1. What Is Surface Air Consumption Rate?

Surface Air Consumption (SAC) rate is a measure of how much air a diver consumes at the surface, expressed in cubic feet per minute (cfm). It's a crucial metric for dive planning and air management.

2. How Does The Calculator Work?

The calculator uses the SAC equation:

Where:

• \( Starting\ PSI \) — Initial tank pressure in pounds per square inch
• \( Ending\ PSI \) — Final tank pressure in pounds per square inch
• \( Tank\ Volume \) — Tank capacity in cubic feet
• \( Time \) — Dive duration in minutes
• \( Depth \) — Average depth in feet

Explanation: The formula calculates air consumption at depth and converts it to surface equivalent by accounting for pressure differences.

3. Importance Of SAC Calculation

Details: Knowing your SAC rate helps in planning dive times, selecting appropriate tank sizes, and ensuring you have enough air for safe ascents and decompression stops.

4. Using The Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What Is A Good SAC Rate?
A: For recreational divers, 0.5-0.75 cfm is average. Experienced divers may achieve 0.3-0.5 cfm, while new divers might be 0.8-1.2 cfm.

Q2: How Does Depth Affect Air Consumption?
A: Air consumption increases with depth due to higher pressure - at 33 feet you consume twice as much air as at the surface.

Q3: Can SAC Rate Change?
A: Yes, SAC improves with experience, fitness, and proper buoyancy control. It increases with stress, cold water, and heavy exertion.

Q4: How Do I Calculate Air Time?
A: Divide usable air by (SAC rate × depth pressure) to estimate remaining bottom time at a given depth.

Q5: What Factors Affect SAC Rate?
A: Experience level, physical fitness, water temperature, current, workload, equipment efficiency, and stress levels all impact SAC.