Safety lifecycle according IEC-61511

The compelling why of the Safety Lifecycle

I have been working in the chemical process industry for almost three decades now. In those years I’ve seen several process safety incidents occurring. Fortunately, these were limited to near-misses or (significant) property or environmental damage only. Fortunately sounds a bit harsh in terms of process safety, however it’s incomparable to injuries or death to people. Although present in my subconscious mind, it only moved to my conscious mind a couple of years ago. It was on the Process Safety congress in the Netherlands when I heard a touching story. A story of someone who was responsible for process safety in his company and witnessed the decision of parents who had to switch-off a breathing apparatus which kept their son alive after an explosion on a chemical plant. It was this moment that I realized that what I was doing for a long period already, made sense. This revelation still contributes to the sound foundation of our company: Creating a better world by making processes safer and more efficient. It’s the drive, the ambition, the vision where you want to adhere to, the reason why you do what you do, what you will contribute to the world. 

  This is also known as the big compelling why.  During our search to find the optimum strategy i.e. the vehicle to fulfill our mission, we learned about the Safety Lifecycle (to emphasize that we are dealing with Process Safety instead of occupational safety, I consistently call it Process Safety Lifecycle). This Process Safety Lifecycle is comprehensively described in Industry Standard IEC 61511: Functional safety: Safety Instrumented Systems for the process industry sector. 

The heart and soul of the standard

The standard consists of several phases: 1 – Definition phase In this phase risks are analyzed and assessed, and the focus is on reducing errors due to incorrect specifications. This is achieved via quantitative risk analyzes (QRA’s), Process Hazard Analysis (PHA) like HAZOP’s and risk reduction techniques (LOPA) that result in a correct specification of the safety systems via a Safety Requirement Specifications (SRS) 2 – Implementation phase In this phase the focus is on minimizing errors in the design and commissioning of the safety systems. This is achieved by defining procedures, alarms, mechanical protections, and control system (DCS) interlocks. When necessary, Instrumented Protective Functions implemented in Safety Shutdown Systems are also designed in this phase and the associated design documents are produced like SIL calculations, validations and verifications, SIF designs, finalize SRS, Cause & Effect diagrams and test procedures. 3 – Operational and Maintenance (O&M) phase In this phase the focus is on minimizing risks during the use and maintenance of the safety systems in the plant. Tracking and recording shall be executed on demands on sensors, transmitters and valves in the safety system, how often errors and repairs occur, how often overrides are used, how often the system has been tested and how many near-misses and incidents with safety systems occur. All these data have been assumed in the definition phase. In the O&M phase though it’s determined how good your assumptions have been during the study phase. 

Implementation of the standard is simple: or not?

In short, to be best in class in Safety performance, follow the requirements of the standard, document all the studies and designs carefully, apply Management Of Change (MOC) to guarantee that changes do not degrade the Safety of the plant and make sure to assess the real plant safety behaviour with the assumptions which are made in the studies. This approach is intended to be straight forward and generate a standardized work process in Safety Management of the process plant.  The big compelling why of the originators of the standard would have been to really make chemical/process plants safer and not only rely on studies. Although it sounds simple and straightforward to comply with the standard, it’s not. What we see is that most companies do adhere to parts of the standard, but do not consistently manage all the before mentioned steps.

Creating a better world by making processes safer and more efficient

So, ask yourself the question: are you doing what you should do and what is your compelling why?  In a sequence of blogs we will expand further on this subject.  We will be presenting on the Process Safety congress in Dordrecht, the Netherlands, September, 15th the practical aspects of the Process Safety Lifecycle and like to brainstorm with you what your experience is in the implementation of the standard (if any).  Inspired and want to know more about Process Safety Lifecycle, please visit this page.