1. What is Surface Air Consumption (SAC)?

Surface Air Consumption (SAC) rate measures how much air a diver uses per minute at the surface. It's a crucial metric for dive planning, helping divers estimate their air consumption at different depths and plan safe dive profiles.

2. How Does the Calculator Work?

The calculator uses the SAC equation:

Where:

• \( Starting\ PSI \) — Pressure at start of dive (pounds per square inch)
• \( Ending\ PSI \) — Pressure at end of dive (psi)
• \( Tank\ Volume \) — Tank capacity in cubic feet
• \( Dive\ Time \) — Total dive duration in minutes
• \( Avg\ Depth \) — Average depth in atmospheres absolute (ATA)

Explanation: The formula calculates air consumption at depth and converts it to surface equivalent by dividing by average depth in ATA.

3. Importance of SAC Calculation

Details: Knowing your SAC rate is essential for dive planning, air management, and safety. It helps determine how long your air supply will last at planned depths and conditions.

4. Using the Calculator

Tips: Enter starting and ending tank pressure in PSI, tank volume in cubic feet, dive time in minutes, and average depth in ATA. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical SAC rate?
A: Average SAC rates range from 0.4 to 0.8 psi/min for experienced divers, but can vary based on fitness, experience, and conditions.

Q2: How do I convert depth in feet to ATA?
A: Divide depth in feet by 33 and add 1. For example, 66 feet = (66/33) + 1 = 3 ATA.

Q3: Why calculate SAC rate?
A: It helps plan dive duration, choose appropriate tank sizes, and improve air consumption through awareness and practice.

Q4: Does SAC rate change with experience?
A: Yes, SAC rates typically improve (decrease) with experience as divers become more efficient and relaxed underwater.

Q5: How can I improve my SAC rate?
A: Practice buoyancy control, streamline equipment, move efficiently, stay relaxed, and maintain good physical fitness.