What causes water hammer in a steam line?

Water hammer in a steam line is primarily caused by steam coming into contact with liquid condensate. When steam travels through pipes, it carries energy and pressure. If there is liquid water (condensate) in the steam line, the steam can suddenly condense, creating a vacuum or low-pressure area. This rapid transition can cause a shockwave that travels back through the piping system, resulting in a banging or hammering noise. The sudden change in pressure and the violent interaction between the steam and condensate leads to this phenomenon.

The other factors can contribute to issues in a steam system but do not directly cause water hammer. For instance, while rapid condensation of steam can affect system performance, it is the interaction between steam and liquid condensate that specifically leads to water hammer. Excessive steam pressure and loss of heat in the steam line can impact the efficiency of the system but do not initiate the water hammer effect in the same way that condensate does.