I had an email from a girl asking my advice on singing the Biork song "Oh so quiet"
She wanted to know how to scream or shout at the louder parts of the song without damaging her vocal chords.
My reply to her was...
... don't ever scream or shout when singing. You will eventually damage your vocal chords.
What may sound like screaming or shouting in a song is a controlled for of singing.
As a vocal coach I know only too well that lots of people who don't learn to sing properly or have any form of vocal coaching will attempt to sing loudly without knowing the correct singing technique.
Anyone who wants to sing should find a good singing teacher, vocal coach in order to sing properly.