IBCD calculations

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mobu
Posts: 44
Joined: Tuesday 27. March 2018, 20:01

IBCD calculations

Post by mobu »

Hello,

respect to IBCD. I would like to know what increment value in a tissue there must be to display the IBCD warning.

Thanks.
Clownfish
Posts: 167
Joined: Sunday 1. July 2012, 15:22

Re: IBCD calculations

Post by Clownfish »

What is IBCD? Have never heard of this term in 33 years of diving and over 4,400 dives.
mobu
Posts: 44
Joined: Tuesday 27. March 2018, 20:01

Re: IBCD calculations

Post by mobu »

Isobaric counter diffusion.
You can activate the warning in the ppO2 setup.
Ralph
Posts: 657
Joined: Saturday 24. June 2017, 11:31

Re: IBCD calculations

Post by Ralph »

The IBCD (sometimes also called ICD) attention message is not based on a certain increment, but on a set of conditions. The IBCD message is in all hwos Tech versions and can be enabled via the menu. IBCD can only occur in a trimix dive. The following conditions all need to be met to set off the IBCD attention message:

- the partial pressure of He is rising while the partial pressure of N2 is falling in a tissue, or the other way arround,
- the tissue where this is happening is the leading tissue,
- the net balance of on- and offgassing in the tissue is positive, i.e. the total pressure in the tissue is rising,
- the tisssue pressure is greater than the ambient water pressure, i.e. the tissue is in super-saturation.

When all these conditions are met, and the net tissue pressure does not stop rising, it will surpass the M-value and may cause a subsequent DCS. Therefore when the OSTC prompts an IBCD attention, it is important to observe the supersaturation value: The saturation percentage value will be going up, as it looks directly at the tissue experiencing the IBCD. If the rising does not seem to slow down and stop before reaching 100% - change your gas !!!

BR
Ralph

PS: for even more information, have a look at https://thetheoreticaldiver.org/wordpre ... diffusion/
karip
Posts: 17
Joined: Sunday 25. March 2012, 19:18

Re: IBCD calculations

Post by karip »

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