SAC Rate Poll What is Normal? Female Only

[pasley]

SAC Rate Poll What is normal? Females ONLY

This poll is for Females only. We will do males on a separate poll.
Take the average of your last 5 dives, what is your average Surface Air Consumption Rate as expresed in SCFM? Since it is widely rummored that females have a better SAC rate than males, I have expanded the lower end of the scale here.

SUUNTO and other dive computers will automatically caculate this for you. For those who have to do it manually use this formula:

SCR = (1-P2/P1) x Vf/Aa/Tm

Where
P1 = pressure in psi at beginning of test dive
P2 = pressure in psi at end of test dive
Vf = actual volume of air in tank in cu. ft.
Aa = pressure in absolute atmospheres
Tm = time of dive in minutes

This is from Scuba Diving Mags site:
http://www.scubadiving.com/training...mption_rate)/

Why a SAC rate? To help with your gas management when planning a dive for yourself and your group.

For the Metric Crowd (and it is IMHO a better system) here are the liter equivelents thanks to http://www.onlineconversion.com/volume.htm
0.60 cubic feet = 16.99 liters
0.52 to 0.59 cubic feet = 14.72-16.70 liters
13.87 - 14.44
12.3-13.59
12.7 - 13.02
11.89 - 12.459
11.04-11.6
10.19-10.76
9.34-9.91

 

[Boogie711]

Women obviously have a lower sac rate.

They have tiny lungs and no hearts.









KIDDING! JUST KIDDING!

 

[mania]

To vote I would need these figures in liters - otherwise honestly I have no clue. My average SAC ranges from 8 to 12 liters which is rather small. 12 was for the last two dives which were my first in my life dives in the dry suit.
Mania

 

[FreeFloat]

Women obviously have a lower sac rate.

They have tiny lungs and no hearts.

KIDDING! JUST KIDDING!

Ha ha.

Sounds like personal experience talking........

Seriously though, mine varies depending on conditions. Off the top of my head (without my logbook handy, in which I actually do compute my SAC rate most dives) if I'm doing a winter wetsuit dive in cold swift water, it can get as high as .5 or even .6 cuft/min. A lazy shallow summer dive where I hardly move, I've had it as low as .31 . So I guess I'll average and vote on that.....

 

[lostinspace]

err - liters & bar please?

On average, I use about 100bar of air on a 10L tank for a 45 minute dive, no-deco, max depth 30m. So what's that?

 

[mania]

To answer your question we need the profile of the dive with average depth. Otherwise you will not be able to calculate your SAC.
As liters and bars - yeah I agree. PLEEEASE....
Mania

 

[pasley]

To vote I would need these figures in liters - otherwise honestly I have no clue. My average SAC ranges from 8 to 12 liters which is rather small. 12 was for the last two dives which were my first in my life dives in the dry suit.
Mania

Hmmm, yes, I should have included that as this is an International forum. My bad. Mania, could you help me out and add the equivelent in liters? http://www.onlineconversion.com/volume.htm provided the help. I have added to the first message the liters.

 

[mania]

Done. Voted.
Mania

 

[lostinspace]

okay, here goes:

P2/P1=100bar/200bar=0.5(dimensionless)
Vf=10L=0.3531467cu.ft
Tm=45 minutes
Average depth (no deco) ~15m (30m max, includes 6m safety stops)
Aa ~ 2.5bar ~ 2.5atm (hey, the rounding is ok as I'm guesstimating my average depth anyway?)

SCR = (1-P2/P1) x Vf/Aa/Tm = 0.001?! I'm obviously calculating something wrong here!

Anyways, looking at my 'puter it looks like 11.2L/min is average over last 5 dives. dont know what that is in SAC/SCR terms?

 

[mania]

Lets start from the beginning.
10liter tank
Used - 100 bars
100 bars x 10 liters = 1000 liters
1000liters/time of diving 45 = 22
average depth 15 meters = 2.5 ata
SAC = 22/2.5 ata = 8.8 liters/minute
Which is not a bad result - I would even say a very good one. But honestly - you don't guess average depth as you probably did. In that dive your average depth is rather something like 8 - 10 meters, not 15. Average depth is calculated by the computer from the whole dive profile. My computer doesn't show it I have to transfer the data into PC -and PC calculates.
Mania