Here are some common equivalents
TANKS
AL80 is an 11 liter 207 bar tank.
28.3 liter / cubic feet.
So a 15 liter, 232bar tank = 15*232 /28.3 = 123 cu ft tank.
DEPTHS
every 10' = 3 meters, so
20' = 6 m
.....
100' = 30 meters, etc.
Going from meters to feet, either multiply by 3.28, or easier ..
divide meters by 3, then add a zero
e.g. 15 meters /3 = 5, add zero to 50'
10msw (meters salt water) is 1 bar. Close enough to 1ata for scuba.
33fsw (feet salt water) is 1ata
PRESSURES
1 atmosphere = 1013.25 millibar = 1.01325 bar, so in most cases
bars and atm are interchangeable.
The common AL80 tank has a fill pressure of 3000 psi, or 207 bar.
1500 psi is about 100 bar
every 1000 psi is about 70 bar
the common 500psi reserve is about 35 bar
the common 50 bar reserve is about 725 psi, or
750psi using the approximation of 15 psi / bar.
VOLUMES
1 cu ft = 28.3 liters
so a reasonably good SAC of 0.5cfm is 14lpm.
WEIGHT
A 1 kg chunk of lead is about 2.2 pounds
saltwater weighs about 64 pounds/cu ft
fresh about 62.5 pound / cu ft
fresh water is very close to 1kg per liter
Anyone is free to take this, modify it, add stuff, or whatever.
