Average Gas Consumption

[scubadada]

SB friends,

Several posters have brought up a very important point, the influence of different kinds of diving on your RMV. My intent, when initially posting this in the Basic Scuba Discussions forum, was mainly to address recreational/sport diving, but, that was not explicitly stated. Clearly, there is a very wide spectrum represented by recreational diving, technical diving, single cylinder, doubles, multiple cylinders, wetsuit, drysuit, warm water, cold water, current, no current, good visibility, bad visibility, challenges on the dive, an easy dive, great effort, little effort.....and many other variables. Obviously, one's RMV data is most useful to the diver that generated it, under the conditions in which it was generated.

I have learned quite a lot from calculating my RMV. I have my RMV for 1364 of my last 1380 dives, over the last 9 years. My diving is relatively narrowly focused, mostly recreational, 5% light deco, all back mounted single, with or without one additional slung cylinder, all wet. However, I have dived under a very wide range of conditions. I did not start measuring my RMV until I had about 500 dives, it has improved only a little since then, but, the variation has decreased. Fully 95% of my dives are within +/- 0.08 cf/min of the average. Feeling cold, not necessarily diving in cold water, is a major determinate of my RMV, as or more important than relative effort. I use a little over my average RMV for routine gas planning and this works very well. However, I use twice my average RMV for contingency planning. I have not had the need to try that one out, yet.

For each of you, I hope your RMV helps with your diving and gas planning. The main reason for posting the poll was to give us all a very general idea of the approximate distribution of the RMV

Good diving, Craig

 

[Storker]

Wouldn't be applicable if using argon though

Who's using argon if they aren't diving trimix? With a suitable undersuit and a good wicking layer, I can manage between 45 and 60 minutes in 4-6C water with just backgas in my suit without noticeable discomfort. No He in my backgas, though.

 

[Andrei Astra]

@scubadada, Could you please show in the poll the L/min values as well?

 

[scubadada]

@scubadada, Could you please show in the poll the L/min values as well?

From post #1:

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

 

[scubadada]

Thanks for the 81 new votes in the poll in the last month.

 

[Tribal]

After like 20 dives in a week on a LOB, warm water, single tank, almost no navigation, fighting to not fall asleep (not so much of a fish lover so after a week i’m bored) it will be around 12l/min

Drysuit, twins, dark cold water, current, navigation, ... it will be 18l/min. Put some new stuff in the dive to get used to and it’s 20+

Not feeling uncomfortable or anything but the consumption goes up when adding those things.

 

[wnissen]

I feel like the results in this thread are significantly informed by the What's your highest certification thread. With the caveat that it's in Advanced Scuba, and all the usual self-selection about online polls, it suggests that the majority of Scubaboarders have a certification that's beyond Rescue. Basically, the respondents are as likely to be divemaster-certified as any of the lower categories.

 

[scubadada]

I feel like the results in this thread are significantly informed by the What's your highest certification thread. With the caveat that it's in Advanced Scuba, and all the usual self-selection about online polls, it suggests that the majority of Scubaboarders have a certification that's beyond Rescue. Basically, the respondents are as likely to be divemaster-certified as any of the lower categories.

Hi @wnissen,

This thread has always been in Basic Scuba Discussions, see post #101. On multiple occasions, I have pointed out that this poll has all the caveats of a SB poll. Responders are posting members of SB, they know what RMV is, they measure or calculate their own RMV and know approximately what the average is, are willing to post their information in this thread, etc., etc. However, there are now 260 responses in this 2016 poll as well as the 150 from a nearly identical poll from 2009. There are probably even some duplicates between the 2 polls. These 410 responses appear to be the best we have for answering the question, what is your average RMV? Take if for what it is worth.

I hope you have added your RMV to the poll.

Good diving, Craig

 

[hammet]

After diving with @scubadada last week I can attest that he actually breathes through gills behind his ears which accounts for his exceptionally low RMV.

 

[mcohen1021]

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.

AMEN...

Typically on a caribbean dive, I go 60-70 minutes, ending with 500 psi