How Long Is 2200 Psi Of Air For Diving

Diving is a popular activity among many people, but it is important to know how long you can stay underwater with a certain amount of air. 2200 psi of air is a common amount of air to use for diving, but how long it will last depends on a few factors. The depth of the dive, the type of breathing apparatus used, and the individual’s diving proficiency all play a role in how long 2200 psi of air will last.

How Much Psi Do I Need For Diving?


There is no one answer to this question as it depends on a number of factors, including the depth of the dive, the type of diving being done, and the experience level of the diver. Generally speaking, most divers will need an average of around 40-60 psi in their tanks in order to safely dive.

On the dive board, you’ll find the terms ‘bar’ and ‘peek’. When we use pressure, we measure how much force is applied. The bar measure pressure; gram per square centimeter (Kg/cm2) is the metric system’s method of measuring pressure. Only three countries, Myanmar, the United States of America, and Liberia, currently use the Imperial system. As a newly qualified scuba diver, I had to convert my PSI measurements to bar in my head. ( 1 BAR = 14.5037638 PSI) is the ratio of BAR to PSI. Atsea levels exert a great deal of pressure, which is referred to as atmospheric pressure.

The amount of weight that is held by an object is what pushes it downward. We have the ability to generate another ATM of pressure every ten meters (32 feet) of depth. This pressure change will be felt in our air spaces, not in our bodies; most of our bodies will not experience this change. When the pressure rises, the rate at which the air is consumed rises. The bar and the pressure index (PSI) are not noticeably different. If one of us had a $1 million dollar savings account and then compared it to one of the other two accounts, would he/she be better off? I find that by using a bar, you can do a lot of math and calculations. In general, technical divers prefer the use of PSI because it makes the rule of thirds more simple to manage.

Divers And Their Air Usage

Divers breathe air at an average speed of 8 cubic feet per minute, which means they are consuming 80 cubic feet per minute of air. In this case, there is one atmospheric pressure at sea level. As a result, the diver’s total pressure at 30 meters depth is 4 atm, which is also due to the water column, which causes a pressure of 1 atm per meter.

How Long Does A .5l Scuba Tank Last?

A certified open water diver will be able to stay underwater for approximately 45 minutes before surface with a safe reserve of air following an open water dive if he or she uses a standard aluminum 80-cubic-foot tank on a 40-foot dive.

Depending on how physically demanding a diver is, how much air they use varies. Long-term maintenance is also directly related to the depth of the scuba tank. Divers can use scuba tanks in a variety of applications due to the wide range of materials and sizes available. Petite divers may prefer to fill smaller tanks to improve air flow and comfort. Water pressure causes air to compress as it exits the tank and flows through the scuba diver’s regulator hoses and second stage. The greater the amount of air required to cover each breath, the deeper a diver goes in the water. It makes no difference whether the air in the tank is still warm or cold; a diver can swim indefinitely if his air temperature is still above freezing.

How Long Is A Typical Scuba Dive

Most scuba dives last around an hour, give or take 15 minutes. Of course, this dive time can be affected by a number of factors, such as the depth of the dive, the level of experience of the diver, and the conditions of the water. Generally speaking, however, most scuba dives fall within that one-hour timeframe.

It is primarily dependent on nitrogen absorption and air consumption in order to have sufficient time to dive underwater. As you dive deeper, you can expect a pressure increase of one atmosphere every 33 feet (or 10 meters). You will burn faster through air as you dive deeper into the ocean. To dive to 66 feet requires three different levels of diving. When you are submerged, your body loses heat in water 20 times faster than when you are in the air. You will be able to swim for more time if you dive shallower. It is the temperature of the water that is most important in determining the type of thermal protection you need.

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How long is enough time to do what you want? The length of a scuba dive is determined by a number of factors, but nitrogen absorption and air consumption are two of the most significant. A scuba diver who was 95 years old when he died on July 5, 2019, will be the world’s oldest scuba diver for the rest of his life. To stay warm while scuba diving, you must wear adequate thermal protection.

For recreational divers, it takes an average of 2 hours and 20 minutes to dive 35 feet below sea level. A dive at 100 feet takes about 15 minutes on average. If a diver wants to dive deeper than 100 feet, he or she must purchase a scuba certification. A controlled environment, such as a scuba diving resort, can take much longer to complete. A controlled environment scuba dive lasting 192 hours, 19 minutes and 19 seconds was the longest in history. This dive was done at the Atlantis Resort in the Florida Keys. In general, a controlled environment requires a dive time of four to 20 minutes. The depth of a dive at 35 feet or less is approximately 8 hours.

How Long Does Air Last In A Scuba Tank

How long a scuba tank’s air will last depends on a few different factors, such as the size of the tank, the rate of air consumption, and the depth of the dive. Generally, a scuba tank will last for around an hour at a depth of around 30 feet.

How long does air stay in a scuba tank? Robert Bauer (La Feria, TX USA) wrote this book. I had a new scuba tank a few years back that I never used. A tank has been in use for over a decade. Why is air still in the tank? These are practical (and GROSS) facts that are not taught in certification courses on scuba diving. Here are a few tips to reduce your air consumption while scuba diving. Our maps of these beautiful islands include aerial views as well as interactive maps.

