O2 Calculations

[Staunch111]

Hi All,

How much supplementary O2 is required - if at 20,000 feet for 18 hrs?
Can anyone refer me to literature which outlines the different O2 rate / requirements at altitudes from 10,000 - 25,000 feet.

PS: I have contacted an Australian supplier and am waiting on feedback.

Thank you in advance.

[eddieseve]

You might start with using a pulse oxy meter and then adjust O2 flow rates to keep your stauration level above 95%, this will at least make the delivery rate relative to your own age, health and fitness.

Cheers

[Staunch111]

Thanks Eddie.

K here is my solution.

Referencing FAR 23.1447 the amount required is 1 liter of O2 per minute every 10,000 feet. Therefore at 18,000 feet a flow of 1.8L p/m is required or 2L p/m at 20,000. Though at 20,000 feet a mask is required for installed systems which use O2 at a rate 4 x more than a cannula.

Given 1 cubic foot = 28.3L
And using a Tank factor 0.283

Tank duration (in Mins) = (Tank factor) x (PSI) / litre per minute gas flow.
= 0.283 x 1800/ 2
= 254min or 4.25 hours.

Alot will depend on the PSI of the tank - greater PSI - greater volume. For example if PSI was increased to 2200 gives 311 min or 5.18 hrs.

[Mark Dickens]

You might also reference some of the information available from the various o2 system vendors, such as http://www.mhoxygen.com/index.php/co...s/download/627

What kind of oxygen system and breathing apparatus do you have?

[turbo]

if you add an electronic device that only pulses o2 when you inhale your duration will increase a lot.

[Staunch111]

I've been reading up on Mountain High Systems - particularly the eds o2d1 system with 680 litre tank - rated for 15hrs at 18k. Very impressive Now combine that with a Kevlar wrapped tank and the weight comes down to approx 4.4 lbs.

[BobTurner]

18 hours?
Is this in an aircraft? If you are walking around as opposed to just sitting the need goes up, of course.

[flightlogic]

As mentioned, the only way to know what YOU need in terms of oxygen, is a pulse ox meter. They are readily available and low cost.
Your physiology probably will not match a chart... and you may either waste oxygen or need more than you are getting.
BTW, trivia.... a doctor showed my wife a trick. The readings on her finger tip were blocked (IR light) using the meter, due to nail polish. Solution, just rotate the device 90 degrees to read the sides of the finger, rather than front and back.
Now, why didn't I think of that?