Surface Air Consumption (SAC) Rate and its Calculation
What is SAC?
Succinctly, SAC is the amount of air that a person consumes at sea level in one minute while at rest and under 'normal' envirnonmental, physiological, and emotional conditions.
What is the SAC rate for the average person?
The 'average' person theoretically consumes one cubic foot (28.3 liters) of air in one minute (females generally consuming less than males).
Why do I care?
Using your SAC rate, you can estimate how much air you will consume at various depths. This will enable you to estimate how long you can stay at depth or how much air you will need to stay at depth for a set amount of time.
Should I bet my life on calculations made from my SAC rate?
NO!! There are far too many factors that come into play when actually at depth (let alone just determining your SAC rate). That is why you have a submersible pressure gauge and a timing device, right?! SAC is good for estimating air usage at various depths and in starting bar fights.
As was promised in the book, SCUBA Scoop, Answers to Your Commonly-Asked SCUBA Diving Questions, the following references will give you further information regarding SAC, its calculation, and usage. The links are presented in no particular order. Ernest Hill Publishing does not necessarily agree with nor do we advocate your use of any information obtained from them. Use your head!
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