Problems with pipe wall thickness

The pressure generated by water hammer is extremely high; no matter how thick the pipes are designed to be, it’s not enough. Other safety devices need to be considered for releasing the pressure caused by water hammer – this is something that only professionals in design can take into account

The impact force of water hammer on the pipe wall is quite small; only at bends is the impact force very large. Therefore, when considering measures to prevent water hammer, the thickness of the pipe wall should not be taken into account, but rather other approaches should be explored, such as installing water hammer arresters or setting up devices at the source of water hammer to reduce its occurrence and impact.

What was said above is correct; water hammer represents a special case. When designing, one should not base the design on abnormal conditions but rather on normal operating conditions. For example, one should not take into account the wall thickness after an explosion – the wall thickness is determined based on normal conditions only. For other special cases, it is necessary to design additional components to prevent such situations from occurring

Indeed, traditional pipe wall thickness design primarily takes into account static pressure, that is, the internal pressure of the system under normal operating conditions. However, in practical applications, especially in pipelines for transporting liquid media, dynamic pressure issues such as the water hammer effect also arise. The water galling effect occurs when the flow state of a fluid in a pipe changes suddenly (such as when a valve is closed quickly), causing the kinetic energy of the fluid to be rapidly converted into pressure energy, which in turn leads to a sharp increase in pressure within the pipe. In the example you mentioned, the design pressure is only 0.2 Mpa, whereas the water hammer effect can cause the pressure to surge to 3 Mpa. This increase in pressure is clearly far beyond the design value, and it is very likely that the pipes will burst or deform as they are unable to withstand such high pressures. To prevent this from happening, the following measures need to be taken during pipeline design and installation: 1. **Increase wall thickness**: Recalculate the pipe wall thickness based on the highest possible dynamic pressure (taking into account the water hammer effect). 2. **Install water hammer mitigation devices**: Such as water hammer arresters or accumulators, which can absorb or dissipate the energy generated by sudden changes. 3. **Reduce operating speed**: Control the closing speed of the valve to avoid rapid closure. 4. **Reasonable layout**: When designing, consider the path of the pipes and the structure of the supports, and try to minimize right-angle turns in order to reduce the impact of water hammer effects. By taking into account both static and dynamic pressures and implementing appropriate protective measures, the safety and reliability of pipeline systems can be effectively improved. .