AWWA JAW68589

Rapid changes in flow rate can cause serious problems in water distribution systems. High water hammer pressure can permanently deform or rupture a pipeline and its components, and low pressure can collapse a pipeline, causing leaks, disrupting service, and contaminating pipelines. One way to protect distribution systems from damage is to install a pressure relief valve (PRV). The authors illustrate the challenges inherent in PRV design and show that an appropriately designed PRV can protect some systems from excessively high or low pressures and that inappropriate use can actually worsen a system's transient response. The general principles of PRV use and selection are presented in two case studies along with a sensitivity analysis of PRV parameters. This study contributes to a cost-effective solution to excessively low- or high-pressure control in distribution systems, making water suppliers more aware of the need for numerical simulation of transient flow and water hammer control issues in water supply and distribution systems. Includes 4 references, figures.