Uh... Where was I?
Posts: 1,342
NASA knows well. They had this question with Apollo13
Microburst2002 is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service