How Engineers Fix the Loud Knocking Sound Your Pipes Make

Water hammer is caused when the tap or valve on a water pipe is suddenly turned off. Learn what engineers do to create systems that avoid it.
Jessica Miley

What is water hammer? Despite its cool sounding name, it isn’t the latest addition to the X-Men series. Rather, it's an engineering phenomenon that can have superhero scale consequences for pipes and valves. You have probably seen or at least heard the effects of a water hammer. It occurs when a tap is shut off quickly and the force of the water stopping suddenly causes a force against the valve. The resulting pressure spike from this sudden shutting off of water can cause serious damage to water systems. Water and hydraulic engineers take great care to reduce the likelihood of the water hammer effect occurring within a system. 

To find out more about the water hammer effect and how engineers design systems to avoid it, check out this great video from Practical Engineering. Channel host, Grady walks through a great explanation of water hammer. Reminding us that water isn’t compressible or springy which means when it experiences pressure its volume doesn’t change. Grady then builds a working model of a simple pipe system to demonstrate how the water hammer effect occurs and what its impact can be on pipes and valves. Interestingly Grady shows some of the solutions engineers use to reduce water hammers, such as slow release valves and anti-surge devices. Watching the educational video it is great to be reminded just how complex plumbing is and how it has evolved over the centuries to become such a complex but reliable system.