CALCULATING YOUR CONSUMPTION
To your out increase how dive many plan, the cubic learn precision to feet figure of of air per minute you typically consume. Establish a base consumption figure with a test run of 33 feet for 10 minutes (five minutes out and five minutes back) at your normal dive pace. Then plug your data into this equation:
SAC = (1-P2/P1) x Vf/aa/tm
P1 = pressure in psi at beginning of test dive P2 = pressure in psi at end of test dive Vf = volume of air in cylinder in cubic feet (divide the actual pressure by the full pressure, and multiply by the volume in cubic feet of a full tank)
Aa = pressure in absolute atmospheres
Tm = time of dive in minutes Want more explanation? Go to scubadiving.com/sac.