I once stumbled on a question on which someone suggested to consider buying ear protection for the child who was learning violin, because on the long run, playing violin can damage the child's ears.
I have yet to stand next to an individual who is playing violin on their own, so I don't know how loud it truly is.
But during my last visit to the piano store, when one of the piano seller was playing Chopin's Nocturne Op. 9 No. 2 as a demonstration for me on an acoustic upright piano, I was very surprised by how powerful it was, even though it wasn't a grand piano (then again, I was standing right behind him). This makes me wonder how loud it can actually get if the piano seller was playing something loud instead.
This got me to wonder whether or not playing on an acoustic piano for too long without ear protection might cause hearing loss?
I can't seem to find any information online about ear damage due to piano practicing (unlike for the violin), but I might not be searching properly.