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Water hammer analysis and surge prevention

Pressure transients, also referred to as surge pressures or in case of water distribution systems water hammer, are caused by changes in flow resulting in pressure waves either positive or negative propagating along the system. Pressure transients are therefore unavoidable due to the continuous regulations systems are in need of, nevertheless it is possible to devise strategies and use products to contain them as their effect can be fatal for piping , valves and components in general exposed to the dynamic loads.

Most of the time water hammer is neglected underestimated by users and water authorities and additional costs involved in repairing damages, equipments and maintenance to face it are substantial.

The most common worst case scenarios responsible of water hammer are:

  • pump stop due to power failure,
  • uncontrolled pump start-up or pump start up against a system partially depressurized,
  • opening and closing of sectioning devices,
  • pipe filling.

CSA Hyconsult provides surge consultancy service and solutions to prevent unwanted surges, thanks to the use of advanced numerical tools and years of expertise in the field. Through CSA Hyconsult simulations can be used to predict system responses to a wide range of conditions without disrupting the actual system. Using simulations problems can be anticipated in proposed or existing systems , and solutions can be evaluated before time, money and materials are invested in a real project.

In addition to engineering support CSA manufactures a wide range of products designed and used specifically to contain water hammer such as anti-shock air valves, fast acting pressure relief valves, surge tanks and most of the time the best solution is the combination of some of them chosen by the result of the analysis.

Click on the image/link below to see the pressure flow that propagates along the contour of the pipeline in real time. Indicators show cavitation and flow direction providing a full picture of the water hammer phenomenon. Transients at selected locations along the pipe network are plotted simultaneously on the screen.