How to calculate Design Pressure?

[vinothsvk]

Dear all,
Now i am designing one horizontal vessel. The design pressure is Full of Water. The Dimension of the vessel is 3150(I/D) and 6500(T/T). i was calculate the design pressure by using the formula of P=(dendity of water X 9.81 X 3150) and and i get the value of design pressure is 0.30921 bar. But the vessel is operating at ATM (atmosphere) pressure. Here, vessel design pressure is low when compared with ATM(atmosphere = 1.01325 bar). Please clarify to me.

 

[JohnGP]

vinothsvk, you're mixing up gauge pressure with absolute pressure. Atmospheric pressure is 0 bar gauge (barg), and your design pressure is 0.309barg.
Cheers,
John

 

[DSB123]

A few questions here:-
1. "The design Pressure is Full of Water". That is not a design Pressure it is a condition which cause a static head pressure at the bottom of the horizontal vessel.
2. What is dendity of water?
3. The pressure you have calculated is in Barg. Nothing to do with atmospheric pressure.

 

[JStephen]

If the stated design pressure is "full of water", that means you have an atmospheric vessel/tank. If you use vessel software for the design, you'd have zero pressure plus the static head. Thicknesses will be controlled by minimum thicknesses in most cases like that. You may need additional thickness to get saddle designs to work out, though.

 

[europipe]

This is indeed no des. press. , this is operating pressure.