It illustrates that there is no way to round the O2 percentage conservatively when it is used to calculate nitrogen loading, MOD, and O2 exposure for CNS limits.
Rounding the percentage of O2 down, while making the nitrogen loading calculations more conservative, makes the MOD and O2 exposure for CNS limits less conservative.
What I do is round the O2 percentage down resulting in more conservative nitrogen loading calculations. Then I round the percentage up and use a table to calculate the MOD, I typically use a 1.5 O2 PP. Then I adjust the computer PP down to get the same MOD.
This results in more conservatism for both nitrogen loading calculations and MOD calculation. As far as calculating O2 exposure for CNS limits, I dont think it is practical to reach the limit if you maintain the O2 PP under 1.5. But I keep an eye on it and dont get anywhere near the limit.
Mike
Rounding the percentage of O2 down, while making the nitrogen loading calculations more conservative, makes the MOD and O2 exposure for CNS limits less conservative.
What I do is round the O2 percentage down resulting in more conservative nitrogen loading calculations. Then I round the percentage up and use a table to calculate the MOD, I typically use a 1.5 O2 PP. Then I adjust the computer PP down to get the same MOD.
This results in more conservatism for both nitrogen loading calculations and MOD calculation. As far as calculating O2 exposure for CNS limits, I dont think it is practical to reach the limit if you maintain the O2 PP under 1.5. But I keep an eye on it and dont get anywhere near the limit.
Mike