Independent Alarm Layers in the Digital Plant

Digital transformation has given process plants better visibility than ever, yet one basic principle of process safety has not changed: the system controlling a process should not be the only system responsible for protecting it. This article examines why independent alarm layers remain essential as facilities become more connected, from alarm floods that overwhelm operators during an upset to common-cause failures such as a failed network switch, a lost shared power supply, or a cybersecurity incident. It explains how independence underpins Layer of Protection Analysis and Safety Instrumented System design, and why alarm management standards like ISA-18.2 and IEC 62682 can only go so far on their own. It also addresses brownfield plants where full system replacement is impractical, and the gap between single-loop alarm trips and Safety PLCs, where compact multiloop logic solvers offer voting logic and functional safety capability at a practical cost. Readers will come away with a clearer understanding of why control systems keep the process running, but independent protection keeps it safe Read the full article in the October 2026 issue of HazardEx below

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