APPD Appendix D 101
Appendix D
MATHEMATICAL FORMULAS
USED IN NITROX DIVING
CALCULATIONS
U.S./IMPERIAL CALCULATIONS
Boyle’s Law
P1V1 = P2V2
Dalton’s Law
÷ ÷
Or, as formulas:
Pg =Fg × Ptotal
Fg =Pg / Ptotal
Ptotal =Pg / Fg
Converting Depth to Absolute Pressure
or
Converting Absolute Pressure to Depth
or
Calculating Maximum Operating Depth
In two steps:
followed by:
Or, in one step:
Calculating Best Mix
In two steps:
followed by:
Or, in one step:
Calculating Equivalent Air Depth
In two steps:
followed by:
Or, in one step:
Pata = D f s w + 1 atm
33 fsw / atm
Pata = D f s w + 3 3 f s w
33 fsw / atm
D fsw = (Pata - 1 atm) × 33 fsw / atm
D fsw = (Pata × 33 fsw / atm) - 33 fsw / atm
Pata = PO2 limit / FO2
D fsw = (Pata − 1 atm) × 33 fsw / atm
D fsw = ( P O 2 l i m i-t 1 at m) × 33 fsw / atm
FO2
Pata = D f s w + 1 atm
33 fsw / atm
FO2 = PO2 limit / Pata
FO2 = PO2 limit ÷( D fsw 33 fsw / atm
+1 )
= PO2 limit × 33 fsw/atm
D fsw + 33 fsw
Pata = D f s w + 1 atm
33 fsw / atm
D fsw = (Pata − 1 atm) × 33 fsw / atm
(D fsw + 33 fsw) × FN2
EAD fsw = ( )0.79
- 33 fsw Partial
Pressure
Total
Pressure
Gas
X Fraction