Diving Formulas

Equivalent Air Depth Formula (END Formula) 

 EAD=( ( (1-fO2) /.79) (D+33) )-33

 

Best Mix of Oxygen given depth and PPO2 limit of 1.4 ATA 

fO2= 1.4/( (Depth/33) +1 ) 

 

Pressure at a given depth

P(ATA)= ((Depth in fsw)/33)+1

 

Depth of a given pressure

Depth= (ATA-1)(33)

 

Pressure of a gas given fraction of O2 and depth

P(gas)=f(gas)((Depth/33)+1)

 

Maximum Operating Depth given fO2 and 1.6PPO2 (MOD Formula)

MOD= ((1.6/FO2)-1)(33)

 

NOAA Oxygen Partial Pressure Time Limits, CNS Oxygen Limits

PO2 (ATA) Single Dive % CNS/Min Daily Limit
1.6 45 mins 2.22 150
1.5 120 mins 0.83 180
1.4 150 mins 0.67 180
1.3 180 mins 0.56 210
1.2 210 mins 0.48 240
1.1 240 mins 0.42 270
1.0 300 mins 0.33 300
0.9 360 mins 0.28 360
0.8 450 mins 0.22 450
0.7 570 mins 0.18 570
0.6 720 mins 0.14 720

 

Dalton's Law of combining pressures

P(total)=P(gas1)+P(gas2)+P(gas3)+P(gas4)...P(gas(n))

Boyle's Law

PV=k

Pulmonary Oxygen Toxicity Calculation (approximately)

 OTU= t((PO2-0.5)/0.5)^.83