Field validation of transient analysis for in-line valve condition assessment

Abstract

The University of Adelaide has performed pressure transient tests for the South Australian Water Corporation along approximately 20 km of 600 mm diameter mild steel cement mortar lined (MSCL) pipe near Iron Knob in regional South Australia. The aim of the tests was to assess the hydraulic seal of two in-line gate valves scheduled for replacement and five other in-line gate valves along the pipeline. Each valve was closed and tested with a controlled pressure transient and the measured reflection and transmission of the transients were used to back-calculate the size of the aperture under the in-line gate valve and the leakage through the valve. The results of the tests indicated that one of the two in-line gate valves scheduled for replacement was in satisfactory internal condition and sealed properly. However, two other in-line gate valves not due for replacement were found to not seal properly and this was confirmed when they were replaced. The South Australian Water Corporation were saved the expense of unnecessarily replacing valves that were in good working order and two problematic valves, that had not been previously suspected, were identified. The in-line valve condition assessment technology can be applied to both pressured transmission and network pipelines. © BHR Group 2008.