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On Sat, 17 Jun 1995, Scott Cherf wrote:
> At 11:52 AM 6/16/95, Chris Elmore wrote:
>
> > I don't know a specific formula (formulae for those across
> >the pond) but my handy Physiology of Flight manual indicates a
> >standard sea level pressure of 29.92 inches of mercury (14.69psi)
> >and 2000' is 27.82 in Hg. (13.66psi).
> >Hope this helps.
>
> Thanks Chris. To use this, I took the percentage difference between
> 2000' asl and mean sea level (.07 or 7%) and adjusted the volume
> of my tank by that amount (sherwood 120 @ 3500psi, 120 cf + 7%
> = 128.4 cf @ 2000'). Then I divided 128.4 by 35 to get the cf/100psi.
> (3.66 cf/100psi). Then I timed myself breathing 100psi of gas (EAN32
> left over from my last dive) at 1900' (14 minutes). I came up with
> .262 (.27) cf/minute @ sea level.
>
> I ran the same test again, this time using my wife, and she measured
> .13 cf/minute @ sea level (took her 29 minutes to use 100 psi of gas).
>
> According to Gilliam ('Deep Diving' pp 140, 1995), the expected range
> of RMV is between .3 and 3.0 cf/minute @ sea level. This puts me at
> the bottom of his range, and puts my wife at less than half of the bottom
> of the range. For the record, I'm 6'2" 220lbs, my wife is 5'5" 125lbs.
>
> The thing that worries me is that I only know one diver that uses more
> gas than I do on a normal dive; ie, I'm a known gas hog. Should I suspect
> my equipment (SPG), my method, or Gilliam's numbers? I expect most of
> the other divers here have run this test on themselves. How do you compare
> with Gilliam's 'typical' range of resting gas consumption?
>
Scott,
Obviously you are less relaxed in the water than on your couch!
Why don't you try figuring your consumption from a dive so that it is
accurate?
Bob F.
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