Layer of Protection Analysis, LOPA
Updated 2026-08-10
INTRODUCTION
English translation pending.
CORE DEFINITION
Layer of Protection Analysis (LOPA) identifies a sequence of independent protection layers, including design, controls, alarms, physical barriers, and emergency response, and evaluates how much each one reduces risk. The method enforces defense in depth, so no single measure carries the whole burden and the combined layers lower the probability of system failure far enough to be tolerated.
SCAFFOLDING EFFECT
Reduce cognitive load
- Enumerate the shields: list every independent protection layer standing between the hazard and the loss - Rate each layer: estimate each layer's failure probability and its share of risk reduction - Enforce independence: verify that layers cannot fail together from a shared cause
Anchor fast decisions
Risk passes through several barriers in series, so the probability of total failure multiplies across independent layers rather than resting on the weakest single one. Each layer's failure probability and risk-reduction contribution can be quantified, which makes the residual gap visible and shows exactly where adding or strengthening a layer pays off.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- en.wikipedia.orghttps://en.wikipedia.org/wiki/Layers_of_protection_analysisverified
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