SAC rate calculation - compressibility

[seclo]

Does the SAC rate in Dive Log factor in the compressibility factor for the gas at higher pressures or is it assuming an ideal gas?

Compressibility factors (Z factors) are described here for example: https://www.divegearexpress.com/library ... -for-scuba

Started wondering about this as I ended up doing a cave dive with double 7l 300 bar tanks rather than my standard double 12l 232 bar tanks. We started debating what the real amount of gas in the tanks were as the gas gets increasingly non-linear at higher pressure. After doing some research and checking it would have a rather high impact on the SAC rate if you treat the gas as ideal, especially in a cave dive situation where you tend to utilise the "top" 40-50% of the available gas only.

[support]

No, compressibility is not factored into either the SAC or the RMV calculation of air consumption rate.

Cheers,

Greg