Average Gas Consumption

[Kevrumbo]

Wow! Seems like a great explanation. Could you please explain this in CuFt and PSI. It would make it much simpler for those of us who have always used the Imperial System.

Which is the quicker easier subtraction to see & figure in your head: 200 bar minus 80 bar equals 120 bar? Or: 3000 psi minus 1080 psi equals 1920 psi? Can you figure this out on the fly how much gas pressure you have consumed and keep a running total of how much remains? (Never mind --get yourself an Air Integrated Computer).

 

[Kevrumbo]

It anyone participates in the poll and then decides their answer was incorrect, the "Change Your Vote" function has been enabled and your answer can be corrected.

Others might want to post personal best RMV as well (usually 30% to 50% better than nominal in tropical warm water drift diving for example); to personal worst at extreme exertion/thumbing a dive (130% to 300% of nominal, kicking into a current at depth).

 

[KenGordon]

Conditions and kit matter too. On a single in easy warm water conditions my RMV is a third less than on a twinset with a drysuit in more serious conditions, so 12 vs 18l/min.

 

[scubadada]

As pointed out above, RMV varies due to many variables, for me, less than I would think. I posted my average for the last 750 dives. My average RMV is 0.37 cu ft/min with a std deviation of 0.04. So, 95% of my RMVs are between 0.29 and 0.45 cu ft/min. The range for those 750 dives is actually 0.28-0.63 cu ft/min. For me, being cold influences my RMV at least as much, if not more, than effort.

 

[NAM001]

Wow! Seems like a great explanation. Could you please explain this in CuFt and PSI. It would make it much simpler for those of us who have always used the Imperial System.

here it is in imperial. you have an al80 which in 77 cuft at 3000 psi divide 3000 by 77 and get roughly 39-40 psi per cuft. or 100 psi = 2.5 cuft since you pressure gage is easier to read increments of 100 psi then here is the problem. you are at 100 ft or 4atm you are using 500 psi in 6 ,minutes. what is your sac or rmv. 500 psi is 12.5 cuft divide by 4atm and that is 3.1. divide that by 6min and you are .5 cuft per minute.

 

[scubadada]

this poll will only be successful if many participate, a poll in 2004 had 70 participants, not enough, if you know your RMV, please contribute

 

[boulderjohn]

There has been extensive discussion lately regarding average gas consumption. A poll may help give us a better idea of what the normal distribution of RMVs is.

this poll will only be successful if many participate, a poll in 2004 had 70 participants, not enough, if you know your RMV, please contribue

Are you really expecting this poll to show a "normal" distribution?

I see a few problems.

1. ScubaBoard participants in general are nowhere near normal. A similar poll a few years ago indicted that a slight majority of divers (at least on ScubaBoard) use back plates and wings; in the real world, BP/Ws amount to about 1% of BCD sales annually.

2. You are asking people to self report a figure they are likely to want to boast about or not report if they are not feeling boastful.

3. Self reporting surveys regularly are oversampling people with a motivation to report.

4. How accurate are the reports of these people? A year or so ago, I had a new tech student tell me he already knew his RMV because he had an air integrated computer that gave it to him. Now, that was all recreational diving, but it was impressive--much better than mine has ever been. I am sure he was telling the truth, but our work in class showed he was nowhere near that. We have done a number of dives together since then, and he has never done as well as I.

Sampling bias - Wikipedia, the free encyclopedia

 

[KDAD]

Cast my vote. I keep a running average of my SAC. It is based on mostly cold water diving and uses uses tank factors. It does not include dives that would skew it one way or another such as a very shallow dive or some training dives.

 

[gcarter]

Lifetime 0.8
3 Year 0.72
This year 0.68
Lowest 0.43

My SAC is hugely temperature / exposure gear dependent.

 

[CuzzA]

My computer usually says a range between .4-.5 for exploratory dives. As a newer diver I don't have a solid average yet. When spearfishing or working rock I'm .6-.8. Hard to cast a vote.