What is average surface air consumption?

[ZzzKing]

Male, 45 yo, 5'-10", 180#

.30 in 3 mil WS

I messed up on the SAC calculator and entered 120 under time when it should have been 1:20, or 80.

SAC=.45. The other stats are still correct.

I knew it sounded low and I couldn't believe it was lower than a lot of much more experienced divers.

It got me interested enough to write a spreadsheet to calculate SAC and Bottom Time for use on my PDA, though.

 

[Azza]

Azza, I would say that's a tad extreme . . . !

the K-onked Out !!!

LMAO. Thats what I said when my first TDI instructor made me do it. My SAC rose to 50 litres for that 2 minutes. (Imperial-1.76cuft)
But if for some reason you get caught in a wicked current or down current, then you could be looking at that kind of breathing rate.
I call it the Sudden High Intensity Training (S.H.I.T), to borrow a phrase from Lamar English.

 

[IwakuniDiver]

OK, I'm way jealous of you girls' SAC rates. I thought mine was decent.

I'm 5'11 and 170lbs.

My typical SAC rate for diving in waters with a bottom temp in the mid 50's is .58. I have had it down to .42 at times though. During periods of Occasional Hyperactive Surprise Heightened by Irrational Terror (O.H. S.H.I.T.!) it has been as high at .8.

Scott

 

[Azza]

:lol:

 

[ccohn2000]

Thanks! I'm feeling a bit better about my rate now. The .46 - .48 is my fun dive rate. I'm a newbie Dive-Con and my rate goes to anywhere between .55 and .68 when there are students involved. I chase around much more in class. Normally, I'm just mosying around looking for camera targets for my husband and navigating our dives. 99% of my dives are in cold water 48 to 54, usually 50 -52 in Monterey and Carmel.

PerroneFord - thanks for the advice, I really do appreciate your help. The only dangly in that pic (or on me ever) is my flashlight, which was clipped to my D-Ring as I was starting my ascent and no longer needed it. My trim is upright there because I am for the gazillionth time looking at my hubby and asking why he keeps pointing the camera at me, instead of all the lovely critters running around.

 

[*Floater*]

Male, late twenties, 6'1", 183#:

Warm water, wetsuit SCR across my last 20 or so dives was 0.3-0.7.

It's a big range but my SCR just does vary that much depending on the conditions.

To be more specific, my deco SCR was 0.3-0.45. i.e. that's when I just drift there breathing 50% O2. However, it does go up if I have to work during deco for some reason.

For the working portion of the dive my SCR was 0.45-0.7. The lower end represents easy rec dives (no current, etc.) or relaxed tech dives, and the higher end represents dives when I had to work against a current, deal with lots of task loading, or cover lots of distance. I'm sure it would go even higher if conditions deteriorated sufficiently.

 

[aHeavyD]

5'11'
265#
47yo
.8 to .9, cold water, dry suit
.5 to .6, warm water, wet suit
I'm not a floater and do swim all the time

 

[Cave Diver]

I'd like to point out that most of us (including myself) have been answering the question based on RMV rather than SAC :blush:

RMV is a measure of volume, SAC is based on pressure.

For more information see this post: http://www.scubaboard.com/showpost.php?p=2010917&postcount=12

in this thread: http://www.scubaboard.com/showthread.php?t=148782

 

[HilaryRN71]

In FL...mine varies from about .34 in shallow water at a leisurely pace .38 to .4 on depth in easy conditions...to .47 on a deep dive in current when I was cold. It is alot higher in CA with a drysuit... It used to be that it would vary alot..the first dive I'd suck air, and subsequent dives I would relax. Now it seems more steady...guess regular compressed air usage helps.

 

[H2Andy]

I'd like to point out that most of us (including myself) have been answering the question based on RMV rather than SAC :blush:

i don't think so. RMV is not the same as SAC expressed in cubic feet per minute.

while SAC expressed in cubic feet DEPENDS for calculation
on how many cubic feet of air you started with, SAC expressed in cubic
feet as a final result expresses the amount of cubic feet per second used,
and that does not depend on the cylinders you will user thereafter.

in other words, to CALCULATE SAC in cubic feet to begin with, you need to
factor in the cubic feet you used (and that means factoring in your tank
volume and pressure). however, once you figure that out, you can then
express SAC in cubic feet and that is an absolute measure that will not
change depending on what tank you use.

if your SAC in cubic feet is .76 per minute, you will use .76 cubic feet per minute
whether you have an AL 80 or a steel 95 on your back.

hope that makes sense