(117h) Are Your Safety System Barriers Still Work for You?

Process Hazard Analysis is the tool to assess the systems in terms of the process safety scenarios and to determine the ALARP level of the risks that may arise. All the barriers in the Process Hazard Analysis is assumed to be working in the normal operations. However, how you manage to sustain the ALARP level? Do you know any deficiencies and by-pass during the operation? How do they effect the ALARP level? Are you still in the safe side?

All the barriers like Emergency Shut Down Systems, Pressure Safety Valves, Fire and Gas Detection Systems work for your system and you need to follow up in terms of any deficiencies or by-passes made on these. This process starts with reliability of these systems and continues to follow up during the operation. Emergency Safety Systems by-pass are undesired activities but during the operation there would be a need to do this. Here the important thing is how you manage the system with these by-pass and how you follow up these by-pass procedures. Industry and automation systems are improving and there are lots of ways to simultaneously cover all these changes and do the risk analysis to operate the systems safely during these by-pass times. So many companies would be using different ways of controls, in our refinery we have improved a system to follow up all the emergency safety systems with a hierarchy of control and approval automatically including the “Plan B” risk assessments for safe operation of this time periods.The important point here is the type of by-pass (conditional or non-conditional), duration of by-pass (approval hierarchy), what else do you have to operate safely, what other parameters should be followed up by the operator during the by-pass and does he know it?

These automated systems should be covered and controlled during the manual operation or by-pass time intervals in order to eliminate the human errors and not to have any kind of process related incidents. We do need to remember important Process Safety Incidents related with the by-pass of emergency shut down systems like Chernobyl. This solution and automated system would be a barrier not to have such incidents.