← All chapters Chapter 20

Quality Criteria of a Fault Tree

Check the tree's quality first; analyze it second.

Measures read off a faulty tree can miss the real single point or guard a phantom, so the tree must be checked before it is trusted. Treating the tree itself as a system that implements the safety analysis, the chapter derives its quality criteria and condenses them into a reviewer's checklist. Most of those questions answer themselves when the tree was derived from a complete ibd.