Understanding water hammer and the role of PB-1 in mitigating its effects

Water hammer, a prevalent issue in plumbing systems, occurs when a sudden change in water flow leads to a pressure surge or shock wave within the piping. This phenomenon can generate pressure spikes that far exceed the normal operating pressure of the system, potentially causing significant damage over time. High temperatures and water hammer are major factors that compromise the durability of piping systems.

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Water hammer

The Effectiveness of PB-1 in Absorbing Water Hammer Impacts

Polybutene-1 (PB-1) has been found to be exceptionally effective in mitigating the impacts generated by water hammer. The key to this lies in PB-1’s unique material properties, particularly its low Elasticity Modulus value of 450 MPa, making it the most flexible material currently used in plumbing, heating, and cooling systems.

Fundamental Water Behavior and PB-1's Response

To understand why PB-1 is effective, one must consider two fundamental aspects of water behavior:


  • Incompressibility of water: it is generally known that water exhibits a quality close to "incompressibility".
  • Compressibility factor: a less widely spread yet highly relevant piece of data is the value of the water's compressibility factor, which amounts to 0.0000458.

This implies that to decrease the pressure by 1 bar (14.5 psi), an increase in volume according to the previously mentioned factor is all that's needed! Hence, even the slightest increase in volume will lower the water pressure inside the pipeline. Of course, this principle also works conversely: a reduction in volume by said factor would increase the pressure by 1 bar.

In this context, the remarkable and unique ability of PB-1 to flex considerably, attributed to its smallest wall thicknesses, while still meeting the highest standard requirements regarding pressure rating, becomes notably relevant.

Water hammer Polybutylene

Water Hammer Test on d16 and d50mm TERRAIN SDP pushfit unions

Innovative Joint Systems Enhancing PB-1 Performance

When combined with TERRAIN SDP Polibutylene push-fit joints, PB-1 systems can offer even greater resilience to water hammer. These joints allow significant movement, which helps in absorbing shocks and preventing damage.

Empirical Evidence of PB-1’s Efficacy

Testing of the TERRAIN SDP push-fit system, made from PB-1, showcases its robust performance against water hammer. The system not only meets but exceeds standards such as ISO 15876-5 and ISO 19892 (EN 12295). In rigorous tests, the PB-1 push-fit system has demonstrated the capability to withstand over 1 million pressure cycles from 0.5 to 20 bar (7.25 to 290 psi) every 2 seconds, far surpassing the minimum requirements.

Real-world Applications and Benefits

The practical application of PB-1 in high-rise buildings, district heating, and other demanding environments has proven its reliability. For example, the BD Bacatá skyscraper in Bogotá utilizes PB-1 piping for its flexibility and resistance to water hammer, ensuring long-term durability and reduced installation times due to fewer required joints​​​​​​.

Water Hammer Test for TERRAIN SDP Push-fit System made of PB-1 (polybutene-1)
Pressure Cycle tests are carried out according to EN ISO 15876-5 and 19829 standards in Nueva Terrain’s laboratory.


The combination of PB-1’s low elasticity modulus and advanced joint systems provides an innovative solution to the challenges posed by water hammer in plumbing systems. The inherent flexibility of PB-1 not only absorbs pressure surges but also enhances the overall longevity and reliability of piping systems. As such, PB-1 stands out as a superior choice for modern plumbing, heating, and cooling installations.

Want to know more?

With the piping system made from Polybutene, you can enjoy the numerous advantages of PB-1 across a wide range of projects. Reach out to Nueva Terrain or to one of our other member companies to learn more about their PB-1 piping systems and applications.

This article is an adaptation of two previously published articles on LinkedIn by Javier Alejandro Eiriz, Export Manager at Nueva Terrain. You can find the articles here: Part 1 and Part 2.