Sat/desat factors versus GF factors

[Yves]

Hi,
I am trying to figure out how the saturation/desaturation factors stand against the gradient factors. It looks clear to me that the gradient factors (GF) are simply a shift of the M-Values to bring more accurate stringency to the decompression calculations. However, although I understand that the saturation factor accelerates the speed to saturation, and that the desaturation factor slows down the speed of desaturation, I wonder how these factors are taken into account in your software. I assume that these factors (anticipation of the saturation, and slowdown of the desaturation) are just parameters used to weight the results of the sat/desat calculations, but in any case, they have nothing to do with the M-Values.
Could you, please, advise whether it is correct?
Thanks and regards

[algo]

HW has a create brochure about "Gradient factors in the OSTC" - i fear only available in german. And the sat/desat factors are also explained there.

https://www.heinrichsweikamp.net/downlo ... GF_web.pdf

@HW: that screams for an english translation

[Yves]

Thanks for your response.
Precisely, I have the english and french versions of this document, and my question derives from my understanding of this document.
Probably, my question was not clear enough.
In short, I wanted to know how sat/desat factors interact with the gradient factors when both are used in combination.
Is that clearer ?

[gr3yw0lf]

hm...

should be described at ~page 10

[Ralph]

Hi,

both, gradient factors and sat/desat factors, can be used at the same time because they tweak the Bühlmann model at different spots:

- The gradient factors move the M-lines, so they interact within the step of transforming current tissue supersaturations into min permissible diving depth ("ceiling").

- The sat/desat factors interact with the change of the tissue saturations by accelerating the computed uptake and/or slowing down the computed release of inert gasses.

The computer does these processing steps (simplified):

1) current tissue saturation, selected gas & ambient pressure -> uptake/release quantum -> scaling by sat/desat factor -> new tissue saturation

2) tissue saturation & ambient pressure -> original M-lines -> apply GF factors -> modified M-lines -> compute ceiling

3) repeat (2) for whole ascent -> deco plan, gas needs, CNS at end of dive, ....

4) next computing cycle: back to (1)

The english version of the brochure can be found here: https://www.heinrichsweikamp.net/downlo ... web_en.pdf
and the French one here: https://www.heinrichsweikamp.net/downlo ... web_fr.pdf

BR
Ralph

[Yves]

Hi Raph,

This is exactly what I expected to hear to confirm my understanding.
Thanks for your explanations.
It is all clear now.

Best Regards,
Yves