Pipe header calculation

[PipingApprentice]

Hi Everyone,

I'm a newbie here at eng-tips. I'm a pipimg designer and I find this website very helpful. So I decided to join because for sure I will learn a lot of things here. I might help newbies also in the future.

Anyways, my question is about calculating pipe header size. I am currently working on a flare system. I've got six relief lines going to the header. The outlet lines of the relief valves are as follows:

20" -1x
10" 1x
8" -2x
6" -2x

How do I calculate the size of the relief header? I know this is a process issue but unfortunately the header size is not marked in PID yet. As a piping designer I want to know how to calculate it in order for me to come up with preliminary size and in order for me to reserve a space in the pipe rack. What I only need is a preliminary calculation but if you can provide a detailed calculation (like what process engineers do) then that would be lovely.

Thank you very much in advance.

 

[BigInch]

For a preliminary size, lacking all simultaneous flowrates into the header and inlet pressures, pipe lengths and all the rest of the info you need ....
Add up the inside area of all pipes entering the header, we call it A. Calculate the new diameter as
D = sqrt( 4*A/3.14)
You may be able to drop one standard size diameter.

Independent events are seldomly independent.

 

[PipingApprentice]

BigInch,

Thank you very much for your help!