What is a signed safety case, and why does a robot fleet need one before it runs unattended?

What is a safety case?

A safety case is an argument, not a checklist.

It states what the fleet will do, where it will do it, what could go wrong, and why the evidence shows those things are controlled. A checklist can be complete and still describe an unsafe site. A safety case has to convince the people who sign it.

Sirdar publishes a Safety Case Standard so that every partner writes the argument the same way and every customer knows what to expect.

Why does a robot fleet need one before it runs unattended?

Because unattended operation removes the human who would otherwise notice.

Under supervision, an operator watches the Kinetic units and can stop them. Unattended, the stop chain, the fleet policy and the site model are doing that job. The safety case is where the site proves those things are in place and traceable. Kinetic Autonomy ships enabled for supervised operation. Unattended operation follows the signed safety case, on every site, with no exceptions for size or urgency.

What evidence does a Sirdar safety case cite?

Four records, each produced by a different layer of the site.

Halo calibration records. Every accepted Halo node carries a timestamped record of its sensor references, residuals and acceptance decision, verified to ±5 mm at 40 m. The safety case cites them to show the site is measured, not assumed.

Atlas lineage. Every Atlas version names the observations that changed it and the version it came from. The safety case cites the version the fleet's safety zones were verified against. When the floor changes, a new version is trained and the zones are re-verified.

Aether decision logs. Every planned task, the exception the agent raised and the operator decision that released the dispatch are logged. The safety case cites the logs to show that a human override exists on every dispatch and is used.

Sentinel records. Device identities, policy enforcement and investigation timelines show the fleet is protected from the factory onward and that a security event pauses the units it should.

Which standards sit behind it?

The Kinetic M4 is certified to ISO 10218-1 and ISO 3691-4, carries a safety-rated stop chain at PLd / SIL2 and is CE and UL marked. Sirdar's product security development follows IEC 62443-4-1, and the company holds SOC 2 Type II and ISO 27001.

The standards say what the machine and the manufacturer must do. The safety case says what this fleet, on this site, with these people, will do.

Who writes it and who signs it?

The partner of record writes it, often from quotation onward. The partner and the customer sign it.

Writing a safety case is a certified practice. The Safety Case specialization says a partner has certified people doing it today, and safety-case authorship is one of the two practices that define the Elite tier. Vale Norte Mining's partner, Cinder Ridge Automation, holds both; the mine reports 16 units commissioned, 24% less downtime and signed safety cases on 100% of them. The safety director's own words: the partner documented every site boundary.

What changes on site once it is signed?

Three things.

1. Fleet autonomy is enabled on the FC-1 for the units and zones the case covers.
2. Every dispatch keeps its human override; the difference is that an operator approves plans rather than watching robots.
3. The case becomes a living document. A new Atlas version, a new zone or a new task type is a revision, signed again.

Nordvik Steel's plant manager put it simply: the signed safety case made deployment practical. The mill runs 14 hours of daily operation with 31% fewer stoppages.

What are the most common mistakes?

• Starting the safety case after the robots arrive. Start it at quotation.
• Citing a drawing instead of an Atlas version. Drawings do not carry lineage.
• Treating calibration as done once. Residuals drift; the case cites the current record.
• Assuming a site network is safe because it is isolated. Sentinel records are part of the evidence for a reason.

How does a buyer prepare?

Name the person who will sign for the customer early. Give the partner access to the network team and the survey. Agree the operating envelope in words before it is drawn. Ask your partner to walk you through the Safety Case Standard before the first draft, so the argument is yours as much as theirs.

Last updated 2026-09-30.