Water Hammer Testing

When fluid flow is suddenly stopped or subjected to a change in direction, a pressure surge commonly referred to as a water hammer event will occur. The momentum of the fluid abruptly stopping creates a pressure wave that travels through the media within the pipe system. This same principle is also applicable when the flowing medium is steam rather than water. In the case of steam, the pressure surge is known as a steam hammer event. Both water and steam hammer events have the potential to cause catastrophic damage.
Waterhammer in FAI Flume Lab

Water hammer events are transmitted through the system at the speed of sound as applicable to the fluid-pipe combination (speed of sound varies with the density of the fluid). For water in a steel pipe, this is essentially the speed of sound in water (~4600 ft/s or 1400 m/s which is close to 1 mile/s). With this high transmission velocity, pipe segments are loaded in a highly transient manner causing them to shake. As a consequence, significant dynamic loads can be transmitted to the piping supports as well as the system components, i.e. valves, instrumentation, etc.

Testing Services

A structured approach to addressing water hammer solutions provides an efficient, cost effective and safe solution to address your water hammer issues. Our engineers have the ability to determine the associated loads with water hammer testing and analysis tools.

Our expert team of engineers has extensive experience addressing and resolving various types of water hammer issues utilizing the following: 

  • Analysis using key industry recognized transient analysis software including GOTHIC, owned by EPRI (Electric Power Research Institute) and RELAP5 , a product of Idaho National Laboratories, and FAI-developed GW2
  • Experimental testing simulating water hammer events
  • Training on how to mitigate or resolve future water hammer issues

Our experimental facilities are designed to conduct non condensable gas-water or steam-water water hammer tests simulating conditions of interest in plants including those situations where a non-condensable gas volume is formed in the pump discharge piping. Water hammer pressures are measured during the experiments and translated to plant conditions. This data can be used to set the limits of acceptable gas accumulation. Tests are conducted in an extended length piping configuration of the plant system and most importantly, the tests are run for a range of initial void sizes in the piping high point.

Our experts have experience testing multiple components at our facilities including:

  • Different piping high point configurations in terms of riser, downcomer and high point lengths
  • Influence of a check valve and mini-flowline
  • Multiple void distribution
  • System rigidity, and flow visualization (as an aid in model development) through transparent PVC piping

Water hammer Experiments in Support of a Feedwater Leakage Control System Modification.

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