Question

Please answer Question 2

1. Consider a system with two fire pumps in parallel, where each pump can provide 100% of the required firewater. The two pumps are made by the same manufacturer, of the same model and are maintained in the same way. They are both located in the same room. Identify examples of intrinsic and extrinsic dependencies between the two pumps. 2. From the two fire pumps mentioned above (item #1), there are identical steel pipes delivering water to the users. The pipes are both exposed to vibration causing fatigue. However, the cracks do not develop exactly in the same way, but all pipes fail within a few months of each other. Discuss whether this is a common cause failure or not.

Answer 1

Ans-

Piping Vibration

  Piping Vibration can be defined as a continuous to and fro motion from an equilibrium position. Piping vibration problems cause serious integrity risks.

Effect of Piping Vibration.

The vibration of the Piping System can cause fatigue failure on process piping and small branch connections and reliability problems on equipment. Equipment nozzles, Relief lines, instrumentation ports, drain connections, and valves can also be subjected to Piping Vibration.

Cosideration while Designing Pipes

Due to the fact that most of the piping design codes do not address the vibration issues in a detailed fashion, the damaging effect is normally ignored during the design stage and simple static analysis without attention to vibration is performed on piping systems.

And as we know that fatigue occur suddenly so two pipe of same characteristics fails at different point of time and it is one the important characteristics of fatigue failure due to vibration.

Thus I can say that it is a common cause of failure which is neglected many time while designing piping system.

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