Haldane in plain english

[Sharkdiver289]

Hello all,
I'm in my IDC right now.
When I took my Divemaster Cert, the Haldane theory was taught only to the lowest common denominator. I forgot it anyway, now as a technical diver, I actually have a genuine interest in learning about the history behind Haldane, I know he was a british officer who created the first dive tables, so my questions are...

1. Padi teaches 14 tissue compartments, the navy has 16. What is a compartment. Is it actual tissue, ie, soft tissue, cartilage, bone. Why does the navy have two more

2. Basically how does it work, in laymans terms please.

Thank you

 

[Dr Deco]

Hello sushidiver289:

Here are some short answers in an attempt to answer your questions.

1. PADI teaches 14 tissue compartments, the navy has 16. What is a compartment? Is it actual tissue, i.e., soft tissue, cartilage, bone? Why does the navy have two more?

[a] There are not a specified number of compartments. Haldane originally had five as this was sufficient to describe all of the diving conditions of his day [1908]. As depths and bottom times increased, it became necessary to expand the set. The US Navy dived to 500 fsw for hours and needed 16. PADI produced tables for scuba and found that 14 were sufficient, roughly in between the other two systems.

A compartment is a mathematical entity that describes and helps calculate the amount of dissolved nitrogen in your body. Originally, it was thought that ‘compartments’ represented actual tissues [such as, soft tissue, cartilage, bone] of the body. This is not thought to be true today, but is taken to be only a mathematical calculation tool [an algorithm].

2. Basically how does it work, in layman’s terms please?

The Haldane system proposed that limited superstation of dissolved nitrogen was possible. This is not quite true since the body actually has micro gas bubbles in it. Surface tension effects make it appear as if ‘limited supersaturation’ existed.

With ‘stable supersaturation’ being possible [thought Haldane], one could ascend near the surface and curtail the uptake of nitrogen. The other decompression methods of his day brought divers slowly to the surface and spent much too much time deep in the water.

That is basically it - in 25 words or less.