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