Referring to IOGP 544 publication, cathodic protection itself is required to be a preventive barrier.
Through an example, as in attached snip, you can see the affect here stands within preventive.

A good book.

tuan wrote: 25 Oct 2025, 22:09 Jeem,
Try to get the title:
Alarm Management for Process Control by Rothenberg, Douglas H
I attached the info in the attachment.
Screenshot_20251026-020408.png

thanks ivani1.
This is what you are talking about the permanent plant changes?

The scope itself is different however addresses the same issue.
API 500 & 505 addresses the hazardous area classification on division & zone wise basis.
API 540 itself addresses the details on the design, selection etc. part.

Considering a reasonable sized petrochemical unit, how many plant /process /mechanical changes should be considered as "too many" changes?
Looking for thoughts here.

That happens with the impurities in the feedstock or process stream chemically bond with the catalysts's active sites, blocking them from participating in the desired reaction. Major contributors include Sulfur compounds (H2S, thiophenes), heavy metals (As, Pb, Hg, Ni, V), organonitrogen compounds ...

What is the minimum number of tubes to be inspected for a heat exchanger when it is made available for inspection?
Is there any criteria available?

There are supplementary requirements over and above ISO9001 to come on-board with ISO29001.
Would strongly recommend you to start with a gap analysis of your current practices versus these supplementary requirements of ISO29001.
Once you identify those, then only formulize a plan to implement what ...