Steam hammer is absolutely a problem

I’ve been trying to fix it on one of the lines in my building for a few years.

One drop of water makes a liter bottle of steam. That a lot of displacement. If your condensed water return line isn’t pitched properly anywhere it can be blasted back and forth with tremendous force.

Someone replaced their big cast iron radiators with pressed sheet metal ones & the hammer knocked it right off it’s wall mount.

The problem with steam IME is they were designed around slow rise & long cycle coal boilers & the valves for air to escape are way too small.

Unfortunately a lot of the companies in the industry just follow conventional wisdom passed down the generations. When my building had to replace it’s boiler I asked the organization that drafted NYC code for recommendations.

Bigger valves at the top of risers, TRVs on the radiators & pressure just low enough to reach the furthest radiator from the boiler & everyone will be perfectly pleasant. Insulating risers can also help a lot if a unit is still hot.

Getting all the residents to allow that to happen is the real hang up.