Dive_TC_Calculator
This version includes a new sheet called CHECK. If a formula was changed you can check the new results on the DIVE sheet against the original calculations shown on the CHECK sheet. I added documentation on gas exchange, tissue compartments, half-times, and interpreting the results. I added more information to the NDL and ALT sheets to help evaluate the calculations. The revision date is 28-MAY-2015. Click on the link above to download dive_EFX_rev5.xls.
---------- Post added May 29th, 2015 at 05:48 PM ----------
Dive_TC_Calculator
After playing with the spreadsheet I noticed that the NDL's for dives using the DSAT table were increasing with increasing altitude. I fixed a problem in the Pi formula to correct this. The previous version showed an NDL of 43 minutes in the first profile for a descent to 60 feet at sea level. The current version now shows 58 minutes which agrees closely with the PADI RDP slate. After reading through Baker's general discussion paper (yet again) I realized I had glossed over some important information. The rate I was using in the P formulas was simply the value from the rate column. The R in the formula is the rate x the fraction of inert gas (FN2). Fortunately, this change resulted in very minor changes to a few P values (0.2 fsw) and a few NDL's (1 minute).
I changed the first compartment in the Buhlmann table from Baker's paper from 1 to 1a. The 1a compartment has a half-time of 5 minutes vs. 4 for the other. Baker mentioned that the 4 HT compartment was relevant only for divers who bounce to very deep depths - not a typical profile for rec divers.
I deleted the CHECK sheet. At first I thought it was a good idea to provide hard-coded values as a check against values accidentally changed by the user. But, I realized there were two flaws. First, only the first profile was saved which was useless for changes in the second or third profiles. Second, if I included the other profiles it would very tedious to update this sheet if the formulas had to be changed for legitimate reasons. The best way to protect users is to do what I already suggested in red in the documentation - to save a copy before you make any changes.
While reviewing the NDL calculations on the NDL sheet I though it might be cool to provide the controlling compartment number for each dive segment. So, I added a column on the DIVE and NDL sheets called CC (controlling compartment). This is the compartment with the lowest NDL.
This revision is dated 29-MAY-2015 and can be downloaded by clicking the link above. The file name is dive_EFX_rev6.xls. Hopefully, this will be a stable release.
