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Understanding Water Hammer Arrestor Size: Importance and Considerations

Updated: Jul 5, 2023


Water hammer arrestors play a crucial role in mitigating the damaging effects of water hammer in plumbing systems. These devices absorb sudden pressure surges and help maintain the stability of the system. One key factor that influences the effectiveness of a water hammer arrestor is its size. In this blog post, we will explore what is meant by water hammer arrestor size, why it matters, and the important considerations to keep in mind when determining the appropriate size for your plumbing system.

Defining Water Hammer Arrestor Size:

Water hammer arrestor size refers to the capacity of the device to absorb and control pressure surges caused by sudden flow changes in the plumbing system. It is typically measured in gallons per minute (GPM) or liters per minute (LPM) and represents the maximum flow rate that the arrestor can effectively handle.

Importance of Correct Sizing:

Choosing the right size for a water hammer arrestor is crucial for ensuring optimal performance and preventing potential issues. Here are a few reasons why correct sizing is important:

  1. Pressure Absorption: An appropriately sized arrestor has the capacity to absorb and dissipate the energy generated by water hammer effectively. It helps maintain stable pressure levels and prevents excessive strain on the plumbing system.

  2. Noise Reduction: Water hammer can produce loud banging or knocking noises that can be disruptive and bothersome. A properly sized arrestor is designed to minimize these noises, providing a quieter and more comfortable environment.

  3. System Protection: Correctly sized water hammer arrestors help protect the plumbing system from damage. By absorbing pressure surges, they reduce the stress on pipes, valves, fittings, and other components, preventing leaks, bursts, and premature failures.

Considerations for Sizing Water Hammer Arrestors: When determining the appropriate size for a water hammer arrestor, the following factors should be considered:

  1. Flow Rate: Evaluate the maximum flow rate of your plumbing system to determine the size of the arrestor. Consider the fixtures, appliances, and peak water demands to ensure the arrestor can handle the expected flow.

  2. Pipe Diameter: The diameter of the pipes in your system also plays a role in sizing the arrestor. Larger pipe diameters may require larger arrestors to accommodate the increased water volume.

  3. System Pressure: Consider the working pressure of your plumbing system. Higher-pressure systems may require larger arrestors with greater capacity to handle the increased energy from water hammer.

  4. Location: Different areas of the plumbing system may have varying flow rates and pressure characteristics. Assess the specific locations where water hammer is likely to occur and ensure the arrestor is appropriately sized for each location.

Consulting a Plumbing Professional: Determining the correct size for a water hammer arrestor can be complex, as it involves various factors specific to your plumbing system. It is advisable to consult a plumbing professional who can assess your system, consider the relevant parameters, and recommend the appropriate size and type of arrestor.

Conclusion: Water hammer arrestor size is a critical aspect of their effectiveness in controlling pressure surges and preventing damage in plumbing systems. By understanding what is meant by water hammer arrestor size and considering factors such as flow rate, pipe diameter, system pressure, and location, you can ensure that your arrestors are correctly sized for optimal performance. Consulting with a plumbing professional will help you make informed decisions and ensure the long-term stability and reliability of your plumbing system.


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