But it’s more complicated than that since a diver’s air consumption is certainly influenced by their level of physical activity. However, the depth at which a scuba tank is utilized directly affects how long it lasts. A typical open-water certified diver will be able to stay underwater for roughly 45 minutes using a normal aluminum 80-cubic foot tank on a dive to a depth of 40 feet, according to personal experience.
What Elements Affect the Duration of Air in a Scuba Tank?
The aluminum 80-cubic-foot tank, which can carry 80 cubic feet of air pressurized to 3000 pounds per square inch, is one of the most popular tanks used for recreational diving. Scuba tanks are nevertheless offered in various sizes and materials for a range of purposes (learn more about the difference between steel and aluminum tanks). Tanks having a larger internal volume may be preferred by divers who perform lengthy or very deep dives. Smaller tanks may be more comfortable for little divers who use little air. A tank with a larger volume of air will last longer underwater, all other things being equal.
Depth The pressure around a scuba diver increases as he dives (learn how depth affects pressure in scuba diving). The air in the diver’s scuba tank is already compressed to very high pressure, and the scuba tank is a rigid container, so this increase in pressure has no effect on it. The air that leaves the tank and travels through the regulator hoses and second stages of the scuba diver is compressed by the water pressure, though. At a depth of 33 feet, the amount of air that would normally fill 1 cubic foot of space will only occupy 1/2 of that space due to the compression of water. As a result, at 33 feet, the amount of air that fills a diver’s lungs at the surface will only fill them halfway. A diver will use up the oxygen in his tank more quickly the deeper he dives since it takes more air to fill his lungs with each breath.
Rate of Air Consumption A diver’s air consumption rate, also known as his Surface Air Consumption Rate (SAC rate) or Respiratory Minute Volume (RMV), will influence how long the air in his tank will last in comparison to the average diver, all other things being equal. A diver with a large lung volume (tall or huge persons) will often need more air and consume it at a faster rate than a diver with a small lung volume. An individual’s air consumption rate is influenced by a number of variables, including stress, experience level, buoyancy control, and how much exercise the diver gets during a dive. The greatest technique for a diver to decrease his air consumption rate is often to breathe slowly, deeply, and comfortably.
Air Supply Is Not Always the Limiting Factor: A diver frequently has to finish a dive before running out of air. Examples include running out of air with a diving companion or hitting the no-decompression limit for a dive (in which case divers may want to use enriched air nitrox). Diverse sites and dive plans are used. Even if a diver has air in his tank, that doesn’t guarantee he should or even wants to continue diving until it runs out. The amount of time the air in a tank will endure for a specific person and dive is ultimately determined by a number of factors. The question is challenging to answer because of this. Knowing the physics of water pressure, tank capacities, and air consumption rates are necessary to forecast how long a tank will stay underwater. If a diver asks me how long his tank will last underwater, I only have one response: Never long enough!
