Master Diver Formulas

Laws/Principles
Rankine (absolute temp.) R = F + 460, F = 9/5C + 32, K = C + 273
Archimedes' Principle Buoyancy force = Weight of fluid displaced
Boyle's Law P1 x V1 = P2 x V2
Charles' Law V1 / T1 = V2 / T2
Amonton's Law P1 / T1 = P2 / T2 **Remember to use Absolute Pressures
General Gas Law P1 x V1 = P2 x V2 and Absolute Temperatures in formulas
........... ....................T1.............T2
Dalton's Law (Partial pressure) Ptotal = P1 + P2 + … Pn
Henry's Law At given T: Gas weight PP of gas on liquid

Standards/Formulas
Tank volume
3AA = 71.2 cubic ft
3Al = 80 cubic ft

Water Density
1 cubic ft salt water = 64 lbs.
1 cubic ft fresh water = 62.4 lbs.

Partial Pressures of Air
Oxygen = 21% + Nitrogen = 78% + Other gases = 1% = 100% Air
Oxygen = .02 + Nitrogen = .08 = 1 ATA

Air consumption
1 ATM = 14.7 psi Surface consumption rate (SCR) = Air used / Time
Depth consumption rate (DCR) = SCR x P (in ATA)

Pressure
1 foot salt water = .445 psi x Depth = Gauge pressure (Salt)
1 foot fresh water = .432 psi x Depth = Gauge pressure (Fresh)
Absolute Pressure (ambient) (In PSI) = Gauge pressure + 14.7 psi = PSIA
Absolute pressure (ambient) (In ATA) = Depth + 33 ft / 33ft (Salt) = ATA
Absolute pressure (ambient) (In ATA) = Depth + 34 ft / 34ft (Fresh) =ATA

Displacement/Lifting
Weight of water x cubic ft of water displaced = displacement value (aka water weight)
Dry weight - water weight = actual weight needed to lift
Actual weight needed to lift = Cubic ft of air needed to lift (at surface)
Weight of water
Cubic ft of air needed to lift (at surface) x P at given depth = Cubic ft of air needed to lift (at depth)

Volume/Consumption Rate Conversions
Cubic ft = PSI x Tank cubic ft Minute
Minute Working pressure in PSI <= Working pressure (eg. 3,000)

PSI = Cubic ft x Working pressure in PSI Minute
Minute Tank cubic ft

Tank contents in cubic ft = Tank contents in PSI x Tank size in cubic ft
/ Working pressure in PSI

Tank contents in PSI = Tank contents in cubic ft x Working pressure in PSI
/ Tank size in cubic ft