Scuba Sac Rate Calculator

SAC Rate Formula:

\[ SAC = \frac{(Tank Pressure Used \times 14.7)}{(Time \times \frac{Avg Depth}{33})} \]

Surface Air Consumption Rate (SAC):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Surface Air Consumption Rate?

Surface Air Consumption (SAC) rate is a measure of how much air a diver consumes per minute at the surface. It helps divers plan their dive times and manage their air supply effectively.

2. How Does the Calculator Work?

The calculator uses the SAC rate formula:

\[ SAC = \frac{(Tank Pressure Used \times 14.7)}{(Time \times \frac{Avg Depth}{33})} \]

Where:

\( Tank Pressure Used \) — Pressure consumed during the dive (psi)
\( Time \) — Duration of the dive (minutes)
\( Avg Depth \) — Average depth during the dive (feet)
\( 14.7 \) — Atmospheric pressure at sea level (psi)
\( 33 \) — Depth equivalent to one atmosphere in seawater (feet)

Explanation: The formula calculates the air consumption rate by accounting for the pressure used, dive time, and average depth to determine surface-equivalent air consumption.

3. Importance of SAC Rate Calculation

Details: Knowing your SAC rate is crucial for dive planning, air management, and safety. It helps divers estimate how long their air supply will last at different depths and plan their dives accordingly.

4. Using the Calculator

Tips: Enter tank pressure used in psi, dive time in minutes, and average depth in feet. All values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical SAC rate for divers?
A: SAC rates vary by diver experience and physical condition. Beginners typically have rates of 0.75-1.0 cu ft/min, while experienced divers may have rates of 0.4-0.6 cu ft/min.

Q2: How can I improve my SAC rate?
A: Improve buoyancy control, reduce unnecessary movements, maintain proper trim, and practice relaxed breathing techniques to lower your SAC rate.

Q3: Does SAC rate change with depth?
A: The calculated SAC rate is normalized to surface conditions. Actual air consumption increases with depth due to increased pressure.

Q4: Why use 14.7 in the formula?
A: 14.7 psi represents one atmosphere of pressure at sea level, which is used to convert tank pressure to volume.

Q5: Can SAC rate be used for different tank sizes?
A: Yes, SAC rate is independent of tank size as it measures consumption rate rather than total consumption.