What counts
A mandatory occurrence is an event, or a risk of one, that could cause a significant number of deaths or serious injuries through the spread of fire or the failure of the structure. It covers things found as well as things that happened: a missing fire stop found in a riser can be an occurrence even though there was no fire.
Everyday incidents that do not carry that risk are not mandatory occurrences, though they still belong in your incident records.
The deadlines
Two steps, each with its own clock:
- 1A notice to the Building Safety Regulator within 10 days of the principal accountable person becoming aware of the occurrence.
- 2A full report within 10 days of that notice, with what happened, why and what is being done.
The system behind it
The duty is to run a system, not just to send reports. People working on or managing the building need to know what to report and to whom, reports need to reach the principal accountable person quickly, and each one should be recorded with what was sent and when. Occurrences also belong in the safety case: each one is evidence about whether the barriers are working.