One of my favorite parts of teaching the 1-day PSM Intro course at ASSE SeminarFest is the vast numbers of students and all of their learnings and experiences being shared. This year was even better than years before – in fact, we had so many side-bar discussions because of the great input from the students – that I ran out of time (also due to a 90-minute lunch break this year). The one topic that I was challenged on was the definition of “Loss of Primary Containment” (LOPC). I start the course by telling the students that there are four main takeaways I want them to leave with:
1) process safety is all about PREVENTING the event, PROTECTING assets when it does happen, and MITIGATING the consequences from the event
2) looking at risk in the traditional Occ Safety and Health scheme is flip upside down in process safety – in traditional Occ Safety and Health we are chasing high frequency- lower severity events (i.e. OSHA recordable injuries) – in process safety we worry about the low frequency-high severity events.
3) Everything we do in process safety is to prevent an LOPC event
4) RAGAGEP(s) is true process safety – not 1910.119 or Part 68
So we get into a discussion around LOPC and how is it defined. Here’s the “trick question”… do you consider an RV lifting or an RD bursting as an LOPC event?
By the most basic definition, I certainly do, but I have seen some businesses claim that a release via an engineered pressure release system that does NOT produce an EHS consequence (and these are qualified by all types of definitions!) is NOT an LOPC event. I have come across this in my PHAs, Audits, and investigations and although no one will be able to convince me otherwise, in my world this is without a doubt an LOPC event and must be investigated to understand what led us to the situation where our last line of defense had to save us.
Scenario:
We do not manage our LOPC event (e.g. an RV lifts) as a PSM/RMP incident because during this event there was not EHS consequence. Later, we have some contractors working in a lift in the vicinity of our vent line discharge and we have the same LOPC event as before. This time we “gas” two contractors with our HHC/EHS, so we all agree this was an LOPC event and we investigate as a PSM/RMP incident.
Do you see where I am going with this? Had we investigated the first LOPC event, even though there was no EHS consequence, we could have understood our failures that led up to the RV lifting. We then could have intervened with some corrective actions to prevent the 2nd LOPC event where we did suffer a significant EHS consequence.
Pressure Relief Systems are certainly designed to protect our process equipment from overpressure scenario’s, but their activation should be RARE and viewed as a SERIOUS failure of our process safety management. They are after all not a “pressure management” device – they are a last line of defense and their activation should be viewed as an LOPC event. For one to be activated we would have had to EXCEED BOTH our Safe Operating Envelope AND our Safe Design Envelope!
What are your views? How does your business view an RV lifting and discharging the HHC/EHS to a “safe location”?