Caribe Diving, nitrox, oxygen, enriched oxygen, nitrogen, pressure

Nitrox is the short name for Air which has been
enriched with Oxygen. Air consists of +/- 21%
Oxygen and +/- 79% Nitrogen.

Nitrox indicates that the Oxygen content has been
enriched beyond 21% but not more than 40% for
recreational purposes. The correct term is Enriched
Air Nitrox or abbreviated EAN, followed by the
percentage of Oxygen EANx.

For example EAN32 would mean a mixture of 32%
Oxygen and 68% Nitrogen

Diving with Enriched Air Nitrox allows you to remain
at the same depth for a longer period of time, OR if
you choose not to stay longer at depth you will
absorb less Nitrogen.

Look at this and see the benefits:

A dive to 24m / 80ft on EAN36 would be equivalent
to a dive to 18m / 59ft on Air. Looking at the tables,
the bottom times for these two depths are:

Max bottom time for 24m / 80ft: 30 min
Max bottom time for 18m / 59ft: 55 min

Your bottom time increased from 30 minutes to a
staggering 55 minutes!! Almost double!!

OR, alternatively you can look at this as a safety
factor. A dive to 24m / 80ft for 30 minutes on EAN36
will result in almost half as much Nitrogen absorbed
compared to the same dive on Air.

The question you should ask is: Why not use
Nitrox?

It is safer than Air and reduces your risk for getting
DCS.

As you dive and descend the pressure increases. As
the pressure increases your body absorbs more
Nitrogen in an attempt to equalize the pressure of
the Nitrogen at that depth with the pressure of
Nitrogen in your body cells. The pressure inside your
body cells will always attempt to reach an equilibrium
with the pressure outside your body.

We also experience this when we fly or travel to
higher altitudes where the air pressure is less. As
the pressure decreases as your body will "off-gas"
the non-metabolised gases until the pressure inside
the body cells is equal to the pressure of that gas
(typically Nitrogen) in the surrounding air, also
referred to as ambient pressure.

Likewise when you travel from a high altitude to sea
level, the air pressure increases. Your body will
"on-gas", equalising the pressure of the ambient
pressure of Nitrogen with the pressure in your body.

The pressure changes during a scuba dive are much
more severe than when travelling to or from high
altitudes. Descending from the surface to 10m/33ft in
sea water will double the ambient pressure. It is
easy to see how your body will go through cycles of
"on-gassing" and "off-gassing" in a relatively small
period of time during a scuba dive.

Thus if you can find a method of reducing the amount
of Nitrogen that you are breathing, then you will
"on-gas" less Nitrogen during a scuba dive and will
have to "off-gas" less Nitrogen during your ascend.

As divers we are all wary of getting Decompression
Sickness (DCS) or the "Bends". We do all we can to
avoid this very dangerous condition.

The "Bends" occur when during the "off-gassing"
period, not enough time is given for your body to
release the gas, and the absorbed gas forms
bubbles.

Enriched Air Nitrox is one of the "tools" we can
implement to reduce the risk of getting DCS.