Best Mix Calculator
Warning: This Best Mix calculator is for aiding in the
calculation of decompression obligations when diving using Nitrox.
It is not suitable for calculating narcotic effects and decompression
requirements when using Trimix or Heliox.
Disclaimer: I take no responsibility for the accuracy of the
calculations and data below. Always verify against other sources.
This calculator can be used to find the Enriched Air Nitrox "Best Mix" (FO2)
for dives with the planned maximum partial pressure of oxygen (ppO2)
at the planned maximum diving depth in metres when breathing Enriched Air Nitrox.
Just enter values for "Maximum Partial Pressure Oxygen (ppO2)"
and "Maximum Depth" and click on the "Submit" button.
Diving with a planned Maximum Partial Pressure Oxygen (ppO2) of 1.4 bar
at a planned Maximum Depth of 33 metres (108 feet)
your Nitrox Best Mix rounding down is:
or 32% - EAN32
This calculator provides information about gas use in scuba diving.
UNDER NO CIRCUMSTANCES is there any implication
that any gas mixture is safe or even life supporting at any depth.
If you have not recived training in technical scuba diving,
Nitrox, Trimix or Heliox you should not attempt
to use any of these results. Improper use of gasses in diving
can result in injury or DEATH.
We can calculate the "Best Mix" for when we dive
using breathing gas mixtures that contain
Nitrogen (N2) and Oxygen (O2) in different
proportions to those in air. Such mixtures are known as Enriched
Air Nitrox (EAN), or more commonly, Nitrox.
The Nitrox "Best Mix" is the highest fraction of oxygen (FO2)
permissible in the gas mixture, based on a desired maximum
partial pressure of oxygen (ppO2) when diving to a
planned maximum diving depth.
To calculate the "Best Mix" using Nitrox for a specific maximum ppO2
and maximum diving depth, the following formula is used:
Metric - metres
Best Mix (FO2) = ppO2 / ((Depth / 10) + 1)
In which FO2 is the fraction of oxygen in the best mix Nitrox gas,
ppO2 is the maximum desired partial pressure of oxygen in bar,
and Depth is the planned maximum diving depth in metres.
For example, if the maxium desrired partial pressure of oxygen is 1.4
and the planned maximum depth is 33 metres,
the Best Mix (FO2) is (1.4 / ((33 /10) + 1)) = .32 FO2.
Friday, 18 February 2011