UPDATE: Many thanks to my friends who must remain nameless on my website for sharing their article on this topic. They are MUCH more elegant than me and quite a bit more technical, but all in all we agree... not all safeguards should be counted! For those doubting my position, you need to pay close attention to what these safety engineers have to say as what they say COUNTS! CLICK HERE (pdf) to download their article from Process Safety Progress.
Over the past 20 years I have facilitated hundreds of Process Hazards Analyzes (PHA) and participated in hundreds more and there is one thing that I still find troubling... too many are doing these revalidation exercises so they can "check the box" they were done in the name of "compliance". When revalidating a PHA, we MUST challenge the facility's "risk assumptions" and their "safeguards" all the way down to their very core in order to establish their true effectiveness. This is what I mean...