Inhibition management procedure


I have to prepare a document about "Inhibitions management prcedure" of our plant.
We are an oil&gas plant and we frequently make somme signals inhibitions for maintenance purpose.
I need your help if somone have a document which talk about inhibitions management to use it as a guide line and for inspiration.

Thank you.
Best regards
Is this like "forcing" something to prevent tripping or shutting down? "Inhibiting" a trip or a shutdown?
Yes, I mean forcing, overriding signals for somme process or maintenance operations without a trip or a shutdown.
The procedure that I have to prepare is not how to make forcing tchnically, because it dépends on each system.
The document will talk about how to manage these forcings or overridings like:
- Who can ask for forcing.
- Who can force.
- How to record this forcing to not forgot it.
- At the end, the precautions to take before unforcing the forced signals .
So, it will be nice if there are any documents which talk about this subject.

I have only seen one site that truly had a process (I don't know as I ever saw a written procedure)--that EVERYONE followed.

They used a "Frig Log"--a logbook kept in the Central Control Room where ANY and EVERY Control System change (variable/setpoint change; forced logic; adding a jumper; lifting a wire; logic change; scaling change; etc.) was written down in the logbook and dated and signed. They had a special place for the logbook, and there was a "flag" (a small chartreuse flag) that was stood up any time a logic signal (or signals) were forced or jumpers added or wires lifted. This was a sign to the incoming shift personnel to check the "Frig Log" for new information. The personnel were always good about checking the logbook for any other information, and it was considered critical and essential to safe and proper operation of the plant (4 GE-design Frame 9E heavy duty gas turbines with hydrogen-cooled generators, in combined cycle operation with two Alsthom steam turbines). The peer pressure to use and follow the process of logging changes was very intense.

(The site was in the UK, and several of the personnel were ex-Navy personnel, and I think I was told that "frigging" was a term used for jumpering things (the old analog equivalent of forcing logic signals).)

You have a very good start to a procedure. Some sites call it a JHA--Job Hazard Analysis. And, before anything like forcing logic, or adding a jumper, or lifting a wire site procedures call for completing a JHA, which involves a couple of levels of supervision and management to sign off on the analysis before any work could be completed.

I imagine some sites have something very similar if not even more involved. One has to remember when writing any kind of "procedure" or "process" that it is a dynamic document, subject to change and revision as experience will require. So, it doesn't have to be perfect on the first try. And, you should involve other disciplines on the plant (Mechanical Department; Operations Department; Safety Department; I&C/Electrical (Instrumentation & Control) Department) in the review process before publishing your first document--and when revisions are made. Someone needs to own the document--that should be key to any such procedure or process document; it can't just be written and posted and forgotten with no responsibility for review and revision on anyone's part.

Best of luck! If you want to share what you produce, you can attach a copy of the document to this thread. I'm certain many people will be extremely interested and grateful in your efforts!