Risk Assessment

1. Consider a fault tree with an AND gate under the top event. The first tier contains four failure events with respective failure probabilities of 0.005, 0.002, 0.01, and 0.0001.
a. What equation should you use to compute the probability of the top event?
b. Using the equation, what numerical value do you get for the top event probability?
c. For the top event, what is the probability of the complimentary event (i.e., success probability)?
2. Examine the success tree in the Figure 7.7 in the course textbook (p. 78). Write in outline format the logic for the first tier.

3. Describe some of the criteria that should be used in determining a top event or condition for a Fault Tree Analysis. Provide some examples (other than the ones in the course textbook).

4. What does the fault tree in Figure 7.6 of the course textbook (p. 77) tell you about strategies for extinguishing a fire?

5. Explain why common-cause failure analysis is important when dealing with redundant systems. Provide an example that illustrates your point (other than one from the course textbook).