Surface Air Consumption (SAC) is a measure of a diver’s rate of breathing gas consumption at the surface before or after a dive. It’s typically expressed in psi (pounds per square inch) per minute and is used to estimate gas usage during dives. Lower SAC values indicate more efficient air use, contributing to longer dive durations and increased safety.
Surface Air Consumption Calculator
| Dive Depth (feet) | Dive Time (minutes) | Starting Pressure (psi) | Ending Pressure (psi) | SAC (psi/minute) |
|---|---|---|---|---|
| 0 (Surface) | 5 | 3000 | 2800 | 40 |
| 33 | 20 | 2800 | 2500 | 15 |
| 66 | 30 | 2500 | 2200 | 10 |
| 99 | 40 | 2200 | 1900 | 7.5 |
FAQs
How do you calculate surface air consumption? Surface Air Consumption (SAC) is calculated by dividing the starting tank pressure (in psi) by the time (in minutes) and the volume of air consumed (in cubic feet) during a dive. The formula is: SAC (psi/minute) = (Starting Pressure – Ending Pressure) / (Time (minutes) * Cylinder Volume (cubic feet)).
What is good surface air consumption? Good SAC values vary among divers, but a lower SAC is generally considered better. A good SAC rate is often around 0.5 to 1.0 psi per minute, indicating efficient air use.
What is surface gas consumption rate? Surface gas consumption rate is the rate at which a diver consumes breathing gas at the surface before or after a dive. It’s typically measured in psi (pounds per square inch) per minute.
What is the air consumption rate at 66 feet? The air consumption rate at 66 feet will vary among divers and equipment. However, it is typically higher than at the surface due to increased pressure, which causes the air to be consumed more rapidly.
What is the surface consumption rate? Surface consumption rate refers to the rate at which a diver consumes breathing gas at the surface before or after a dive, measured in psi per minute. It is used to estimate gas usage during dives.
Do you use more air the deeper you dive? Yes, air consumption typically increases with depth because the increased pressure at greater depths results in denser air and higher gas consumption.
What is a good SAC rate in psi? A good Surface Air Consumption (SAC) rate in psi per minute is often considered to be around 0.5 to 1.0 psi per minute. Lower values indicate more efficient gas usage.
What is the air consumption rate? The air consumption rate is the rate at which a diver consumes breathing gas during a dive, typically measured in psi per minute. It depends on factors such as depth, diving technique, and equipment.
How much more air will a diver breathe at 20m compared with the surface? A diver will breathe more air at 20 meters (approximately 66 feet) compared to the surface due to the increased pressure at depth. The exact increase depends on factors like depth, dive time, and individual breathing rate.
How do you calculate surface consumption rate? To calculate the surface consumption rate, divide the change in tank pressure (in psi) by the time (in minutes) it took to consume that amount of gas. The formula is: Surface Consumption Rate (psi/minute) = (Starting Pressure – Ending Pressure) / Time (minutes).
How do you calculate average gas consumption? Average gas consumption is calculated by dividing the total gas used (in psi or cubic feet) by the total dive time (in minutes). The formula is: Average Gas Consumption (psi/minute) = Total Gas Used / Total Dive Time.
How do you calculate gas consumption per hour? To calculate gas consumption per hour, convert the gas consumption rate from psi per minute to psi per hour by multiplying by 60 (since there are 60 minutes in an hour).
What is the calculation for air flow rate? The calculation for air flow rate depends on the context. In diving, it’s often measured as Surface Air Consumption (SAC) in psi per minute, as mentioned earlier.
What is a depth that is equivalent to one atmosphere in the ocean is equal to? One atmosphere of pressure is equivalent to approximately 33 feet (10 meters) of depth in the ocean.
Which of the following limits should be established prior to every scuba dive? Prior to every scuba dive, important limits that should be established include maximum depth, dive time, air or gas supply, and decompression requirements.
