Originally posted by bismarcksea
Aprox 1 minute for every foot squared of total space.
This is a rough estimate but close enough.
From my diving training this is how you do it.
Calculate your litres of air per minute (consumption rate) and then calculate your total volume of the room (air reserve).
Divide the air reserve by the consumption rate and you'll get your total breathing time.
To work out your consumption rate a scuba set is required along with a timepiece.
Calculate the total litres of compressed air inside it by multiplying the psi by the size of it (usually the size vary's from 3 to 15 litres).
(Watch the dial go down over a minute and however many bar / psi it loses you use that figure, multiply it by the size/capacity in feet / litres and
you'll get your consumption rate.)
So a 200 bar x 12 litre tank = 2400 litres of air.
Say you consume 2 bar in one minute
2 x 12 = 24 litres of air per minute.
Note: Obviously this is at a rest state, if you want to calculate a 'working' rate you need to do some macho moves / excercise etc then breathe down
the tank for a minute.

edit on 23-11-2010 by WatchRider because: (no reason given)