No, your steam lines are not supposed to be noisy. The Beatles are considered to be among the best musicians of all time. But the cacophony you get from noisy steam lines is far from considered music at  all.  

 So what is causing the noise within my steam system? It can be any number of factors.  

 Often, it is a litany of factors largely related to poor operation, maintenance,  and the design of your steam heating system.  

 Let’s look at some of the reasons you can have steam hammer and pipe banging:  

 l. The pipes are not pitched properly. Condensate is supposed to go downhill by gravity to return to the steam boiler. I have seen cases where a pipe hanger has broken, resulting in a sag in the  steam line where the condensate has collected; the steam comes down the steam  line, and bangs the condensate to the end of the line where is makes a thud  against the hard stubborn steel.