Fluid dynamics question, pretty basic.

[lendaddy]

I need to know what static pessure (psi) there will be at an orifice at the bottom of a 4" diameter tube (8' high) filled with water.

We are fitting a poppet valve and need to know what the cracking pressure should be so as not to leak while filled but unpressurized.

Thanks guys.

[sammyg2]

2.31 feet of water equals one psi.

[lendaddy]

Originally Posted by sammyg2

2.31 feet of water equals one psi.

Thanks, I got 3.46 as well but made it much more difficult than I had to. I see now that the diameter doesn't matter, thanks.

[stevepaa]

http://www.keidel.com/mech/pressure-head.htm

[sammyg2]

Diameter only comes into play when you need to calculate total pressure or total weight. Then it's psi times area. Remember that 2.31 is based on water at 60 degrees F, if it's hotter or a different liquid you need to factor by specific gravity.
I have to engineer pumping and piping systems fairly often so I have this stuff burned into my frontal lobe.

it gets more fun when you get into calculating suction specific speed and NPSHA. I usually try to pawn that off to one of the junior engineers

[on2wheels52]

"I usually try to pawn that off to one of the junior engineers"

That's not the typical way I hear that infinitive used.
Jim