Multi Family Building Operator Practice Test

Water hammer is a surge in pressure that happens when a liquid moving in a pipe is suddenly stopped or redirected, creating a shock wave. In steam systems, condensate forms in the lines and can be carried along by the steam. If a steam pipe is leaky, steam escapes and then condenses as it travels into cooler areas. That creates pockets of liquid water in the line that are then driven forward by the remaining steam. When this moving water slug hits a bend, valve, or another restriction, it suddenly stops or changes speed, producing a loud banging and a pressure spike—the hammer. Other issues can cause problems in the system, but a leaky steam pipe directly sets up the conditions for a hammer by introducing and propagating condensate slugs that are violently redirected in the line.