There's no way a 15w amp is loud enough for that!
First time I cranked up the Blues Junior all the way, I was at a buddy's shop where he had a rehearsal room. I was set up in the main shop though, and he was arc-welding and another guy was working a piece of steel on the grinder. I played for a few seconds and he took off his mask and yelled, "J* C*! Turn that down!"