Nitrox- check my math plz

[lastbornjoker]

Hello all. Just took a nitrox course and double checking my math. These r using ssi tables.

36% will give me an MOD of 94' using PO2 of 1.4
Dive one - 40' for 20min one hour SI dive two - 25' for 30min.
If im right after dive one ill be a B diver with a clock exposure of 11% The one hour SI does nothing for me so i start dive two as a B diver. RT is 39 BT is 30 TT is 109 and that puts me at a C diver with an additional 17% on my clock.

thanks alex

 

[WetDawg]

Alex,

You are close, but re-check your addition on the second dive:

RT 39
+BT 30
= TT 69 min not 109min

Going back to table 1 on the SSI Combined AIR/EANx Dive Tables on 36% at 25' (call it 26') for 69 min (call it 70 min) makes you a "B" at the end of this series of dives.

Your PO2 would be 0.65 (from table 1 36% at 26').
After 30 min at a PO2 of 0.65 (call it .70) you would add an additional 5% to your clock bringing your daily total for these dives to 16% (11 + 5).

 

[lastbornjoker]

Haha it figures the easy stuff is the stuff that will get u. Thanks man