What gas is in scuba diving tanks?

Answer 1

The majority of gas used in most Scuba tanks is compressed air. This air is composed of the same elements everywhere - 21% Oxygen 79% Nitrogen. Advanced SCUBA divers may use an "enhanced" mixture of 32% (up to about 40%) Oxygen with the balance being Nitrogen. The number of divers who use a mixture like this is about 2 to 5% of all certified divers. Less than 1% of all divers may use a special Tri-mix of some rather exotic gases to allow very deep dives - however, it takes years of instruction and training to use these exotic mixes.

Answer 2

For normal "sport" diving, scuba tanks are filled with just plain old air! That's just the mix of gases you're likely breathing right now, and it contains 78% Nitrogen, 21% Oxygen, and 1% other gases.

But nitrogen can cause problems for divers ("bends" and "narcosis"). So for technical diving (below 100 feet), divers sometimes use Nitrox, less nitrogen than normal air, and more oxygen.

But even pure oxygen can be dangerous when breathed under pressure. In fact, breathing pure oxygen while scuba diving below 25 feet can be fatal!

So for very deep technical dives, the inert gas helium is often added into the gas mix; which can be heliox (oxygen & helium), or trimix (oxygen, helium, and nitrogen).

Answer 3

Divers generally use regular (but specially filtered) air for shallow (>100 ft) dives, and can use nitrox, trimix, heliox, or hydrox for deeper or extended dives. As you descend deeper, the pressure of the air you breathe increases, and this leads to greater concentrations of the gas in the blood. Scuba tanks use specially filtered air to remove potentially toxic compounds such as carbon monoxide. This is one reason why a normal compressed air generator should not be used to fill scuba tanks. At high concentrations, even oxygen becomes toxic, so therefore pure oxygen is a BAD gas to use underwater. Nitrogen also dissolves into the blood, causes nitrogen narcosis and the "bends" or decompression sickness and is a main problem for divers. This is the reason that nitrox, which has a higher percentage of oxygen and a lower one of nitrogen, is used. More exotic blends are more expensive and require multiple cylinders as well as a separate tank to travel through shallow depths safely. Trimix avoids some of the problems of nitrogen and oxygen at high pressures by adding in helium, which is not narcotic and is more easily removed from tissue. It allows you to dive to 100 m. Heliox is just oxygen and helium, and is therefore used for diving to depths of ~300 meters without much risk of decompression sickness. However, due to the price of helium, heliox is expensive. Hydrox, a mixture of hydrogen and helium, is currently being tested as an alternative to heliox. However, hydrogen - oxygen mixtures are extremely flammable, so care must be taken.

Answer 4

Typically, ordinary air (78% Nitrogen, 21% Oxygen, and other trace gasses) is used for diving. However, increasing the percentage of oxygen (a mix called nitrox) can increase the time and depth a diver may stay underwater during a given period without experiencing the harmful effects of decompression illness. However, increasing the percentage of oxygen also decreases the maximum depth a diver may descend, as oxygen becomes toxic if a diver breathes too high a percentage at a certain depth (typically about 200ft for standard air). To dive deeper, helium is added (a mix called trimix) to offset the percentage of oxygen.

Answer 5

In recreational diving, most divers use compressed air (as in the normal air we breather at the surface). Some divers are also trained to use special gas mixes called Nitrox which have a higher oxygen content and lower Nitrogen.

Professional (or commerical) divers tend to use more advance mixes such as Heliox or Trimix which combine Oxygen, Nitrogen and Helium.

Answer 6

Unless you've been specially trained to use any other form of air, it's the same as normal air, just compressed with impurities removed.

Answer 7

air, nitrogen, oxygen, trace gases, and sometimes helium

Answer 8

A blend of Oxygen (20% normally) and Nitrogen (80% normally)

This is almost exactly the same as our normal atmosphere we breath in daily.