Calculating Air Consumption

Constants Used

METRIC

• 1 litre of salt water weighs 1.03 kilograms
• 1 litre of fresh water weighs 1 kilogram
• Pressure increases by 1 atm every 10 metres of salt water
• Pressure increases by 1 atm every 10.3 metres of fresh water Pressure changes per unit of salt water = 0.100 atm/m
• Pressure changes per unit of fresh water = 0.097 atm/m

IMPERIAL

• 1 cubic foot of salt water weighs 64 pounds
• 1 cubic foot of fresh water weighs 62.4 pounds
• Pressure increases by 1 atm every 33 feet of salt water
• Pressure increases by 1 atm every 34 feet of fresh water
• Pressure changes per unit of salt water = 0.445 psi/ft or 0.0303 atm/ft
• Pressure changes per unit of fresh water = 0.432 psi/ft or 0.0294 atm/ft