Average Gas Consumption

What is your average RMV?

  • less than 0.3 cu ft/min, 8.5 l/min

    Votes: 12 1.4%

  • 0.3-0.39 cu ft/min, 8.5-11.2 l/min

    Votes: 105 11.8%

  • 0.4-0.49 cu ft/min, 11.3-14.1 l/min

    Votes: 235 26.5%

  • 0.5-0.59 cu ft/min, 14.2-16.9 l/min

    Votes: 269 30.3%

  • 0.6-0.69 cu ft/min, 17.0-19.7 l/min

    Votes: 130 14.7%

  • 0.7-0.79 cu ft/min, 19.8-22.5 l/min

    Votes: 90 10.1%

  • 0.8-0.89 cu ft/min, 22.6-25.4 l/min

    Votes: 22 2.5%

  • 0.9-0.99 cu ft/min, 25.5-28.2 l/min

    Votes: 9 1.0%

  • greater than or equal to 1.0 cu ft/min, 28.3 l/min

    Votes: 15 1.7%
  • Total voters
    887

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A quick thousand views, now more than 74,000. Seven more votes in the poll, now 872

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The median, mode, and weighted average remain 0.5-0.59 cu ft/min or 14.2-16.9 l/min.

If you have not voted in the poll, please consider doing so. If your average RMV has changed, please change your vote.

Go diving
 
More than 75,000 views and 878 votes in the poll

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The median, mode, and weighted average remain 0.5-0.59 cu ft/min or 14.2-16.9 l/min.

If you have not voted in the poll, please consider doing so. If your average RMV has changed, please change your vote.

The best of diving to everyone
 
scubadada:
More than 75,000 views and 878 votes in the poll The median, mode, and weighted average remain 0.5-0.59 cu ft/min or 14.2-16.9 l/min. If you have not voted in the poll, please consider doing so. If your average RMV has changed, please change your vote.

The best of diving to everyone
Click to expand...

I did a dive a few dives today with an American technical diver on vacation. He has no camera rig and dang, he was in great horizontal trim and barely moving the last dive. Me I have my camera rig and was taking a couple of videos and some photos and moving around to get my filming done. I thought I wasn't doing too well on gas consumption.

Something definitely not right in my head...... Sac rate 8.03 I just felt a bit off
AL 80 200 bar start 90 bar end. Really slow dive.

Thing is Shearwater cloud shows it as bar/min 0.73 The tec diver was at 1.00 as he uses a transmitter so checked after the dive. So is the new standard bar/min?

SAC RATE 19 MAR 2025.jpg
 
Blackcrusader:
So is the new standard bar/min?
Click to expand...
No. Whether it's pressure in bar, or pressure in psi, SAC is tank-dependent. In order to compare your consumption with your American technical buddy, you have to account for your potentially differing tank sizes. If you two each had the same tanks, yes - you could compare your differing consumption via bar/min. But then you couldn't compare with the other 877 divers in @scubadada 's poll.
RMV remains the standard, whether it's l/m or CFM.
 
rsingler:
No. Whether it's pressure in bar, or pressure in psi, SAC is tank-dependent. In order to compare your consumption with your American technical buddy, you have to account for your potentially differing tank sizes. If you two each had the same tanks, yes - you could compare your differing consumption via bar/min. But then you couldn't compare with the other 877 divers in @scubadada 's poll.
RMV remains the standard, whether it's l/m or CFM.
Click to expand...
What gets so confusing for newer divers like me is that it seems SAC and RMV are often used interchangeably, when they really are technically not the same thing...

When I first saw that post from @Blackcrusader I thought "How can it be 8.03 if it was 0.73 bar/min? Isn't the conversion rate from bar to psi ~14.5?"

I had to look at that screenshot very carefully to understand that the 0.73 is bar/min and the 8.03 is litres/min. And that put my sometimes-OCD-ish brain at ease again...
 
rsingler:
No. Whether it's pressure in bar, or pressure in psi, SAC is tank-dependent. In order to compare your consumption with your American technical buddy, you have to account for your potentially differing tank sizes. If you two each had the same tanks, yes - you could compare your differing consumption via bar/min. But then you couldn't compare with the other 877 divers in @scubadada 's poll.
RMV remains the standard, whether it's l/m or CFM.
Click to expand...
Yes, there has always been confusion regarding the use of SAC and RMV. I define SAC as pressure/time, either psi or bar/min. As @singler points out, this is cylinder dependent. I define RMV as volume/time, either cu ft or liters/min. This is cylinder independent. My Average Gas Consumption poll, started over 8 1/2 years ago, uses RMV, volume/time.

I started a thread a little over 2 years ago addressing the definitions of SAC and RMV. Less than half defined SAC as pressure/time and defined it as volume/time. Nearly everyone defined RMV as volume/time. I doubt this confusion will ever be resolved. As long as one gives the units, psi or bar/min or cu ft or liters/min, the meaning should be clear.

There, I'm sure that is clear to everyone :)

scubadada

Question Thread 'Definitions for SAC and RMV?'

This topic comes up over and over. Let's see what you think. Please vote once for SAC and once for RMV or vote for #5 and elaborate in your post or #6 if you don't know what this is all about.
 
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