Fault Tree & Event analysis
LOGAN is a program for the construction, evaluation and printing of Fault and Event Trees. The program has the following features:
- Full Microsoft Windows™ operation.
- Fault trees can be linked to event trees by specifying the fault tree which calculates the probability of a branch in the event tree.
- The results of non-independence from common events are fully accounted for.
- Creates transfer events allowing trees to be split over several pages with simple navigation up or down the transfer events.
- Ability to enter data in different units (e.g. failure rates in failures per million hours, proof tests in months and repair times in hours).
- Automatically tests for the use of inconsistent data helping to prevent errors in fault tree construction.
- Generates minimal cutsets for fault trees and event trees with linked fault trees.
- Optional Binary Decision Diagram based calculations for exact results.
- Sensitivity analysis can be performed in a number of different ways to determine the dependency of system results on the failure rate or probability of each event and on repair times and proof test intervals.
- An additional feature is a calculation which finds an optimum set of proof test intervals, minimising the test requirements whilst maintaining the required system failure frequency or probability of failure.
- Export/import fault tree data to and from a Microsoft Access™ database. This facility can be used to create a central databank of component or human reliability.
- ‘Drag and Drop’ editing features.
- Full colour print outs
Option to represent fault tree logic as a reliability block diagram with automatic conversion between the two representations.

