SAC Rate

[lead bottom]

I'm trying to get a feel for what an average SAC Rate would be. I'm running around a .61 to a .68. Obviously my consumption is a little high. I'm just trying to find out what the benchmark is.

If this has been discussed before, I appologize, but I couldn't find it in my searches.

 

[Al Mialkovsky]

Mine changes from .35 to .55 depending on many factors. Water temps, if I'm with a class or just doing relaxing fun dive.

 

[HowardE]

Also if there's swimming involved with getting to the reef... That usually pushed my consumption towards .6 - .7 as well...

When I am relaxed and not moving a lot, my typical consumption is between .35 and .55 (I know this thanks to my SmartCom)

 

[Charlie99]

I'm just trying to find out what the benchmark is.

Just go do a few group dives and see when you go low on air compared to the others .

I often dive off boats that dive as two groups of 6, each with a guide. Diving with the more experienced group, it's rare that that I'm ready to go up when all of the other customers have had to surface due to low on air. Small women DMs will generally have a bit lower SAC. Many of the male DMs use more air than me. My SAC is usually around 0.4cfm on a slow dive, rising towards 0.5cfm or so when swimming around quite a bit. Based on my experience in multiple locations, those numbers are pretty much towards the bottom end of the scale.

When I buddy up with a diver that has only 10-25 dives and doesn't know what his SAC is, I plan the dive assuming it will be around 0.66 -0.75cfm (i.e. 2/3 to 3/4cfm), and that is usually in the right ballpark.

 

[The Kraken]

L/B,
From having run SAC rates for new divers, I've found that they're generally in the .70 to .60 range. Needless to say, anxiety, excitement and exertion will make the rates go up significantly.

You'll probably hear from many of the divers here, and rightfully so, that more diving and experience will lead to a significant decrease in your consumption rate, overall.

the K

 

[Diver0001]

I'm trying to get a feel for what an average SAC Rate would be. I'm running around a .61 to a .68. Obviously my consumption is a little high. I'm just trying to find out what the benchmark is.

If this has been discussed before, I appologize, but I couldn't find it in my searches.

Well....this is pretty personal. There really isn't a benchmark. Everyone has to establish their own personal benchmark....

Something that might help a little is that a normal sized adult in ok physical shape will use about 12 litres (+/- .43cf) while a rest, for example sitting. The obvious conclusion is that .42 is getting towards the lower end of the scale while diving. In practice this number is pretty close to what you see. Some people can use less some of the time, getting down to about 10 litres/.35cf or so but any lower than that requires either extraordinary physical condition or cyber-superhero exaggeration.

R..

 

[JustinW]

I am roughly running .4 to .55 on an average shore dive. I have data from other dives but just haven't run the numbers. My smartCom makes it easy to calculate too.


Edit: I should add, if I get my sac rate close to .4 on occasion I get a headache during the dive from what i presume is a CO2 buildup. It doesn't feel like I am retaining too much CO2 but the headache is the feeling I get when I breathe very slloooowwwwyyyy.

 

[Soggy]

Some people can use less some of the time, getting down to about 10 litres/.35cf or so but any lower than that requires either extraordinary physical condition or cyber-superhero exaggeration.

Probably less of the former and more of the latter...

In warm water single tank dives, I tend to be around .45...Had a cavern dive in Mexico where I managed a .41. In cold water single tank dives, I tend to be around .55. Add a set of doubles and a deco bottle to that and it goes up to .65-.7 or so. Cold water deco tends to be around .55ish, sometimes more. I'm 6', 155 lbs and have very little fat or muscle...basically a twig.

 

[SharkRider]

SAC rate stands for STUPID ***** CALCULATION.

The time spent figuring out your SAC is a totally worthless and meaningless waste of your time. Regardless of what your SAC is, you will dive by the simple RULE OF THIRDS... Keep an eye on your gauges and stop doing math problems.

 

[ItsBruce]

Here is the oddity of the whole thing. We are told to breath deeply and slowly. We are told not to hold our breath. Doesn't that limit how far one can stretch the SAC?

BTW: In a test on dry land, my yoga teacher did a 0.23 per minute over a 10 minute test... without trying particularly hard.