Operations Analysis method

Barrier Analysis

Barrier analysis examines present, missing, and failed barriers between hazard, target, and unwanted event.

Barrier analysis defines the hazard, target, and energy or information path. Physical, administrative, and human barriers are tested by function, performance requirement, and actual condition.

Core question

Which barrier should interrupt the path, how did it fail, and which independent control is missing?

Plan Barrier Analysis Method guide

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Participants: 2-6
Time: 2-4 h

Barrier Analysis uses hazard-target path plus barrier function, condition, failure mode, and correction. Assessments remain justified and context-bound.

Paper illustration of Barrier Analysis with its method-specific working model.

Define path
Define path
Specify hazard, target, and transfer path.
Inventory barriers
Inventory barriers
Inventory preventive, detective, and mitigating barriers.
Analyse failure
Analyse failure
Test intended function, actual state, independence, and failure mode.
Improve barriers
Improve barriers
Add missing or weak barriers and run negative tests.

Update after new evidence or a material context change and retain the previous version.

A good fit when

For incident or risk analyses with a clear hazard-target relationship.

Ideal for

Safety incidents
Incident and near-miss analysis
Control system reviews
Defense-in-depth assessments

Not good for

Pure strategy questions
Behavior and culture topics without a clear barrier structure
Problems without namable protective layers

Outputs

barrier analysis table
barrier analysis table with traceable sources, assumptions, and domain decisions.
Decision and review trail
Owners, dates, and next review for barrier analysis table.

barrier analysis table

Fictional worked example

hazard-target path plus barrier function, condition, failure mode, and correction as a precise working structure with a fictional example.

barrier analysis table
Subject	Hazard/Target	Barrier	Condition	Correction/Test
barrier analysis tableWorked example	Unvalidated data → export → customer.	Schema check; preventive; mandatory fields complete.	Present, nulls not covered.	Quarantine stop; null blocks export.

1. Hazard/Target
barrier analysis table
Unvalidated data → export → customer.
2. Barrier
barrier analysis table
Schema check; preventive; mandatory fields complete.
3. Condition
barrier analysis table
Present, nulls not covered.
4. Correction/Test
barrier analysis table
Quarantine stop; null blocks export.

The example demonstrates the domain logic of Barrier Analysis; worksheets remain blank.

U.S. Department of Energy: Accident Prevention and Investigation Program

First step

Start with the core question: Which barrier should interrupt the path, how did it fail, and which independent control is missing?

Open the method guide

Good to do first

Operations

MORT Analysis

Supplies identified oversight gaps that are checked here for barrier effectiveness.

Where to go next?

Operations

Failure Mode and Effects Analysis

Assesses the barrier gap systematically by failure mode, effect and risk.

Operations

Fault Tree Analysis

Also models the weak barrier as a fault tree to examine deeper causal paths.

Deep dive

Purpose

For a risk that can only be managed through multiple layers of protection, the method examines the effectiveness of each barrier. It shows where safeguards are missing, too weak, or fail under real conditions.

How it works

Between hazard and harm, the existing protective mechanisms are checked one by one and tested for robustness. The analysis shows which barriers really hold and where a failure can easily break through. The resulting measures then strengthen the weakest points of protection in a targeted way.

In detail

Barrier Analysis examines protective mechanisms where hazard and harm should be separated by multiple layers. Every barrier is checked for existence, function, and sufficient strength. Value emerges when missing or weak barriers are improved in a targeted way. The method fits especially well when an event was possible despite seemingly existing controls.

Facilitation

List existing barriers across prevention, detection, and recovery, and check them against the specific scenario. The critical point is reached when it becomes visible which layers exist only on paper and which hold up under load. End the analysis with improvements per layer of protection and a priority for the weakest barriers.

The method guide walks execution through 4 phases, timing, 4 pitfalls, and clear stop criteria.

Open method guide

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Sources and topics

Topics

Root cause Safety Incident

Sources

U.S. Department of Energy: Accident Prevention and Investigation Programenergy.govCurrent U.S. Department of Energy page on its accident prevention program, linking to the Accident and Operational Safety Analysis handbook.

In playbooks

Narrow Down and Sustainably Fix a Technical Root CauseMove from a precise problem specification through structured cause investigation to a documented 8D report.

Artifact templates

Barrier Analysis: WorksheetPlan Barrier Analysis around its domain steps and the concrete decision question.

markdown

barrier-analysis-working-template.md

Plan Barrier Analysis around its domain steps and the concrete decision question.

Barrier Analysis: Worksheet

Question

To be confirmed

Desired outcome

To be confirmed

Scope

Full workshop Time: 60–120 minutes

Complete this worksheet on paper or in your own document during the work.

Preparation for this scope

Method setup

Materials: Incident or scenario description, system and process data, barrier and test evidence, shared workspace, source links, and decision log.
Roles: Investigator · operator · safety/domain expert · control owner
Advance information: Collect Incident or scenario description, system and process data, barrier and test evidence in advance and mark open assumptions.
Overall time needed: 60–120 minutes
Setup: Prepare hazard-target path plus barrier function, condition, failure mode, and correction visibly and calibrate assessment terms before starting.