OIL & GAS
• Coordinated cyber-physical distraction or degradation,
• Uncertainty in availability of ESD – Emergency Shutdown Valve Assemblies after a near miss or intrusion.
IEC 61511: Safeguarding critical facilities
IEC 61511 implementation by itself does not make the facility“ drone-proof” or UAS( Unmanned Aircraft System) safe. It makes the safety life cycle disciplined enough to identify new initiating events, protect SIF independence, validate safety performance, and manage change when security technology is added. Everything begins with adding external events to the HAZID / HAZOP activities for due diligence. The LOPA is designed to acknowledge and act only for validated real threats. The SRS is revisited for the safe state, response time based on the criticality of the event, and the loss of communication to ESD systems. All in all, the whole philosophy of design of the SIS should be design-independent, well separated and should define established protected field routes. The judgement of the system is continually validated through proof testing, bypass control, post-event checks, and corresponding actions.
IEC 61508: Safeguarding ESD integrity
In the whole safety loop, it is well established that the valve, actuator and control assembly( s), called the final elements, account for 50 % of the overall failures. This is significant in the sense that if we can control or mitigate failures of the ESD( Emergency Shutdown Valves) assemblies, then we can eliminate a major portion of the risk or threat.
Final element design priorities
• Fail-safe action on loss of signal, motive power or degraded controller state,
• Diagnostics: position, actuator torque, solenoid & smart positioner health, travel time, partial stroke,
• Protected tubing, glands, local panels and cable routing,
• Secure configuration, firmware governance, activity logs, backup and recovery,
• Safety action must not depend on security dashboard availability or GUI – Graphic User Interface intervention.
In conclusion, the goal is not to turn SIS into a counter-UAS / Drone fighting system. The goal is to ensure that if an external threat event occurs, the safety function remains independent, validated, cyber-physically hardened and able to place the process in a safe state.
About the Author
Vimal Ghumman is based in Houston, Texas, United States and is a Mechanical Engineer and an MBA in International Business by training with 30 plus years of experience in the valves and controls industry in the US, India and the middle eastern countries. He is an SME for automated valve solutions and a Functional Safety expert with a focus on deployment of valves and controls in critical safety applications. Mr. Ghumman is also a senior member of the ISA Houston, Texas chapter and a senior member of the ASQ, American Society for Quality. He can be reached at vimalghumman @ gmail. com
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