Comment by mapontosevenths

55db is lower than the noise floor in the average office. They were probably just measuring the background noise of regular-ass being outside.

For perspective, the inside of your home is probably about 40. When I turn on my box fan it's about 55.

That said they can be loud when the generators are running. It's possible that when the grid can't keep up the volume goes up, but thats not meant to be a long term state.