Bow Tie — Simple mode

The bow tie graphically represents the causes, the ERC and the consequences of a scenario. The simple version is qualitative: it structures causal links without probability calculations.

Structure of a diagram

Cause 1 ─── Barrier ──┐
Cause 2 ───────────────┤──► ERC ──┬── Barrier ──► Consequence 1
Cause 3 ───────────────┘          └── Barrier ──► Consequence 2

• ERC (central node) — the reference accident event
• Causes (left side) — direct or contributing causes leading to the ERC
• Prevention barriers — on the left-hand arcs, to avoid the ERC
• Consequences (right side) — potential effects of the ERC
• Protection barriers — on the right-hand arcs, to limit the consequences

Managing diagrams

Create several diagrams (one per major scenario) via the tabs at the top of the panel. Rename each diagram with the label of the corresponding ERC.

Editing

• Click on a node to edit it (label, type)
• Drag nodes to rearrange the layout
• ＋ Cause / ＋ Consequence — adds a cause or consequence arc
• ＋ Barrier — adds a barrier on an existing arc