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Process and knowledge management

Modelling processes with BPMN

The key elements of the notation, one example from drawing approval throughout and the rules we model by.

Updated on October 1, 2026Contact: Markus Boden

Why model processes?

Anyone who wants to improve a workflow first has to be able to see it. In conversation every process sounds simple; on paper loops, waiting times and hand-overs appear that nobody consciously planned. A process model makes the workflow equally readable for everyone involved and is the shared basis for discussing improvements.

We model with BPMN (Business Process Model and Notation) because the notation is widespread, standardised and understandable without long training.1

The key elements

Core elements of BPMN 2.0 that are enough for most workflows
ElementSymbolMeaning
EventCircleSomething happens: start (thin) or end (thick) of a workflow.
ActivityRectangleA task, named with object and verb, such as "check drawing".
GatewayDiamondSplit or merge: exclusive (either, or) or parallel (at the same time).
Sequence flowArrowThe order in which the steps run.
Pool and laneSwimlaneWho is responsible: an organisation (pool), a role within it (lane).
Data objectDocumentInformation a step needs or produces, such as a drawing or minutes.

Example: drawing approval

A typical workflow on many projects: a drawing goes to the specialist planners by e-mail, comments come back through different channels, and only after several rounds is it approved. In the model the loop becomes visible, as does the point where knowledge gets lost.

Current drawing approval processyesnoDrawingreceivedDistributeby e-mailPlanners reviewone by oneDefects?RevisedrawingConfirm approvalby e-mailDrawingapproved
DiagramCurrent process: distribution by e-mail, reviews one after another, defect loop without tracking.
Target drawing approval processDrawingreceivedUpload to thedata environmentStructuralreviewMEPreviewStatus"approved"Drawingapproved
DiagramTarget process: drawing in the common data environment, reviews in parallel, comments on the drawing, approval with status.

Whether the change works shows in metrics such as lead time, see Process metrics.

Our modelling rules

  • A model answers one question; the purpose sits above the diagram.
  • Activities are named object plus verb: "check drawing", not "check".2
  • Only as many steps per level as fit at a glance; details go into sub-processes.
  • Every split is labelled, every flow has a clear end.
  • The model is checked with the people who run the workflow every day.
BPMN 2.0 in brief

BPMN is maintained by the Object Management Group (OMG). Version 2.0 was released in 20111; the equivalent version 2.0.1 has also been published as the international standard ISO/IEC 19510 since 2013.3 Beyond the core shown here, BPMN knows message flows between organisations, timer and message events, and sub-processes.