How to define Process Connection sizes for Instruments on piping and equipment? 2

[Niladri79]

Hi all,

We have an issue with the defining the size of a Pressure and Temperature (TW) connection size on a flare stack. I need to have guidance on this. Also as a general practice what is the deciding factor to define instrument process connection sizes on piping and equipment. We have general practice to use 1/2" or 3/4" connections for Pressure/Level etc and 1-1/2" for Temperature (TW) on piping. Generally it is minimum 2" on equipment. But what drives such sizing criteria? Thanks in advance for your help.

Niladri Sekhar Roy
Engineering Manager
L&T Technology Services

 

[mk3223]

The proper size of the instrument connection is typically based on the Client/Company instrument detail as well as the manufacturer's detail. The sizes of the process connections can be different from 3/4" minimum to 2" or 3" as required, which applied for the pipe and equipment.

 

[georgeverghese]

There are no fixed rules for this. Such connection sizes are defined by EPC contractors in their offer design docs when they bid for EPC jobs. Else it would be included in the plant Owner's bid docs. There is no basis for contention when it is not defined in either party's documents.