1. Dive Tables and Equivalent Air Depth

2. Introduction Recommended Nitrox Dive Tables
Equivalent Air Depth metres sea water (msw)
Use of EAD & Tables
Air Tables & computers
Nitrox computers

3. Nitrox Tables Buehlmann Tables Definitions Use – as air tables
Specific Nitrox Tables:
EAN28
EAN32
EAN36
EAN40
See Appendix 2

4. Nitrox Tables Extra Rule Longer RNT
when moving from one mix to another the RNT is calculated using the table of new mix to be used
Longer RNT
Rule applies from any mix (EANx or air) to any other mix (EANx or air)

5. Equivalent Air Depth Nitrox – ppO2 > ppO2 Air
Nitrox –ppN2 < ppN2 Air
Depth where EAN ppN2 equivalent to air
Depth where ppN2 of Nitrox = ppN2 of Air
Known as EAD

6. EAD - example
Example: EAN36: ppN2 = 0.64 bar At 25m = 3.5 Bar (absolute) x 0.64 = 2.24 bar ppN2 Air: ppN2 = 0.79 bar Depth using air at which ppN2 = 2.24 bar 2.24 / 0.79 = 2.83 Bar or 18.3m The equivalent air depth using EAN36 at 25m is 18.3m

7. EAD Used for any mix Given depth Determine no-stop times
EAD 18.3m - use air tables
Calculated in two ways:
Use EAD formula
Use EAD table (Appendix 3)

8. EAD Formula
EAD (Bar) = FN2 in mix x P / 0.79 (FN2 in air) FN2 = decimal fraction of nitrogen P = pressure of dive (absolute) EAD in bar – convert to metres for equivalent depth in msw

9. Example: Using Nitrox 32% at 33 metres. Go across to reach 32%
Example: Using Nitrox 32% at 33 metres. Go across to reach 32%. Go down to 33 metres. Follow the row across to the left, where the E.A.D. can be read: 27 metres.

10. Using EAD and Air Tables
Use EAD with any Buehlmann Air table
Determine no-stop time
Care not to exceed depth
Used for repetitive dives
Keep within no-stop times
Extra benefit of nitrox over air on safety stop

11. Air Tables & Computers Nitrox mix with standard tables or computer
Advantage
Reduces risk DCI
MOD (max ppO2 1.4)
CNS%
No-stop times

12. Nitrox Computers Use specific nitrox computer
Specify mix used prior to every dive
Include in buddy check
Track oxygen
Track nitrogen
CNS%
No safety advantage
Pre-selected % safety margin built in latest models
Multi-level diving
Always follow manufacturer’s recommendations

13. Summary Nitrox Dive Tables EAD concept and use
Air Tables and computers
Nitrox computers
Safer options
Plan the dive and dive the plan

14. Questions?