Hi all, I've got a big open rack sitting in my home office that can get pretty loud when some equipment is at high loads - I've been trying to think of cheap sound dampening solutions and thought about sticking foam on the sides to absorb some of the vibration in the air.

Since the airflow is front to back and everything is decently spaced vertically, it shouldn't affect heat too much, but I want to avoid using any material that might melt or is flammable in case of an emergency/power short/whatever unforeseen circumstances.

Does anyone know of a material that would fit the bill?