Technical information
11
2 Aladin
®
Air Z O
2
– More Safety in Diving
I Uwatec
®
Aladin
®
Air Z O
2
I
But the higher share of oxygen in the Nitrox-mixture also causes additional physiological problems by the
toxic effects at a higher partial pressure of oxygen (ppO
2
). When breathing oxygen at a higher partial pres-
sure, two kinds of oxygen toxicity can occur:
• CNS damages:
Symptoms of poisoning occuring at short notice in the central nervous system (CNS). Such symptoms
are: irritations of the respiratory organs, sickness, headache, pulmonary oedema, cramps, unconscious-
ness. The symptoms occur at a ppO
2
of more than 1 bar and depend on the term of exposure and on
the partial pressure of oxygen.
• Damages of the lungs:
Symptoms of pulmonary poisoning occuring in the long run. The symptoms occur at a ppO
2
from 0.5 bar
and higher and with terms of exposure in the range of hours/days.
Aladin
®
Air Z O
2
considers the short term toxic effect of oxygen (CNS damages) by means of the so called
„oxygen-clock“. It is based on a list which shows the units of toxicity for oxygen per unit of time and is
dependent on the ppO
2
. The indication of toxicity uses „CNS O
2
%“ (= relative toxicity of oxygen for the
central nervous system). CNS O
2
LIMIT= 0% corresponds to the normal state before the first dive, and CNS
O
2
LIMIT =100% corresponds to the critical upper limit. The list, initially published by the US Navy, is nowa-
days known by the name NOAA-list. We modified this list for the use with Aladin
®
Air Z O
2
in cooperation
with Dr. Bill Hamilton, Hamilton Research Ltd. (Tarrytown, NY), a well-known specialist.
The long term kind of oxygen poisoning has practically no relevance for diving with independent diving
equipment and is therefore not considered in the design of Aladin
®
Air Z O
2
.
The physiological peculiarities of oxygen and the changing decompression due to the reduced share of
nitrogen require a profound training, if nitrox is used for diving. Additional technical problems with the
use and the maintenance of parts of the equipment bear further dangers when diving with nitrox or
rebreathers. Therefore, we recommend to adhere to the following guidelines by all means.