Technical information

4 The Calculation Model ZH-L8 ADT

I Uwatec

Aladin

Air Z O

bubbles depending on various assumed influences in arterial and venous blood. In normal, slow ascents,

microbubbles form mainly in venous blood. During fast ascents, microbubbles may also form in arterial

blood and in the body‘s tissues as well. If a particular dive profile may result in the creation of micro-

bubbles according to the Aladin

Air Z O

‘s model, decreased bottom time and/or increased decom-

pression times as well as increased “no fly“ time will be indicated.

• Microbubbles can form if the diver makes too fast an ascent, ignores required decompression stops, or

makes repeated ascents during a dive (yo-yo diving). These microbubbles can form in arterial blood as

well as in the body‘s tissues. If these microbubbles partially impair circulation, the rate of gas diffusion

and saturation tolerance for those tissues immediately surrounding this area of impaired circulation are

changed. If required, both decompression time and RBT ( ) will be adjusted in such a way that alrea-

dy existing microbubbles will stop growing. Increased decompression time will also assist those local

areas of impaired circulation to desaturate with less risk of decompression sickness.

• The calculation of microbubbles results in altered ascent instructions. If microbubbles are assumed to

be present based on the data used by the Aladin

Air Z O

, the ascent rate to the surface is reduced to

23 feet/minute. This will help prevent the formation of microbubbles in the arterial circulation and mini-

mizes formation of microbubbles in the venous circulation after the dive.

4.2 Advantages

On the first dives following responsible diving procedures, a diver using the Aladin

Air Z O

should never

be required to decompress, although a one to three minute safety stop between 10 and 15 feet recom-

mended for every dive. If, however, unplanned circumstances arise during the dive which increase the risk

of decompression sickness, the Aladin

Air Z O

can, if closely followed, reduce the risk of decompression

sickness by reducing remaining bottom time ( ) and/or increasing decompression time. Some of the

more common risk situations are as follows:

• Repetitive dives, especially those deeper than 60 feet and those with short surface intervals.

• Repetitive diving over the course of several successive days.

• Diving in cold water.

• Diving with increased workloads.

• Yo-yo diving (repeated descents and ascents to the surface during a given dive).