What is the minimum surface interval recommended between two dives? The recommended minimum surface interval between two dives is typically around 60 minutes to allow for off-gassing and reduce the risk of decompression sickness.
What is the pressure at 10 feet deep? The pressure at 10 feet deep in seawater is approximately 4.34 psi (pounds per square inch) above atmospheric pressure.
What is the 1 3 rule in scuba diving? The 1 3 rule in scuba diving suggests that a diver uses one-third of their air supply to reach a specific depth, one-third to return to the surface, and one-third as a safety reserve.
What is the pressure at 33 feet underwater? The pressure at 33 feet underwater is approximately 2 atmospheres or about 29.4 psi (pounds per square inch) above atmospheric pressure.
How can I reduce my SAC rate? To reduce your Surface Air Consumption (SAC) rate, focus on improving your diving skills, maintaining good buoyancy control, using efficient equipment, and practicing relaxed, slow, and deep breathing.
How many cubic feet are in one psi? One psi (pound per square inch) corresponds to approximately 0.016 cubic feet of gas at sea level and standard temperature and pressure (STP).
How many cubic feet is 2400 psi? At STP, 2400 psi is equivalent to approximately 38.4 cubic feet of gas.
What is CFM air consumption? CFM (Cubic Feet per Minute) air consumption is a measure of the rate at which air or gas is consumed or delivered, often used in various applications, including HVAC systems and pneumatic tools.
What is the average air consumption per day? Average air consumption per day varies widely depending on individual activities and conditions. It can range from a few cubic feet per day for breathing to much larger volumes for industrial processes.
How many air changes an hour? The number of air changes per hour (ACH) refers to the rate at which the air in a room is completely replaced with fresh air. The recommended ACH varies depending on the application and indoor air quality requirements.
At what depth does oxygen become toxic? Oxygen toxicity can occur at depths beyond 130 feet (approximately 40 meters) when using breathing gases with a high partial pressure of oxygen.
How deep can you dive with surface air? The depth to which a diver can safely go with surface-supplied air depends on various factors, including equipment, gas mixture, and decompression requirements. Commercial divers may go as deep as several hundred feet with surface-supplied air.
What is 20% of the air we breathe? About 20% of the air we breathe consists of oxygen, which is essential for human respiration.
How do you calculate average consumption rate? Average consumption rate is calculated by dividing the total consumption (e.g., gas usage) by the total time. The formula is: Average Consumption Rate = Total Consumption / Total Time.
What is the formula for average consumption? The formula for average consumption is: Average Consumption = Total Consumption / Total Time.
How do you calculate specific consumption? Specific consumption is calculated by dividing the consumption rate of a particular resource (e.g., fuel or energy) by a specific parameter, such as distance traveled or work done. The formula varies depending on the context.
How do I calculate gas consumption calculator? To calculate gas consumption, use the appropriate formula for the specific context, such as dividing the total gas used by the total time for scuba diving gas consumption or calculating fuel consumption for a vehicle using distance traveled and fuel efficiency.
Do you waste more gas when you speed? Yes, driving at higher speeds typically results in increased fuel consumption and decreased fuel efficiency, leading to wasted gas.
How much is 1 gallon of gas? One gallon of gasoline (in the United States) is equivalent to approximately 3.78541 liters or 128 fluid ounces.
How much gas do you use in 5 hours? The amount of gas used in 5 hours depends on the gas consumption rate of the specific equipment or vehicle. To calculate gas usage, multiply the consumption rate (e.g., gallons per hour) by the number of hours.
What is the gas rate calculation? The gas rate calculation involves determining the rate at which a gas is consumed, often measured in units like gallons per hour (GPH) for vehicles or psi per minute (psi/min) for diving equipment.
What is the easiest way to calculate fuel consumption? The easiest way to calculate fuel consumption is to divide the distance traveled (in miles or kilometers) by the fuel used (in gallons or liters). This gives you the fuel consumption rate in miles per gallon (MPG) or kilometers per liter (KPL).
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