PetroStreet

Where should process safety information data get enlisted when we talk about leading & lagging indicators with reference to API 754?
A gap in PSI information should be taken as something like operating & maintenance procedures?

To me, gaps in process safety information package indicates weakness in leading indicators.
However, PSI itself with a gap would be a lagging indicator.

That is the point. All contributing elements to updated PSI would be falling in Tier-4 as leading however PSI itself a lagging indicator with gaps.
An important discussion this is.

Now if you consider the documentation part, like operating and maintenance procedures, that would be tagged as leading indicators in Tier-4.
But PSI package itself, I would agree with neo, should be a lagging indicator if found with gaps.
What sort of gaps are you expecting to have within that?

Important part here is to identify why there are gaps in PSi package, this itself pose a threat.
I mean if the available documents including P&IDs, PFDs, MSDS, mechanical drawings, F&G layouts and I am not sure where exactly the gaps are, may not be available to all users in their updated form, this requires an immediate action without any delay.
That is why this stands out to be the 1st element of process safety in all the available management models.