Check out some similar questions!

ladracul · May 1, 2008, 07:02 PM

What is the difference in pressure at ground level between a two columns of water both 60 inches high, one 10 inches in diameter and the other 5 inches in diameter.

jlisenbe · May 2, 2008, 02:29 PM

There is no difference in so far as psi. The determining factor is the height of the water, not the diameter of the pipe. Now, the water in the 10" pipe will have a great many more square inches (78.5) than the 5 inch pipe will have (19.6), so the TOTAL pressure for the large pipe will be much greater. Pressure amounts to about .43 pounds per foot of head.

Why do you ask?

speedball1 · May 2, 2008, 02:49 PM

Originally Posted by jlisenbe

There is no difference in so far as psi. The determining factor is the height of the water, not the diameter of the pipe. Now, the water in the 10" pipe will have a great many more square inches (78.5) than the 5 inch pipe will have (19.6), so the TOTAL pressure for the large pipe will be much greater. Pressure amounts to about .43 pounds per foot of head.

Why do you ask?

.Here we go agan! You are correct, Jlisenbe, when you say the PSI will be the same in the 10" pipe as the 5" one.
Howerver,

Now, the water in the 10" pipe will have a great many more square inches (78.5) than the 5 inch pipe will have (19.6), so the TOTAL pressure for the large pipe will be much greater.

Damm! And you were doing so good! If both pipes are 60 inches tall the head pressure will remain the same no matter how much each pipe has in it. Don't you mean "so the TOTAL weight of the large pipe will be much greater". That old bugaboo of Volume vs. Pressure rears its ugly head again. Regards, Tom

jlisenbe · May 2, 2008, 08:06 PM

Actually, we are both saying the same thing. I'm simply saying that 5 feet of water will produce about 2.15 pounds of pressure per square inch. However, that amount of psi will obviously produce a total of 168.7 pounds of pressure over the 78.5 square inches of area at the bottom of the 10" pipe as opposed to only 42.14 pounds of pressure on the 19.6 square inches of area at the bottom of the 5" pipe. And yes, that is basically seen as weight. Granted, I could have worded it more simply, but the question was asked in regards to pressure so I just stayed in that framework.