SAC Rate Changes with Depth

[boat sju]

SAC abbreviation stands for Surface Air Consumption

Respiratory minute volume - Wikipedia

I would surmise, from these definitions, that SAC is RMV corrected for depth.

 

[hammet]

By the way, for those who say getting your SAC rate in psi is worthless because of the possibility they will change tank sizes, I had more than 400 dives under my belt before I saw my first steel tank. I had seen and used nothing but Al 80s before that. Knowing my SAC/RMV/SCR/whatever in PSI would have been very practical.

Ever since i got my perdix, I couldn't agree more!
The perdix allows you to have the SAC rate displayed all the time.
I dive hp100s and al80s depending on my destination. I know my rmv will be under .5 cf/min if I keep my SAC rate below 19 psi/min for a AL80 and below 17 psi/min for an HP100.

So i use it as a biofeedback device to monitor my breathing rate if I'm doing active stuff like hunting. I take a quick glance at my SAC rate after I finish the task at hand (while checking depth and air) and if it's high, I know I have to chill out a bit and slow my breathing or my dive will be over faster than I would like it to be.

 

[Joneill]

Ever since i got my perdix, I couldn't agree more!
The perdix allows you to have the SAC rate displayed all the time.
I dive hp100s and al80s depending on my destination. I know my rmv will be under .5 cf/min if I keep my SAC rate below 19 psi/min for a AL80 and below 17 psi/min for an HP100.

So i use it as a biofeedback device to monitor my breathing rate if I'm doing active stuff like hunting. I take a quick glance at my SAC rate after I finish the task at hand (while checking depth and air) and if it's high, I know I have to chill out a bit and slow my breathing or my dive will be over faster than I would like it to be.

I use my Perdix SAC display the same way - it’s a great real time feedback device! It’s a great feature (on a great dive computer)!