I used to work at a pilot plant that did large scale synthesis of pharmaceuticals. The plant was a concrete structure with each reactor surrounded on three sides by two foot thick concrete walls.

The interesting thing was that there was no outside wall to the building, just a woven steel curtain. If something did explode you wanted a path for the debris. On the outside of the building was a curved ramp, like a skateboard half-pipe. That way any explosion would be directed upward rather than outward.