Average Gas Consumption

[scubadada]

150 responses from 2009 poll, 279 responses from 2016 poll

1 cu ft = 28.3 liters
1 liter = 0.035 cu ft

< 0.3 cu ft/min = <8.5 l/min
0.3-0.39 cu ft/min = 8.5-11.0 l/min
0.4-0.49 cu ft/min = 11.3-13.9 l/min
0.5-0.59 cu ft/min = 14.2-16.7 l/min
0.6-0.69 cu ft/min = 17.0-19.5 l/min
0.7-0.79 cu ft/min = 19.8-22.4 l/min
0.8-0.89 cu ft/min = 22.6-25.2 l/min
0.9-0.99 cu ft/min = 25.5-28.0 l/min
>1.0 cu ft/min = >28.3 l/min

Disclaimer: as usual, many caveats in interpreting a poll on SB

 

[KentB]

I plan my dives now at .6 for both bottom and deco
Deco is typically avg .1 less than bottom gas

 

[FreeFlyFreak]

6' 185lbs

Lowest ever, 0.52 cuft/min warm water very low exertion.

Highest ever 0.93 cuft/min
Cold water, shivering, turned out i had a 101 fever when I got home.

Normally im around 0.71 cuft min cold and 0.55-0.6 warm water.

 

[scubadada]

293 responses from the 2016 poll now, and 150 from 2009. See #121 for imperial/metric conversion

 

[scubadada]

2016 and 2009 separately, if you would like to compare

 

[scubadada]

Some more responses since the last update. Only the 2016 poll has changed

 

[Rickk]

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).

I am an engineer and used to doing calculation in my head. I can do SAC and RMV approximations using either metric ( MUCH easier) or imperial equipment. ( Actually i convert the imperial to metric in my head before doing the calculation.)

I take a guess at my average depth to that point on the dive, with a typical dive profile dropping to depth then gradually working towards a shallower dive I will use maximum depth at the start, then switch to average between max depth and current depth. By the end of the dive I generally am within about 10% of what my computer log calculates when I get dry. I am usually on the high side because of the lower average depth due to the decent portion of the dive not being considered.

Good guide on gas consumption as well as a good way to self test for gas narcosis. If I have no idea how to do the calculation, I am narced, If I don't know why I at my computer, I am really narced. lol

 

[scubadada]

Update, few more responses to 2016 poll

 

[ATJ]

I haven't participated in the poll yet. I was wondering if for the calculation we (incorrectly) assume that air/Nitrox compresses linearly or take into account the actual variation in compression with pressure (as Subsurface does).

For example, on a recent dive my RMV using linear compression was 11.7L/min but 10.3L/min in Subsurface. This was using a 300bar tank where the differences between linear and actual compression are a lot higher. The day before I used 2 x 230bar tanks and had RMV of 12.0 and 11.3 respectively.

 

[DiveClimbRide]

I haven't participated in the poll yet. I was wondering if for the calculation we (incorrectly) assume that air/Nitrox compresses linearly or take into account the actual variation in compression with pressure (as Subsurface does).

For example, on a recent dive my RMV using linear compression was 11.7L/min but 10.3L/min in Subsurface. This was using a 300bar tank where the differences between linear and actual compression are a lot higher. The day before I used 2 x 230bar tanks and had RMV of 12.0 and 11.3 respectively.

So that's why subsurface is different from my paper calculations! Thank you!