One of the most common challenges designers and installers of water and heating systems face is water hammer. The mass of water moving through a pipe network is constantly in motion and responds to any change in flow rate or pressure.

If not properly considered during system design, water hammer can compromise pipe integrity, reduce system efficiency and increase maintenance costs. The good news is that it can be prevented and controlled through appropriate material selection and correct pipe sizing and installation.

What Is Water Hammer?

Water hammer is a sudden pressure surge caused by a rapid change in the velocity of a flowing fluid. It occurs when water moving through a pipe is forced to stop or change direction abruptly, generating a pressure wave that travels through the system.

Common causes include:

• Rapid valve closure
• Sudden pump start-up or shutdown
• Abrupt changes in flow rate within a distribution network
• Filling, flushing or draining of pipes and storage tanks

As this pressure wave travels through the pipework, it can place significant stress on the system, causing vibrations and mechanical loads that may damage components over time. If the system is not designed to absorb these forces, the consequences can include:

• Deformation or failure of pipes at vulnerable points
• Excessive and disruptive noise
• Loosening or damage to fittings
• Micro-cracks that shorten the service life of the pipework

Why Material Selection Matters

The severity of water hammer is strongly influenced by the material used for the piping system. Rigid materials such as metal pipes tend to generate higher pressure surges than materials with a viscoelastic response, such as polymers.

The viscoelastic properties of polymer pipes allow them to deform slightly under pressure and absorb part of the energy generated by the pressure wave. As a result, the peak pressure caused by water hammer is reduced. Metal pipes, by contrast, have very limited capacity to deform and therefore transmit most of the pressure wave through the system. This means that, under the same operating conditions, the maximum pressure reached in a polymer piping system can be significantly lower than in a metal piping system.

Thanks to their lower stiffness and energy-absorbing properties, polymer pipes can often be installed with wall thicknesses similar to those of metal pipes while requiring less restrictive support conditions.

Designing Safer Systems with Multilayer Pipes

Aquatechnik provides detailed recommendations for pipe support spacing based on pipe diameter, material and operating conditions.

Some key installation guidelines include:

• Position supports at regular intervals and avoid excessively long unsupported sections
• Follow maximum support spacing recommendations for the operating temperature
• Use anti-vibration supports where appropriate to reduce noise transmission
• Incorporate both fixed and sliding points to manage thermal expansion and movement

The combination of multilayer pipes and Aquatechnik Safety-Plus fittings offers an effective solution for managing pressure surges and improving long-term system reliability.

With the right design approach, systems can be safer, quieter and more durable. Preventing damage, unnecessary costs, and operational disruption requires careful planning and proven, technologically advanced solutions.

To learn more about the Aquatechnik Safety-Plus range and how it could benefit your installation, you can view our downloadable brochure here: Aquatechnik_UK_Brochure.pdf