Safety Stop/Decompression stop

[Snafu]

Hi Doc,

Why do SAFETY STOP/Decompression Stop are done at:

1. 6m
2. 5m
3. 4.5m
4. 3m
*Final stop

Different diving book will write differently.

I would like to know the reason behind it, regarding the ingassing&outgassing... partial pressure...etc.

Why must it be at this depth.

What is the best depth for it.

Thanks

 

[Dr Deco]

Dear Snafu:

Stops:

There are certain factors in diving and decompression that are “God given” and set by nature. The No Decompression Limits (NDLs) are one example. This is why all algorithms have very similar values in their NDLs. These NDLs are set by the number of micronuclei at or above the Laplace limit (the minimum tissue gas pressure needed to exceed the inward pressure of the bubble surface tension). This concentration of nuclei [I believe] varies from diver to diver and will confer more sensitivity to DCS or less.

Safety Stops

Safety stops, on the other hand, are pauses in the ascent from a dive that would be considered safe even without the pause. The pause is and attempts to reduce the size of the nuclei and reduce the risk of DCS when one reaches the surface. These stops are based on studies performed with Doppler bubble detectors and are considered a good idea.

The depth of the stop is arbitrary and different tables, agencies, and instructors might have differences of opinions. These differences would probably be based on technique as contrasted with differences in bubble growth dynamics.

Dr Deco :doctor:

 

[BRW]

Snafu,

Stops are now used to control both dissolved gases and
bubbles. Deep stops address bubbles mostly. Shallow stops
deal with dissolved gases plus bubble gas diffusion of same.

Both are important in modern staging regimens. The 10 ft
decrements are both historical and convenient.

Bruce Wienke
Program Manager Computational Physics
C & C Dive Team Ldr

 

[Snafu]

Hi Doc&BRW,

Thanks you for your simple explaination.

Ta.