Average Gas Consumption

[scubadada]

I started this poll nearly two years ago. The question was, what is your average RMV? There was a nearly identical poll posted in 2009. The combined results are shown below, 324 respondents, some may be duplicated between the two polls. These results are in cf/min, the conversion to l/min is shown below the graph

RMV cf/min * 28.32 = l/min

 

[scubadada]

This topic was recently activated again Air Consumption. If you did not have the opportunity to vote in this poll, please consider entering your average RMV at this time.

 

[caruso]

I read somewhere, either on this thread or elsewhere that there's another reason one diver might use more gas than another, all things being equal except for one factor- one diver is doing a lot of camera work, as I do. There's a lot more moving around, repositioning, finning, etc to get those shots and that can add up in terms of energy expended and gas consumed.

 

[Diving Dubai]

I read somewhere, either on this thread or elsewhere that there's another reason one diver might use more gas than another, all things being equal except for one factor- one diver is doing a lot of camera work, as I do. There's a lot more moving around, repositioning, finning, etc to get those shots and that can add up in terms of energy expended and gas consumed.

Unless you’re finning hard into current, or failing about underwater using a camera shouldn’t impact your average consumption. It shouldn’t affect you’re instantaneous consumption either, since your most likely to be breathing in a relaxed manner hovering over the subject

 

[yle]

Unless you’re finning hard into current, or failing about underwater using a camera shouldn’t impact your average consumption. It shouldn’t affect you’re instantaneous consumption either, since your most likely to be breathing in a relaxed manner hovering over the subject

It shouldn't... but my experience (from observations) is that cameras have a very real effect on air consumption for newish divers. I suspect it's because cameras add just enough to the mental task list to push a newish diver toward task overload. Once a diver gains enough experience so that buoyancy and related control becomes subconscious, the effect seems to fade.

 

[mi000ke]

0.44 here. (0.05 StdDev, 0.64 max, 0.36 min). Almost all of my diving after #10 has been in the Caribbean, and most of that on Grand Cayman - pretty easy going for the most part. I ran splits for the first half vs second half of my (140 or so) dives, and it was pretty stable.
First half: Avg 0.45, StdDev 0.06
Second half: Avg 0.43, StdDev 0.04

I'm a sax player, and have been practicing diaphragmatic breathing for years, so that seems to have helped early on.
On the other hand, my daughter with all of her 10 dives so far, has a RMV in the mid 0.3s. Go figure.

 

[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.

for imperial. determine how many PSI surface equals 1 cuft and mark it on the tank for an al80 it is (al77) = 39 psi round it to 40 psi and call it quits.

at surface it is 40# 33 ft 80# 66 ft 120psi at one hundred feet expect 160psi drop for every cuft you breath so if you have a SAC of .5 than you should see a drop of 1/2 that psi. or 80 psi per minute at 100 ft. If you are seeing 150 a minute than you are breathing at .75 cu ft a minute.

now for a lp95 you would mark your tank 28# a lp120 could be 22# a hp100 would be 35#

so no matter what tank you are using you can calculate your current cu ft per minute at that depth.

you are at 70 ft on a al80 after 5 minutes your psi drops 300psi. that is 60psi a minute at 70 ft youare roughly at 3 atm devide 60 by 3 and get 20. now 20 devided by the tank marking of 40 and you get 1/2 that is 1/2 cuft per minute.

 

[scubadada]

Thanks, 15 new votes in the poll.

 

[caruso]

You're welcome.

I averaged my last 11 dives to get .60 but did not include 3 dives where my SAC rate was as high as .93 because I was either retrieving a heavy anchor off a wreck or working against a brisk current which is not typical.

My SAC rate is a bit above average but I'm a big guy 6'1 weighing in lately at about 198 lbs.

 

[jlcnuke]

I put in the .5's, but if I'm in warm water I'm in the .4's, and drysuit cold water diving is almost .6, so that averages out to about there.