how many PSI per foot does it take to pump air under water?

Question

Im working on an at home project to supply someone with a constant air supply under water. does anyone know how many PSI of air pressure is needed to pump air per foot of water.

Answer 1

I hope you know what you are doing.
1. If air is used for breathing use oil less compressor and clean air (no fumes).
2. Depending on period of exposure and the amount of pressure a pressure decompression could be required (check on bends).
Again I hope you know what you are doing...

If it is a purely physics question then here is my answer.

Density of the liquid determines the pressure in question, for instance about 32 feet of water is 1 atmosphere or 14lb/in^2 (pounds / square inch )

so for 20 feet you will need to supply

x=20(14)/32=8.75 lb/in ^2

Answer 2

Psi Per Foot Of Water

Answer 3

Well the conversion of an atmosphere is 34 feet of water equals 14.7 psi, just like a barometer. So to pump air out at 34 feet deep requires 14.7 psi. However, you need to consider the size of hose that you are going to use and the volume because you will have losses as the air flows through the hose. If you use a compressor make sure it is suitable for breathing, does not generate carbon monoxide.

Answer 4

As others have pointed out, the pressure increases roughly by 1 atmosphere for every 33 feet under water. To provide air at 33 feet, you need to pump it at more that 14.7 psi. But for every 33 feet you will need to double the quantity of air pumped as twice the pressure will halve the volume. You do not need to force air into the lungs. This will only damage them. Scuba divers easily swim down to 100 feet and breathe by simply inhaling on their mouthpiece. The air in their tanks is not being forced into their lungs.

Be very, very careful to provide clean air.

Answer 5

I won't answer this question since I doubt you have considered a clean air supply and appropriate safety measures. Household air compressors or even industrial air compressors will not supply breathable air. The safety instructions for them even say so. The air compressors that will supply air that you can breathe are specialized and not cheap.

These breathing apparatus also have features to prevent over pressurizing the lungs. That would be deadly, not like in cartoons (no offense intended, but it really is critical to consider).

Sorry, but I could not sleep at night thinking that you might be using the same compressor for your car tires or pnuematic tools to breathe underwater. You might get lucky, but this can be very dangerous if you aren't trained and using the proper equipment.

Answer 6

Each foot of fresh water (no salt) requires .433 psi to balance it.

So if you have a tube 2 feet under the water and you want a bubble to come out the end of it, then you will need to apply .866 psi at the surface. If the tube is 10 feet down then the pressure is 4.33 psi

Answer 7

you have to take into account the persons lung capacity, usually around 4000 ml by volume, you have to also take into account water pressure. your gonan need a lot of air. if they are just under the surface, probably 20 psi because the atmosphere is 14.5 psi and 20 psi would be sufficent to inflate the lungs under the pressure of the atmosphere and the water. it will most likely need ot be forced into their lungs, thats the reason for the 20 psi. btw this isnt all that safe.

Answer 8

The pressure needed is propotional to the depth of the water.
as easy as that.just calculate the water pressure at the depth u want and that is the pump pressure you'll need.


i'm not good in american units but i can tell u in SI units.

water pressure under height (h) of water = dgh
d= density of water = 1000kg/square meter
g= gravitational acceleration = 9.81
h = height of water

the answer will be in Pascals
1 pascal = 1kg/cubic merter

by the way any home compressor definately has its outlet pressure written on it in pascals.