How Long Does the Air in a Scuba Tank Last?

How Many Minutes Can a Scuba Diver Stay Underwater With a Single Tank of Air?

Natalie Gibb owns a dive shop in Mexico and is a PADI-certified open water scuba instructor and TDI-certified full cave diving instructor.

Vertical Reef Diving Scene

How long does a scuba tank last? Although the question is simple, the answer is complicated. Let’s examine different scenarios.

An Average Diver, at an Average Depth, With an Average Tank

Based on personal experience, an average open-water certified diver using a standard aluminum 80-cubic-foot tank on a 40-foot dive will be able to stay down for about 45 to 60 minutes before surfacing with a safe reserve of air still in the tank.

Three Factors That Determine How Long a Diver’s Air Will Last

1. Tank Volume
One of the most common tanks in recreational diving is the aluminum 80, which holds 80 cubic feet of air compressed to 3000 pounds per-square-inch (PSI). However, scuba tanks are available in different materials and sizes for a variety of applications. Divers who engage in very deep or long dives may prefer tanks with a greater internal volume. Petite divers who use very little air may choose to use smaller tanks for comfort. All other factors being equal, a tank that holds a higher volume of air will last longer underwater.

2. Depth
As a scuba diver descends, the pressure around him increases. This increase in pressure does not affect the air inside the diver’s scuba tank because it is already compressed to a very high pressure and the scuba tank is a rigid container.

However, the water pressure does compress the air that exits the tank and flows through the scuba diver’s regulator hoses and second stages. For example, the quantity of air that fills 1 cubic foot of space at the surface will only fill ½ cubic foot of space at a depth of 33 feet due to the compression of water. Similiarly, a diver will consume twice the volume of air at 33 feet as he uses at the surface. In other words, the deeper a diver goes, the more quickly he will use up the air in his tank.

3. Air Consumption Rate
A diver’s air consumption rate will determine how long the air in his tank will last compared to the average diver. A diver with large lung volume (tall or large people) will require more air than a petite or short person with a smaller lung volume, and will usually have a higher air consumption rate. A variety of factors affects an individual’s air consumption rate, including stress, experience level, buoyancy control and the amount of exertion required for the dive. Relaxed, slow and deep breathing is usually the best way for a diver to reduce his air consumption rate.

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Air Supply Is Not Always the Limiting Factor

In many cases, a diver must end his dive before reaching the limit of his air supply. Examples include reaching the no-decompression limit for a dive (in which case a diver may consider using enriched air nitrox) or ascending with a buddy who has reached the limits of his air supply.

Dive plans and dive sites vary. Just because a diver has air left in his tank doesn’t mean he should (or will even want to) stay underwater until it runs low.


In the end, several factors determine how long the air in a tank will last for a particular individual and a particular dive. This is the reason that the question is so difficult to answer. Predicting how long a tank will last underwater requires an understanding of the physics of water pressure, tank volumes and air consumption rates.

Gas Laws of Scuba Diving – The Science Behind Scuba Diving

Gas Laws

Gas laws for scuba diving

There is a whole science behind SCUBA (Self-Contained Underwater Breathing Apparatus), diving. These laws are what protect a SCUBA Diver from the pressure that the water exerts on the human body as well as safety standards for your air tank and other factors.

For every 33 feet of water, the pressure increases by 14.7 psi, so pressure builds up very fast. So for example at the surface (1 atm), the pressure is 14.7 psi and then at 33 feet (2 atm), the pressure is 29.4 psi, then at 66 feet the pressure is 44.1 psi (3 atm), and so on …

IMPORTANT: SCUBA diving is a sport filled with many dangers and requires specialized training and equipment. Do not attempt any diving activity without proper training and always have a buddy diver or someone topside with you.

Some Scuba Basics

The atmosphere that we breathe every day is composed of 78% Nitrogen, 21% Oxygen, and 1% of other gases.

SCUBA Divers use a scuba tank (air tank), of compressed air to breath with underwater and they are made out of steel or aluminum. The air is fed from a valve at the top of the tank, via a hose and a regulator that takes the high pressure (≈ 3000 psi) of the tank and drops it down to safe levels for the diver to breath off of.

Gas Laws

Gay-Lussac’s Law

P1 / T1 = P2 / T2

In SCUBA diving, Gay-Lussac’s law impacts the amount of breathable air you have in your tank. It has to do with the heating and cooling of the air in the tank during filling. An empty tank has a pressure of around 500 psi. You must always keep some pressure in the tank to help preserve and always make sure that you are filling it with dry air.

As you fill a tank the pressure and heat go up. A tank can reach temperatures around 150° F and when it cools the pressure will drop too. So for our example let’s assume the ambient temperature is 70° F. Now that we got these values we can apply Gay-Lussac’s formula by converting to the temperatures to the Rankine scale as follows:

T1 = 150 + 460 = 610 R

T2 = 70 + 460 = 530 R

P1 = 3000 psi

3000 psi / 610 R = P2 / 530 R

P2 = 2606 psi

So based on the above calculation we can see that after filling up from empty we are not quite full yet. So we could now that is has cooled down we can top up the tank.

