Oxygen duration?
Thread Starter
Joined: Sep 2006
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From: Los Angeles, USA
Oxygen duration?
Does anyone have a link to a table of how long a certain size oxygen tube will last at certain altitudes? I have a built in system that I'm thinking of re-pressurizing and getting legal again. I don't know the exact size of my tube, but will find out during my annual next week.
Peter maybe?
Peter maybe?
Last edited by AdamFrisch; 30th August 2012 at 23:51.
Joined: Jan 2001
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From: In the boot of my car!
Depends very much on the size of bottle you have as well as your breathing rate as well as the pressure or lack of it your in 
Depending how high you are I have experimented with On Off. Taking the mask off to make radio calls as well as 2 minutes off 2 minutes on.
So how long is a piece of string?
Normally for an average bottle around 3 hrs
Pace
Depending how high you are I have experimented with On Off. Taking the mask off to make radio calls as well as 2 minutes off 2 minutes on.
So how long is a piece of string?
Normally for an average bottle around 3 hrs
Pace
Last edited by Pace; 31st August 2012 at 00:43.
Joined: Feb 2002
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From: Inverness-shire
Depends on bottle volume and working pressure, consumption rate + reasonable reserve.
Volume stored = bottle internal volume in litres x pressure in bar = total gas stored in litres.
Consumption rate. The old constant flow systems often had only two settings, 2 litres/min and 4 litres/min
The FAA recommendation was 1 litre/min of supplementary oxygen per 10000 feet of altutude so 2 litres/min ought to be ok to 20 000 feet but I'd personally be on 4 litres/min before that!
The new pulsed systems etc are however much more economical on oxgygen than constant flow (4 times or more is claimed). Canulas normally max out at 18000 feet and constant flow is said to max out at 25000.
Depending where you live, your bottle will probably be out of test by now. Diving cylinders in Europe require a visual inspection every 2.5 years and a hydrostatic test every 5 years. I think the same applies to aviation oxygen cylinders but you'd need to check that locally.
All the above is written only as a glider pilot with a lot of diving experience, so check with the professionals. The person selling your demand equipment should know consumption rates and the organisation filling your bottle should be aware of the test regulations applicable.
Volume stored = bottle internal volume in litres x pressure in bar = total gas stored in litres.
Consumption rate. The old constant flow systems often had only two settings, 2 litres/min and 4 litres/min
The FAA recommendation was 1 litre/min of supplementary oxygen per 10000 feet of altutude so 2 litres/min ought to be ok to 20 000 feet but I'd personally be on 4 litres/min before that!
The new pulsed systems etc are however much more economical on oxgygen than constant flow (4 times or more is claimed). Canulas normally max out at 18000 feet and constant flow is said to max out at 25000.
Depending where you live, your bottle will probably be out of test by now. Diving cylinders in Europe require a visual inspection every 2.5 years and a hydrostatic test every 5 years. I think the same applies to aviation oxygen cylinders but you'd need to check that locally.
All the above is written only as a glider pilot with a lot of diving experience, so check with the professionals. The person selling your demand equipment should know consumption rates and the organisation filling your bottle should be aware of the test regulations applicable.
Last edited by astir 8; 31st August 2012 at 03:12.
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From: S Warwickshire
I use a portable system with oxy-saver cannulas. They recommend .3 litres/min at 10,000' rising to 0.6 at 18,000'. Above that you will need masks and the consumption rate rises considerably.
My 9 cu ft bottle gives 9-10 man hours at 10-12,000' at the low setting and keeps my saturation up in the 95-96% region.
1 cu.ft is 28.3 litres, so a few quick sums should give you the answer.
The dive shop in San Pedro does a refill for $15. A lot cheaper than the local FBOs.
My 9 cu ft bottle gives 9-10 man hours at 10-12,000' at the low setting and keeps my saturation up in the 95-96% region.
1 cu.ft is 28.3 litres, so a few quick sums should give you the answer.
The dive shop in San Pedro does a refill for $15. A lot cheaper than the local FBOs.
Thread Starter
Joined: Sep 2006
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From: Los Angeles, USA
Thanks guys.
I have an old built in Scott regulator. We're talking 50's technology here. I don't know if a pulse controlled device could be spliced in after that regulator, or if it has to be used as it is.
My oxygen tube is most def timed out, so I'd have to get a new one. But the good thing is I could probably get a bigger bottle then.
I have an old built in Scott regulator. We're talking 50's technology here. I don't know if a pulse controlled device could be spliced in after that regulator, or if it has to be used as it is.
My oxygen tube is most def timed out, so I'd have to get a new one. But the good thing is I could probably get a bigger bottle then.
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Do a search of aerox.com and mhoxygen.com. They have various tables. Not that they are all that reliable.
It much depends on altitude, obviously, and whether you use a demand regulator.
Your Scott regulator is prob99 the first stage regulator and in the ancient systems one used to plug plain cannulas directly into that, via a manual flow adjuster. Have a read of this.
It much depends on altitude, obviously, and whether you use a demand regulator.
Your Scott regulator is prob99 the first stage regulator and in the ancient systems one used to plug plain cannulas directly into that, via a manual flow adjuster. Have a read of this.
Joined: Dec 2011
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IIRC, I updated some links on my writeups on that one. It was fairly pricey - c. 10k. Probably good for high usage ops e.g. high alt paradropping. But for private flying, the costs are roughly
$700 for the 48cu ft MH carbon/kevlar cylinder
$300? for the MH 1st stage reg (4 outlets)
$800 for the O2D2 electronic demand reg (includes some cannulas and a mask)
$10? for a plain cannula (x # of likely passengers)
and that's it. That kit will be good for 10s of hours at FL180 for 2 people, so the almost inevitable refill hassle is well postponed.
You need a 540-thread refill adaptor - MH do those too. But I use a hose; details in the writeup.
Given that oxygen doubles the operating ceiling of any half decent IFR tourer, it's extremely cheap. Also the Eurocontrol routings are often much better above FL120.
$700 for the 48cu ft MH carbon/kevlar cylinder
$300? for the MH 1st stage reg (4 outlets)
$800 for the O2D2 electronic demand reg (includes some cannulas and a mask)
$10? for a plain cannula (x # of likely passengers)
and that's it. That kit will be good for 10s of hours at FL180 for 2 people, so the almost inevitable refill hassle is well postponed.
You need a 540-thread refill adaptor - MH do those too. But I use a hose; details in the writeup.
Given that oxygen doubles the operating ceiling of any half decent IFR tourer, it's extremely cheap. Also the Eurocontrol routings are often much better above FL120.
Joined: Jul 2007
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From: 51.50N 1W (ish)
Cylinder/system duration chart here:
1/ Mountain High oxygen system endurance chart
The MH pulse system is easy to use and economical on O2 quantity. I use one when making my annual gliding safari to South Africa, where operating heights are 10-18,000 ft and typical flight time 6 hours; not needing to refill the system daily avoids hassle (= delay on getting to the bar to rehydrate) although there is on-site refill there.
1/ Mountain High oxygen system endurance chart
The MH pulse system is easy to use and economical on O2 quantity. I use one when making my annual gliding safari to South Africa, where operating heights are 10-18,000 ft and typical flight time 6 hours; not needing to refill the system daily avoids hassle (= delay on getting to the bar to rehydrate) although there is on-site refill there.
Last edited by Fitter2; 31st August 2012 at 10:02.
