Work out bow tie barrier count instantly with clear inputs, formula shown and shareable results.
A bow tie diagram places the top event at the centre, threats on the left with preventive barriers, and consequences on the right with recovery barriers. Counting them gives the barrier inventory that must be assigned owners, performance standards and verification activities, and the pathway count shows how many distinct escalation routes exist.
Barrier count
Preventive = threats x barriers per threat; recovery = consequences x barriers per consequence
Pathways
Pathways = threats x consequences
Preliminary estimate only. Bow tie analysis must be developed by a competent facilitator with operational input and each barrier assigned a performance standard.
Preventive = threats x barriers per threat; recovery = consequences x barriers per consequence. A bow tie diagram places the top event at the centre, threats on the left with preventive barriers, and consequences on the right with recovery barriers.
No. Barriers that are not independent, not verified or not maintained give false assurance. A small number of well managed critical barriers beats a long list of nominal ones.
This calculator takes 4 inputs: Threats identified, Preventive barriers per threat, Consequences identified, Recovery barriers per consequence. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.