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Flowcharts

Flowcharts are the engine's criteria flow rendered as a graph — not a visualization of an underlying table, but the structure the engine actually walks. Each node is a criterion entry that evaluates an input and directs the engine to the next applicable entry. Reading a 1.1 flowchart, for example, lets you see every node the engine considered, which path it took for the current analysis, and where the walk terminates in an analysis code. Where the analysis path is a sentence-level narration of one walk, the flowchart is the entire graph visible at once.

Learning objectives

By the end of this lesson you should be able to:

  • Open the flowchart view for a hazard division
  • Locate the engine's decision points on the chart
  • Use the chart to predict how an input change will redirect the walk

What a flowchart shows​

Each flowchart represents the engine's full criteria flow for a single hazard division under a specific criteria set. Each node is a criterion entry — a relationship check, a type-code check, a quantity threshold, an attribute test — and the edge labels show which input answer leads to which next node. Terminal nodes resolve to analysis codes — K9, K18, fixed-distance rules, formula references.

For any given analysis, the engine traces a single path through the chart. The flowchart view typically highlights that path, leaving the un-taken branches visible but de-emphasized. This makes the chart a fast way to see not just what happened, but what would have happened if the inputs had landed slightly differently.

Three flowchart views​

The calculator typically exposes three flowchart entry points:

  • PES — the subset of the chart relevant to a specific PES based on its type code and attributes resulting in the PES Analysis Code
  • ES — the subset of the chart relevant to a specific ES based on its type code and attributes resulting in the ES Analysis Code
  • Per hazard division — e.g., the 1.1 flowchart shows the full decision tree for 1.1 given the starting PES and ES Analysis Codes (currently only 1.1 is displayed in the calculator)

Using flowcharts diagnostically​

Flowcharts shine when a result is surprising and you want to know which fork changed. The diagnostic flow is:

  1. Identify the analysis code in the result
  2. Open the flowchart for the relevant hazard division
  3. Trace the highlighted path back from the leaf (the code) to the root (the inputs)
  4. At each fork, ask "what input drove this branch, and what would change if that input flipped?"

This is the same diagnostic the analysis path supports in narrative form — the flowchart is the visual cousin.

Try it​

Run an analysis that produces K18 with a sameline relationship and no barricade. Open the 1.1 flowchart and trace the path from K18 back to its root branch. Identify the fork where adding a barricade would redirect the path to K9 — the fork that asks "is there an effective barricade?" Now add a barricade and re-run. The highlighted path should redirect through that fork to K9.