Trimix MOD app
IPhone version - Android version
You can display the output in either metric or imperial units
When technical diving it is vital to correctly calculate the maximum operating depth for a given gas mix. Getting this correct is especially important when diving deep on a rebreather. The work of breathing from diving an unduly dense gas mix can cause increased CO2 production as well as decrease the ability to eliminate the CO2 which in the case of a rebreather can cause loss of consciousness and likely subsequent drowning. Having a mix too rich in nitrogen (and to some extent oxygen as well) can leave you unduly narked and inhibit your ability to safely complete a dive.
This maximum operating depth (MOD) is influenced by the specific combination of oxygen, helium and nitrogen within the mix. When calculating this the app considers
- The maximum safe depth of the oxygen in the mix for a given maximum partial pressure of oxygen (PPO2)
- The acceptable narcotic depth to ensure a clear head (END)
- The acceptable gas density 1
Existing tools allow you to calculate this but are cumbersome and can be error prone so this app will calculate all this for you in a convenient manner. The app will also report what is the limiting factor for depth as it is good practice to write not only the MOD of a given gas mix but also why the MOD is what it is so you can apply judgement when reaching the MOD or potentially exceeding it.
Gas densities can be tweaked as well as the acceptable maximum END and it also supports imperial units if you are that way inclined.
Technical diving is dangerous, using this information incorrectly may end up with you dead. Whilst best efforts have been made to ensure the accuracy of this app there may exist bugs and you must verify that the results make sense within the specific gas mix.
Gas density calculates are derived from this GUE article. Note that there is a minor error in the spreadsheet that has been corrected in this app. ↩