Supplementary Material 4.5

Chapter 4 – Effects of Surge Pressures


Surge Analysis and the Wave Plan Method

Supplementary Material: Example Problems and Solutions

Chapter 4 – Problem 4.5

4.5 The owner of a proposed cross-country pipeline project has shortlisted mild steel (MS) and ductile iron (DI) as two alternatives for the pipe material. Preliminary surge analysis has indicated that while the highest pressure during the unsteady flow conditions is only about 10 bars, several sections of the pipeline will experience sustained vacuum pressures in cases where the air valves do not operate as intended (due to insufficient maintenance, for example). The pipe barrel of a standard DI pipe of the required (positive) pressure rating can also withstand the full vacuum pressure. A welded MS pipeline of certain thickness capable of withstanding the full vacuum pressure can also withstand the highest transient pressure of 10 bar. Further, the cost of MS pipeline of such thickness is almost identical to the cost of the DI pipe of the required pressure rating. If no other surge protection is provided for the pipeline, which material would you choose for this project? Justify your answer by listing all the pros and cons associated with each pipe material.

Summary of revisions to this page: