Hi

I want to know if Instrument logic diagrams are included as a design activity in FEED jobs or is it a part of Detail engineering?

Please guide.
Thank you

 

Rightly part of the process design/HAZOP phase long before Detail engineering is involved.

Where they are left for the detail engineering design phase, there is no time for a proper review process. Changes in the control logic can have profound cost/safety implications for the project, if implemented in design.

 

Hi
Generally Instrument logic diagram are considered to be part of detailed engineering. However based on client requirement if required, can be considered.

 

the logic diagrams generally involve much the same review process as HAZOPS for a project. These can take anywhere from six months to a year depending on the complexity of the controls, and involve P&ID revisions. Some projects can take over a hundred logic diagrams.

If it is a simple process involving only one or two diagrams, yes it can be done in detailed engineering, but only where the controls and interlock schemes have been thoroughly reviewed before hand.