Boyle’s Law

P1V1 = P2V2

Boyles Law

A fundamental rule of SCUBA diving is to never hold your breath. Boyle’s law explains why this rule exists. When a diver breathes in air from a tank, the air is at ambient pressure. This is the pressure that is surrounding the diver at the time they take a breath. So a regulator adjusts the pressure to the ambient pressure surrounding it.

When a diver breathes in the air at the surface, then their lungs would be at 1 atm. Now say that diver dives down to 99 feet, which is 4 atm. By knowing this and assuming that the diver’s lungs hold 1 L of air we can complete the left side of Boyle’s law.

P1 = 4 atm

V1 = 1 L

P2 = 1 atm

4 atm × 1 L = 1 atm × V2

V2 = 4 atm

This means that if the diver is at 99 feet and takes a breath of air then rises to the surface holding their breath, their lungs would expand to 4 times the limit thus rupturing the lungs and probably killing the diver. So NEVER hold your breath while SCUBA diving!!

By Boyle’s law we can now also see that a diver at 99 feet would require 4 times as much air per breath than on the surface so keeping a close eye on your air supply is critical, don’t you think?

Because a Freediver takes a breath of air on the surface, 1 atm, and holds it, they do not have to worry about the effects of Boyle’s law on them. Their lungs actually get crushed in size, so a diver at 99 feet would have lungs a quarter of the normal size.

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Charles’s Law

V1 / T1 = V2 / T2


Ok, I am going to explain this law using the example of what happens with a dry suit.

Dry suits are worn for extreme cold waters, like ice diving where you actually go and dive under the ice. You wear a pair of wool long- johns and some other warm clothing under the dry suit and the suit keeps a layer of air between you and the suit.

When a diver has been down for a long period of time the air in the suit can become colder, and thus less dense, than the air outside. So when they get out of the water the suit gets squeezed around them and they either have to put air into the suit to alleviate the squeeze or unzip their zippers.

And that shows the effect of Charles’s Law on a diver.

Dalton’s Law

PTotal = P1 + P2 + P3 . . .


Dalton’s Law states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its component gases.

Oxygen poisoning can occur when the partial pressure being breathed is above 1.6 atm. It will cause seizures, dizziness, vertigo, and changes in vision. Any of these can be fatal to the diver. Imagine being at 99 feet and having a seizure or you start to vomit because of dizziness or vertigo. It would be a really bad situation don’t you think?

So to calculate at what depth this may occur we can use Dalton’s law. As mentioned earlier dry air is made up of mainly 78% Nitrogen and 21% Oxygen. Thus at 1 atm, the partial pressure of Oxygen would be 0.21 atm. So to get the partial pressure of Oxygen to 1.6 atm we would need a total air pressure of 7.6 atm (1.6/0.21 atm). So, therefore, you would need to be at around 216 feet to begin to be in the danger zone.

Remember the 78% Nitrogen in the air? Well, a diver can get Nitrogen Narcosis whose effects are very similar to being drunk. The deeper you go the more the effect intensifies. Nitrogen Narcosis can start occurring as shallow as 45 feet and deeper.

You will get head spins, nausea, and fumble around trying to use your equipment just as if you were drunk or start doing stupid stuff like feeding the fish your air.

Henry’s Law


Henry’s law states that the solubility of a liquid is directly proportional to the partial pressure of the gas above the liquid. To a diver, this means that as you go deeper the pressure will increase. Because of this, the air is forced into your bloodstream at a faster and faster rate the deeper you go.

So when ascending to the surface you need to “bleed” off all that air in the bloodstream. This is why there are decompression stops after long deep dives. This is to get all that air/gas back out of the bloodstream SLOWLY. If you ascend too fast then the air/gas comes out too fast in the form of tiny air bubbles (like Champagne), that stay in the bloodstream and get distributed throughout the body.

These tiny bubbles tend to collect in the joints and under the skin. This causes extreme pain, convulsions, blisters and even death. This is called DCS, Decompression Sickness or more commonly called “The Bends”.

decompression chamber

This is why using your Dive Tables is so important. If you would like to know how to read your Dive Tables then take a look at the article on how to use your Dive Tables .

You have to be treated in a Hyperbaric Chamber to be cured of DCS and they are very expensive and are few and far between (not readily available around the world).

Archimedes’s Law


Even though this is not a gas law it still applies to the SCUBA diver. Archimedes’s Law states that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body.

Well, that wraps up the science behind SCUBA Diving, I hope that you found it interesting and informative.

Combined Gas Law

Combined Gas Law

Ok, when we take Boyle’s law, Gay-Lussac’s law, and Charles’s law and combine them we get the Combined Gas Law which states:

Pressure is inversely proportional to volume, or higher volume equals lower pressure. Pressure is directly proportional to temperature, or higher temperature equals higher pressure.

Please if you have any comments or questions, please feel free to leave a comment below and I will gladly get back with you. Thanks for stopping by.




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