Buhlmann zhl 16.

Allan_o

Hi Rebreather World.
The algorithm Zhl 16 defines 16 different compartments.
But are anybody aware of what the 16 different compartments?

E.G. : compartment 1 = ???? Compartment 2 = ???? etc. etc. etc.


Regards Allan.

Padowan

It's all theoretical, there's no direct correlation with specific tissues, although the half-times (from the longest to the shortest) are chosen to approximate the fastest and slowest tissues - off the top of my head I can't remember the fastest and slowest - I think fat is pretty fast, and bone would be pretty slow.

The 16 half times for the ZHL Algo are (in mins):
4.0, 8.0, 12.5, 18.5, 27.0, 38.3, 54.3, 77.0, 109.0, 146.0, 187.0, 239.0, 305.0, 390.0, 498.0, 635.0

At the end of the day, there's so much difference from person to person from one day to the next its all just a big guess really!

__________________

Sten

Bühlmann states that the blood itself is a very fast tissue and continues all
the way to slow tissues such as fatty nervs and bone marrow. The "speed" of
a tissue is a combination of the composition (fat vs. water) and the amount of
blood that passes through the tissue.

An an exampel you can think of your skin that might be rather warm, with a
lot of blood passing by at the beginning of a dive, and then at the end the skin
is cold and much of the blood flow has been withdrawn. Thus the skin might
be considered rather fast during compression and change to slow during
decompression.

/Sten

Allan_o

Dont know if im correct here but.
In some way there must be some scientific proof of what kind of tissues tested??
Otherwise i sounds rather stupid to call the algorithm zhl 16, based on 16 different tissues???

Further more, i do not concure with fat being a fast tissue, but a rather slow one, due to the low diffusion in that specific tissue, and with that in mind it should be a standig invitation to loose the love handles (myself included)

/Allan

Mixaddict

Given that it is pretty much universally agreed that too much fat is a known contributing factor to DCS, even during somewhat benign dives, when "supposed slow tissues should not yet be effected", I think we can conclude that fat is generally a "fast tissue".

That said, fat also negatively inpacts a diver's overall physical fitness level, which can contribute to excessive CO2 generation which is also a known contributor to DCS.

Time to pull out those tennies and hit the jogging trail!

Regards,
MixAddict

decoweenie

... but fat has "advantages" too like being warmer and consume less O2 (unless stressed)...

Mixaddict

Yes, but more importantly, how will you appear in that brand new Speedo?!!

Sutty

Extract from the Uwatec website FAQs:

ZH-L8 ADT Decompression Calculation Model
Which are the compartment half times of the decompression calculation model ZH-L8 ADT and which are the related tissues?
The nominal compartment half times are:

• Compartment 1: 5 minutes (kidney)
• Compartment 2: 10 minutes (stomach, bowels, liver, central nervous system)
• Compartment 3: 20 minutes (central nervous system, liver, stomach, bowels)
• Compartment 4: 40 minutes (skin)
• Compartment 5: 80 minutes (skin, muscles, heart)
• Compartment 6: 160 minutes (muscles)
• Compartment 7: 320 minutes (muscles, joints, bones, fat)
• Compartment 8: 640 minutes (fat, joints, bones, rest)

The compartments can adapt their compartment half times and their supersaturation coefficients depending on their perfusion rate (workload, skin cooling) and on the estimated amount of microbubbles in the tissues.

__________________
Never forget that life is a finite resource.

John Bantin

These are THEORETICAL tissue half-times and do not relate directly to any particular part of your body. The Buhlmann 16 tissue model is older than the later 8 tissue ADT model. But it is all guesswork!

Mixaddict

I stand corrected! Thanks for the information.

Regards,
MixAddict