1. What is Surface Air Consumption?

Surface Air Consumption (SAC) rate is a measure of how much air a diver breathes per minute at the surface. It helps divers plan their air consumption for different depths and dive durations.

2. How Does the Calculator Work?

The calculator uses the SAC formula:

Where:

• \( \Delta PSI \) — Pressure change during dive (psi)
• \( Tank Volume \) — Tank capacity in cubic feet
• \( Time \) — Dive duration in minutes
• \( Avg Depth \) — Average depth during dive in feet

Explanation: The formula calculates air consumption at surface pressure equivalent, allowing divers to estimate air usage for different dive profiles.

3. Importance of SAC Calculation

Details: Knowing your SAC rate is crucial for dive planning, determining safe bottom times, and ensuring you have sufficient air for your dive and safety stops.

4. Using the Calculator

Tips: Enter the pressure change during your dive, tank volume, dive time, and average depth. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical SAC rate?
A: Typical SAC rates range from 0.4 to 1.0 cfm, depending on diver experience, physical condition, and environmental factors.

Q2: How can I improve my SAC rate?
A: Improve buoyancy control, reduce exertion, practice proper breathing techniques, and maintain good physical fitness.

Q3: Why calculate SAC at surface pressure?
A: Surface equivalent allows comparison between dives at different depths and helps predict air consumption for future dives.

Q4: Does water temperature affect SAC rate?
A: Yes, colder water typically increases air consumption due to physiological responses and thicker exposure protection.

Q5: How accurate is SAC calculation?
A: Accuracy depends on precise measurement of all variables. Multiple measurements under similar conditions provide the most reliable SAC rate.