Fault Tree and Event Tree Analysis

Consider that your hazard analysis process resulted in the fault tree in the figure. As safety engineer, your assignment is to perform a failure analysis process for the given fault tree. For that purpose, you will need to answer the address the following open items using the fault tree analyses techniques in your textbook (Chapter 15). The events on the fault tree, starting at the top, are: A, then on the left hand side: B1, C3, Z1, Z2, C4, Z5, Z6, Z11, Z12, C6, Z7, and Z8, and on the right-hand side: B2, C3, Z3, Z4, C5, Z5, Z6, Z9, C6, Z10, Z7, and Z8. You can enlarge the figure to better identify the events on the tree. No numerical probabilities calculations are needed.

1. Derive the final fault scenario that leads to the top event for the fault tree
2. Calculate the probability of failure of the left-hand side branch: B1, C3, Z1, Z2, C4, Z5, Z6, Z11, Z12, C6, Z7, and Z8; consider all probability of failure for basic events to be 0.05

In addition, if you consider that the top level gate changes from AND to OR, you will need to develop an event tree analysis process for the branch A B2 C5 C6 Z8. The initiating event is Z8 (which has a probability of occurrence of 0.05), and B2, C5, and C6 are intermediate events (with respective probability of occurrence of 1.4 10^-2, 2.5 10^-3, and 1.8 10^-3).

1. Build the event tree diagram for the branch A B2 C5 C6 Z8.
2. Calculate the probability of failure on the event tree diagram.