Surge Suppression: Care at all Stages

A large twin sewage pumping main had experienced excessive surge pressures during commissioning, and staff of the Water Research Centre were retained by the contractor (responsible for constructing the pumping station) to determine the cause. This paper describes how the problem arose, even though a surge analysis had been carried out. The approach which was adopted for the re-analysis is described, together with the results. Alternative surgesuppression measures were investigated and sized. The importance of air valves in this situation is discussed and an explanation is given on the reasons why the original analysis led to inadequate surge suppression and unacceptable pressures.