The routes through the fault tree between the root causes of the critical event and the critical event are the cut sets. A minimum cut set is the shortest path through the fault tree from the root cause to the critical event.

The Cut Set Details Report provides detailed information about each of the minimal cut sets for a given fault tree. The report can be generated as a list of cut sets or as a list showing the different cut sets associated with each primary failure (both shown below). With three different output formats (i.e. RTF, XML and MS Excel), user-selectable columns, sorting, grouping and filters, this report is likely to be essential to all FTA efforts.

Cut Set Report as a List of Cut Sets

Cut Sets report showing cuts sets associated with each primary failure

Metric Descriptions

Failure Rate

The Failure Rate column contains the failure rate for a particular primary failure (or external event).

If the failure rate has been adjusted to account for prognostics, it is displayed using magenta text; otherwise, it is displayed using blue text.

## Failures – Number of Failures

The Number of Failures column contains the number of primary failures (or external events) in a particular minimal cut set (also known as the “order” of that cut set).

Exposure Time

The Exposure Time column contains the time interval used in calculating the Probability of Failure for a particular minimal cut set.

PoF (Q) – Probability of Failure

The Probability of Failure column contains the likelihood that all members of a particular minimal cut set will occur within the specified exposure time.