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UL 4600 safety case
Standards tour · stop 17 of 20 · ← ISO/IEC TR 5469 · Automotive SPICE →
A safety case as a tree: a top claim, an argument, sub-claims, evidence with its review state, and a defeater that keeps a claim open until it is closed. Field data return to the top claim as safety performance indicators. Generated by tour_figures.py; it explains the standard's idea and claims nothing about the arm.
In one sentence. UL 4600 asks for the safety argument itself: claims, the argument that supports them, the evidence under them, the reasons to doubt them, and field indicators that would show a claim has stopped being true.
UL 4600, Standard for safety for the evaluation of autonomous products. It is written for autonomous products and is goal-based: instead of prescribing designs, it asks the maker to argue that the product is acceptably safe, and checks that the argument covers what it must. The record uses its principles for the safety case only.
- A claim is something asserted about the product: it is acceptably safe in its envelope.
- An argument says how the claim is broken down: over each hazard, each safety function, each assumption.
- Evidence supports each sub-claim, with its review state.
- A defeater is a reason to doubt a claim. It is published, not hidden, and the claim stays open until the defeater is closed.
- Safety performance indicators from the field show whether the claims still hold in use.
A safety case makes the gaps as visible as the progress. Every finding of the gap assessment is a defeater against a claim, so anyone can see what is not yet true.
| What the record takes | Where |
|---|---|
| The safety case: claims, arguments, evidence and defeaters | WP-K-01 |
| The machine-readable records, their validator and the dashboard |
assurance/case/; Reading the safety case
|
| The first defeaters: every finding of the gap assessment, all open | Gap assessment |
| Field monitoring as indicators | WP-O-04 |
Any UL 4600 conformance; the standard is used as guidance.
- Claim, argument, evidence: what is asserted, how it is supported, what supports it.
- Defeater: a reason to doubt a claim.
- Safety performance indicator (SPI): a measured value that shows whether a claim still holds in the field.
No standard is held by the project, so every clause number on this page is to be checked against a licensed copy. The lead decided to buy them only when an assessor is engaged (DQ-011). The record uses the standard's principles for the safety case as a whole rather than by section.
Standards tour · stop 17 of 20 · ← ISO/IEC TR 5469 · Automotive SPICE →