You may use resources beyond those associated with the class, but cite all of your sources.
Keep answers short and to the point. You will not get credit for being excessively verbose or providing too much information.
Consider a water pump system (used on a fire engine) that has two internal pumps driven by a single engine:
The pump has a single valve that is fed by two pumps. Water is sourced independently for the two pumps. Ideally both pumps should be operational. However, the system can work with only one pump. Both pumps are powered by a single engine.
- Discuss the safety and human health implications of this device being engineered to perform reliably. (10 pts)
- Describe this system using a tree chart and identify possible hazards for each of the system components. (10 pts)
- Assume that component failures can only occur at each pump (pump 1 or pump 2; so there can be a separate failure at each pump), the engine, and/or the valve (treat these as your only initiator events, do not use any other initiator events). Construct a fault tree describing a failure of this system (no water released by the system). (10 pts)
Note. In an ideal situation, insights you would gain from problem 2 would influence what hazards you consider in the fault tree. However, for this particular assignment, please only use the initiator events we provide. This is done to ensure that you understand fault trees concepts and can apply them in a simple application. It also helps facilitate the grading of the assignment.
- Identify all of the minimal cut sets associated with your fault tree. (10 pts)
- Without considering probabilities, which cut sets constitute the highest risk? Why? (10 pts)
- Identify the path sets for your fault tree. (10 pts)
- Assume you have the following information collected over the lifespan of this type of system:
# of times worked # of times failed
Engine 26071 2607
Pump 52142 14600
Valve 35326 4239
Calculate the probability that each component will fail. (10 pts)
- Use these probabilities and your fault tree to calculate the probability of a system failure (no water released by the system). (10 pts)
NOTE: Do not use rounded numbers in these calculations. Keep precision all the way through. Only round when your report your answer.
- Calculate the probability that each of your minimal cut sets occurs. (10 pts)
- How could you use the information you gleamed from the above fault tree analysis to make improvements to the system if resources (money, time, etc.) are limited? Explain your answer. (10 pts)