Security PHA Review for Consequence-Based Cybersecurity

Security PHA Review for Consequence-Based Cybersecurity presents a practical, process-centric method that uses existing process hazard analysis (PHA) outputs, such as hazard and operability (HAZOP) studies, to determine appropriate cybersecurity requirements for industrial process plants. The objective of the security PHA review (SPR) is to identify process hazard scenarios that could be caused by malicious cyber actions and then either recommend non-hackable safeguards to remove the cyber vector or assign an appropriate ISA/IEC 62443 security level (SL) to guide cybersecurity design and implementation. This approach emphasizes assessing initiating events, reviewing all safeguards (both cyber and non-cyber) and evaluating consequences in the context of an organization's risk tolerance criteria.

This book explains how SLs apply to security zones and how conduits inherit the highest SL among connected zones and situates SPR within the ISA/IEC 62443 lifecycle. It emphasizes a process-hazard perspective rather than equipment-only vulnerability listings, describes practical documentation methods (highlighter annotations, dedicated SPR reports or PHA-software integration) and highlights common non-hackable safeguards (such as mechanical relief devices, buckling pins, motor overload relays and external current monitors) that can reduce required SLs when feasible.

Written so that process engineers, control systems professionals, IT professionals and cybersecurity specialists can learn to integrate IT security with process-safety practices without unnecessary duplication of effort. It provides practical, implementable methods, centered on the SPR approach, to identify cyber-enabled process hazards and to assess and reduce risk in real industrial settings.